الفهرس 
Experimental proceduresOnly 14 pages are availabe for public view
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Abstract
The present investigat;’,m was carried out t o study I) the genetic variability among nine corn populations designated as PISo and F2S0 generations of one d i a l l e l crosses and the f i r s t generation of ’mother d i a l l e l cross of their E1 lines derived from the previous populations which designated as PISI, 2), heterosis importance for grain yield and some other t r a i t s , 3), general and specifi c combining a b i l i t i e s f o r the varieties and their different d i a l l e l crosses t o derive the most suitable breeding procedure f o r the production of synthetic varieties of high yielding ability, the Scheme field working and s t a t i s t i c a l procedures were conducted as follow : I- The varieties under study consisted of American Early Dent (A,E,D,), Giza Baladi, Comp, 108, Comp. 105, Comp. I13 , Tep-5, Shedwan-3, Syn-Kital and S3m-La Posta, . me checks were included t h i s study, double cross 19 and double cross 355. 2- Diallel crosses were carried out among the nine varieties (SO) in the early sumner of 1974. 3- The FISO crosses were planted in the early summer of 1975 t o obtain the F2S0 crosses. 4- Nine lines derived from the nine varieties in (1974) and were crossed in a l l possible combinations t o get the F1 pnerction which rsff cred as FISI(in the early summer of 1975) 5- During 1976 growing season, the three genotypcs l?ISO, F2S0 and PISI were tested in tkree separate experiments at two locations Gemmiza (LI) and Sakha (L2) Agriculture Research Stations, each experiment contained 36 varietal crosses in addition t o the nine varieties aria the two checks, the experiments l a i d out in a rmdomized complete block design with four replications. 6- The data were taken on grain yield (grns/plnnt), silking date-number of days from planting , ear height, number of rows per ear, number of kernels per row 2nd weight of 100 kernels. 7- The analysis of variance f o r the six experiments f o r the three genotype groups and the combined data were calculated according to Snedicor and Cochran 1967, 8- Average heterosis was calculated relative t o the midparent, high parent and constant parent. 9- The variations among crosses were further partitioned into the general and specific combining ability components according to G r i f f ingg s model (I) method (4), (19561, f o r the three genotype groups.