Genetic Analysis and Graphic Analysis of Wheat Dialell Crosses Using Biplot

Obtaining genetic information on how to control traits and becoming aware of the genetic potential of breeding populations is the most important prerequisite for success in cultivar breeding projects. Graphic analysis of the data obtained from the diallel design by means of the (GGE biplot) biplot method allows the breeders to obtain a larger volume of comprehensive genetic information with higher resolution than the conventional methods. The aim of this study was to obtain genetic information and create various breeding materials with high potential in terms of grain yield and its components in bread wheat.

This study started with identifying and collecting 10 bread wheat cultivars with various and complementary characteristics in terms of grain yield and other related and important economic and agronomic traits. The crossing of parental cultivars and the evaluation of the progeny diallel crosses were carried out in 2018 and 2019, respectively. The progenies of the 10×10 full diallel were studied in a randomized complete block design with three replications and examined for grain yield, 1000-seed weight, plant height, spike length, number of seeds per spike and spike weight.

Based on the results of analysis of variance, the mean squares of genotypes were significant for all traits (α≤ 1%), indicating the existence of sufficient diversity among the studied genotypes. Effects of general combining ability for the parents on plant height, spike length, 1000-seed weight and grain yield and effects of specific combining ability for crosses on plant height, spike length, number of seeds per spike and grain yield was significant. Also, the difference of reciprocal crosses was significant for plant height, spike length, number of seeds per spike and 1000-seed weight. The results of bioplot analysis showed that Ehsan had the highest general combining ability among the parents for grain yield, 1000-seed weight, plant height, spike length. Accordingly, the highest specific combining ability for grain yield was observed between Ehsan against both Gonbad and Shoush cultivars. Also, the spesific combining ability of Ehsan in crosses to Kalateh, Barat, Shoush, Sirvan and Gonbad cultivars had the highest value for 1000-seed weight, plant height, spike length and spike weight. The highest narrow sense heritability was observed for spike length however, for plant height, number of seeds per spike, grain yield, 100-seed weight and flag leaf area, the narrow sense heritability was low.

In general, cultivars Ehsan and Gonbad were able to transfer most of the characteristics to their offspring, therefore they can be used in breeding programs to improve grain yield and yield components in bread wheat. Due to the greater importance of the dominance component in control of grain yield and its components, can be used to determine suitable parents for crossbreeding and production of new varieties.