Rev. Biol. Trop.,41 (1): 23-26,1993

Seed germination and emergence of pallidefuscaand Pennisetumpedicellatum (Cyperales: ) in Nigeria.

A.J. Afolayan' & S.S. Olugbami>

• Biology Depanment,National Uníversity of Lesotho,p.o. Roma180, Lesotho.

• Depanmentof Biological Sciences,University of norin, norin,Nigeria.

(Rec.3-XIl-I991. Acep . 14-Vill-1992)

Abstract: Seed weight,viability, gennination and emergence of Setariapallidefusca and Pennisetumpedicellatum weredetermined undercontrolled conditions. Theseeds of S.pal/idefusca and P. pedicel/atum had 97% and 94% vía­ bilityrespectively. Optimum gennination ofallseeds occurredat 25°C. Maximumseedling emergenceoccurred at the soil surface, therewas a progressive decrease at greaterdepth. Maximum depthfor emergencewere 5 cm (S . pallide­ fusca) and 7 cm (P. pedicellatum). Seeds of bothspecies germinated well under variedlight conditions. However, the­ re was less genninationunder continuouslight or darlmessconditions than under altemating day and nightconditions.

Key words: Setaria pal/idefusca, Penniselum pedicel/atum, germination,emergence, temperature, soil depth,li ght conditions.

Setaria pallidefusca (Schum.) Stapf & MATERIAL ANDMETHODS Hubb., commonly known as cattail grass and pedicellatum Trin.; are widely dis­ Mature seeds of S. pallidefusca and P. pedí­ tributed in Nigeria as weeds of arable crops and cellatum were collected from the main campus in waste places, roadsides and lawns (Hut­ of the University of Ilorin, Nigeria; in No­ chinson and Dalziel 1972, Akobundu and vember, 1989, and stored at room temperature Agyakwa 1987). Literature on the two species during four months. are scanty. S. pallidefusca was reported to be Seed weight was determined by weighing among the serious weeds in Senegal, Sudan, separately 100 seeds of each grass using an Zambia, Fiji, Kenya and (Holm et al. analytical balance (TurnbuIl 1975). 1979). Bogdan (1977), reported on the palata­ Viability was determined by placing sectio­ biíity of P. pedicellatum to livestock. ned seeds in 0.5% triphenyl tetrazolium chlori­ The effect of grass weeds in reducing crop de solution (Etejere and Okoko 1989); again yields through competiton cannot be over-emp­ using five replicates with 100 seeds of each hasized. The knowledge of the developmental grass. physiology of grasses is of considerable impor­ The effect of temperature on germination of tance in the management of grass weeds. seeds of S. pallidefusca and P. pedicellatum Germination and establishment of seeds of S . was determined in incubators set at 10, 15,20, pallidefusca and P. pedicellatum were investi­ 25, 30, 35,40, 45 and 500C. Twenty fíve seeds gated as prerequisites to the development of ef­ of each grass species were surface sterilized in fective control measures. 0.1 % mercuric chloride solution for 60 seconds 24 REVISTA DEBIOLOGIA 1ROPICAL

to prevent fungal attack; rinsed in several chan­ TABLE1 ges of sterile distiled water and plated on dou­ lnfluence oftemperature on the germination ofseeds of ble layers of fiIter paper placed in 9.0 cm petri Setaria pallidefusca and Penniseturn pedicellatum. dishes. Filter papers were initially moistened Data in means offive replica/es with 5 mI sterile distiled water. This was repli­ cated five times. Emergenee of radicIe was the Temperature (oC) Germination (%) eriterion for germination. Germination was S. pallidefusca P. pedicellatum counted after 14 days of incubation, and data were subjected toanalysis of variance and me­ 10 0.0 0.0 ans eompared using I;>uncan's Multiple R¡;mge 15 2.5a ll.Oad 20 tests. 18.8bf 41.4b 25 83.8c 78.9c The effeet of depth of sowing on seed ger­ 30 6l.3d 70.1c mination of the two species was determined by 35 48.3e l4.0d sowing 50 seeds in plastic pots filled with heat 40 25.0b 5.3a sterilized top soil at depths of 1, 2, 3,4, 5,6, 7, 45 13.5f 0.0 50 0;0 0.0 8, and 9 cm under five replicates. The pots we­

re subirrigated to minimise soiI crusting and Means within a vertical colurnn followed by thesame letter compacting. The experiment was conducted are not significantly different at P < 0.05. outdoors, where day temperatures were 30- 350C and night temperatures were 24-280C. seedlings ofP. pedicellatum emerged up to a Seedlings were counted and removed as they depth of 7 cm. A distance of 1 cm belóv'"soil emerged for 40 days. There were five replieates surface significantly reduced emergence of each pIanting depth for each grass. (P<0.05)of seedlings in both species. Germination of seeds of the two grass spe­ The twospecies díd well io all Iight condi­ cíes was also tested under different light condi­ tioos,but S. pallídefusca showed only 28.1% tions viz;(l) continuous white light supplied germination under contiouous dark conditioo from four florescent tubes of 40 W each and (Table 3).

maintained at 1.5 m above the seeds;(2) conti­ TABLE2 nuous darkness, and (3) alternating 14-h day­ light and lO-h darkness at night, all at room lnfluence ofsowing depth on germina/ion and emergence temperature (30 ± 2°C). of seeds of Setaria pallidefusca and .Data in means offive replicates

RESULTS Sowing depths (cm) Germination (%) S. pallidefusca P.pedicellalum Seed weight and viability tests: The weight o of 100 seeds ofS. pallidefusca ranged from 113 90.0a 95.2a 1 62.5b 73.5b mg to 115 mg while the same number of seeds 2 6O.1b 52.4c oí P.pedicellatum ranged from 140 mg 10 160 3 52.5b 39.7d mg. Therefore,the average weight of a seed of 4 31.3c 30.Od these grasses was 1.14 mg and 1.5 mg respecti­ 5 17.4d 29.1d 6 0.0 l8.2e vely. Also,. the seeds of the two grass species 7· 0.0 Uf showed highviability: S. pallidéfusca 97% and 8 0.0 0.0 P. pedicellatum 94%. 9 0.0 0.0

Germination and emergence: Although both . . grasses appeared to have optimum germination Means within a vertical column followed by thesame letter are not significantly different at P<0.05 at 250C, the optimum range for P. pedicella­ tum included 300C(Table 1). Below and aboye these teniperatures,germination decreased pro­ DISCUSSION gressively for. both species. Maximum germination and emergence -for The establishm�nt of weed seedlings is con­ both specíes occurred at soil surface aod decli­ tigent not only upon successful production of a ned progressively with depth (Table 2). S. p a­ high number of viable seeds, but on seed ger­ llidefusca did not emerge below 5 cm while mioation. With the high viabilities of 97% and AFOLAYAN& OLUGBAMI: GenninátiooUlclemergence of Poaceae 25

TABLB 3 The trend of germination of the twospecies in different light conditions showedthatthey Injluenceof light 011 seed germiM.lio1l01 peñormed better in alternating day and riight Serariapallidefulca alldPennisetum pedicellatum. , afIS than therest conditioDS. Th� sharp reduction in Datain ffUl olfivereplicates. TemperQtllTea130:f20c �m. ·· germi�tion.per�ntages �ternating day to Lighté

Blejere.E.O. & T.A. OItoko. 1989. SeedproductiClll ,germi­ in louthcm Nigcria. Nigcaan 1. Wccd Sci. 1(2):83- nauClll and emergence of Euphorbia kt,rophyllQ L. 89. NigerianJ. Botany,2:143-147. RusseU,E.W. 1973. Soil oonditions and growth, 10 Hobn,G.L., D.L. Plucknet,J.V. Pancho & J.P. Herberger. cd. Longman,LoodClll. 849p. 1979. A Geograpbica1 Atlas of World's Weeds. Wlley, London.333 p. Shanna, D.M. 1984. Ec:ophysiologica1 studies of ElelUine indica (L.) Gartn. and SporobollU pyrQmidalis P. HuldWuon,J. & J.M. Dalziel. 1972.Flora ofWestTropical Bcauv. alIbadan,Nigcria.J. Rangc Manag. 39(3):275- Afaca.Vol. m. ClOwn Agents,LondClll . 574 p. '1:16.

Ogbonnaya, C.I. 1988. Alpects of thc autccology of ThmbuJI,S.W. 1975.FAOIDANIDA Training oouncin fores!. TridaJt procumbeu, a prcvalcnt wccd of cropland sccd colJec:ti.ClIlhandling. and VoL2 FAO,Romc. 2SO p.