Drought stress occurring during the post-flowering growth stage of sorghum can cause considerable reduction in yield. In order to identify drought tolerant Eritrean sorghum landraces and assess efficiency of drought tolerance indices, twenty five sorghum (Sorghum bicolor L. Moench) accessions were evaluated in split plot design with three replications. Fully irrigated and drought stress treatments were assigned in main plot and the landraces were evaluated in sub plot for drought stress tolerance at post-flowering. Seven tolerance indices including stress tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), stress susceptibility index (SSI), tolerance index (TOL), yield index (YI), and yield stability index (YSI) were estimated for each genotype based on grain yield under drought stress (Y s) and irrigated conditions (Y ir). Significant correlations between Y ir and Y s with GMP, MP, STI and YI were recorded indicating that these indices were good predictors of drought tolerance among genotypes. The other stress tolerance indices namely, TOL, SSI, YSI and YI were not significantly correlated with Y ir and Y s indicating that they were poor predictors of drought tolerance. The study further showed that drought stress reduced the yield of some genotypes while others were tolerant to drought and gave stable yield. Based on the tolerance indices, accessions EG 885, EG 469, EG 481, EG 849, Hamelmalo, EG 836 and EG 711 were identified as superior genotypes for post-flowering drought tolerance that could be used by breeders in further sorghum improvement programs.

Maize (Zea mays L.) is a major commercial crop, with high potential for production due to high solar radiation and low night temperature in sub-Saharan Africa. It is also the second most susceptible to drought among cereals, although phenotypic traits can be altered to improve drought resistance. Pot and field experiments were conducted to study the variability in root and physiological traits in different maturity groups of maize. Genotypes used were Sammaz 14, Sammaz 29, 2009 EVDT, 2009 TZE-W, TZE COMP-5 and 2009 TZEE, laid out in a Randomized Complete Block Design with 3 replications. The results obtained revealed no significant difference among the genotypes. However, the genotypes showed a good response to leaf temperature, canopy temperature, stomatal conductance and chlorophyll content. Variability was observed in three traits; days to anthesis, silking and anthesis silking interval. There was a significant correlation in leaf temperature in relation to fresh root weight, fresh shoot weight, dry shoot weight, dry root weight and shoot length. Root traits had positive relationship with grain yield. The genotypes had good rooting pattern development and combine with their physiological response they could be hybridized to develop drought tolerant varieties.

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