GENETIC VARIABILITY AND DIVERSITY ANALYSIS FOR YIELD AND ITS ATTRIBUTES IN F2 GENERATIONS OF WHEAT (Triticum aestivum L.) UNDER STRESS CONDITIONS
SULTAN F. ALSHARARI
Department of Biology, Faculty of Science and Humanities, Quwayiyah, Shaqra University, Saudi Arabia
SALAH A. OKASHA *
Department of Agronomy, Faculty of Agriculture, Suez Canal University, Egypt
*Author to whom correspondence should be addressed.
Abstract
During winter 2018/19 season, 15 wheat genotypes, including five parents and 10 F2 crosses, were cultivated on the field conditions at two sites and chosen sites reflecting the contrast of soil and salinity. Analysis of variance depicted that the genotypes and salinity stress showed a significant difference for all the studied traits. The interaction between genotypes × salinity showed a significant difference for number of effective tillers/plant, plant height, number of grain/spike, grain yield/m2, Na+, K+, and their ratio. Increased salinity levels caused the mean value of all traits to be decreased. The coefficient of correlation has been divided into phenotypic and genotypic correlation coefficients with 9 traits showed highly associated among themselves and with grain yield under both conditions. Genotypic path coefficient values of all the traits with grain yield/m2 under salinity stress conditions had a direct positive effect on grain yield/m2 exhibited by the number of grains/spike, number of spikes/m2, 1000- grain weight, number of spikelets/spike, spike length and SPAD read. For all traits in both conditions, the scope of the phenotypic variation coefficient was higher than the genotypic variation coefficient (GVC). Under salinity stress conditions, heritability ranged from 11.71% for days to 50% heading to 89.17% for the number of grain/spike and is considered the only trait with high heritability.
Keywords: Wheat, F2 population, heritability, phenotypic variance, grain yield, path analysis.