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MICROCOPY RESOLUTION TEST CHART MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS·J963-A NATIONAL BUREAU OF STANDARDS·1963-A and in Guayule 1

By A. DOROTHY BERGNER

Formerly associate cytogeneticist, Special Guayule Research Project, Bureau 0/ Plant Industry, Soils, and AgriculltLral Engineering, Ag/'icultura~ Research Administration CONTENTS Page Page Chromosomal range in gllaYllle __ 1 Loss of by aber­ Polyploid series in natural stands rants______22 and commercial strains______2 Chromosomal varianLs within Euploid populations and the p.ol),ploid series ______24 Btrains______2 Ol'igm ______24 Aneuploid stmins______3 Hapluids from tetraploids .. _ 25 "Int.ermediate" type______3 Anellploids from diploids__ _ 25 l\Iaterials and methods______4 Offtype normals from trip- mOl'phology______5 loids and tetraploids___ _ 26 Chromosome behavior in pollen Aberranls from triploids and ~lOther cells ______'_ 7 tet,raploirls______28 :.... Diploids______7 Offtype normals from aber­ ~ Tl'iploids______8 rants______30 • ~;.: Tetraploids______12 Sectorial chimeras______30 ::i Plants wit,h :;higher chromo- Factors limiting aneuploidy and 15 polyploidy in guayule______31 . so~ nU1~rs------18 Summary______~ HapMds------34 ~llen __ ~______O _ 20 Literature cited______36

;, 7-J ~ ~ c\1 vi ~ ~ llected seeds of these same species in Texas. Early in 1943 many of "these seeds, together with those of certain of the commercial strains developed previously through selection by McCallum and probably of Mexican origin, were germinated and planted in fields at Salinas, Calif. Chromosome studies, especially the determination of chromo­ some' l1umbers, were begun as soon as possible in order to facilitate genetic and breeding experiments. After a few months of exploratory'studies, it was apparent that a polyploid series exists among natural populations and commercial strains of gnayule. Stebbins and Kodani. (13),2 working indepen­ dently, came to the same conclusion at about the same time.

1 Submitted for publication February 27, 1946. • , Italic numbers in parentheses refer to Literature Cited, p. 36. 61J0587-46-·1 2 TECHNICAL BULLETIN 918, U, S. DEP'1', OF AGRICULTUHE

Recognition of this was facilitated by the fact that the whole series. was l'cprpsented in the seeds collected in Mexico, Stebbins und Koelani (13) and Powers and Rollins (10) IOllll(l a similar series ill • mariola, From papers written by Russians prior to 11.)36 (9.,3, 5, 6),. it is now evident that they had diploid and t('truploid strains of muriola. and uIso tetraploid strains of guaynle but that they faiLPtl to recognize a polyploid series in their lluttel'ial. Up to the presl'nt no guayule plullts IU1Ve been found with h'ss than 36 clll'OmOSOnH's, 'I'll(' higlH'st lllllnb('r reported thus fill' is 144 among offspring of 108±-cill'OlllOSOIlW 3 plants (8), Probably ('YPl'y numlwl' betweell 36 and 14-1 eouid be found if el10ugh indiyiduni plauts w('t'e exauuneu, Pr('3umaLly some gl'l1ic combiuatiol1f; are yiable for any particular Chl'OlllOSOllW num\)t'r; howt'Y('r, :t distlllctioll should 1H' made betweell th(' predominant clu'omosome nUmb('I'S of populations (stllnds). of gUfiyule aud thosp of Vtll'inllts which OCClll' ill sueil populnliolls or which wpre a result of crossps mndl' in gl'('('l1!tOlH'H'S and flplJ. plantiJlgs at Salinas. A.t Salinas arC' the makinrrs of It gl'('tlt vari.et.y of eitromo­ some nlllnbl'1's, beCU1ISl' dh-('l's(' )'[1('P8 ~of gUfI}'u}p whith In natnl'(' are separated by gl'ographit'al nnd t'tologienL burri('l's hay(' h('('tl nss(\ll1hll'd thert'. 1-.101'(' aneuploids would he' foullcl l111(\(,l' l1aturnl ('oll(lilions wC're ii, not for the fnet tll!lt fn('ultaliyc npomixis is predominant among the higher chrOlHOSOllll' ml'l11bel's of ill(' seri('s (,~, 10),

POLYPI,OlD SERIES 1::\ l\NI.TRAL STA~DS AXD COM\IERCIAL STHAL\S ECVLOlD POPGLATlO:'iS A:'iD STlUl;>\S • .Although Stphbins and I\:oc\n.nt (13) suggt'stc'd tlll' hfLsie numh('r of :r. equnlR U for tll(' polyploid s('ri('s, no plnnts whicb hnyp 2,j~ C'qullis 18 haw bc'en found 01' l'l'poI'ted, EN'nus/' of thC' fOI'J11ntion of biyrdl'nts , in 3G+-C'lll'omOSOI11l' 4 plnnts nnd of tri\-n/C'nts in 5-!± -('\tl'omosome plnnts, ,,: t'qunling 18 will \)p wwcl as till' busi(' IHlm\)(,I' in lhis buUl'lin. Aecol'(lingly, :~n elln 1)(' ('ollsi

3 ± uCtpr a J1umlwr inclirnip1' a polyploid rla~ll, the indhidual l11pmh('r,; o(whi('h • van' in p;mrt tllllllhpr of chromo:;(HlH'''_ .+ nft('r 30 imJh'nlp,; t Ill' diploid rln:;;;, 111<' indh'idunl 111< mucr!l of "'hid\ m!ly be aueuploid,; with 0111' or more ndditional ('hI'OIlIOS(JIlI('';, POLYPLOIDY AND ANEUPLOIDY IN GUAYULcl 3 following 10ciLtions: Onr fro111 nn indiyiclual plant gl'OWillg ·within the populn.tion from which the ('ollrction 4255 mlS obtllinr(lj nnothel' from secds ('oU('eLeel nCilt' Snn JUiLll, N u('\-O Lron j iL third from Catorce, .­ San Luis Potesi, and tlir l'C'111nilling (j f!'Om ':\InjomiL in northt'nst Zacatccns, Th(' tmilS-Pc('Os arCH, of 'J'(lxns is l'!'j>l'Pselllp(l by 362 collcctiolls, Of th('sc ('xtcnsin~ eollcctions eytologi('nl work hHs becn done 011 only 5.:5 nnd pollpu studit's on 4 mOl'e, J.JI hatl72± chromo­ somes, Elcven of thl' 20 lo('alions in T('xns fl'Om \\-1Ii('11 nu' ::;('('(ls wpre coUr('t<'Cl hny(' 1)('en smnpkd. Thus JaJ' 25 of :\ [('('aUtun's !'OIllIlH'l'eiI11 stl"Hins huv(' bppu found to han' n± ChI'0I110S011lPS. TllI'v !11"(~ Nos. :3SH, 49, 180,402,404, -lOO, 40liF, 'HI, 41:3, 41U, 41R, 41!l: 42ti, 42R, 480, 4an, 440, H 1, .,IAA, 4,'i:1. 4;j(j, 4iifJ, 59:1, and 7:~;j2 fill!t l\. ~\[pxinLU sll'ain (42·178 in POWPI'S' Collp('liol1S1. Thus fur no Jwntnllioid or hexnploid llitlul't11 stunds 01' ('o1l1nwl'cinl stmins lulY" ht'!'Jl found. High('" eltl'omosonl<' lluml)(ll's hny(' I)('('n limi(!'!! to ('!'l'(nin indi\-i(!unls in triplOid nll(! tdt'o,ploid populations 11m! ,,(mins undlo lhpil' o1Tspl'ing. Allor the :\I('xicn11 coll!'('tioHs hnw /)('('11 snmpJpd (,)-tologi(,lllly nnd S0111(' hn,Yo brctt studip(i intt'l1Si\-l'ly. IH'!'n liSP lhl' ,\'It01e polyp]oid SPI'II'S is l'('prpsPl1U'd in tltPl1l. and tl!l'I'PJ'Ot'P tlll'Y ufron! tll,t oppol'tunity to wOl'k out tht' J'rlntion umong liL(' l1wmlH'l's or th(' ::;('tw::; •

.A "'EUPLOID STHAlXS 8i1,(,P l'('pl'odudion in :It l;i4:±: -('It. ro nlOSOl1H") nnd 4J' (72±-clu'o1no­ SOJ'lWl popu]ntioll::; is pl'pdolllilllllltl)" fuC'ulttltinly Ilpolllietil' dO), it hus lui ill SOIlll' instmIC('S to till' (lstnhlisluHt'llt (If ",Iult nI'l' lss!'lItinlly cl01H'S 01 tlll(luploid ;;.1: and .1.( ('ombillat iOllS. FOl' illStllll('C', conunei.­ • ciul strain 210 8('('mS to JUlY!' ,is chromosom(s, the nllrnb(ll' thut Stebbins und J\.:odimi (1.3) rt'pol'tpd Jor st!'Hill 111. :-Ill'nins 45n and 735-2 8e0111 to hUn' I'~ I'll1'OmOSOllHs i\1 ndditioJl lo Ill(1 pnit' of minia­ tures which is prt'sl'nt, in muny 4,r populations.

A. morphological tYPl' C'nll{'(l "in\l'l'll1('dint(''' h.," Pm\"{'I':' S alld de­ s(,l'i1)('(1 by ]{()]~ins tIL) !~tld !·!It'I'(':,polllling" to ill(' I>l'Oadh'U['l'd t.qH' nnml'd Prtl't/lltr!1(nt !llJlIl/if But,tll'lt hail 7:2± chl'(lmosoll1l's.•\. POI'­ tion or all or u 11111111)('1" of coIl!'c,tiolls [mIll :'d('si('o IIl1d 'I'(';ms as w(111 as s('\"ernl ol' :\[c('n.llnm's c(lmmt'I'('iul .strains til'!, "intl'l'llll' (11, 1.tl nlld :-;(('ll111I1S :llId Kod:l.lli (1:3i. .As ill tlll' ('I\S(' or nl1Pllploi(l (['ipIoi!1 stands Hud stl'ninc:, l'C'lJt'O­ duC'tioll 11.," apomixis hilS ]PeI to tl)(' (lstal>lisl1ll1l'1l1 of 'whnl :11'1' ('SSI'I1­ tinily C]OIH'S, whi(,1t ditl'p[' SOll1('Whal :t11l01lg 1ItI'Ills('k!':, ill 11l0l'plto­ lo~i('nl appL':lt'lI11!'P b('('HlISP tlu'.\' hayp u! is(,11 mOI'p thall on!'p ulld in difl'0)"('nC pIu!'('s hilt Hl'l' sl1ffic-i('lltly simiIul' in nppplU'/lIH'P to WItITHlll clnssifientiol1 us "intpt'11l(ldiut('s," Thl',- ,":lIT in ehrolllOSnnll' lItllll­ b('l', SUH'(' pInnl:; with 71,72, 7:l. tllld" 74 !:hrOl1Jo:>Olll('S 11:1\-11 b(,l'll found (sP(' t:thl(' -~ I. J{('gnrdll's:, of I'hl'OIllOSOI1l!' llllllll)('t" 01' ['rt'()­ grn,phi!~n.l origill mu ny ot (h('il' poll!,11 mothpl' ('('lis l'ih()w.lu~ging dll'o7no­ son1l'S ut IlIlUphns(' I Illl(l ] I alld (jl{I!"(' :11'(, 111:1.11)" l11H'l"o('ytps mnOIlg'

• 5 POW.ERl'. L. l'f:I'.D ("Or.J.J.:cTT<1X"; OF nr,\n'u: FRO\[ '1 EXH'O "I'D THE TR.-I.~S­ PECOS AREA (BIn m~XD COl','IiTIlY) OF T,"X.\";. j!J 12. [l-nJ)ubth-h«:'d.] 4 TECHNICAL BULLETIN 918, ti, S, DEPT, OF AGRICULTURE malure pol1('n gmins, The only observNI (WI't'I:('Il(,(, nt meitLphnsc~ bdwccll ttintcl:medintes," nnd the good gua.yule type was th~ t,(,Jld­ t'lWy oJ tht' n lI\terllwdmtes" to form 11101.'C polyvulent assoeHLtlOlls, • This tendt'ncy WitS int(,l'prt't('(l u.s indientin~ stnwlurn.l hybridity; I('ss homology among the cltromosonll's is ('onsistpnt with thcir hybrid an('cstl,)" ConseqtH'ntly, the' presencc 01 lugging ('hromosol1lcs nt ann.phfts(' I unci II indi('nLl'S difikulty in Sl'PfU'Mioll nmong the ml'm­ ht,l's of thl'sP polyyalent nssoeitLtiolls, Tltl' finding of 2 "illtl'r111e­ diak" ,,}4±-C'hromoson1l' pln,nts among the offspring from 110n­ ('olltrolkd polli')ntion of H afi-chl'omOSOIlll' plitnt grown ut Sulinas :mggl'sts thut 54±-('hromosome ttint('nn('clitLt('S" iU'C possible nnd mn)" 0('('lit' in nn.turl',

:MATERIALS AND METHODS TIll' mntl'rin\ uspd. for studying guaYll\p ('hl'omOsomN, ('ollsisted 111niIl\~~ or po1\l'n moUl('l' (,elk It wus allgmenkd by tn.pC'tnl ('(,11s o('('nsionl1,1\~T found in didsion and by root-tip ('ells, Young flower hel1ds w(,re fixPel in lL (: 1 tthso\ut('-it!eohol-nePli('-itcid mixture, "ilen 11 ('{'PS:'Ull'Y lhl' nutLl'l'inl'wus stOI'('

or second prophase stage waS sa,tisfadol'Y, sillce the chromosomes were less diffuse a,ud better stailll'd thUll tiu'S(' stagcs in36+- or 54±­ chromosome plants, Fairly l'('liuble d<'U'l'minntiolls could be Inade by averaging connts 111n([<' of scyet'al cp11s in thcse stagps on the same slide, This wus shown ~whcnpwl' f1 c1!l'('k ,\'as possiblp by mpans of n. count of somatic ehl'omosol1lPs in ('1' in th(' samc pllU1.t Sl'0mS to bp limit('d to two SOtU'('('S: (1) Addi tionn1 fragmcnts rcsulting from crossing OWl' in in\'(,1'5ion5 all(l (2) lht' ('limiuatioll of dU'0ll10501ll('S by nb('r.rallt plnllls (p. 22), Tlwl'l' may OL' ma~· not 1)(' a, difT<'r!'lW(' in C'itl'OIllOSOl1W llUllllH'r hrtW('l'll mOt'plwlogi<'ttlly disliuet purt, of u plant which is a s('cLorinl ehim('r!1.

CllRO\[()SO.\[E ~rORpnOLOGY BcC'ause of tl1<' r('lati\'C'ly smn.ll size n.nd ('ompactncss of gunyu]e chl'omosoll1rs dUl'ing 111<'iosi;:;, little could hc IC'al'l,l('(1 nuout the dif­ fcrcnces in lenp;th 'cand th0 loC'ation of the insertion n\gion, No attempt has bl'l'Il ma,dc to work ou t iclio~ral1ls fol' thc ynrious collec­ tions nne1 stmins. HOWC'VC'I', somatic' ('hromosomes in tap(ltn.l-oell 11uclC'i (fig, 1, A. and B) show difl'N'C'llCC'S in o\-C'r-al1 and 1'c)n,ti\-e lcngth of each ann; s('me (11'1' J-sha.pNl. hut tlll' mu.jol'it~· are V-shapcd ~with, a mcclinll or suhnwdin.ll insertioll region, In figure 1, ...1, thpl'e S1'0m to he multiphs of a fpi\" hnsil' tn)cs'sueh as n. lC)llg chromosome. with • a suhnwdialt insertioll r('gion, a J-shnpNl onc, n. nwcii1l1l1 ('Cjual-arm('d, a J)l('diuIll llll('qnal-arml'cl, a small <,qua.l-Ui'lllNl. and fl, sll1ulluJlC

(/• (" .. ~.

•(0 /£

•• • •• e, ~, •

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• FIGURE I.-For explanatory legend see opposite page. POLYPLOIDY .-\XD ANECPLOIDY IX Gt:AYl:LE 7 medium-sized V-shaped chromosome ill length and width (fig, 1, A, a), Aetual attnchment to regulnr cln'omosomC's is rarely seen but is shown in fi~ure I, D, where !l. smull chromosom(~ is H,ttnched to the ends of 2 chromosomes belonging to a ('onfigul'fl,tion of 4, Although .' Stebbius!l.nd Kod!l.ni (13) referrcd to such chromosomes as s111n11, they will be c!l.lled miniature chromosomcs G in this bulletin to distinguish them from smull biurmed chl'omosom('s and hom ()('('asiollal frugments resulting from crossing oveL' in illYCl'siollS. Theil" fUlleliol1 i::; unknown, Qut they can be transmitted through the poIit'n grain as ,,-ell as through tllO . 1

Cl1RO)roSO~IE BEHAYIOR IX POLLEX ~LOTnER CELLS

DJPLOII)S Inform!l.tiOll about in pollrn motbpr cells of diploid plnnts is bnsecl on obs(,l'vations mn('r Imt arc Tl'pf(';

EXPL.\:\ATORY 1.EGE~D FOR n'il'RE I

FIIH'm: 1.-.1. The' 73·~ C'hrnlllO"Oml''; fwm a'tap(·tal <,pH of a plant of .;train 593. ::\ote 2 milliat IIfr ('hr«Jmo~lllll(,~ t{L' and Chrolll!hOIll(' 0" that ha;; 1 afm of the "ize atH} :;happ of thp miniatl1f(' chror\l(l~()mp, H, Thp 37-1 chrom()~otl'p;; from n tapetal C('I1 of a haplOid from colh'ctioll 42::;.), ::\ot<' JIIiniatllrc chrolllosome 'al. C, Two llIiuiaturp chTOm()~Olllp:i IU' and 3 bivalpJlt~ at mr.taphn..-c I from 11 pollen Ilwllwr ('I'll of a 72·1-chroll1o~oIllP plant, J), ~ixt{'{,l1 hivalpnts, 1 uAivalpnt. nnrl a eirrl(l of 4 rl\rn1l10"OIllP'; with minintllrp chromosomp (Ill at­ tached nt ll1('\aphn..'lf' I from a pollpn moth/'r ('('11 elf a haploid from collection 42357. B. LatNul \"iew o( rhromo:;olllp" at It1Naphnl'tl1, Wh(lIl hh'alent (orma­ tion was alrn()~t cOll1plptr, from a polh·n motlwr ('t·1l of a haploid from collpction 4267. );"0(1' tll!' 1 tlllh-a!put ':/';. F. ;,ix bi\'a!f>uh IUHl 24 Ilnh'alpnts at meta­ phn..<;e I from a pnll('tl moth!'! cf'll uf a baploitl frum coUC'ctiOll 42108, G, :.\Iultipolllr "piudl!' with 4 !!;roJlP~ of' rhrnIl1o;;lIme,; at allaphns(' I from a poll{'u mothpr ('(Ill of n 106-<,hromo"l!me ab('rnl!)1 plant. J[ and 1, Chromo,:om(l,; in 4 nuclei (J[. and in 2 'I, nt proplias(' II from POlIpll morlH'r cell.; of a 107­ chrom()~()me plaut. .f. (,hrnrno~()nl(''' at propha: II in pollpn mother c('l1s partly squepzNI P!lt ,If a ruptured COUl11l0Il {':dl1e o( a 107-chrolI1o:,ome abt:'rrant plant. ::\otc the 2 nl1rl('i Ul padl c!'11 and tll(> 40 ('hrQlllo:'()lll<''; in one cell and tht:' 61 in ill(' otht·r. K, ChrOn\{)~olll(':> of 2 Hudei at prophl1.'e II from a 78-chro1I10501l1t:' pollpn lllothpr ('('11 of the l07-chrolllo~On1(' plant that produced thos{' shown in J{ and I. r., Cllrom()~OJllC'" of 2 lluc\pi at prophni;{' 11 from a (i!}·chrolIlosome poll('n lIlo(llPr (.(.1\ of thl' 107-chrolllo;.;oul(' plaut m(,Jllioned in fI, 1, and K. .II, C'hromo:;ollw5 of -1 nnclt'i at teiophtts(' II fr<1l11 a 60-('hrotlll);;orue pollen mother cplI of the 106-chrolllo;;oIlW plant Ilwlliiollt'd ill G, S, Tapetal c(~ll ('ontaining 46 cbrOIIl050Illf'S from n di"k f!orN of an nht:'rrnnt plant witb about • 108 ('hromosom(:5, All drawing;;. (':\:Ccpt .I, ant! .f arp of tilt:' "ame magnification. The shading of some chrolI1osomes has IlO significall("c exc{'pt to illcrcnse clnrity, 8 TECHNICAL BULLETIN 018, U, S, DEPT, OF AGRICULTURE Bivalent formation at metaphase I is not invariable, however, One plant showed as many as 3 quadrivalents in some poUen mother cells; 3 others showed one quadrivalent each in some, This • multivalent formation indicates either reciprocal translocation or polyploidy and may lead to unequal distribution at anaphase I, The presence of inversions was indicated in plants belonging to 4 of tha 36+-chromosome collections by the occasional presence of bridges nt anaphase I or II. Two meiotic irregularities which afl'ected the quality of pollen werc founel in collection 426'=5, In a sn.mp1e of 2\)0 plants 4 had 90 percent or mol'c of the pol1('n aborted; 3 of the 4 were examined cytologically and found to be asynn,ptic: n,t metaphase I tlH'l'e were a few but varying number of hival(,I1ts plus unival('nts. '1'11('), ha,d 5, 6, and 7 miniature chl'omosom('s, r<,sp<'('th'('l~T, Th(' oth('1.' irl'<'gularity was partial or ('omplete failu1"(, oj' cytokinesis, 'fhis wns f01llldin 3 plants which ('n.m(' from noncontl'olled pollinations, Only 1 was studied at metaphase, r. It show('d 10 hivnlel1ls plus a clln,in of 4 (or 18 bi­ vn.l('nts) plus 6 minin.tllres. No oceUl'ate determinntion of aborted poUeD could he mn.d('. 80l11e of the grnins were compound, consisting of a tetrad of incompletC'lV sC'pa.l'fl.tNl spores, frC'quentlv of unequal sizC'. OthC'1' large gmins ":('1'(' ohyiously the result of dind instead of tetrnd formn,tion, Giunt grn,ins, the ('Cjwiyalent of pollen ll1oth('r cells, also were JUUl1C'l'QtlS, THIPLOIDS

Tnforl11ntion nhOIl t Illl'iosi:; ill pollt'n molhpl' ('ens of 3.l: nnd on('u­ • ploid :tl' plnntl" is hn,,('d on sumplpH of thp fiyp :>4 ±-<'ltromOHOlll(' eo1­ ll'diollS from ~('xit'o und of tIll' ;j·l±-c}ll'omosol1w ('0111 111 (,1'('i 11.1 stl'air:~ und nh,() OIl Homp of thp ;i4±-chroll10S011H' ofJ'spI"ing from lH)lleOJ1­ troll('d pollinnlious of :W+-chl'omoscmw plonls or ('ol1('('liOI1 4255 and nO.11(,OJl I rolled jlollinH IiOllS of ;i4 ±-(']u'0]110S011H' pIn nIs of ('olJ('etion 420;3 growiJ1~in Uw Iipl(1 nl ~nlinnH, Thl' :t)· nn(,lIploi(]s whi('h ho,d ](,5S t111111 ;)·1 ('hl'omosonH':; nnd SOJlW ",hie]) lwd l110rp thnn 64 ('nme from 111('s(' nOJl('onll"Ol1t'd pollinH t iom; nt !-'nlinns. In('llldpd n180 \\'(,I'C 2 ofl'tYlw-lIol'mn I plull Is [10m n 72 ± -ehrOl110S01l1C' 'I'pxns ('ol1('elioJ1. (,hro1110S01l1<' h('ltnyiol' dWl'!lell'rislie of triploids wng ohs('1'nrJ, At dinkinC'sis nlld llwtnphns(' T tl'iyul('nts \\"PI'P Ht'(,I1, hut 111.(' numl)('1.' vUl"i('(1 with It (,oJ"l'('spondin~ yurying Jlumlwl' of hiynknls nnd u1\i­ vnlplltl", \'lwlll'Y(,I' t]l(' nJl'lnplJn~(, r SU1~l' ('ould hp obg('l"y<'d, n.t Ipast a I\'w tl-i'rnl('nt>; W('I"(' S('('I\, 'J'Jte ('x("('ptiOllS \\"('1'(' 111(' 2ofrtyp<'­ 110l'1nn1 'I'('XIlS plnnts nne! 1 olhl'l', nH of '\\'hi('h Hhowl'd pllrlinl nsynn.p­ sis, At nTlnphnsl' T 01(' 1llnjol"it~· or po}l('11 moUlt'I' (,('lIs s])()',\"l'd Ing­ ging ('hI"01110H0l1H'S, ~onH' or whi('I! divid('c\ PI·('('o('\()usl~·. '1'ho~(' polkn 1l10th('I' (,('lIs of ;j·I-du·OIllOSOI11(' nlHIlI;:; whi<'ll show('d Inglfing du'omo­ SOl1)(,;:; H.'"('I·ng!'(] ~,l lnggel's; whpn'Hs t1lO~1<' or 1l1ll'1l pJolds nvP!'og('d 4.0, hut Ihis higlwr nY!'I"llgt' wns (,tllls<,d l1lostl~· h~' onJ~· n. fc'w of lh(' ('plls ill whi('h thp 11111111)('1' of Jngf,!;t'l's W:I:; lUI·gp. TIlt' I11lmi>N of laf,!;g('J"s, whi('h is glYPH n~ n singh: 'll111n1>PI'. d()('s nol inci.ieni(' how s('trttpl'('d the'y \\"('1'(' in Ul<' ('y(()pln~m (1111>1(1 n, C'hJ"Plllatid hl'iclg('s and smnll fni~nwllls \\'('1'(, s(,'(,11 illfl'NI1ll'nlly, Lngging ('hl'01110S0l1H'S • W('I"(' >;('('11 I1lso nt nllHphilsP I r, as I;:; ~h()\\"Jl hy UJ(' disll'ill1ltion 23 :2:~ :ao ::~ :27. ~\ [pw ('('lis :-;ilo\\"('d Ill(' "rl'c'ds of Ingging at, llOth n.1lt11)luHws, as in Ihe dislribution 2fi:2(i:2::W:l :2.i. Log~('l's form POLYPLOIDY AND ANEUPLOIDY IN GUAYULE 9 microcytes, which later can be seen as minute empty cells among mature pollen grains.

T ADLE I.-Distribution of chromosomes at anaphase I in pollen mother cells of 8;& and aneuploid 8x (49- to 56-chromos01lle) plants of guayule [Miniature chromosomes not Included; laggers indicated by ccntrnlllguro in serios or 3]

Ohromosomcs In 2 groups Ohromosomes in 2 groups I only plus loggers Group or plants Plants IPollen mothcr Pollen mothcr fO~f W/'~ Chromosome Y;;~1C::il~S CdhisrtOrllllbOuStolomnO ch~on~~sgrno distribution chromosome distribution dlstrlbuti0n

I Number 1o.-u7IIber Number 40·chrolllosomo_._. ____ ••_•••__ .___ 1 1 24:25 20:4:25 10:5:27 ii1·chromosomo•••••••••••••______....-- ...... 20:10:21 - -{ 23:3:25 1 23:20 1 2HI0:21 1 24:28 '1 22:-1:26

2 20:~ 1 16:10:21 t ...... ~ ..._...... 1 21:1:31 t ..__ ...... __ ...... _. 1 21::1:20 fi3-cbrtlmosoIllO •••_•• ____ •_____ •__ _ 5 : .... ,., ... ,...... ,...... - .... "' .. ---- 1 21:9:23 ~ ....-...... -"' .... -.. ., ...... -.. __ .. -,..-.. - 1 22:7:24 2 ~3:0:24 .. -... ~ ...... --- .. - "' ...... -...... -....--- 1 25;3:25 .... _-- ...... _- ..... "~- ...... -....--- .. - 1 21:2;26 • I...... -...... -.. --~ ..... "'--- ...... -.... 22:32 1 23:5:26 2:1:31 1 2·1:1:20 5 25:2U 2 2·1:2:28 ! 3 27:27 2 24:3:27 54·chromosomc __ •______._._._ •• j 8 .• _._...... __ ...... a 25:1:28 I ...._. ___ ...... __ .... 1 25:2:27 1 )!5:3:26 1 20:1'27 I::::::::::::: :::::::::::::: 1 20:2;26 '{ 1 25;31 1 25:5:26 li6-chromosomo ••_•••__ ••• _. __ ••••• I 2 2fu30 2 20:3:27 j 5 1 27:20 1 27:2:27 I 2 28:28

NIiniaturG chromosomes are less conspicuous as the number of 11 t nol ntOl't' gl'oups willi fl's;; [hall 2·1 ('hl'OllHHOlll('S, UltllOUgh tIlt' Inttl'l' would bl~ eXpt'('[(,11. This 11<'1<1 lnll' also for tht' ij(J-('hl'omoSOlllt'. plnllts_ 1<'01' tlH' 40- to ;j:~-dlJ'(lln(J;;ollll' plunls tll(, PI'P,>('ll('P of 1lI01'(' Ingf!l'I's !IN' pOn(,1l lllo1h('l' (,pH llot (lIlly (lpl','('ns('d I h(' lHI11l1lPl' of ehl'O)llo:"Olll(' groups with 11101'(, thltll half or thl' somnJi(' ('hl'01110S0111(' IlU1l1bPl' but fI.l~O itH'[,pas('d tl)(' lU1l1l1ll'I.' whit-I! had l('s.; lhun hnlf. If thr rhl'omoso]))(' gJ'oups from nil or 111(1 polil'1l motlH'}' ('('lis nrc considl'rrd innbly \TCI'\' j'PW ('(Hlhl fl'l'tili7.(l fUl l'g'Y Illlclt'us, 1)OW('I'A !wd Hollins S rfl.it'd 54 ±-ehroll1oso])W ph11lls POOl' ~l~ ]>olh'l\ pH 1'('11 ts, ;:;OIlW dUlIt indi('n.ting lh(' {'III'l)lllO:lOnH' Humber of futletionnl pOlll'll • gl'nill~ pl'Odu('('d by 3.c plnnls were ootn.ill('(l hy cl('Lel'mining th~

8 POWNS. L" /llld nollin~, n. C, rllpuhli~hcd to 87 chl'omo­ 50mr5, i1Hliculing fertilizu.tiol1 by n. 31- to a:3-chromosonlP pollE'1l gl'ltin,

TAllLF: 2,- R,~Lilllalfrl 1l11111lifr af rhl'()IJIO,ql)ml,~ ron/rUm/rtf ["1 pallnt grains irwo!t'ed in productioll of (Ibrrrllni plants in three ,,;: fltlLtlll,~ of g!lU!lllle

"~______o_o__o_~ ______0

Sum~fT Sumher 'l'''tl :.'1;-32 "'l ~'; 27-3.'1 ,I"'U :;'-36

In ot'(IPl' to }Pal'll whl'tlll'l' UllY pOlll'll g'l'llin,; that ill'!, pl'Olhwl'd by Illlli \'1' IhUll ~Ii ('hl'l)1ll0~()1ll1''; ('1m I'fr!'1't triploid,; lin 11'';'; i'1'l'tilizflolion J • fL ('(lilt l'olh,d ('1'0';'; was llmdt' h.'~ ll,;il1g phllts h!'longing to ('ollpI'tion ·t!:)i) (:~!i;- ('\u'omOSOIl1PSl ns 11ll' ';1'('11 PUI'Pllt illltiplunts lH'longing

to ('oll!'!'t iOll 4~()2 ! ,j.,!::!:: I'!U'() mo,;olUI'S I :1;; ° tIl(' pollell PIU'Plll. The ('hl'OmOsolllt' lUllltlH'I'S of tl !'P\\' of t Itt' ofi'spl'illg \l"I'I'P dl'tl'l'mine

!~rjrulltttr~\ ('l~ri nH'''~'r:l.'$ UII~ It.f !u'it d, la;!;:t-·r .. lf1;.b:~Vf,d by (t,ntr:l1 fl!-!Urtl in s(~rh '\: ',f {~

r'l.lr·,tn(I""r::t·'; H12 .:rl,ull<{ f'hrl'tr.,tI>olt,m,,' In :? J:r~m(:H lin;;. plu"i !~l:.!::;HS

I'. :nH I "hrumo$"rne ,1htnbuuQII

43-chromoslIlIW, ..• , •. Ivo 1:~'3 ~:2:21 • 2O:3:2'l 12 TECHNICAL BULLETIN 918) U. S, DEPT, OF AGRICUL'l'URE Meiosis was ohsorve(l in one 43-chromosome plant and two 45­ chromosome ones, At metapluLse I, 1 of the laUel' showed 19 bivo,lents plus 7 univalents in a pollen mother cell whereas the other showed 16 • bivalents plus 7 univalents plus 2 trivolcl1ts. The approximation to equal distribution in 9 pollen mother cells at anaphase I is rather good (table 3). TETRAPLOIDS Information about meiosis in pollcil mothel' cells of 4x and alleu­ ploid 4x plants is based on samples of the 9 collections from Me::-..ico J 15 percent of the extensive Tcxas collections, 25 of M cOnllum's com­ mercial strnills, und nOllapomictic progeny of controlled pollinations in experiments. 'rlus sampling of tetmploicls includ(ld 2 morpho­ logical type:;, the so-called good gunyule type, W11ich gives no evidence of previous ndmixtuJ'c with 1l1fll'ioJa, and U1e "intel'medinte" type, which docs show some of the characteristics of mariol!\' and for the origin of which introgrt'ssive hybridization with l11al'iola has been proposed by Rollins (11) Dnd Stebbins and Koul1ni (is). From such wide sampling a gent'l'OJizcd, over-oIl picture of meiosis in tetroploids was obtained. In apomicticl,l.lly produced 4x plu,nts of both "jntel'medin.tes" nnd good O'unyule types quadrivaknts were seen but the number of quuclrivafents and'trivalCllts varied among collection;;; some showed very few of 1.hem and others more. Possibly as many os 6 chromosomes were involved in occasional configUl'Q.tions. In genero.l, at llletu.phase I plonts which had 72, 73, Ot' 74 chromosomes showed mostly bivulcnts plus 1 Ol' a few quacll'ivalcnts, possibly tl'ivalents, and n. few univulents. The "intermcdiate" type seemed • to have more quadrivalents and polyvalents than the good guayule type and correspondingly fewer bivalents .. In view of the origin of "intermediates" inyolving introgressive hyhridization with ma1'iolu, some of these polyynJe~lts probably are cutenations of clu'omosomes f01'111ed os a consequence of structural hyhridity. MallY pollen mother cells showed lagging clu'omosomes at unnphasc I. All of the "intermediates" ayemgecl higher tho,n the good guayule type in the number of cells having lagging chromosomes, and the 72- and 73­ chromosome "intermediates" n,vemgocl morc laggers pel' pollen mother cell thnJ? the good guayule type of the same clu'omosome number. The good gultyule type (72, 73, and 74 chromosomes) had fewer cells showing loggers than the 54-chromosome plants; but the avemge number of laggers pel' cell was about the same for' both. However, in proportion to the totu.l chromosome complement the number of lv,ggel's per cell mnong the 72±-chl'omosome plants wu.s less than among the 54± - chromosome (to.bles 1 and 4). Chl'omo,titl bridges with or without imgments weTe not common, but they were seen occasionully in many plants of diverse origin. Some lu.gging at anaphase II wet'e observed 0.1so. Meiosis in some of tho plants classified morphologically as offtype normals was inc1isLinguishable froIll no rIllQ.ls, whereas others showed meiot.ic il'l'egulo.l'ities. Two of the il'l'cglllo.rities observed in a few diploids were found also among aneuploid 4x plants. They were partial.osynnpsis seen in somo alleuploids, the clu'omosorne numbers • of which ranged from 65 t.o 71, and less frequently failure of cytoki­ nesis seen in a few aucuploids, the chromosome numbers of which POLYPLOIDY AND ANEUPLOIDY IN GUAYULJil 13

TABLE 4.--Distributiol1. of chromosomes at anaphase I in pol/en mothel' ceU,~ of 4x artd aneltplotd 4:1)' (87- to 74-chromosome) plants of gltayule [Miniaturo chromosomes not includedj laggers indicatod by contrnl figuro in series ot 31

Ohromosomes in 2 groups Ohromosomes in 2 groups only plus Inggers

Group ot plants Plnnts Pollen mother PoJlon motherI cells with Ohromosome cells with Ohromosomo cl~~g~g;g~}lo dIstributIon cl:~~~~gig~Je distribution distributIon distrIbUtion

Number NU1IIber NIL11lbcr 67-chromosomo_. ______1 33:3,1 1 31:3:33 C------:...... 1 33:1:3:1 69-chromosomo______3 33:36 28: 11:30 L------~- ...... , ..... - 31:7:31 70-chroUlosoUlO ______3 33:37 1 31:4:35 2 3,1:30 1 33:2:35 2 35:35 1 34: 1:35­ 71-ehroDlosomo______4 35:3~ 1 29:7:35­ L------~- ...... 1 31:3:3; Do ______••_ 11 35:30 2 33:1:37' L------~- .... - ...... __ .... --- .. 1 34;2:35­ 7 34:38 31:3:38­ 12 36:37 33:3:31> 72-chromosomo. ______•___ • 20 10 36::J(l 34:1:37 ...... --...... 34:2:311 .... - .... -...... -~ ...... --_ ..... 34:8:35 - ...... ---...... - ...... 35: 1:36 32:40 1 32;7:33 33:39 1 33:1:38 Do_ • ______• _____ ..______3,1:38 2 33:3:36 • 110 35:37 33:5:34 36:30 34:2:36 ...... -...... 1 34:3:35 t::::::J: ...... 2 3.1: 1:36 73-chromosomo ______•__ 2 34:39 1 35:3:36 3 2 a5:38 2 36:1:30 { ·1 30:a7 --- ...... ---...... _...... - ... 35:38 1 32:5:30 30:37 1 33:2:38 Do______.. ______• (-...... :. --_ ...... _-- ...... 1 33:4:311 18 .. - ...... -- ...... _...... _.... 2 34:1:38 - ...... --- ...... - .. 1 35:1:31 .. ---_ .... - ...... - ...... _-_ .... 1 35:2:36 .. ---_ .. _------'i,.---_ .... 1 35;3:35 _.. _------...... _...... -.. - .. ---- 1 36:1:36 1 34:·10 1 33:1:40 74-chromosomo____ ",______1 35: a!! 1 35:4:35 { 8 311:38 . 1 30: 1:37 (I 37:37 ...... -...... - ...... --...... - .. 2 3'1:2:38 Do______1 2-1:3:37 1 35:1:38 2 35:2:31 " ...... ·············-1 1 35:3:311 1 30:1:31

I "Intcrmedinto" typo,

rangeJ from 68 to 'i2 clll'omosomes. Two offtype normals belonging to the good guayulo type showed many Jaggers at anaphase I and II but ll?t many miol'ocytos among maturo pollon gl'ains. }IowevC'l', the­ • one WIth loss than 72 c4romosomos showC'cl 50 pC'l'cent of pollC'n aborted and the othel', with 72 chromosomes, about 98 percent. :r'l'fale stel'il­ 14 TECHNICAL BULLETIN 91S, U. S. DEP'l'. OF AGRICULTURE ity, us evidenced by scunt sporogenolls tissue, WitS found in sevCI'fLI plants (69- to 72-chl'omosome), Restitution nuclei (scmihptel'otypic or pseudohomcotypic) wcro SPCll, but thpy WCl'C confincd largely to • plallts ,,,ith lcss thfLn 70 e1u'omosomcs n,nd usually nssociitLcd with IJiLl'tial fLsYllapsis. Often 2 or morc irrcgu1tlhtit's wcrc found i[l the same pIunt, t'spc(!ially mnong the 65- to 69-c1u'omosomc pln.nts, . MiniaturC' chrOlllOSOIl1l'S Wl'J'e SC'('l1 in somC' 4,r and fLllC'Uploicl 4x pln,nts. AL most they wcrc lirnih'd to 2. ThC' )'lC'xienu materjal cx­ cept cOllection 4258 'scC'llwcl to bc without nny; tlw sceds fo], 4258 came from IUl individual pla.uli growing within tho diploid POpuIfLtioll Jl'om \\'hic'h collcction 4255 was obtained. (Ill collection 4255 the numbcr of miniu.tuJ't's l'nngcd from 2 to 10.) }\[ost of the plants from the commereinl stl'nins had as n~any fLS 2; hOWeVl'1', some pln,nts with only 1 W('1'(> found in st1'nins 406 nud 44·t, 1'he clistrjJmtion of c1u'omoson1C's n,t nnaphnsC' I in pOl1t'Il mothcr c'ells of 4,t tlud fllwuploi same 3 clnsses. This lack of close fLgl'Cl'ment bctwccn obsC'J'vl'd distribution fJ'equeneies at metn.phnse I and thosc cnlclllntcd nceOl:dillg to the l'itlldoJ)l distri­ bution of 18 qundrivnlents is thl' l'Psult of [tn obvious tc'ndt'ncy townrd equn.1 distribution of du'omosomcs to t1tt' 2 poles of the spindle nt anfLphu.sc 1. If 72-ehromosome pIn,nls fOl'l1led only 3G bivalcnts at melfLphn.sc I, n, 30: 36 distribution would be CX]wctccl nt nUfLphasc 1. If they fOl'med only 18 quadl'ivnlents fLt mcULphnsc I, closc agrccment woulll bc expectcd with distributions cnJcuhLt('(l necording to the random dislribut.ion of 18 qundl'ivalents. Aetunlly fLll sho\\'ed some bivfLlcnts nt metfLphn,sp I, the good gtliLYulc, type ill gCJ1C'rnl showing more thnn the "interJ1lNlifLtrs." Therefore the ObSC1'ycd distributions are consistent with thp obsl'L'wd t.endency towfLrtl bivnlcnt fOl'ination at the 4:r level in the polyploicl s{'rics, Fot' cells showing no Ingging clu'omoSOllll'S in fLllPUploids with more 01' less Hum 72 clu'omosonlt's, the tC'nclcncy towfLrd n,n cv('n distribu­ tion of chromosomc's to cnch pole is cvident nnrt nowhere dops the distribution fit OIlC bas<'d on qUfLtlrivnlent formation. For po11('11 mother cells showing lagging chromosomes in 72-chromo­ some pliLlltS, the muga of the fLl1fLphnsl' I clistributioncloscly approxi­ mated that of POUNl mother cells without laggl'l's, although there • wcrc fewer chromosome groupS with morc tlmn 36 and more with less thnn 34 chromosomc~. 'rhc samc WfLS tme for thG aneuploid POLYPLOIDY AND ANEUPLOIDY IN GUAYULE 15 4a: plants, namely fewer groups with more than half of the somatic chromosome number and more with lops than half. If the chromosome groups from all of the pollen mother c('11s which showeel lagging chromosomes arc eonsiderecl indiyicLually, only 11 • consisted of less tilltll 33 chromosomes. For the 72-chromosome plants 88.6 percent contained from 33 to 36 chromosomes, inclusive. Even the 67- to 71-chromosome plants had 54 percent of groups with 33 to 36 chromosomes. The 73-clu'omosomo plants hnd 62.5 percent of groups with :35 to 36 chromosomes, and the 74-chromosome plants had 63.6 percent of groups with 35 to 37 chromosomes. There­ foro, even after additionn.l lagging of chromosomes at anaphase II, most of tho pollen grn,ins 'probnbly eontaincd not less than 33 or more than 86 ehromosoll1(,s. Some data indicn,ting the chromosome l1Umbrl' in funcf;ionn.l pollon grrt.1ns was obtained by determining the chromosome llllmber of 50 aberrant plants belonging to 4:1: collecLiolls and lil10n subtracting the probable numbet· of chromosomes contributed by the egg. The rn.ngo extond('d from 28 to 40, usun.lly from 31 to 38. Also 7 aber­ rants obtainl'cl from controlled pollinations, wherc tho chromosome numbcr of the pm'ents also had been detcrmined, showed thn.t the functional pollen grains contained 31 to 39 chromosomes. '1'heso data on aberrants, ther('fore, inclicatrd a widor range of elu'omosome numl)('rs ('ontn.inedin funetional vollell grn.ins tlum WilS estim;1ted from the nnn.phn.se dnta in iho pl'l'cl'ding pal·agmph.

l)LANTs \VrI.'H HiGHER CIlHO.l[OSO~m NU.llBEllS • Information about meiosis in pollen mother cells of plants having '81 01' more chromosomes is based almost entiroly on abel'l'ant plants which occurred in natural popu1i1tions and commercial strains and among progeny of con trolled and 11oncon trolled pollillations in experiments. Aberrant plants occurring in 54±-chromosome populations and strains and among progeny of 3x seed parents rangeel in chromosome number from 80 to 93. Observations of the metaphase I stage were confined mostly to plants belonging to collection 4257. Some tri­ villents find polyvalents and a fow uniyalents were seen, but bivnlents preclominatrd: therefore, the tendency toward bivalent fOl'mation which was evidenLin 4.1: plants contillllCc1 on up tlu'ough the poly­ ploid series. 'fhe fl'equrllcics of chromatid bridges and c111'omosome lagging n t ann,vhase I and II were about the same as for normal vlallts in the snme .cultures. As many as 3 minin,tul"C chromosomcs were seen in some plants; somo had fewer, n.ncl othel's had none. rfwo plants with about 85 chromosomes had scn.nt sporogenous tissuo and therefore were practically;nale sterile. The ten

plant. As in the cas(' of 31.: and 4x plants, cells with lagging chromo­ somes had fewer groups of chromosomes consisting of more than a half of the somatic numb('1' as compaTed with those which do not haye • laggers. If the chromosome groups from aU of the pollen mother cclls are considered individunJly, only 1 consistNl of l('ss than 35 clll'omosoI11(,s. For the Sl-chromosome plants 75 p('rct'l1t of the groups consist('cl of 39 to 43 chromosomes, il1clush~c. Because of more lagging chromo­ somes in the So-chromosome plants, th('y had prncti(~ally the same number of groups (71 p(,l'cent) consisting of 39 to 43 du·omosoI11(,s. For all of the c('Us 69 percent of the groups eonsist('cl of 39 to 43 chroI11osol11('S find 85 P(,l'c(,l1t 39 to 46 chromosomes. Probfib~y most of the pollen gmills contained fit least 3S clu'omosomcs bLtt not more than 43.

TABLE 5.-Distribution of cllr01ll0soll/('S at Clnaphase I in pollen molher cells of 81- to 98-chromosomc plants from 8x (5.1±-chromosollle) seed plants. of Ulwyule

[?:.finiaturo chromosomes not incluCled; loggers indlc'j\led by central fl!(Urc in scries or 3J

Chromosomes in 2 groups i Chromosomes in 2 grOups I onl,' I plus laggers , ,------Group oC plants Plants PollcnnlOther. iPollen mother! ; Cl'll~ with . C 1 cells with i C i indicated I ~ro!'l0s~mc: inClicnled hromosome chromosom~ . dIstribution 'chromosome distribution I distribution I i distribution I ------, ------Xltmber I Xil7llbcr I I ]o,-umber I .il 1 , 30:45 I 1 3S:1:42 v , 1 I 3.:-14 I 1 1 39:2:40 aI·chromosome••••••••••••••••••••I1 , • I iI !gm !:::::=::::::}::::::::::::: 82-chromosome••••.••--•••••-••- ••i I I 1 J 41:41 I 1 I, 39:2:41 I I . S3.ch romo~ome •••••••"'" ••••••__ i ! 2 i.{, : I :~;~: 11············~·;······~;~:;;: 1 ! 42:44 1 I 35:9:42 86-chromosomc••••••, '" ••_••_••••[ 6 I 1 43;43 j 1 I 3U;~:43 , ::::::::::::+:::::::::::::1 1i 3~~~~~~ I l{"" .... ··~'l···-·'··~~;~~-!} 1 I 4_.1.43 88-ch romosome •••••___ "'_'" ••__ .l 1 ,. . 1 I 44:44 ' .•- •••••••--.....I -...-••••• 90·chromosome•••••••••••-.-••-.-.1 1 { !~;!~ ···r·-···..·--·­ t tI ,J··-··--.. g3-chromosome - ...... --.-.-••i 1 1 ...... ,...... \ 1( 40:8:4& I .

Aberrant plants occLlrring in 72±-chromosome populations and strains find llmong Pl'Og(,IlY of ·.lx st't'd parents rang('d in ('hl'on~os0ll1c numb('l' from 90 to l:!O. OhS('lTU\io))s of the ml'tnphas('. I sblge showed a prppoll(lt'rnnce of hiYlllpllts; ho\\,ey('[', SOIllt' plants showed many triyalpnts and quaclrivah'Jlts alHl othcrs many uniyalents. This Yfiried behn,yior nlny dp]H'ncl upon tlH' fnrt thnt some of the abel'l'aI1 ts in populations of the good guayule typt' had mariola as tlll'u: pollon pn1'l'nt llnd SOUlC Wl'l'~, from C!intCl'llwdiatc" populations. • Chromatid. hridgt's nt iU1uphnse I w('n' S('(,11 only infIWlUel1t1y. :xot more than 3 mlllifLturc chromosomes W('l'P COlUlll'd in 1 plant. Clu'o­ POLYPLOIDY AND ANEUPLOIDY IN GU~\YULE 17 mosome lagging at anaphase I was frt'quC'ut but limitNI to only a fC'w chromosomes so that, in proportion to tht' total, it did not materially reduce the number of chromosomes in the 2 groups in ('ach POll(,ll • mother cdl. Lagging at anaphase II was s('('n only infrl'quC'ntly. :Malc sterility in the form of scant sporogenolls tisslle was obscrved in a lOO-chromosome plant. The tellcil'ncy toward equal distribulion of chromosomes in poll('n mother cells of 90- to 109-chromosome plants to tlw 2 poks of the spindle at anaphase I is cvident (table 6). Among ('('lis without lagging chl"Omosomes the extreme d('viation from ('qual distribution was 49: 5S (instead of 53: 54) and among those' with laggers it was 47: 4: 57 in a lOS-chromosome plan t. C\'l!s "'hich had lagging chromosomes IUld somewhat fewer groups consisting of morc than a half of the somatic number than those which did not haYl~ laggel·s.

TABLE 6.-Di.~tribution of chromosomes at ana phase I in pollen mother cells of 99- to 109-chromosome p/(mls from 4x (7:2±-chro/l108o/lltJ) seed lJ1a1lls of gllaYlIle

[l\nnilltur~ ehromOSOIl!~S not illelt1d~d: lO~j(~rS ir1!If('ot('(1 by e('ntrnl tl~llr~ in s~rles of 3)

I C'hromosome~ in 2 groups t Chromosome. III 2 groups ,ol1l~' plus laggers ,! , 1------,------I G roup of plants Plants h'O!letll~~ther polIN~ ",:olheri ~ells \\ Ilh C'hrIJIIIOSoIllC! cell" itll 1 Chromo"omc mdlcated j' t 'b 't' i IndJclI1('u 'd· lb' J chromosome (IS rI U 1011 • chromosome l' Islr ut on I distribution I ! llistrJbulloll ------~--- --.------_.- ----­ Sumber .\'I/.mber Sumber gg·chromosomc. _•.•••._.. _••.•. _..1 1 ! 411:3:50 • ...{ 1 ·t;:2:50 I f lOO·chrolllosome .•. _. _•. " •.••• ' 1 4S:2:f~) 21 '{ 1 I 40:2:4Y I ;) 1 48:1:£.5 lO4·chromOSQIIIC. _ ... _. w ~",. ~" • . .1 1 I ... I I 40:I:f>I t 1 i 51:1:52 , I{ 2 [;(J:;ili ! 4~:I:W lOS-chromosome...... _...... '". r 2 ~ " .. - .. ,. -" ~ ~ ~ i ·l!l:2:54 51:1:53 i I06-chrolllosomc••. 2 fl~!5'1 I 1 49:2:£5 { J 51:3:52

1 49:5~ 1 4S;2:5i J I 51 !flG 1 50:I:rtI 1 52:55 1 5O:2:f5 f, 53;[,,1 lOi·chrOIllQSQII1().• .. ' ~., ...... -'.­ a : 1 51:3;[a .. --""'. : 2 52:1;04 '( . ~ ~ ~ 1 52:2!~3 2 sa:l!5~j , I [)():5-.. 1 4i:-t:.ZJ7 IOS·clIromosomc._ .. .. 1 fil::ii: J 51:5:52 ,{ Ii r;:J;b5 3 , 52:1.:55 l : 2 fi2:5; 2 53:1:;;5 IOU·chromosome.... 3 '{ 1 :H~55 L 53:2;"·' , . 1 5-1;1;£4

If the chromosome groups from all of the pollen mother cells fl.re considcl'ed indi,-idllal1)~,ollly :1 consisted of less tban4S ('hrol1losoTlles. For tbe 107- to 109-chromosome plants 73 prl"c('nt oJ the groups • consisted of 52 to 5f) ebromosomeB, inclusive. For all of thc ('rUs, 62 percent of the groups C'onsislc'd of 52 to 55 chromosomes and 83 pcr­ . GfJ05S' ··010--3 IS' TECHNICAL BULLETIN 91 S. TT. >:i, UEPT. OF AGRICULTURE cent 49 to 55, Probo.bly most of the pollen grains contained at least 48 chromosomes but not more thun 55, Aoong the pl'ogcny of aberrant plants belonging to collection 42 ,1(l3 • there were some plo.nts that showed only 0. few of the morphological characteristiC's of abCITants, a1though the ehromosome numbers ranged from 74 to 03, rrhe~r werC' eullC'd ofHype normals from abel'rlwts, Pollen mother o('lls of (3 plnnts, whose eh"0l110S0me Ilumhpt,s rnnged from 85 to 92, W(>J'O studicd, Lagging at anaphu$c I WilS limited to n. relatively few cl!I'0l110S0l11es, Although the dntn, for I1nnphll,sC' I distribution arC' scant (table 7), they show thC' sam(\ tendcnc'y toward equal distribution to tIlC' :2 poles of the spindle that was C'\-jdent in the abcrmnt 11\unts which had n.pproximatrly the saIlle number of chromosomes (tabl!' 5). Thf' ('xLr('J1)('s ill deviation from f'quality canle withirl the limits of deviation showlJ by thf' abelTants, From the standpoil1t of meiosis in pollf'1l molhel' ('('ils, thC'I'C'fore, lhiF. group did not difl'er from othe~' plants having high chromosome numbers,

TAllI,E 7,-VistrilJ!llion. oj cilrOlllosomrs at £l1ll1plwse I I'n 7JOllen mother reUs oJ ojJIYlJ(! normals jrom u/Jerrmlt 8li- 10 9;2-r/(ro/llosome plants oj fllIa.yule [;\llnln\ure chromosomes not included; tnggers Inellentcel by central llgurc In sPriC$ 01 31

('hrom()somr~ in l! groups ChromnSIlJUI'S in 2 !(roups I ouh' plu., ll!g~ers

' Plants ----- Orou(l of (J13I1t~ ;:~~l:;:;;:i r(ll:-t::;:rt.·~---·-- ('('lIs with I ('('lIs with ltldic!ltr!l IC'!~rom)(),o(lJl~ iltdk"Jtl'<1 ,Chromosome rhwtnu'flnH'

HAPLOIDS As pl'cviOl1Rly ]'('por{pd (1) [), f('w plants with :36+ ('hl'omOsomC'5 WNe found in 7~±-chromoS(lnH' populn,lioI1s, Infonnn.tioll n.bout llwiosis in poll('J) lJ1o\.ll('r ('p]J,; of sll{'h Imploid plnnls is hi\:,wd on oh:3pl'\-n.lions mfl.(\(' on n of llH'm widell \\,(,1'('. sl ud iea eylologi('il.lly; :1 had :~G+l 2 chromosomes, ;i luH1 ;{7+ I , nnd 1 Iud :17+ , III t1 lap('tnl ('(,ll of thc hn.ploicl from conN'lion 4~~ii. :17+ 1 eitromosonH'S W01'(' C0\111t(l(1 (fig. 1, B). All tht' hUl)loids ht)(l at lenst.1 llliuin,tun' t'h 1'011l0S() l1lC'. 8rlO l'og(,11011S li:-;st1P was srttnt. (l,nti tll(' \\'t\Ils of l)olh'll motlH'l' c('lIs W('l'P (:xtrt'mC'ly thill, 'I'll(' l1wtn.phns(' I st:L!!l' \\'n.s obs('l'Yt'd in S pln.nls. 11,11 of whi('h ;;howPll some hjYI\,\Pnts; :2 pinnls sho\\'('d only (\ ft,,," itnd 4 pm('ticnlly all ([tg. 1. f), h'. ftnd rl. .\. ('il'plp of <1 ('\n'o11105011\('S wns • S('(I[l in SOIll.t' pollell lllotlH'1' (·(,lIs of tht' huploid from T(,~·HlllS. Tpx., (fig. I, D) and 11 dmin or 4 in ('PUs of the' Jutpioill from "train laO. TliC'sc collfiglll'lttions of 4 chl'otnosollll'S mny indi('nt(~ l'eeipl'oenl POLYPLOIDY AND ANEUPLOIDY IN GUAYULE 19 translocation. In 1 cell the miniature chromosome was attached to the circle of 4 (fig. 1, D). Distribution of chromosomes at allophase I in 7 haploid plants (table 8) was less regular than the distribution in • diploid 36+-chromosome plants. One pollen mother cell at anaphase II WitS observed; the distribution, 18 : 18 : 17 : 19, indicated an il'l"(}g­ ulurity at this stage also. Practically nIl of these haploids produced very little pollen, or the pollen grains were mostly empty.

TA Bl.E 8.-])i,~triblllio7t of chromosomes In 1Jollen mother cells at anaphase' J of hap­ loid" from 4z (86- and 87-chrOlllosome) seed planls oj guayule •

[Miniature chrOlf osomcs not iDClud~d: Inggers iuUicnied by central figure in ~erics of 3]

, Chl'OlllOSOllll'S ill 2 groups ; Chrolllogomp~ in 2 group, : ortly 1)lu5 laggers .--,,----,-.-----_...... -....----.. _-- I 01'0111' of plnltls j'lnuls Poll~tlmOih"r, Pollen mother! i cells With Chromosome ~'('Il, with 'Chromosome t c~~~;:;g~g~,c dl,lrihut!otl cl;~~~:~;:!~~~\C tlistribution Idistribution! di,trfbutloll ; ",,",,-' ~-~ ~"---'- , ..-­ ' xumber '{ XIIII/ber )6:'20 } 30-chrorno$onlC, • , _ 2 17:10 • _ 1,;18 ! ; 37-chromosomo. ______•.-._.___ i 1 1 : 17:2:18 ! 1 ' °i l~;~l IS:l:18 ------'------'---_.I --'-". Bivalent formation in these haploids demonstrates that there is • consiclemble homology amo~g the 4 sets of cllJ'omosomcs ill the 72±­ clu'omosomc plants from wIndl they arose. Howe,,'pt-, such homology ought not bc used as evidence fot' autopolyploidy as opposed to allo­ polyploidy, since it is known that some puidng OCellI'S even between gun,yule and mariola clu'omosomes in hybrids between these 2 species, For instancc, two 54-chl'Omosome naturnJ hybrids were the result of fertilization of 18-chl'omosome gultyule ('ggs by 36-chromosome mariola pollen gmins. In 1 hybrid a maximum of only 10 uni\~a.1ents was se('n, whereas in the other, where the ma:.-:imllm of unhalents was only 6, from 1 to scyeral triyalents were observed, These studies of chromosome behavior hayo centered around associations at metnphase I, distribution at anaphase I, and, for plants haying 54± and 72± chromosomes, the ('ffl'cts of this distribu­ tion on the production of functional pollen grains. Throughout this series from 36 (both diploids nnd haploids from tetraploid::;) to 120± it is evident that meiosis in pollcll moth('t, cells in most gunyule pla.nts at all levels in the polyploid series is complete; reduction ot' chromo­ some numbCl' is effect('pore<; is formed within the cell by division of 1h(' cYlopliLsm after telophnse II_ Itl only a few variltnts hltve exeeptions to tltis llOl'mlt1 bl'lm"io[' been found (such us lack of sporogenolls tissue, ilbol'tion of aU pollen, Ot' other meiotic uTcgulal'ity). In geneml thel'c was a tendency towurd equal di:;tl'ilmtion of chromosomes at ilnaph!lSe I, throughout the polyploid sel'ips, l'l'gllrd­ less of whetheL' the plnnts were of Itmphimit,tic or apomictic ot'igin • Itlld l'egnL'dless of the llllmbN' of dll'omosOIM:;. Among 8li+-chl'omo­ some diploids ill1ltphase I di::;tl'ibulion \\,:1.8 pt'edominttntly 18: 18. 20 TECHNICAL BULLETIN 91S, 1.', S, DEPT, OF AGRICULTURE

Among 36- lllld 37-Chl'OIllOSOI1H' haploids from 72± -chromosome POPUlll,tiolls the distribution wus kss regulul', Among triploids ana-:­ phase I distribution "'US not in disng['(>(,IlH'llt with eu,kulntions b0.5('(1 on tb(' rnndom distribution of 18 triYnl('nts, uJthongh the number of • obs('l'Yo.tions wus too slllull for sto.th;ticul unulysis, Among tC'tl'U­ ploids at ullu,pbusC' I th('t,C' was au obvious tl'lldl'[w,Y toward equnl distl'lbu t'ion , Among p1tlnts with morl' thun 81 ('h1'omosoll1('s there was n. prolloune('d t('n([('nc,Y towurd ('quill distribution, Tltis t('nd­ ency was C'vltknt ulso in thosC' ('C'lIs from ab('l'l'ants whieh C'ontnin('(l few('1' chromosomC's tha.n tllC' lUuub(,I' L,)1)icnl of tIl(' n.hC'ITtlnts ill which they were produced us well us in tlw u.mphimicti('ully produc'('(\ off­ spring of abCtTunts, ThC' inequnlity of distribution in the highet' polyploids wns no grC'nt('1' tha.n thnt in triploids und in proportion to t.he total numbC'[' of chromosolllC's inyolyC'd wus much It'ss, This tendC'[]cy townrd C'qunl distribution of ehromosonH's at anuphusC' I wus illterpretC'd as bC'ing thC' 1'C'sult of tIl(' tC'lldency towunl bi\yulC'nt formation at metn,phas(' LC'"suully there wC're 18 bivn.lcuts in POI1C'tl mothC'[' cells of 36+-chl'OlllOSOllW diploids, Among 3(j- 11.11(137-chl'omo­ somC' haploids, howevC'r, thC' numhc'[' of biYalC'nts was vn.l'in,bk, rrhe numbcr of LiyltlC'nts shown by lC'tmpioids YiLl'iC'cl mnong thC' cQlIections, the lltnubC'[' bC'ing gr('tLtC'[' for tllt' good gUII,yuk type. Among plants with higbC'[' chromosomc llumbC'l's, W\tC'l'C polyvalents were expC'ct('(I, ~iyalC'l1t fOl'mation was pronounccd, POLLEN EXfLminntion of shed pollC'n in mU,I1Y instances p['C'cC'ded u study of llwiosis in pollctt 1ll0thC'l' cclls bC'cuuse of thC' ense and speNt with • whic'h pollcll call be obscl'YC'C1. For instanc(', mict'Ocytcs W('I'C' ob­ sC'rwulions in pollC'n mothC'l' cdIs and size, of POll(,1l gmins of many indiyidunl plants throughout the polyploid series (8, table".l. The. fiyc diploid coUpctions diITC'l'C'd in a"('L'uge ilmOlLl1 t of abortC'd pollen un. To whnt pxtPl1t n,llC'uploid:r, iIlY(,J'sions, n.nd nondis­ junction W('I'C 1'C'f1PC'i<,(l in th(' n.nlounJ of n.boJ'tNl POllPll tn.nnot be stated, As not('11 on pn.g(' S, lhl'PC' pl:\'ll ts \\'!tiC'lt ])['oduC'('(\ mostly 1\'l>ort('(1 ~rn.im; sliowpd asynapsis a.t Ilwtn.phnsC' 1. Certn.illl,\' tIll'J'C Wu.s lIO correlation bC'l\\'('('11 mnount of abortion n,nd lllmd)('L' of minin.lm'C' ehl'ol1)osoJ11PS (tiL!>l!' ~n. ~1iCI'O(TtC'S \\'(,I'C' C'ntil'l,ly n.bs('ut or ml't' in all d iploit! pIn nls cxnmil1Nl. POlll'1l of :l,t plant:> may 1)(' dislinguislll'd [!'OllI thnt of ~,r. pinnts by (\tp pI.'PS(,[)('P ofm i('I'o('yt<'s II lloU('1l f['olll [llnnls 1H'lollging' to til(' liy!' t'ollp('tion:; frOlll ~I(\xi('o nlld foul' ('onlllwl'('inl :;(mills th!' Wl'it!'I' found YIlI'.\'ing 1)('1'­ • cc'nlng!'s of g['n.ins nilol'(,(1. rllngillg f!'Om [i to (iii (H'('('('nt. ..:\.n<'llploid 3,1: plants n,vPJ'ngrd higlH'l'; l\t(' rung!' PXlc'IHkd front [i{) to OR ]>l'l'(,t'ut, POLYPLOIDY AND ANEUPLOIDY IN GUAYULE 21 the latter being a eonsequcnce of partial asynapsis at metaphase I. The variable size of good gmins is shown statistically by Powers (8, table 3). Some gmins i1l;e small like those prociuc('d by 2x plants, others are larger lik~ thosc produced by 4x plants, and sttll others • are intermediate in SIze. TABLE 9.-0cctl.rrciu·c of aborted POllCl1 grains 1I11d miniature chromosomes in 88 1Jlantl; of five 86+-chrolllosome (diploicl) collcclio1!.~ , 'I i I Collection No. 'poli~n !!mins! "liniuturll ,i C'oliecl!on No. IPolien gmills I' ,,[jolnturo abort cd ; cbromQsomc~ '; I nbortcd chromosomes ------'I .,._-----' '---- I Percent NU1IIber Perctnl , Z,;umbcr 53 3 (, 3 4:U;O•• •••••••••••••••• j{ 50 2 5 I l> 8 4 !! gj S 11 2 112 10 0 IH ! 6 i~ ! 0 15 I !! ·,,'-················11 2.') i 2 lIS I 4 4255•••••••••••••••••. I 15 I 8 101 1 I 1 Ui i 10 31 i 1 116 . :l 11 43 l 1 f 21 6 "ro....''....•.•.. 4() • 1 ' J 24 2 iO I 1 ! 31 Z I 54 I 3) 0 1>1 4 Il' 2 15S 6, ]0 t 2 95 i 12 I 0' ...... ::1 14 3 .~ () 30' 42 , !!' 5'J , '2:

1 Based on only 100 groins ellch; determinations by E. J. Gardncr. • Pollen of 4x plants may be distinguislu:.ci from that of 2x plants by the In.rger size of the good gruills (8) find from that of 3..1; plants by tbeir morculliform sizC'. The "intermediate" type shows more microc.ytes tlHUl the 3x, but the good gUfiyule typ(' shows fewel'. For the collections included in the study made by Powers and Gardner (0) tlw range of p(,l'c('ntage of grains aborted by the good guayu]e type coincided 'with that of tIw 3G+-chrolllosome collections. The raI}O'C for the Texas Hintermediate" type WI15 somewhat in ex('('ss of thut of the 54+-chromosome collections. The tt intermeciiutes" averaged 2 to 5 tim('s tbe number of microcytes in the good guayule type. The l'!1ug(' of the 4 most commonly grown commercial strains was betw('ell tbn,t of til(' good gun.yul(' type aad the "int('rmediatell Texas type. Only 1 ~r(lxjcull coll(,(,tion was included in Powers and Gardner's stuch·. Pollen sampf~s of all nine of the ~Iexi('an collections wcro exam­ in('d by the writer. Only one of the good guayulc type Ilveraged highCL' ill pel'c('ntagc' of pollen nbOl·ted thlln the collection included in Powers and Gardner's studY (01, but foul' IlYe1'llged 10WN'. The amount of aborted POUt'll of H ll1 ternlC'diates" wus consistently higher than that of the good guayule type' in those coll('cOo11s where both types occurred. The lH'crngrs of llumber of microc.ytes for the ~Icxicn.ll colle('tions ellUl(' within the l'illlge of the fiyerages for the Texas collections. In ey('ry instnnce the II interm('(liatl'slJ could bc distinguished by tlI('ir mfiny micl'o('Yles. • Sonlc of the-less known' conunel:('ial strains w(,1'e sfimp!cd by the wTiter. FiYe strnins of the good guayu!e type produced wry little 22 'l'J.J('HXICAL BFLLETIX !llSJ -C, ~, DEPT', OF .\G!U(TI;n'llJo:

UbOl'l('d poll l'11 , whl'I'pns fiyp ntlw!'::; pI'OdU('('!1 pl(,llty of polll'n pl'neli­ {'ttlly all ()f which wu::; nbortl'(1. Thi:-: :-;Ol't oj' mnl(' ::;1l'!'iliIY i::; diJ\'l'I'l'lll fl'Oiil t!H' Jnek or sporo~l'1l011~ ti~Sll(, showll by s('\'l'I'~d nlH'uploid • oll'ty]ll' .J)oj'lllnl:; from \h(l Tl'Xlt:-; ('olll'd iOlls.Fl'l' rom' of tho "in\l'l'llll'din(p" !'ontllwl'!'iul stl'uilh about Lj P!'I'('Plll or (Ill' gl'uins ,,"us llhoJ'\l'(L .\g-nill IIH' IlYPI'UgP IIIIII I \)('1' of miC'I'o('yt('s I,j\llgpd frolll two (0 fln' limt'''' IluLl 1'01' tlll' gone! glln~'1I11' I)'P(', TIH' 1I1l10;WI of n]'ol'!l'd llolll'll Pl'otillcl'd h,\' 1111111(-; ('lassiliP(l ns olf­ typt' nOl'lllnls (,j;l 10 "j Chl'OIllO';OJl)l'.. 1 l'lIllgl'd froll! l;j tu !lIl I)('l'('l'nt. Tlt(l polll'1l pl'odll('(,d II,\' ,-)"j ]>1'1'('('111 of thl's!' plllllh ('ollsj"t(ld or II'S:; tlmlt ~.j 1H'I'I'I'Il\ of nhol'll'l\. gl'uills, \\ hl'l'pn-l Ihl' ]lollpll [lI'Odll(,l'd by :i!l,:l P('J'('!'nl of I hp,.;1' phillis {'o!l-li,,!l'd Ill' .iO lll'I'C{'lIt (II' OWI'I' of n\)oJ'«'(] gmill-l, III ~l'llI-I'lll. tllO';(' pl:lI1l-l 1111' poll!'ll of whi('11 ('(lllsi-ltp(l of 75 1)('J'('(,1I1 (II' JllOl'P nho)'I('tl gl'nin,; hud TO 01' 1('..;..; ('h l'OIllO";() 1111''';, Till' most ..;tril e I1g l''('(Optioll wa-l n ,~-('hl'()nHhOJnl' pluntllt(' ]lolll'lI of ",hiI'll ('(j'bi..;l!' or Ilh(;\ll \1:-- 1)('I'(,I'I1( of nlllll'll'd gl'Hill:', P01l"11 of pl:1Il1S \\ i!h ltig-II ('hl'OIllOSOJ1H' 1111I1lh(')' lllny \)(' J'(·(·Ol-rlliz(·d 1,,> t Iw Inl'1.!:I· ,.;i, ,1[" lIll' good gl':till';, :-;\111H' gl':dlJ"; :1J'1' ['(lulJd. hUI 1\10:-;t I'lIl HI ..;IHlwlJ of ttlt'11l Ill'!' 1lli. ill shllpl'. .\..; hy PO\\'PI'-l IS, table ;3), llll'l I' n gl'l'nll'i "'I.!\' i ... il.l' thnn rOl' plnnls \\ ith T~ 0\' I('-ls ('!IJ'()- 1ll!J";UII,';, Thi.. j:, ;':1)'11\' !\1I!' to llll' \'llr\'ing' lJllJllIH'I' (If ('hl'OIllOSIlIll('S within lit!' gl':lil1"; 1I11(IIH11:II.'" to III!' f:u'l tl;nl tIl!' diall1l'I!'l' W:1:, 1lll'IlSlIl'P(\ ill Ihl' liJlI' of tlw ()('llllll' llliI'J'lll1wtl'\' J'l'gnt'd!('s..; of Ill!' oril'l1tnlioll or the l'lIipli!'111 g'l'ain,.; wilh /'l,f('I'I'Il(,l' to IIIl' lIli('roIllP!l'l'. 'I'll!.- Pl'rt'l'Il[ngl's of g'l'llill"; :lh(ll'l!'d \':ll'i('1I with IhI' ('oll!'('! ion..;: ill g'1'l1l'l'td, tllt,\, f,,1l \\ illdn tIl!' 1'1lI1g''' ur tIl!' lloJ'muls of til!' Stlll\(' pO]ll1lil!iol1s, This \\'IlS • !'';jlP(.inlly II'II!' [01' Ill!' Uhl'I'J'llJ1\Q from :lJ' plnnts, VOl' t\](' alH'l'mllts fl'Olll ·Lr plnnt..; tllPl'(' \\:1.. H tl'ntil'll!'Y to"lIl'!\ iJlt'I'Pll-lP(l p(,J'('(·.lltn~(' of nhor!ion ns ('otnptU'('(1 wi I 11 t lIP no!'mll k Tit.. nllllllwl' of ll1icl'o(',Vl('s ])]'0(\11('('<1 b,v a\H'I'I'llnts I'l'olll :t, planls 1\,11 within (1)(' J'Hllg!' chnJ'(l!'lpl'­ j..;l if' of IhI' 1Illl'mal..; of till' ,;nllH' ('oU!'!'linns, AmOllg n IWI'J'tml:-l from •.IJ~ pIn Ills t hos!' h('loll~il1g' I () (I\(, good !!lIl\'yulp [YPl', j'('gtll'dl('s:-l of -:(1111'('(" "ltnw('d 11 slight iJI!'l'paSI' ill llllllllWl' or mif'J'()(',Vlps 1I,; ('ompllJ'l'd with til(' Iltlllllll'1' IlJ'odlll'pd hy ('ol11pal'nhh- llOl'lllllk In gtltH'rnl the sD-ndlt-d rough n\ll'I'I'llllts tlvl'l'tlll:!'d hid\ ill l1uml)!'!' of Ini('I'o('\'tPfl, In (lilt' of till' '~l('xi('llu "in\l'l'lll('(\fatl''' ['(;Ikl'tiolls ,'I~-l~J, !h!' Ubl'l'l:llnts t\.\'('l'ng '

.\ plh'llol1 ll'1101l wllil'lI ";('l'lllS to \)p I'H I hpJ' witl('slll'pnd n mong iI,\)('I'I'IH1t plnnt:, is' lhl' IOi{s of ('hI'OIllOSnJlll':-l, hoth TllPjO\ i!'Hll)' lind mitotic-nlly, In oddil il))) to tIl!' In,.;,.; of a fp\\, C'hI'0I11O:-l0HlPH in pollett tnOtlH'l' ('('lls through lagging It! Hlll1pllllSP I 11lHI II, ,,,n'h HS wus ;;('('11 ill [j.J ±-und 72±-('hl'0l1lOHOIlW plunl:-;, pSPI'('illll)' (host' of tIl(' "inll'I'Ill!,dint('" t)'I)(', 10s:;1 of IIlJ'g!' gtoup:-; of ('hroIlHlSOJH('H wn;; O!JSl'I'\'Pc! o('('!\sjollnlly dUl'ing Ilwiosis'in ]lolll'l1 l1wtltl'r ('l'lIs of llhl'l'I'tlnt plnll(S, This tl'n

insll'od of 2 gl'oups nt IUlnphnsl' 1. FOUl' gl'oups illsU'nd of th(' llslInl 2 n,t sN'ond pl'opitnsc' (fig, 1, If) 11I'P 1ll(1 j'('sldt pl'ohll,bly of n, Illultipolnr spindle lIlIt'ing lhl' first division, For ('ompIlI'ison, till' usunl 2 g-I'OUpS nt this. stng-l' iLl't' 8ho\\'11 ill H.nothpl' poJJpn lllotlwl' ('dl from Lhp snll1l' • plnnt (fig-, 1,1). AllollH'1' WIly hy whi('h til(' IItUlliJt'I' of' C'hI'OIllOSOlllPS enn bl' d(l('I'c'/ts(l(1 is hy Ihp rOl'nmlioll of' Lwill polll'1l Illollwl' (,('lls, For C'xnl11pll' (fig-, ], J), twillpolkll lllothl't, ('('l1s, in('oJ11plptply st'pn­ l'nLt'd, ('ol1tninl'd 107 C'hl'omOSOIlH's Jwt W(11'1l t1H'It1; 1.0W('YPI', I h('se ehl'ol11osoml's \\'(,I'P ulk'luH.II,\' disll'ihu[pt!, 011(' ]1lI11' hud 40 ('hl'olllo­ SOI1}('s in 2 g-I'OUpS of' 22 nne! 24, 1'(lsp('('1 in'ly, "IH'I'PHS lht' olh('I' half had 7 C'hI'OJ1l0S0IHl'S in 1 !!I'OllP nnd fi4 ill th(' otlWl', TIl(' loss or e1l1'OI1l0S01lH'S 1'1'0111 sonJal ic' (,(,lIs hilS not hpl'1l S(,(,11 htlt mlly 1)(1 inl'l'I'r('d, BC(,fI,llS(' ':\((',\'(,I("S t<'l'hni((llt' (7) WfiS d('y('lojJ('d onl~~ l'('('<'llll,V, obspLTnliolls 011 sOIllH.tiC' dh'isiolls ill root-lip ('(,lIs 111'(' still 111 ('II!!(' I', :I 10w('\'(,I', it, JIllS b('('n Obi:H'('\'pd ill root-I ip ('('lis fl'olll n,1H'I'l.'tlllt pltwlt-. lhnt illln('t ('('lis fro III [h(l samp plunt mny "Ill',\' in ehl'omosoll1t' II urn 1)('1', Tho l blH'h rosse's mil." ()('(,UI' SOIll(' l il11l' priO(' to 1IH' fOl'mation of poll(,11 lllolh('L' ('{'Jls is sil(m"n by til(' fael lhllt intn('(, poll(111 motllPl' ('plls whi('ll ('onlnil1pd f(,w(,1' thull (11(1 tlsufLl nun11)('I' of ('hl'OnU)SoI1lPS ha\,(' 1>('(111 S(,PI1, DilJ'PJ'(,Il('('s ill til!' si%(' of [hl' po)l!'11 mol h('L' ('(llis W(,I'(, disC'(,I'llibIP, sil1('(, Ihl'l'(' is tl ('OI'I'plnUoll hp[\H'PIl (h(lil' si%t' alld Iht' 1l1l1l11H'I.' of ('olllnillPd ehJ'OIllOSOIlH'S, ]n tlH' snnl(' plnnL whieh pl'Odu('('d (h(' j10llpll moth,'(' ('(,lIs whos!' ('ill'oll1o­ 80n1(' ('OlllplltS Ill'(' sho"<11 in figtlJ'(' I, [f and 1. olh!'I' poIl('11 l\1olh('l' ('(llIs whi(,1t ('olltn,il1('d 1'(I\\'l'I' ('hI'0Il10S0111('S W('1'(, fOllnd, On!' had 7S (fig, 1. K), whill' 11110I.h('1' had ;')(J (Ii!!, 1, L). AIIOUll'l' poll(ll1 moth('I' • ('('JI hnd .~ii ('hl'ol1losol\l{'s, AIlOlh('I' (lXlll11plt> is g-in'll ill liguJ'(1 I, Jr, \\,1](,1'(' 11 ('(Ill nL tl'lophns(' II ('ol1lnillS 0111,'" 120 (,hI'OIllOAOIllt'S in lILt' 4 nlH'IC'i. This ('pll must Iin.,,!' ('ontuilwd olllv liO ('lu'oll1oS01l1('S Il<'fol'c 11l(liosis bpgnll. ,Anothl'I' ('(Ill frolll this slInip plnll[ hnd Ii::! ('hl'omo­ sonws. 0111('1' ('h ['0Il10S0111(' Illl ml)('I'S, such flS 40, 45, 40, 5~, 5:), fiG, 57, ;)S, (iii, Ii" UR, ,0, 77, RO, R1, .~4, Hlld 0:3, W('I'!' ('oul1[pd in ('XC'PP­ tiol1i11 poll ('II mol h('[' ('(,lIs from '14 o~h('[' Itt)('ITllIlt plnn [s ",host' ('hI'01l10- SOI11(' llllmlWl's J'llng('(l fl'ol1l 102 to 120 Ilnd whi('h ('HIll(' fl'OIll 10 dif­ f(· 1'e 11 t, ('oIke! ions, Thnt slIth POIll'Il1110thl'J' ('('lis 11111)" goo through both meiolic divisions is known IwcfLllse elu'omosollH'S hl1n' hp('Il ('olllltp(l al; 1('lopJHls(' n, One GO-chromosome (,pll sho\\'l'<1 only I hindpnt nl ll1elnphn.};p I, the 1'l'l11n1n1ng c]u'OJllOSOI1WS lwing ullivfllc·nt. All RO-du'omosol11e e('ll fl'om n.noth('t, pln,nt showl'd both hh'ril('llls nnd 1Illh'nlpnts nt, I1wlll­ phusp 1, lind It 7G-ehl'oJ1l0AOIlW ('I'll sho\\'('d only ulli\'ul('nts, DiMl'ibu­ tion of ehl'OmOSOIllPs Itt Illlllpltnsc' 1 111 OtlH'J' cdIs whos!' ehl'Omosomc llumh('J's UJ'P lis(('d in Lll(' pJ'('cC'Clillg pltI'ugnl.ph follows: Chroulosomcii in pollen IC'hrOJllOROJllCll in POllC'1l 1110ther cell: J)j"lribu'iQn I moth(lr ce'lI; l)i./ri1m/iOll 1 -10. IH:22 MI.. . , ... 27;2:30 ,Iii.. 21:~~:211 Oii. ao: I :3,1 ·HL. 2..1:215 (is. a2:36 52_ 22:1 :20 77. aa:7:37 .oiL 27: 28 78. . aa:2:·13 50. 25:1 ::30 7U . 35: 1 :·Ia .37. 2,1:3;) 8\. .. 80:·12 58.. 27: 1 :30 ~H. 31l: 1:44 • 58. 27:8:2S \l3. "·1:8:46 l l.ng~l·rslmlicfltNI lIy tItl' 1'1'111011. Jlgurl' in tltu srr(co of a. 24 TECHNICAL BULLETIN 018, U. S. D.EPT. OF AGRICUUl'UHE Although these arc ex('cpLiolll11 cells from abelTant plants, the dis­ tribution is not essentiully different from thnt observed in those plants with comparnble chromosome number (tablcs 1, 3,4, and 5). • Reduction in ('hromosollw lltunl)('t' ('an ,{)re('('de the dov(I}opm('n.t of a tapl'tal c('11. For ('xnmplp, It tnpl'lnl c('11 ('ontnining only 40 ('hromo­ soml'S wus found (fig. 1, .:Y) on th(l snml' slid(' ,,-jtll pollc·n moth(ll" ('clls contniuing about lOR. Among nb('1'I'nl1ts in 54±-('hromosoJ1w populntions VCt'y f(lw poIlt'n moth('t· ('clIs whieh ('(J)ltnilwd l('ss thun the usunl 11\1m1>(l1' w('rp found, nlthough th(l rntio of 81 to 54is the sumo ns thnt of 108 to 72, Two cdls show('d 54 nncl 57 ehromosol11(,s, l'('speetiYt'ly. in un Sfi-ehromo­ soml'. pltmt nnd 1 show('d n ('hromosollw:;. in nIl SS-<,\tromosoJl1(' pln,llt. Appnrpnn~ it is the high chl'OmOSOllw lltlll1b('l' (l00 Ot' mol'(') (Il11ong al)(,1'nmls Lll 72± -eltromosom(' ,{)opulntiolls whi('h 1('n

HAPLOIDS FnO;ll TETUAPLOIDS Plants which result frolll the devclopnwnt of nil (lgg which hns the reduced number of chromosomes without f(lrlilizn,tioll hn.Ye been • , Regltrdless of tho sense in which the word is used, howcvel', a hltl)loid owes its origin to the development of nn unfo1'tiliz('d egg nucleus wInch has tho reduced JHlInbl'1' of e1u'oU1o:,I)JlleS, As pl'e'viou~Jy J'('pot'Lpd (1), 11 few haploids wel'(~ found III POPUltltiOIlS "'hieh Itayp 72 ± du'omosoJl1('s, Since then more haye been obtuilwd from seeds eoll(,(,t(,d in 'r('XllS nnd lllso from

How l1lueh lltl['upioid." ('xist::; n11l0ng lll(' dipJoid collc('tions cannot bl' ::;tnt('d cxndly 1)(,(,lw::;(' 01' (hI' ndditiollnl millinllll'C du'OtnOSOIll{'S, Silw(l tlH'l'C is l)ut slighl

OJIFTYPB NOn~lALS FROM Tml'LOIDS AND TETHAPJ,OIDS

A few of tho variants classified us offtypc 1101'111111s in apomictic 3x • and 4x popllln,tions hud ('xuctiy 54 uud ?2 chromosomes, respectively; most of th('m were nnollploids, For the 54± -chl'omosome popuhLtions an cxample of un('uploids muy be cited, As n, clH'ck in all cxpel'imcnt, s(\eiwho!' Hi kinds plus ii of tl1(' sl'Y('nt('('nCh pitts only 3 of OJ(\ l'igh((wnth, In pinnls hnying mot'(' Ot' h'ss limn 72 ('hI'01110S0111('S, tIll' 1>nlnt1('(' is fUt'(hN' llPSl't by tit(' n.bSl'IH'P 01' nddilion of whoh' ('111'01110S0111('S, ~[,h(1 SHUll' sod of ehl'OlllOSomn.l ttnbnlam'(, mn,:\, (Ixisl ill 54-{'hl'omosome pIn.nts and in thosp hH\'ill~ mOt'(1 OJ' h'ss tluw'ij4, Of the oll'typl' 110l'nll1]s whosl' ('l!t'omoso11ll' llllmhC't, wns dp!('['minpd to bl' 4,~' 01' ntH'uploicl 4,1', aa.n l}(It'c'Nt( hn.d Oil to 70 eht'OlllOS0ll1PS; :3R,0 })('t'('(']1(, 70 01' 71; IX.H I>PI'('l'I\(, 72; and S,ii Pllt'l'Ont,73 to 7i'), In nddilion (h{'l'l' \\'(,I'P 2 whkh hnd 133 nnd 5li to 5H l'ht'omosonll's, 1'(,SI)('('­ • tiyPly, 'rhus, il is ('vid(lnt lhaL lllost of UWSl' oIrly}>e norl11u]s W{,l'O ntH'llpIoich; fll\d lhlt.l lht'c'p-!'out,ths of (hC'111 hndkss dum 72 chromo­ sonH'S, .:\\0 1'('0 Y<' t', tIll' C'hl'ot11osot11f1,1 dt'fkil'.l1('Y WHS limited to only 1 POLYPLOIDY AND ANEUPLOIDY IN GUAYULE 27 01' 2 chromosom.es in the mn.jol'iLy of th(ls(' p1nnts wit.h l('ss lImn 72 chromosomes. It is possible thn,t plnnLs with mOI'e thun 72 ehromo­ somes were sufficiently vigorous n,nd nOl'mn.l iu n.ppcnl'lUJeC Lo escnpc • being clnssi6.ed ns 'ofJ'type 1101'mn1s. However, tho pl't'spn('e of addi­ tional ehl'omosol1lt's mny be deleterious, sillec none of the hU'ge oIr­ type 110rmals lind mort' thnll 72 cln'olllosomt's. Analysis of luwphnso I distribuLioll of ehl'omosomes of tctl'nplokls (p, 15) showell thnt pollen grllins produet'd by 72-ehromosomt' plants ('onl,fl,int'd a vnl'ying number of ehi'omosomes, mostly 33 Lo 30. 11' nn ('quivnkllL val'in,­

bility in the ]'('thwed ('hl'OmOSOlllt' 11ll1nhN ill ('gg: Iluelc,j is nsslllllecl i then a 4;1.: poplllntion should Pl'Odll('C' nmphimiels l'llnging in ehl'omo­ S0111e numbC'L' from GO to 72, This l'flng(' in('l1l(1(,s n. dt'vinLioll of nt h'nst 6 from 72, sin('(' (Hi willjw L1H' toLal procim,pd by tl1(' lillian 01' 2 gnm('Les, ('neh of whi('l1 ('ontnins 33 ('11l'01110S0l11('S. TIl(' lInioll of gnmctt's whieit ('onln,in more Lhn,1l 36 ebl'011l0S011lt'S l'ach ]Jl'Odllt'('S p]nnis wiih 1l101'(' ihnn 72 cill'omOSOlll('S, The ObS(,I'Y('d l'I1Jlgl' or li5 to 75 ehl'omosou1(Is nmong oll'typt' normnls in 4;r populn.liohs is in ('lose ngl'ccmt'nt ·with t.hl' ('n.leulntl'tll'flngl' bused on n study of Iltln.phnse 1 diskibution of elit'omosol1ll'S. lIowPYl'J', sin('l' the majoJ'ity of the ofl'type norm'nls WPJ'(' ddieil'llt in only 1 01' 2 ('ill'omOSOI1WR, most or the ('ombinn,tio.lls which itwolYl'd tIl(' lIllton of gn.ll1eL\'s whieh (,Oll­ trdn('d less thnn 34 Cill'OlllOSOml's must hnyp bl'('llitlyiu ble bl't~n liSt' of too gt'(,I1,tly disLll1'h('cl gl'lli(' bnlnncl'. Those pln.nts whidl hnd th(' ·Io\\'('sl, ('hl'omosom(' ll1llnbl'1' mny he mentioned s('plH'n,((,jy. Two of tlt(, T('xfls 0(1'1;\',)(, normnls had. (i5 chromosom('s. This nll('uploidy mlly Ill' l'l'Pl'l'Sl'tlt('d as 4x-7, Both • plu,nl,s Wl'J'e small hUl llnl.ik(" n,ll, 501wI'('('tlt of which were ttbol'tcd. Tlll'l'e ,\'('['(12 Pxc('ptionnl plnnls l'l'om TC'SlltIH. A >'(')'," smnll plnnt ",.hich .hud 50 to 59 chromosOll1{'S {'tUllC' from It llollst'l('ci {'(I COlll'{'tioll of sc('d. ~ [ciosis wns ehul'ne(.(It'iz('(l by pnl'linl nsynnpsis tlnd lugging chromosomes. AbouL 08 pl'l'('('nt of tIl(' pollt-n wus ttiJol'tpd, nlld the good grains probably hu(l Lhe ulll'('(hlc('() Ilumb('l' of Chl'OIllOSOIllt'S, 'rho plant flOWl'I'l'd proJ'us('ly. TIl(' otllet' platlt, which ",ns smnll nnd compnct, hn(l only 5:3 ('hl'omosol1ws. (BOlh it I),n

• 10 Rollins, R. C. UJ;P\lhlishcd data. 28 TECHNreAL BULLE'.rIN 918 J U. S, DEP'l'. OF AGRICULTURE Some ofl'type n01'mn,1s frOUl 72 ± -chromosome populn,tions showed normul meiosis, n,nd the pe1'Celltn.ge of pollen aborted was not gren,ter thn,nthn,t produced by n,pomiets in the sn,me culturcs, ..f~lthough no • pln,nts with less thull 68 cht'omosomes were free from meiotic irreguln,ri­ tics. With a few exceptions plants showing these il'regularitir.s were of small size. :Most of these offtype normn.ls cume from seeds from non controlled pollinations. However, 11 came from con trolled se1£- and cross­ pollinn,tions mn.de by Powers nncl I-tollins (10). '1'he mnge of their chromosome numbers was 66 to 74 und is pmcticltlly ic1enticnl with thut of the whole gl'OUp of ofl'typc normuls. Of these plunts 5 cume from cross-pollinn,tions; since tlley show('d both paternal n,nd mn,ternal characteristics, the:r must have come from the fertilization of eggs which had the reduced number of chromosomes. It has been n,ssumecl that all of these offtype normals were the result of amphimixis. However, from a controlled cross-pollination there was 1 exceptional, sm(~ll plunt which, a,lthough it showed no chul'!1ctel'istics of the pollen pn.l'Cllt, wus distinctly different from the apomicts in the same culture (10). It hud 72 clu'omosomes n.ndln,ckecl the udditional miuiuture chromosome which the seed parent had. It hnd ma,ny la.gging chromosomes n.t n.lln.phuse I n.llcl II and n.bout 98 percent of its pollen wus n,bol'ted. Powel's n.ud Rollins (10) sug­ gested cliplospory to uccount for the origin 01 this plant. Powers has furnished evidence by ll1en.ns of breeding tosts that diplospory is occurring in 1 of the Texus collections (8), und it can be presumed to be occurring in other collections n.lso. How many oiftype normals • are the result of pseuclogumous cliplospory is not known. It is possible thut some of the 54±- and 72±-chromosomc offtype normals arosc in this way. It is mot·c probable that most of thcm resulted from normal mnphimL'\is a:ld that the morphological variances wcre the conscquence of new c,)mbinations of genes brought about through amphimixis.

ABEHHANTS Fnm[ THIPLOIDS AND TETHAPLOIDS Thc morphological vfl.rifl.nt caned aberrant may bc described as follows: Growth generally is slo'wer than thut of the normals of the same cultures; leftves arc thickened n,nd have fin irregular pattern; pollen grains (md flower hcn.ds are la.rger i und the peduncle is thicker. Some plants show this syndrome of chn,racteristics in morc pronounced fa.shion than others i some are fairly vigorous, whereas others fail to livc through the fiJ'st yom'. Another characteristic is their high chromosome l1\1-mbcr, which also is vn,rin.ble, the range extending from 81 to 122. '1.'hc extent to which this syndrome is expressed is not necessul'ily cprrclated with chromosomc number. For examplc, of 11 aberrants obtained fronl the open pollinution of 54±~ch]'omosome plants belonging to collection 4263, 8 had 85 to 90 chromosomes. The 2 most extreme plrmts, however, hncl only 81 and 83 chromosomes, respectively. Also, among offspring from u 72-chromosome plant (42163) a 99-chromosomB plflnt wu.q more cxtremc in type thun • 108 ± -chromosomc pln.n ts in the same culture. As Esuu (4-, 1JP. 353-354-) has shown, where apoIllixis is the predomi­ nant form of reproduction, /{ tlll.lmegnspol'e mother cell docs not form POLYPLOIDY AND ANEUPLOIDY IN GUAYULE 29 tetrads but directly develops into a uninucleate embryo sac with a diploid number of chromosomes." Powers and Rollins (10) have shown that pollination is necessary for the production of apomictic progeny from embryo sttcs which have the unreduced number of • chromosomes (pselldogamous diplospory). Aberrants 'which occur in apomictic stands and have a higher chromosome number than the apomicts in the sume stands are the result of the fertilization of eggs which have the umeclucecllllUnbl'r of chromosomes. That abcrrants occur after cross- as well as self-pollination has been shown by Powers and Rollins (10, table 3). The total chrOmOSOIlll' number of an abl'r­ rant plant·then is the SUll1 of the tllu'l'duceel Hum!' ; r in the rgg nucleus and the numbl'r of clD'OmOSOIlles in the pollen grttin. The yariability in total CIU'oIllosome Jlumbl'r clepenclslal'gely upon the varying number of chromosomes it1 thl' pollen grain. Aberrants which wrl'e found among 54±-ehl'omosol11e populations had 81 to 89 cin·omosomes. From noncontrolled pollination of 54 ±­ chro111osome field plants at SuJ~nas aberrants were obtained whi('h had 81 to 90 clD'omosoml's. Among 54±-('hl'omosoml' commel'cinl strains plants were found which hud 81 to 9:3 chromosoml's. Siner the egg nuclei before fertilization contained 5·1 ± clU'oIllosomes, chromosome numbers between 81 anel 84 suggest fl'l'tiliziLtion h.Y po11l'11 from 54±­ chromosome plants; l1umhC'l'S aboye 90 sngge;;t fertilization by pollen from 72±-chromosome plants. Plants whoSQ chromosome numbers ranged from 84 to 90 ('ould have resulted from fertiliziLtiotl by pollen from eithl'r 54±- or 72±-chromosome plants. Aberrant", found amollg 72 :::-cbl'omo::;ol1le populations had mostly • 103 to 112 chromosonll's, although infn'quC'ntly SUell rxtn'mes as 99 and12!) were founel. Tllt'v we1'(' ohtaillPtl from nIl of the 72 ±-('h1'omo­ some eoUections from ::'I!'xieo. Induded also in the snmple which was examined ntologieallv were nl)('rrants froIll 12 of the Texas collec­ tions, from '9 of the c'oIllIllel'cial strnins, iLncl from a cross hetwern 2 of the Inst-named. Both the good gunYltle aud "intel'l1lctliltte" types Wl'l'e included. ::\umbl'l'S 'nroutl<[ ob sugg('st j'prtilization by pollcn from 54±-C'hromosoIll(, plants or from 72±-C'hl'omosome plants whi('h contained l('ss than :W cill'OIllOSOl1l('S. :-'Ianv of the al)('rrants ,,'('t'e {'ulh,cl rough nbernUlt In' Rollins (11, 12). 'l'lll'Y'wI'l' foulld in stands of the good glltlyuh' tj·pp as w('ll as the "intermediate" type'. Siurl' Rollins !In.s shown ('xpprimell tnJly that Olle way to pl'odtu'l' rough uh'l'rnnls is through the fel'tiJiz:Ltion of guayule eggs ,,11ieh 11ftV(' the' nl1n'du('l'cl numbpl' of elU·OIllosomt.'S by polll'tl from muriola. tht' rough nJlPrrunts found in stunds of the good guayuh' type prohahly tU'(:- fL typ(' of spl'cips hybrid produ('('d by the f('rtilization by marioh polll'll of gnuyu]1' eggs whieh have the ullJ'('(l11('ed number of ('hromosoml's. TJw 120-chI'omosome plnnt referred to was a rough nl)('t'l'ant and probuhly wus tlll' l'esult of £{'r­ tilization by POll(,Il from a OO-('Ilromosonll' mlll'ioln wlti('h. tH'('orc1ing to Stebbins and Kodnni (1J). O(,C'UJ'S in the same gelwrnl region with guayu}e. . . ~,

Stebbins and Kodani (13. p.laSl I'l'f!'tTt'd to ab(\rnttlts as ii itlltO­ triploid with l'espl't't to their imnwdiu.tp parents." They had 110 proof whrther the ('gg or t11(' pollPH gmin con tdbutNl the llllrC'Clucecl • numhrr of chl'omosom('s. Tlmt ttl)(>l'I'llnts might br the result of fertiliz:ltion of flU egg which Juts the l'eclucpel' of dU'omosomes 30 TECHXICAL BCLLETIX 918, L, S, DEPT, OF AGRICtJLTLRE by l1 P011(,ll gL'l1itt which has till' 11l1l'('\lIl('('(L numlwl' wns ('onf;idl'l'l'd as a possibility by ~tl'hhills nll!L l(odnni (1.31. who {'itl'd iItdirN't ('vidpll('p hy showing ·tlll' pl'pnllpll!'p of tl'i:lci" inslptld of (I'tl'(l(\S of • micl'ospol'(,s within POlll'll 11l0thl'l' {,pll", TIll' Wl'itl'l' w!\." not nhlp to confirlll sueh oiJsNTtltions on hl'l' mnwrinl. ~lon'o\'('I', hn'l'ding ('vidplwP dot's not support this jlossihilil', .\" ::>hOWll hy Hollins U 1) t'xpt'rinlPntally produ('l'd n.hl'lTllIll hyhl'ids I'Pspmblpd tIll' mntl'l'Lll11 pl1I'L'nt mol'P clo:;!'ly thnn thl' PHI Pl'Illll parl'ltt it nd fI hiO Jl101'1' ('losdy thnn thl' hybrid:.; whic'h htHl Cl'llll' from 1'!!0:S hnsill!! thl' redut'l'd ('hromosoll1P llumbl'r ill tlw SHIll!' cult II I'P':;, -'. .-

OFFTYPE XOlUrALS FH())[ :\UEllItJ,:'>TS Informntion (,OIU.'l'rn illg till' m('thods of I'l'Pl'o(\ uelioll by ahl.'l'l'flll t plants is limitl'd at tlw Pl'PSl'llt time to Powl'rs' sludy of a\)('rJ'nnts in coll('ction 421113 lSi, '1'11(' chl'omo,:;oJlle numb('rs of a fl'w WN'P detl'l'­ mil1('cl. The rnng(' ('xtl'ndl'd from 0n to H)(l, Among til(' oll'spring of abNl'flnts th('l'P '''PI'P a iil1Ht11 numb('l' of ofi'typl' IlQl'mllls whieh iiho\\'ecL only a J('w of th(' eha1'llct('l'istic::> of a\)('I'I't1nts, Xo 2 phUlts Wl'l'(, alike. The C'hromosoll1l' IlUmUPl'S of 12 of tlll'sP pinnts from Dabl'lT!Ults were dpt(,l'lllin('(l: thl'Y l'tlnged frol1l1-± lO 03, ).[eio,:;i:; in pol1l"1l mother cl,ll:; witS flnulogous te> thnt of nl)('t'L'Hnt,:; haying approximntely the salll(' ntll111)('1' of ehromo:;oll1l':l, Tlwl'l' wa,:; 110 ('on'pLn t ion bl'lWl'ell leaf charactcristic,:; and dll'omo,:;o!llt' number [tii ,,!town as follows: Lraf rharacteJ'i:-ti!''': Ch;~~~~~~;lIt )'fllrh thirkplll'd, ~lightl\.' irrrguiar partPfll. ______•• _. ______03 • Thickrl1l'd; , ~lightl~' il'rC'gn\ar puttPrll______.• __ • __ • ______91.92 Hl'glliur pattpfll ____ .. ______• ______- ,+.82 Rlightl~· thiekl'nl'd, rpgular pam·I'lL ______... _____ So, RO, 91 ); ot t lIlCkpll('(I: Trrl'.glllnI' patterll_. ______.. ____ • __ • __ .. _. __ • ______• ------85 ~lightly irr<'!!;ulnr pIH\('rU __ ...... __ __ _..______• ____ .------IH Rl'gnlar ptlttt'fll______• _____ • ___ • ______--- _------S,j, R8 None of lh('se plants had thickpn('d p('dwwl('s, Binc(' aU of the chromosome lHnnb('rs W('l'(' l('ss than nf>, they probably Wl'r(' the result of f{'rtilizlltion of eggs which hlld till' l'('(luc('d 111l1n\)e1' of chromosomes and r('pl'('sl'nt('(l thr bcst of the g('nie l'l'C'ombinalions that resulted from amphimixis, SECTORIAL CllntEIUS Among tIll' o{l'typP normals wltieh \\,('I'l' eXit.mincd cytologically, at l('ltst 2 w('r(' s('etol'inL chimeras; 1 of thes(' consisted of 2 morpholog­ ically (lisllnet parts lwcl th(' oth('r of :3, Th('se plants had 12 ehromo­ SOl11(,S, X 0 elMr diffcl'f'nees in ('hromosome 1l1uube1' among the se('lors could be disc(,l'I1ed, Among abeLTllllts sedol'in,l chim(,I'fls IU'C' fllirly ('ommon, pn.l'li('uln.riy after the first yC'itr of gl'Owth, Arl'(,('tNl portions of plants of I't'cogniza­ bie size YlllY fl'om s('ctors of lean's to who[l' bmndl('':;, '1\'-0 sectorin.l chim(,l'itS llnlOng abl'I'I'lln t plnnts hnYl' b('en sllldied rytologicltlly, One hnd 09 C'hl'0Il10S011l('S in the SIll!l11 s('clor which had gl'e('ui"h malformcd }t'nxes and 106 in the l'l'st of lh(' pLllilt which had tllc llSlll1.l gray leavcs, • The other pln,nt probably sltlrl('(l with 91 to 94 ('ill'omosomcs, At prcs€'nt only a small pl1.l't of it hIlS this Illunb('.l' b('('allse tll(' part which has 86 chromosom('s fmel grl'cillsh smooth leay('s hits oycrgrown the POLYPLOIDY A:\'"D A)(ECPLOIDY IX GC\Yl:LE 31

91+-dlL'l)lllosome part which htL::; gnty mnlfOl'lllP(l IPllW'S, It is possible that somC' of tlte i['l'C'guln.!' growth pnttC'rn of alH'['['ants is the result of (liffC'I'(,(lt. growth rn.tps among ('(Ill" whi('h nUT in C'hl'OlUOSOl11e • numb('[' if somatic; loss of ('b.rOll10sonll's O('('Ul'S frl'(ju!'ilti)- in tis::;up:'i, Furti1PI' {'yi(L('[wC' ill SIlPPOt't of It ('auiial I'('btion h('tw('('n hi!rh ('hrOm()~()lllf' llumbpl' and the O('CllIT('Il('(' of chiI1lN'n,; may hel ('iu:cl. POW(,l'S [8, oht ainptl hYIWrttbpl'ntnt ofTsp['ing from tlbl'lTlLUts in ('ol!('('­ tion 4:?1fj:3. Of th(lsl' plants. ,;onH~ of whil'h luul n::; muny t1:'; 1-1:4 ehl'OIllOSOl1H'S ltnd all of whic'h p['ohuhly hall at IpHst t ..W, lllttny oln'"joush- wt'rp s('l'tot'"ial chiml'ms In- titt' tiltH' th(l,- wpr!' .;;; mOllth". nitL find pn::;t' tlll' first llnw('['ing ,;tngp, 'In !'llllH' of tIn; phut,; :2.:3. or pwn 4 di,;tirwt pnrtiolls of YUl'ying: sizp ('oul(l ill' (listing:t1i..;IH'(L _\ ft'w of thr Ip..;..; l'xtrpnw portion:' of :,('vpml of till'S!' plunt;; Wl'l'P pxtunilwd eyto]ugindly anti fOllucl to htwl' Il's,,; than !l,i ('hroflw".ouW';.

FACTons JJ\f1Tl.\G .\.\E1 PLOIDY .\.\D POLYPLOIDY I.'i G1 \lTLE

Bp!,tw,::p lllPin,;i" in pnlll'll lHntlwl' ('I'll,; of ~lhL\"llhi plnut,; i..; ('ompll'tE'. II :4w1'e"('onun011 Prohably if it W('re common, :3,); euploid;; would be re5trietl'd to in(Iividllal phmts tlltel t'wn -!.r plan ts would be quite YarifLble, ~Ion'over, by meaIlS of itpomi.;:i:=; the rltre fayomlllp aneuploid ('ombirw.tiollS that arisC' through mnphimixis, since apomi.\:is is facultative. or diplospol')- ]lfi,e a ehallee to :mrvi.-e, to increase in Ilumh('r of plants, and tht'refon' to establi"h what amounts to a done. In efft'ct nonsegregating apomi.;:is is l'qui'1l.1ent to vegetative reproduction, Beeausp most anpuploid:; found in 3,r. and 4x apomictic populations are not as \-igorou:; as the apomicts and pro­ duce fewer or inferior seeds, apparl'ntly not many hnse giycn rise to clones and thp1'e£ore to aneuploid stands or strains, Furthermore, because apomixis is tht' predominant method of reproduction in 3.1: and -!.l; popUlations, in thes(' apomictic stands the['e is now only limIted opportunity for the creation of ne,'," types by means of amphi­ • mhis, For these :2 re!tsOlls aneuploid strains nre uncommon, In contrast to the relati,e paucity of aneuploid individual:; in apomictic 3.1: and -1:..t stands aut! commercial stmins, there Wits an 32 TECHNICAL BL'LLE'l'lN 91 S, U. S. DEPT. OF AGRICUL'l'URE abundallce of o,lleuploids with vo,l'ied chromosome numbers o,illong the offspring of plants which reproduc('d amphimictico,lly. For instance, 0, segregating culture was obtained {!"Om the seeds of a Texas mo,riola. • plant which had some guaY1.11c chn,mcteristics alld probably ho,d 90 chromosomes. The chromosome ll11m1>(,I's of 23 of the pllLlltS in this cllUme w('t·c deLel'miMd. rrlH'Y rfl.llgcd from 70 to 95. No 2 of tbe plants were morphologicnll}~ alike. In size they varied f!"Om VOI'Y large to very s111o,l1. Also, by using diploi(L 36+ -chromosomc plants, \\'11 iell o,re amphimietic, as sced PILl'ClltS, allcuploids were obtained whicb \7aried in chromosoll1c numb0l' from 43 to 49 when pollen from 54± -ehromosomc plo,ots WitS used and from 40 to 56 whcn POllillfLlion wo,s not controllcd. OlH'-lhil'd of thc 4,r± o[rtyp(' nOl'mn.ls sludicd hlLd lcss tlmn 70 chromosoll1C's. Thcs(' plnn Is W('I'C de'fkiell t for :3 Ot' more ehl'Ol11osomps. Othet' e\7idenee shows that (·ollsid(,I'n.blp ('hl'OlllosomnJ unbtLliwcl' existed among "lfLbIc> ('omhinn,lions. FI'OIll 7~±-ehl'OmOS()Ill(, populn­ tions ttIl un hlLln,n('e which nULY be. rcpl'esetltccl itS 4,1'-7 wns found in plfLnts which h(1(l u,s fe'\\' flS HI) ('ht'OmOSOl11l'S, From noncontrolled pollination of ;')4 ± -chromosol1l(, pIn,nts n,04- and it (ill-chromosome plant \\'('1'(, obtained, From )1oneontroll('d pollino,tion of 2,I:pln;uls iLI1('uploid 3)' plu.nts whidl Yltl'iNL in ('hromosome ntllnbel' from 40 to ;')() wcrc obln.iu('(\. Th('J'(\ wns (,Y(,11 gl'C:ttPt' ehl'omosonul.l unbn.ln,I1(,c in some of thc ofl'spl'ing from el'oss('s bl'tWCt'1l 30+- IUHl M± -chromosomc pln,nts, such as thos(' whi(,1t hnd 4a, 4ii, 4n, alHl 48 e\u'0I110S01!l('S. B('('iLUse such unhnlanc'e 1>('tw('el1 t\tp 2,/' :lnd :3.t It'v('ls is possihl(',the widt' d('yintiolls from (,lIploicl Illullipl('s of If; whic·it W('l't' found in • an('uploids with high ('ht'OlllnSOnH' I1l1l11h(,I'" It1'e not, Slll'[)ri:;ing and aetulllly invol\-(' It'ss ehl'ol11o';ol1l:l1 unh:t.lfLll(,C IW('fLUSP 11l111tiplps of NL(,h of thC' IS ('bl'0l\10S0nH's wcre PI'('SNIt. '.1'11('1'('[01'(', if amphimictic J'('pro(\u('lioll WPI'(' moJ'(' ('omrnon in 3,t n,nel .l.r populntions, not only would. 11l01'C' ull('Ullloid,; bp ('X[w(·tNl but tll(' dn'01l10S011W nllmb('rs of lllo,ny of tlH'1ll \\ ould d('yiat(' ('onsid(,l'!1bIy from th(' t'llploi tLlHl ('omin(,l'eial slmins, one' is conscious of the [n('t thitt most of thosp sl udiNl ryto\ogic'nlly WCl'e 1('s8 vigorous IUld hlHl n, lowcL' sUt'"i \'11.1 I'ate bdoL'c l't'ttchillg 11l1tlul'ity. In (,ontl'llst, most of the ttIlcuploid 3,(' ofl'spring obUtin('d from ('t'OSS('8 in whi('h lilt' sPC'd Pttl'Pl1ts \\'('1'(' lilt, jLlllpilimi('lie 2.t' plnnts wt'rc vigorous, in spitp o[ the filet tbal in SOIll(, of lltPlll there Wfl.:'l (,\'(,11 gl'eltt('L" Chl'OlllOS01l1n.l nnbulltl1('e, in proportion to tltc (·otn1 nUI1lb('l' of ('lt1'01110S01lteS iIlvolY('d, than thc ·l.r-1 ('hl'olllosollud unlmllLllN' in t11(' liii-f'hI'OIllOSOJ1H' pltUits found in 'tr populations, 'l.'h(,I'l'fol'P, t\to ksspn('d "igo]' of most of lht' imNlploids found in 3,(' I1nd4,r n.pomidic populations mllst 0(' Itltl'ihntl'd to g('I1i(' uniJnllll1('(, following amphi­ mixis rn,th('1' tluLII to Yltl'i:tliOIl in ('ltronlOs0l1ll' llumbt'l' P(,l' S(:, .'\ forlH of illUph imixls, Jl'l'tilizn lion of Pgg wh i('it hilS Ow Ul1l'l'd tI(·('(l nllmlH'l' of ehl'01l10S0Il1PS, kd to lil(' for11lntioll of thost' pln.nts with high dll'OIll()SOI1W Ilulllill'l's which \\'('1'(' fOllnd ill a,l and ·l.r PO[luitltinlls. Aneuploidy WitS )llOI'l' ('O1ll1l101l thnll euploid)', 'I'lU' e!ll'omosollll' numhprs of plllnte;; (\xn.mined thus fttr (lxl(,ll(\in unbroken ~W(llll'nCe • from RO through 11:3 and in unbrokell s<'<11«'I1('(' feom un throup: I 110, 112, 120, and 122. Tltn dll'0ll10S01lH' I1uml)('l' d<'(wllded upon. the number of Chl'OJl)OSOll1l'S in lhe l'gg (54 ± 01' i'2::!:) pl\li'. lhl' 11llll1\)eL' POLYPLOIDY AN'D AXEL"PLOIDY IX Gl:AYULE 33

brough t in by th(> po11(>11 CTl'llil1, S,incc ('I'OBB- us \\'(>11 us B(>lf-pollinulioll occurs, the illlmb('!' of chromosomes ('ontribut(>(1 by th(> pollcn grain muy be quit(> :"ul'i,ublC', It, lIns b('('n shown from brct'(ling dn1l1~tllil,t • polleu from trlplOlds contn1l1S ubout 25 to 3a eiIl'omosoU1('S and that from tetmploids ItbOll t :n to a9, In a mixcd slund of iH ± -ilnd 72 ±­ eh1'01110S011le plants, thereforl', po11(,11 gl'u.ins would ('ontain ubout 25 to 39 clir01110S01ll('S. ('onsl'q Ul'n tly, if the ('~~ IltHI exnctly 54 ehl'omosol11Ps, tlip PXPP('tN\ l'!UI~(, of ehl'omOSOIll(' Illllllb(,I'S of tho abeJ'l'llnts would bl' 79 to 9;3 and if it had ('xucliy 72, tilt' ran~(' would be !)7 to 111, Thc l'xp<'clNI l'ungp would 1)(' ips8 if most of th(' plants in a stnnd hnd tlit' ,mill(' ('hr01110:;0'1)1(' nUllllwr: out of 5"l ±-clll'oillosomc stands it would be 70 to S7 if tlip Pgg hnd PXtl.('Uy 54 ehrolllosomes, und out of 7'2±-('hroUlosome stHnd:;]l would bl' 10;1 to 111 if the l'gg , hnd cXHetl y 72, Onp mci:y t1.J'bitm1'ily c(111 OO-clll'omosoIlw pliLnts l)('ntltploids (5 tin1('S 18) nnd lOS-du'oIllosonw plltnls /tpxltploids (n tinl('s 1R), but sinee ul1t'uploicly is more common than t'llploidy at tht's(' high leY!'ls in the polyploid St'ril's the tl'l'mjnolo~y hits little lI1NLtling; 'unci the tl'l'rI1S "pt'n taploid" und "IH'xn.ploid" mel ieuJl' only t hu t the total number of chrOlllosollWS equnJs 5 01' G tinl('s :1.', whkh ('qUiLls lX, If chromosomc ussoeintion at llwtuphasl' I W('I'C llSl'd fiS a ('['itprion fot' d('tl'rl11illing polyploidy, tlH'll tlipse pilllltS would be consid('l'e\1 pltl'ti~l ldmploids at most. 'rhus fal' 110 natul'l11 slltuds 0[' t'onuu('l'C'11t1 stnuns which nl'C pl'utuploids or ht'xltploi

of C,him('ras must be ex('cptNlJ but such plltlltS obyiollS1y bl'~ltll with a lugh. chromosome lllllnbpl', frow Illany ll0I1111H'['l'tll1t plfLnts 11aye mo['(' thnn 72 ± chromosome;> is not known, One SO-ehrolllosomc plnllt in a 54+-chl'oIJ10S0111C population WllS ofrtyPl' 110rmal but not ItbplTnnt. That tht, s,Yllciron1l' of eha.raC'll'l'islies by whic'h ahl'l'l'nnts nrc dis· linguished from othPl' mOl'pholo~icnl typl'S ('ltllnot he nttributed to high chL'OmOS0l111' llumbpr alolle was shown hy til<' oCl'typl' llormals (nonflpomic'lic offspring) f1'OI11 niWl'rnnt plltnls, ~\Ilhough 11 of the 12 plants hnd 82 to 03 CliI'OIllOSOIl1l'S. which is till' SIUll(' range of chrolllosome llumlwl's sho\\"n hy ab('ITnnt~ fl'olll [)4±-l'hromosomc populations, none could bl' classrfil'cl as rl'al Itb('ITanls, Thl'SC plnnts difl'pl'Nl, howl'Yp[" in mode' of ori~ill from nl)('l'L'ant:3 in 3x populnLions, 8in('(' llU'ir eh['ornosotnt' llumlH'I'S Wl'l'e ('onsidl'rably 10\\"('[' t.lutn those of theil' 5('('(1 pan'nls, t1wy Cllllle from the fertiliz:ition of <'g'g'S which hnd the l'l'd uecd nII mb('t, of dll'OmOSOl11l'S, TIl(.\'~ ('onsl it lll'('(1 only a smull [metion of thl' totnl llumbt'1' of ofl':3pl'ing ~ from ni>t'['l'lullS lind l'epl'('s(>ntccl till' best of tht' ['l'combinations of genl'S thl1t ['('sulted from nmphimixis, In nttemptillg to u!llI('l'Slnnd why most plants whieh hud IL high • rhl'omosolll(, numlwr wen' nbpl'['tll1l. it should be ('('membered lhu.t tlt(' abel'l'ilnls sLudil'd O(,(,lIITNI in 3.1.' und 4), I1pomidie populations. 34 'l'BCHXI(''\L BCLLETlX 018. L ~. DE!'T. OF AGHICn;LTHE

All nlH'1'I'llnt I'(':ntll:; fl'olll tlw fPl'tilizllliol1 of nil t'J.;g whieh of it:wlf, without ft'l'lUiz!11jon, is u, Thl' 1l1Ol'C vigorous of llll' lli>PI'l'llllls [)l'ohtllJ\y Indi<'utt' It !t'ss disllll'llI'd gt'llic bnluIl('(' . Insoful' us hig:lt {'iJl'Ol11(lSOlll(' 1l1lmlH'l'S ill glllLyu1(\ 111'(' [ill1i('(\ to plllllH \\ hi('11 U1'(' IlHIl'pholoJ.;i!'u 11,\" nl)(,I'I'1I n l, I II(' pst lLillisI 11 11(' 11 I of I1allll'ul ,.;(ullds whil'll huy!' hi:.;h ('ill'OllloSOIU(I llumlJ(,I's. SlIl'll 1\"; Il<'llltL­ ploi!!s ntHt llt':'>t~pl(lids, will ill' limit!'(\ (0 wlml('\'Pl' SW'I'!'SS HllI'l'l'llIll, plttnt..; huyl' in l'sl!\bli"hinJ.; th(,ll1sl'l\C's n..; lllltlu'ni slnlHls. l'/lfol'­ ttHtltll'l,\', lllost ahplTIlIlls ~l'()\\" !\lOl'C' slowl,\' than HOI'nut! plllnls in thl' RIU1)(' ('lilt 1lI'P":;. .\Iso, POW!'!'S I,") ohtltilH'd n \'PI'y low Ppl'{'!'IIIIlJ.;l' of germinal iOll of s(,('ds pl'Od w'Pll 1)\' Itht'ITIUl h. ~ rOI'(,O\'PI', tli!' fr!'C[lIPllt O('{'Ul'j'('Jl('(' of "PI'lOl'illl (,ltill1PI"lS in uld{'t, nlH'I'I'unl" lind tIl(' loss O[ elll'omosoJlH'" o\)sl'l'wll ill indiddttul ('('l1s il1diC'ttl(' instabilit \' o[ ('II l'Omosolllt' llllmlJ('!' alJlon~ Ih('s(I pial! Is, Thl' ('0III billa IiOIl o(slo", gt'{)wth, f('w oll'Sjll'jllJ.;, am 1 illst 1\ hilit,\' of I'hl'OIllOSOlll1' nlllllhl'r pl'oilnhl.v (·xphtins wh,Y no stand.s of nIH'I'I'IUlI.;, and illt'i

TIt<' sllmpip of gllllYllh' planH lIs('(\ for lh(' cll'l('l'minlLtioll of ('IU'OlllO­ som(' IlUIll \>('1':-; illciudl'cl Tt'XtUl nllll ~J ('xic'lut poplliat io Il'" , ;,\lnll' of i\f('('111hull'S (,OIl1Ill('ITilli :-tmins. flnd OfI'SPI'llI:'; from both ('ollll'ollNl and nOIl('olltl'oll('(l l)(1llinatioll"; of s('\C'('('d llhml", '1'11(' :\ll'xiclLIl mu I(,I'ia1 inc] tlll('( I :{(i;--(·It ronwsoll1P (

buLlon umong hight'\' polyploid~ wllsl(':'i~ thl1l1 til(' ilH'{fllnlily in trip­ loid!; in spit(' of tll(, 1111'gN II1Il1l 1)('1' of {'lll'OIlI()~Onl('~, Huploids from t(,{I'np]oids ghowpd SOJll(> l>iYI11(,II(s ul lIH'tn pJIIIS(,. J. .\l1tlphns(' I distribution WitS l('~.., l'('gu]nl' thnlt ill diploid,.;, ~1I('h Ilwiolie il'l'(,~~l1­ • Inl'iti(,R itS nSYIHlpsis II net 1'u U\lI'(' or (,\·t(Jkilll'~i.., \\'PI'p ob~pI'Y('d ill 11'('­ ; was (',.;titJlatl'd fl'olll th(; IlllllJIH'I':4 in tilt, ('hl'OIllOSOll1!' gl'oups ill polll'lt lIloth!'I' ('1·11,.; nrtpl' Htlllphns(' L .«'01' tIl!' :~,I' it was 22 to :W; rOI,tlll' ·lJ\ ;~:~ to:lIi; f!ll'lllll'lTlllIls froll1 tIll' :l,I', :~s to 4:{; aJl(1 (ot' alll'l'I'anls fl'OJ1l tIlt' ·1,1', 'Is to :i,i, ~\" It cll('('k Oil tll('s(I ('~timILt(,s, ('ul<'ululilllls bnsl'd Oll hn'('dill~ IIntn sho\\'(,d thnt 1'01' tlIP :l.f plallts tllt' l'Ull~l' WIIS 2,) (0 a:l Hnt! fOl' tIL;. ,;1.1',:0 to :l!l. Instahility of ('hrolllosolll(' lIltllllJ('1' :t111()Il~ n/!l'l'I'ulIt,.; \\ tiS sll!!:~('s«'d by tltc' loss 'of gl'Ollp~ of !'hl'OlIl(lf,(lIll('S in llillll'll ll1oth!'I' (,('11" ilil'ough such JlI('ehllllislll~ a" Illultipohu' s]lindl!·s lIlId twin ('I'll,.;, Lo~s of dn'()IlI()~om('s PI'I'yiOllS to I hI' fOl'lllll IiOll of jlolll'n mol h ('I' (,('lIs was in­ f(,ITPd ft'om tIll' lilJdiJl~ or ('('lis wldeh ('olltuill('d I'P\\'(,I' dll'OIl\OSOIl1Ps a 1llollg thost' whiC'h 11:1(1111(' higlt 11l1111lwl' IH'oduC'l.d hy Hl)(>l'I'~ll1t!'i in -(.J,~ populntions Illld Ipss fn'qlll'llt]Y ill :1,1'; 111(' ndllnl numhpI' of CI1l'(1I110­ 50111('s WUs Ylu'iahlp. ('onsiulHl\('(' is possibll' • ill gunyuh·. FI'OIll hOlh ('oJlIJ'oUl'd lIud 11011('011 pllllilln of [l'Ollp(1 lions 2,1' plants growing ul :-;ulil1tls WPI'(' Oblllilll'cl oli'spl'ing wllOsl' dH'OlllO­ SOIlI(' lIlUlIbl'l' I'Illlgpd fl'om cl:l to .ili. B(lculIs(' apondxi~ i~ t]l<' }l1'l'do11liJltlJli f01'1ll of j'ppj'oduC'tioIl among tl'ipioid,; Hlld l('tl'uploids, :~,I' llnd ,l.r stands 111'(' fuidy 11Jlifo1'1ll. ~\. f('w of thl' ('OmnA reinl s[I'uill'; HI'!, HllPUploid :tl' Hlld .1.1'. B('I'!lllSl' oi' ]imilpd nJ1l0ullts of alllphimixis lIud I\(lJ'1llul JIll·jO;;jS ill llJ('ga~p()J'l' moth(·), (,pUs, ho\\"(~Yl'l', thl't'p W<'j'(' illdh'idllul vurinll(s IlnHlIlg lllt' :1,1' nile! .1.1' l101Hlln­ {ions. 'nl<';;p 1IJ0l'pho]ogi('nlly distin('t tYPl'S ill(·It)(lpd IHlploids, off­ tYJlt' n(ml1uls, alld uIWl'l'UlIls, XilH' huploid;; from Tl'XllS ('ollp(,tiolls find ('OJ1ulI!'J'l'i.tl ,;t I'll ills WpI'!' st lldil'd.; ;{ hud :W IUlll (i hnt! :H (:'hl'olllo­ SOU){l~. ).[o,;l of tIl(' nli'tY]ll' 1100'JIlnl,; \\,(,),p lult'uploids. 'l'J\(' ('hl'olllo­ SOllW lluml)('rs of [(1(0 a,t oH'tYjlP tlol'll1uls l'IUlgC'd fl'om ;i4 to !iii. Thc 11U121]H'I'S or ,t It!'. 4.1' !lIld H1Y'liploid -1.1' olr~::pp 'llol'mnl;; l'IUll?('d fl'olll Q5 to lil, lll(' dISll't!HI!IOH hl'llIg liS [ollows; .),L!I jll'l'('('nl hnt! J(,:4S thnlll 0 ('lU'OJ)lOSOlllPS; :~~,\l J)('I'('(,I1I, 7() 01' 71; j};.1i ]wl'l'pnt, 72; Hilt! H,ii }>pr­ (,(,Ilt, 7:{ to 7;i. Ah('l'l'ullt~ from lriploids hud bO to H3 chrolllosoll1es; thos£' fl'om. tl'll'ilpl(lid~j\l!J 1[) 1~O, ~\ll alJl'I'J'IlIl!s had It high Chl'(J11l0S0111P nUlllh('l' whi('h ('(IunllPd the ulll'{'dIH'('d lllllnlwl' of tlw ~l'('d pn.rl'lIt pIllS tltP Humh{'l' ('oJlll'illlltNl by thp ]>011('11 trl'ail! wItic,1t (,Il'p!'lpd J'l'l'lilizatioll. Tlwy o('('llL'I'pd uft!'r elthe!' st'lf- (H' ~'l'();;s~p()lliJlnl iOll ill hOlh :U Hilt! -1./' P(1)ullltiolls. The POllPll pUJ'('nt wns ('iilwl' gllnruh· O1'lllllJ'ioln., ~('d(Jl'inl ('hillll'I'HS W('I'C Inid\" common nll10llg oleiN' nl)('ITllllts ill 4,1'llo]luhttiolls. Dili'PI'(,l1(,(,S • in cIiromOl-lOIll(' llumi)(,l's W('I'(' illYoln'cl.ill the fe'''' (,hinwl'll"; ('xtlll1iUt'd. Ab(,I'j'I1I)('.)' st'l'Ilwd to JJ(, n'~tri('ll'd to thost' plants which nds(' in 3.1; 36 TECHNICAL BULLE'l'IN 918, U. S. DE~T. OF AGRICULTURE and 4x populations throtJCYh fthnormal ftmphimixis (nonl'eduction fol­ lowed by fl.'rtilizn,tion) and to their apomictically produced offspring. 'l'w/.'lvc offLypc normnls from abcrl'tlnts whieh yftried in chromosome 11U1111)I.'1' front 74 to 93 probably nrosc thl'Ough amphimixis. Since tlll'SC lattc]' plnnts showed only a few of lhe phenotypic characteristics • of flbelTtl,nts, the·y probably jl1dicn.ted more successful genic balances in spite or high chromosome number. LIT1~ltATCRE CITED (I) BlmG:\Jm, A. n. H).lel. OI·AYl;r.Jo: I'LAl\'l'H W('l'n r.ow ('((UO~IOSO,\lE ~nrnl>fu;. Ekicllce 99: 22·l··22[). (2) ROCI/ANTI'I,rA, Z. 1'. [HO'J.'S('IIANR%gVA, K] H133. K IHOI.()OIl 'l'S\'g'('gNlfA (a'All:LY 1'.\IlTIIENIl'.\1 AR:oiI)\, ZY'l'()B~IJ\Il\'or,('flIi-l(,ln; 1':\TI';U~I'('III'NG I)lm VAHlB­ ~I'X'l'HN \'Il;'; l'.\UTIU;:oitl·~1 "llng:oiT.\·l't~l nllAY !':\I) 1', INI'AXtTM c:uw, Hut, ('cnthl. BpihcClr. Aht. A, ;'lorph. u. Physiol. der l'fltwz.•i3: 2 \)3301', iIlU:l, EHA!', K. II)H. ,\I'O)I1XIS I:\' o (,A1TLI1. Xull. ACllcl. Sci. Proc. 30; 352-355. (5) I(c.lwwA, E. 1H2!l. nH: ],;:\TW({·lu.n;Of;(l1,:srllH·II'rB D.EH ~IXNX1.1CI/J,:-r GA:'IE'I'Ol'HYTBN l1B1 PAWl'fI E:NII'M A IHll~N'I'A'I'l'M OItA Y l'XD 1'. lIYS'l'gUOI'IJ.OlttTS L. A:ssol'. 111;;(. l'hys. :\lllth. FIIC'Ult,\', ).l.m;cow l-nh'. Bul. 2: 145- IGO, illus, (0)-­ 1932. 'J'III~ 1ll;:\,J>!,OI';\IEX'r O~' TIIB FJ,;.'lAr.l:: GA:'IETOI'IIY1'£ 1:\ I'ARTln:NIU:'{ AIIOgN'l'A'I'DI (·'Ol',\Yl'LB"'l. ,lour. Hul. de 1'I:HSS. 17: 72-!)9, mus. [In RU:isinli. Euglish 8\1ll1IUnry, pp. t)'1-95 j English • explnnation of figures, pp. 98-99.] (7) l\[l'n'lm, .T. R, . 1!l.15. l'UEnxr:-rG Wl'l:Ir l',\JlAD1Clll.(\HOlmNZENE TO 1""CI1,I'1'ATE CHROMO­ som: STUDY. l:'lllin Techno!. 20: 121~125, illus. (8) POW1-:RS, L. 10.15. J.'EII'rn,IZA'J'I0N WITIlOl"1' HBDCCTJON IN GCAYUL'E (PARTflENIUM AIIGI~XTNI'l'~l OUAYl ASD A IIY.l'O'l'lItJS1S AS 'ro 'rilE EYOJ,C'rlON OF AJ'O~I1XJS A:\U l'nL1PLOID1. 30: l323]-3'lO, ilIus. (!») --- nnd UAHDslm, E. J. 10.15. l'Hl:;Ql'gNCY OF ABOH'rBD }·O[,r.tJN OHAINS AND ~lIcnOCYTES IN Gt'AY1'1.1~, l'AH1'IUJNlt:'lI AUGBNTATCll GRAY. Amer. Soc. Agron. •Jotlr. 37: 1IH-103. (10) ---nnd HOI,I.INS, It. r. 19;15. l\I~rUODn~TJON A:\I> POLl,INATION S'l,'UDU:S ON GUAYCLB, PARTIlE­ Nlnl AIW1')NTA'lTll anAY ,\:\U 1'. ISCASlllll II. n. K. Amer. Soc. Agron. Jour. 37: 90··112. (11) Ror.LINR, R. C. 10.g. r;nDl,N('I~ FOil NATt'HA1~ IIYBmDlTY nBTWB~;N m·AYUI.B (l'AHTHE­ NJt'll AIlO ESTA'r011 ANI> MAJUOLA (I'Au'rHBSIUM INCANUM). An1<'r. Jour, Bot. 31: 93-99, illus. (12) 1945. I:\TI';Uf;l'l';CIVrc llYllIUU!ZATJON IN I'AR'l'I!BNIl'll r. rHOSSBS BB­ 'rWJ';I~N(H'AYn;g (T'. A1WHS'!'A'!'(';\I) ASD ::\["lUOI,A (I'. INCANU;\I). Amer.,Jour. Bot. 32: 305.. ·1O·l, iIlU:5. (13) R'l'JmllI~R, G, 1,., ,Jr., Ilnd KODANI, :\1. 194-1. CI!HOlIOSOlIAf, YAHJA'J'JO:-" IN Ol'A1'\7!,B AND :'IAIUOL.\. Jour. lIered. 35: Hi2-172, iJlUll. U. s. GOVERNMENT PRINTtHG OfflCtl uu • For snle by the Supcr.illtcn(\(·llt or Documents, U. S. I)o\,crnment Printing Olllec \\'lIshington 2:;, D. C. - l'rle!! 10 cellts \ " 1,0 ';~,') ., TECHNICAL BULLETIN No. 919 • August 1946 • VARIABILITY OF CERTAIN SEED, SEEDLING, AND YOUNG.PLANT CHARACTERS OF GUAYULE

By WALTER T. FEDEHEH

Formerly nssocillte genctieist, Spccilll GUllyul(~ Reseureh Project, Bureau of Plant Industry, Soils, and Agricultural Engineering, AgricuIturul Hcscareh Administration •

L .:;:0 ,.-..; ~ ~ ~ 0 ""' f-I -.. -I tEJ • 0 " ~- ) ~" c­I;'~ -

• UNITED STA'l'ES DEP.AH'I'."ENT OF ACRfCULTCHE, WASlllNCTON, D. C.