QUANTITATIVE INHERITANCE OF YIELD AND SOME OF ITS CONTRIBUTORY CHARACTERS IN COMMON WHEAT

Abstract

Ten bread wheat varieties Gemmeiza 1, Gemmeiza 3, Sakha 8, Sakha 61, Pvn, Vee"s", Bon, Tsi, KVZ and Shi were used in a diallel cross to study; (i) The potentiality of heterosis expression for yield and its components, heading date and plant height (ii) The magnitude of both general and specific combining ability and their interactions with two nitrogen fertilizer levels, as two different environmental conditions, (iii) The importance which should be given to this materials in a breeding programme by evaluating the ten wheat varieties according to their general combining ability effects. The obtained results can be summarized as follow: 1- Nitrogen fertilizer levels mean squares were found to be highly significant for all traits studied with mean values of the normal nitrogen fertilizer level (L2) being higher than those of the low nitrogen fertilizer level (Lj). 2- Genotypes, parents, and the resultant forty five crosses mean squares were found to be highly significant for all traits studied under investigation at two different nitrogen fertilizer levels and their combined data, indicating overall differences among these populations. 3- Parent Vs. crosses mean squares as an indication to average heterosis overall crosses were found to be highly significant for all traits studied at both low and normal nitrogen fertilizer levels and their combined data except fertility at the normal fertilizer level (L2) and combined data.