Genetic diversity, correlation and genotype × yield × trait (GYT) analysis of grain yield and nutritional quality traits in sorghum (Sorghum bicolor [L.] Moench) genotypes in Tigray, northern Ethiopia

Selecting sorghum genotypes with higher grain yield and nutritional quality is essential to tackle food insecurity and malnutrition in arid and semi-arid areas. Therefore, this study aimed to determine the genetic diversity, trait association and genotype by yield by trait (GYT) analysis and to select superior sorghum genotypes. One hundred and ten sorghum genotypes were evaluated at three locations in Tigray during the 2018 and 2019 growing seasons using alpha lattice design. Traits such as grain yield, protein content, ash content, starch content, zinc content, iron content, calcium content and magnesium content were profiled. Results showed that wide range and highly significant (p < 0.001) genotype mean performance in each environment as well as combined environments. Several highly performing genotypes were distinguished for each trait studied that could be exploited as breeding parents or direct use. This study further detected highly significant variation (p < 0.001) among the test genotypes for all the traits studied in individual environments and across environments suggesting the presence of sufficient genetic diversity for selection. The high broad-sense heritability (H2 > 0.9) in all individual environments and moderate to high (H2 > 0.0.41 < 0.82) in pooled environments recorded in the present study assured the possibility of effective selection among the genotypes. Besides, strong positive and negative associations were detected between some of the traits in individual and across environments. The significant positive association between traits indicates that both the traits can be improved concurrently through direct selection. Using the GYT analysis, we suggest ten promising sorghum genotypes for direct use or breeding programs in arid and semi-arid areas in general and in Tigray in particular.