Graphic Analysis of Trait Relations and Genotype Evaluation in Durum Wheat
Trait profiles of genotypes and trait relations are frequently influenced by unpredictable conditions in the Mediterranean rainfed regions. Thus, genotype selection should be based on multiple traits in variable environments within the target region. This study was conducted to (i) examine the performance of 13 durum (Triticum turgidum L. var. durum Desf.) genotypes (11 breeding lines and two checks) and one bread wheat (Triticum aestivum L.) genotype on the basis of multiple traits, including grain yield and (ii) determine the effects of different growing environments on trait relations and broad-sense heritability (h2 BS) of various traits. The genotype-by-trait (GT) biplot analysis was applied to data from the 14 genotypes grown under drought and irrigated conditions for two years. Combined ANOVA showed that the main effects relative to year, location, genotype and their interactions were significant for most of the studied traits. Year-wise and combined GT-biplots indicated that the relationships among the studied traits were not consistent across environments, but they facilitated visual genotype comparisons and selection in each environment. Grain yield, in contrast to other traits, consistently showed wide variation across environments. The genotypes with high grain yield appeared to have high biomass, high harvest index, low grain weight and intermediate time to flowering and maturity. The genotypes with higher grain weight flowered and matured earlier. The estimates of h2 BS from single- and multi-environment trials varied from one environment to another and from trait to trait. The GT biplot was a useful tool for exploring multiple trait data, trait profiles of the genotypes and can help in determination of contrasting genotypes based on the trait(s) for improving genetic materials in durum wheat breeding program.