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Abstract The present investigation was carried out through the five successive seasons 1988/1989, 1989/1990, 1990/ 1991, 1991/ 1992 and / 1993 to investigate the following pointsii)crossabi1ity of wheat with rye, ii)To Synthesize pri_ry triticale, iii)to study the cbrODOSoaal instability of the studied _terials and, iv)to evaluate the studied .aterials on the basis of c-banding teeJmique. The materials used for this study were 11 hexaploid wheat varieties ,4 tetraploid durumwheat varieties, and 2 diploid rye varieties. Plants weregrownandcrossed underfield conditions- For each cross coabination. the nuaber of florets pollinated and seed set was recorded 18 days post pollination . The developed seeds were reooovedand...myos were rescued and culture on artificialJaedia to produce haploid plants, then treated with 0.05’& colchicine + 1.5’& DMSO for 5 hours.The obtained results could be summarizedas follows: I) crossabi1ity of 1Ibeat vi1:b rye : Wheatvarieties exhibit significant differences with respect to their crossability’ with rye, furtberaore the salle wheat variety shOWS different crossability percentages with the s8Ji8rye variety. seed set for hexaploid wheatvarieties rangedfro. 2-3t to 15t in the case of rye Prolific whereas it ranged froa 1.6’& to 11.1’& for rye ~rial. The variety Giza 163 displays the highest seed set with both rye varieties i.e. 15\ with pcolific and 11.1\ with ~rial. lIhi.lethe variety sakba 69 gave the lowest seed setpercentage with both rye varieties i.e. 2.3% with prolific and 1.6% with Imperial. Tetraploid wheat varieties show lower seed set percentage than the hexaploid wheat varieties. Seed set percentages ranged from 2% to %.3% for rye prolific and fro. 1.2% to 6% with rye Imperial • The variety Suhag 1 exhibits the highest seed set percentage 6% with rye Imperial, since the variety Beni-suief 1 showS the lowest seed set percentage 1.2% with rye IJDperial. These data indicate that the genotype of the variety Giza 163 could be KrlKr1kr2kr2 whereas the rest of wheat genotypes could be KrlKr1Kr2Kr2 II) Dle synt:beBisof prJ.a1Y tritica1e : it has been observed that ,there is a wide variation in number of seeds having well-differentiated embryos. The cross suhag 1 X prolific displays the lowest percentage 30%, while the cross Suhag 3 X Iaperial shows the highest percentage 59%. with respect to haploid plants, the different crosses show clear differences in percentage of resulted haploid plants. These percentages ranged frOll 53% to 71%. sinlarly , the different crosses exhibit clear differences in their response to colchicine treataent, the percentages of successfully doubled plants ranged fro. 50% to 80% .The crosses ,also, show different ntmbers of hybrid seeds or obtained fro_ doubled plants, the cross Beni -suief 1 X I.perial exhibits the highest seed nu.ber ,11.5 seeds/plant. on the other hand , the cross Suhag 3 X prolific gave the lowest nuaber 4.5 seeds/plant.XXX)-au:c.-~1 inStabi1ity : i) Mitotic instability : Thedifferent crosses display different degrees of cbro instability as .”.pressed bY the percentage of aneuploids. TheSe percentages ranqed frOll 17’1;to 31.7’1;. the ••••jority of these plants ...,re hypoplOids.(2,.”.40.41.41 +telo. ) • Theoverall - of aneuploidS ••as 21’1; • In the salle ti- the c~l stability expressed by euploid plants .it ranqed fr<Dl69.4’1; to 83’1; in the crOSses Suhag 1 X~rial and Suhag 2 X I~ial. respectivelY ii) Meiosis abnormalitieS : number of cells having univalents• lagqing chrOJlOSOI•l8S cbrQllatid bridges. and .icronuclei ...,re recorded· There are. alSo. condensation probl-. _inly sickness occurred at high freqUencies ••ith varYinq intensities in triticale _terials • These freqUencies ranged from 21.5% to 35.3%. Thepercentages of cellS having univalents ••ere exu-ly lin the parental_tsrials and c<mIlOnin triticale _terialS.siJdlarly • the occurrenc” of la<J9inqc)lr<mOsowoaensd chr<mBtid bridges ••as very 1- in the parental aater ialS • since it ••as on in triticale aaterials. Also the frequencies of abnoraahaving -.icronuclei) ...,re very 1- in the parental aaterials • >lhereasthey ...,re very =-’” in triticale aaterialS • XV)- e-tJaIM’i ag t:;eebnique : Thepresent teebJlique enables to identifying easily different cbrOaosoae& in different genoae& • In general. rye ~.as _ large tel.-r99 andweat chrOllOsoaeshave centroaeric (interstitial) heterochro-- tin bands. Although, there are somevariations in banding pattern of the two chroaosQJl88 belonged to the salle pair, particularly in rye varieties. Ho_jar differences in c-baDdingpatterns could·be observed betweentetraploid wheat varieties,Suha9 1 and Beni-suief 1. In general, The seven pairs of rye chrOmosomes were present in all triticale lines and accurately distinguished. |