hnl f ln nd rtn bt n Erpn brd Chtnt Gnrl n, ll Crdd, 2 Crtn n nd l Slrn Ittt d Cltvzn Arbr dllUnvrt d rn, tr Gr , 026 rn nd, 2 Ittt d rttttr Indtrl dllUnvrt d rn, Or , 026 rn, IAY ABSTRACT. Developmental stages of the growth cycle European chestnut-growing areas. However, chestnut from bud-swelling in the spring, through burr and leaf- blight, Phytophthora root rot and modern nut growing drop in the autumn are described for hybrids of Castanea considerations have stimulated interest in cultivars and crenata and C. sativa. Most of the stages are presented in hybrids of the more resistant C. crenata Sieb. and Zucc. a photographic sequence that details the appearance of from Japan (5). The smaller tree size and more precocious dormant vegetative and mixed buds, bud break, leafing bearing habits of the Japanese cultivars and hybrids would out, staminate catkin development, catkin type (astami- allow for more intensive orchard management and higher nate, brachystaminate, mesostaminate, logistaminate) (some early returns. examples from C. sativa), androgynous catkin develop- The present work shows some aspects of the phenol- ment, pistillate flower development, full bloom, fruit set, ogy, morphology and floral biology of Euro-Japanese ripening, fruit drop, yellowing of the foliage and leaf fall. hybrid chestnut cultivars through photographs that docu- Emphasis has been placed on the floral sequence in order ment the various vegetative and reproductive stages from that future work on chestnut may refer more precisely to bud-break in the spring to fruit and leaf-drop in the fall. the particular developmental moment within the phen- ological phase "bloom." MAEIAS A MEOS Each salient phenological phase and particular detail is described and numbered and most of the phases are Apart from a few scattered orchards of Euro-Japanese documented in photographic sequence. All observations, hybrids planted within the last 20 yr, the Italian (and except where indicated, refer to Euro-Japanese hybrid European) chestnut industry is based entirely on cultivars chestnut (C. rnt x C. tv trees growing at Cumi- of Castanea saliva Mill. These varieties have proven them- ana, in the province of Torino, 530 m above sea level. All selves over centuries of selection throughout the different data are from the 1990 and 1991 growing seasons. r . rnt brnhlt th xd bd. r 2. ttv bd. r . d br. r 4. Grn hn. Figure 5. v vdnt. r 6. d l drp. r . Opnn f th lv. Figure 8. v ll dtrbtd tpl. r . Apprn f th tn. r 0. Ctn drn rl dvlpnt. r . Elntn tn. r 2. Glrl vbl. r . En f th tn. r 4. ll nth. r . Atnt tn. r 6. ntnt tn. r . Apprn f ptllt nflrn. r 8. En f tl. r . Elntn f tl. r 20. tllt flr t fll bl. r 2. tllt flr, dtl. r 22. tllt flr, tn. r 2. ll nth, ndrn tn f C. crenata. r 24. ll nth, ndrn tn f C. saliva. r 2. End f ptllt rptvt. r 26. Andrn tn drp. r 2. Grn brr. r 28. Ylln f brr. r 29. Burrs opening. r 0. Burr open, nuts fallen. r . Fallen burr with nuts enclosed. r 32. Yellow leaf and mixed bud. ESUS 0. Ctn drn rl dvlpnt, lnth 0 . th tnt nd ndrn tn r brn n ttv nd xd bd th lf xl. .rnt brnhlt th xd bd. h brnhlt .tl prtn f brnhlt th lntn tn. hv vttv nd xd (vttvflr bd pr 2.Glrl vbl ln th tn. h tnt nt n r r l l prprtn. ht ll flr r ntd nt xllr lrl f vn r fr th bd. h pl nd bpl xd flr h. An vr f 40 lrl r dtrbtd bd n C. tv, nd th ntrdt nd bpl ln th x f th tn. Ctn lnth vr fr bd n C. rnt, C. ll l. nd thr hbrd r 040 rdn t th p nd ltvr. brn n lt r rth f th t nd v r t th .En f th tn. h ndvdl tnt l nd fl nflrn. flr pd f xprtd prnth nd 82 2.ttv bd. h bd l nl th prr tn. h plln hrtrzd b vr pnnt d f th vttv x. dr. rvlr (, 8 h td th flln dv n f tn tp rdn t th prn r bn f tn nd th lnth f th nthr flnt: Bud-break and leafing-out tnt brhtnt tnt nd, ln Chtnt r nrll lt t bn lf rth n th tnt. prn. pndn n th ltvr nd th rn hr t 4. ll nth. h bln prd vr rn, lfnt bn n t fr th nd f rdn t th p, th ltvr nd th lt Mrh t th nd f Aprl. h t fr lfn t t ndtn. ll nth ndrd t b th nt frt trtn nrll btn 40 nd 8 d. t hh t lt 0% f th tn hv pn flr. d br. h bd b trd, n thn lln b prdd fr r thn nth d t th th pn f f d th brn f th bd l. ld nthr dhn. Ctn drp (pht nt hn, 4. Opnn f th bd l th brnhlt. Grn prrv drn nd flln f th tn rrpnd hn. t dnhn plln prdtn. v vdnt. h n lv b dtn hd. Catkin type 6. d l drp. h n lv bn t nfrl nd th bd l fll . .Atnt tn. h flr tht tn . Opnn f th lv. h dfnt hp f th r rphlll trl n plln prdd. h lv bn t h. ntrl prtn f th flr pd b l flnt. 8. v ll dtrbtd ln th n ht. h h Itln ltvr nn Mrrn r nrll lv r th lnr tpl tht l fll. h hrtrzd hvn tnt tn. lf hp nrll llptlnlt, th rnd rhtnt tn (nt hn. h tn r nt b, rntrrt t rl dntt r fr ln nd d nt xtnd bnd th prnth. n nd th n nt tp. h vr lf lnth h nthr ppr nrl t plln n vr 220 nd dth . h vn r vr vdnt. r. h lv f C. tv hv lthr txtr, r dr Mtnt tn (nt hn. h tn r rn bv nd lhtr rn bl. C. rnt h ll fr 4 ln nd xtnd brl bnd th rn r lv th rrt, l dntt rn. C. ll f th prnth. lln prdtn ltd. lv r ntrdt n z nd tnt bl th 6.ntnt tn. h tn xtnd ll lpdt lnd ln drb bth bv nd bl (0. bnd th prnth nd r fr ln. Abndnt plln prdd. Staminate catkin development Andrn catkin development . Apprn f th tn. h nxl tnt .Apprn f th ptllt nflrn t th nflrn (tn b dtnhd fr th b f th r dtl tn. h fl flr r ndrn nflrn, hh r tn th ptl ntd n rp f ll thr n prl nvlr. lt nflrn t th b. h pprn f th r t t fv (t n f th nvlr tnt tn prd tht f th ndrn t dvlp t rrl r thn ll b frtl. n. h pr f flr dffrnttn n th bd plx, nvlvn nr ntlrphll flowers dftn nd rrn lnth dvlpntl tllt prd. lr dffrnttn bn drn th lt 8.En f th tl. Svn t nn tl r hld r rth (. rn nd n (2 hv b thn h ndvdl xprtd ptllt flr. rvd tht th fnl dvlpnt f th nl l nd .Elntn f th tl. h tl ll vntll fl flr r drn th frt prt f th vt rh lnth f 4 t 6 . tv l f th rrnt r rth. 20. tllt flr t fll bl. h tl r rdd, lndrl, ll t th b nd lbr t th tip. Their color may vary fr rnh ht t very lht ISCUSSIO yellow. The stigmatic surface is ltd t th very tp (11). h n Castanea is rbd t th rdr Fagales 21.Pistillate flr, dtl. It is th pn nvlr tht nd t th fl Fagaceae (Cplfr (. It includes develops into th brr. some 7-13 p (, 2 ntv t th tprt zones 22.Pistillate flr, tn. Each fl flr n f A, A Mnr, Mdtrrnn Erp nd th east- tains 6-9 ovules nd n nfrr 6-9 lld ovary. Each rn prtn f rth Ar. h p f jr flower will give r t n htnt tht , hvr, prtn r C. mollissima (Chn htnt, C. tv contain one or r br. (Erpn htnt nd C. crenata (pn htnt. A n plnt, th htnt h n nnl vegeta- ll bl tv nd rprdtv l tht nvlv ntr rest Full anthesis n ndrn tn. h ntrl of th prd, fr vbr t Aprl n nrthtprt cli- three flowers n h ptllt nflrn ll rh t, nd prd f ntnl tv vttn drn peak receptivity fr r fv d bfr th ltrl flr hh ht, lv, flrl rn nd frt r nd (14). Full bl is ndrd t b hn styles f ll f dvlp. Itln (, 2, 3, 4, 6, nd rnh thr (3, the three flowers r pltl vbl. hv prpd rph rprnttn f th devel- 23. C. rnt. h ndrn tn f th p pntl t. vr, fr th prtlr tr nese and Erpn ltvr ll b tnt tr f th flr r nrnd, nd th dffrn or longistaminate. n th dffrnt p, thr ppr t b l of 24.C.