Twenty-five common bean genotypes were evaluated to assess the genetic variability, trait association, and determine the direct and indirect effects of traits on seed yield. The genotypes were grown in a lattice design at the research farm of the Melkassa Agricultural Research Center, Melkassa and Miesso, in the 2018 cropping season. Analysis of variance revealed that significant differences were observed among the genotypes at individual locations. The phenotypic coefficient of variation values were moderate for number of nodes, seeds per pod, plant height, and hundred seed weight at Melkassa. Moderate genotypic coefficient of variation values were obtained for pods per plant and seeds per pod. At Miesso, moderate phenotypic coefficients of variation values were recorded for number of nodes, hundred seed weight, and plant height. High heritability estimates were obtained for seed yield and hundred seed weight at Melkassa and for seed yield at Miesso, indicating that selection could be fairly easy and improvement is possible using these traits in a common bean breeding program. High genetic advances were obtained for seed yield and pods per plant at Melkassa, while moderate genetic advances as a percent of the mean were attained for plant height, hundred seed weight, and seeds per pod. Similarly, at Miesso, high and moderate genetic advances as percent of mean values were obtained for seed yield and hundred seed weight, respectively. Seed yield showed positive and significant phenotypic association with days to flowering, internode length, and pods per plant at Melkassa and had positive and significant phenotypic association with seeds per pod and hundred seed weight at Miesso. Hence, selection of those genotypes based on the traits with high genotypic coefficient of variability, heritability, genetic advance, and positive correlation coefficient and direct effect on seed yield can be recommended for further yield improvement at the respective location and at the national level in general.

Nitrogen stress is one of the key factors limiting sorghum crop productivity. To identify desirable sorghum genotypes best suited to nitrogen stress, the response of 300 sorghum landraces and two standard checks: KS78, and BCK60 were evaluated using yield-based indices. The experiment was conducted under nitrogen stress and ideal conditions for two years using a split-plot in RCBD design with two replications. Nitrogen treatments were assigned to the main plots, and sorghum genotypes were assigned to the subplots. Fourteen nitrogen stress screening indices, namely, the yield stability index (YSI), stress tolerance index (STI), modified stress tolerance index (KSTI), low nitrogen tolerance index (LNTI), relative decrease in yield (RDY), tolerance index (TOL), yield index (YI), stress susceptibility index (SSI), stress susceptibility percentage index (SSPI), and harmonic mean (HM), were computed using grain yield. The yield under optimal and stress conditions was significantly positively correlated with the HM, MP, GMP, STI, HM, YI, and modified STI. The results from the cluster analysis, PCA biplot, and 3D biplot classified the genotypes into three groups: nitrogen stress tolerant, nitrogen stress susceptible, and poor performers under both environments. Using STI, GMP, and MP, Genotypes (G80) ETSL101255, (G216) ETSL101006, (G35) ETSL101258, (G146) ETSL100813, and genotypes (G244) ETSL100292, (G161) ETSL100539, (G240) ETSL100890, (G93) ETSL101845, (G261) ETSL100625, (G248) ETSL100874, (G258) ETSL100752, (G142) ETSL100921, (G135) ETSL100307 were identified as top nitrogen stress tolerant, and susceptible genotypes respectively. We conclude that the indices MP, GMP, and STI can help in improving sorghum yield by selecting nitrogen efficient genotypes.