GENETIC ANALYSIS OF GRAIN YIELD AND SOME of ITS COMPONENTS IN PARTIAL DIALLEL CROSSES OF BREAD WHEAT GENOTYPES

Ahmad H.A.Anees* Khalid M.D.Al-Zubaidy** Dawood S.M.Al-Ubaidy*Saddam I.Y.Al-Ubaidy**

Abstract

The partial diallel cross was used among nine genotypes of bread wheat, eight of which were introduced from ICARDA. They were selected using pedigree method from breeding program by hybridization, and symbolized as: J12, J19, J6, J14, J15, J17, J3 and J8, in addition to the locally adopted cultivar Cham 6, and using samples of four hybrids for each genotype and then 18 single hybrids obtained. Paternal genotypes and their partial diallel hybrids were planted during the 2012-2013 agricultural season at the Field Crops Research Station of the College of Agriculture at Tikrit University using the randomized complete block design with three replicates to study the general combining ability, heterosis and nature of gene action in parents and hybrids population for traits: the date of the spikes expulsion, plant height, number of spikes per plant, flag leaf area, spike length, number of grains per spike, 1000 grain weight and grain yield per plant. The results of the analysis of variance showed that the mean square of all genotypes, parents, crosses and general and specific combining abilities was significant for all traits except that's which it relates to specific combining ability for plant height which did not reach the significance, that is an indication of the existence of additive and non additive genetic effects controls the inheritance of these traits. The importance of the components of the variance indicated that the additive genetic effects were more obvious for the traits plant height, number of spikes per plant, flag leaf area, number of grains per spike and 1000 grain weight, whereas the dominance genetic effects were more important for the other traits. The two parental genotypes J14 and J17 characterized by desirable significant general combining ability for the largest number of traits, including the grain yield per plant, and the hybrids (J19 x J17), (J14 x J3), (J17 x Sham 6) and (J14 x Sham 6) with high mean performance and desirable significant heterosis for grain yield per plant and some of its other components and can be used in the development of high productivity hybrid varieties as well as to exploit the phenomenon of heterosis. The narrow sense heritability ranged between 32.08% for plant height and 75.25% for the number of grains per spike. It was moderate for the date of the spikes expulsion, plant height and spike length and high for the other qualities.

Key words

GENETIC ANALYSIS OF GRAIN YIELD AND SOME of ITS COMPONENTS IN PARTIAL DIALLEL CROSSES OF BREAD WHEAT GENOTYPES