Modified Method for the Analysis of Genotype by Trait (Gt) Biplot as a Selection Criterion in Wheat under Water Stress Conditions

IN Egypt, water deficits have dramatically increased in recent years due to over-exploitation ofthis resource and other challenges. That restricts reduce or decrease its ability to accomplish economic development goals. The present investigation was conducted at Sakha Agricultural Research Station to assess the genetic behavior of 18 bread wheat genotypes during the two growing seasons of 2015/2016 and 2016/2017 under normal and water stress conditions. The experimental design was a randomized complete block design with three replicates. Results showed large values of broad-sense heritability (hb2) which coupled with high values of genetic advance as a percentage of the mean (GA %) at 10% selection intensity for grain filling rate (93% and 19.91%) and chlorophyll b (82% and 22.22%) in the normal condition, respectively. Regarding the water stress condition, the grain yield (89% and 18.74%) and 1000-grain weight (87% and 17.62%) and proline (93% and 27.87%) recorded the highest values of h_b^2 and GA%, respectively. Genotypes G18, G17, G4, and G13 were the best tolerant under water stress condition and considered as promising genotype in breeding programs according to a genotype by yield*trait (GYT) biplot graph. On the other hand, G12, G8, and G16 were identified as sensitive genotypes. Undoubtedly, GY*T biplot graph is preferred because of it easy to interpret and more informative to identify more accurate selection criteria using grain yield and its attributes.