Genetic variability and identification of potential drought-tolerant Burkina Faso sweet grain sorghum genotypes at the post-flowering stage using morphoagrophysiological traits

Abstract

Sweet grain sorghum is mainly grown in Burkina Faso for consumption of its sweet grain at the pasty grain stage. This orphan crop productivity is strongly limited when Drought occurs post-flowering. Since stay-green is one of the key parameters determining the adaptation of Sorghum to this abiotic stress, this study was initiated to identify potential drought-tolerant sweet grain sorghum genotypes based on stay-green traits. Alpha lattice experimental design, replicated three times, was used to evaluate 50 sweet grain sorghum genotypes and 04 stay green controls using 25 agromorphophysiological traits. The descriptive analysis showed significant variability among sweet grain sorghum genotypes. A strong positive correlation was observed between stay green traits, the number of green leaves at the pasty grain stage and the percentage of green leaves retained (0.91). Each of these traits is positively correlated with stem diameter and negatively with the number of internodes, tillering traits, lodging and plant height. The sorghum genotypes are organized into four different genetic pools, of which group I contains two (02) stay green controls (B35, E36-1) and two (02) sweet grain sorghum genotypes (PBO4, YOH8), and group II, the two (02) others stay green controls (ICSV1460024, Soubatimi) and one (01) sweet grain sorghum genotype (SBR5). The sweet grain sorghum genotype SBR5 showed high stay green performance, as did the two best controls. The three potential drought-tolerant sweet grain genotypes identified could be exploited in the sweet sorghum breeding program.