Tetraploid wheat species from Ethiopia hold ample genetic variation, which could provide a source for improvement of wheat. A total of 196 Ethiopian tetraploid wheat (Triticum turgidum spp.) accessions, including 174 landraces and 22 improved cultivars, were evaluated at Sinana and Debrezeit to assess morphological variation, genetic advance, heritability and correlation based on 11 phenotypic traits. Except for spike length, highly significant variation (P < 0.001) among genotypes for all traits was observed. The observed mean and range values of the phenotypic traits revealed high variability in the accessions. Phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) values were high for grain yield, biomass yield and harvest index. Seed yield showed highly significant (P < 0.001) negative correlation with days to booting and days to maturity and positive correlation with all traits. The estimates of heritability (H2) for grain yield and the number of spikelets per spike respectively ranged from 41.78 to 84.62%. The genetic advance as a percentage of mean was low for the number of seeds per spikelet, days to booting and days to maturity; intermediate for plant height, thousand kernel weight and spike length and high for the number of spikelets per spike, the number of effective tillers per plant, grain yield, biomass yield and harvest index, respectively. The number of spikelets per spike gave a high value of genetic advance and heritability implying high genetic gain from its selection.

In coffee breeding, selection of mother plants based on the yield potential, resistance to diseases and pest and bean quality are considered as the important criteria. Hence, utilisation and evaluation of coffee germplasm is the crucial step in the improvement process. With this background, an experiment was conducted to study the genetic diversity of 41 Arabica coffee genotypes in India during 2020–2021 and 2021–2022. Study reveals that, the analysis of variance revealed significant differences among the genotypes for all the characters studied indicating the presence of variability. Relatively higher values for GCV were observed for number of secondaries per primary (29.77 and 24.84%), total nodes per primary (30.07 and 26.62%), bearing nodes per primary (35.72 and 29.03%), number of flower buds per primary (40.79 and 33.68%), number of fruits per primary (49.64 and 36.39%) and per cent ‘A’ grade bean (37.47 and 37.83%) than PCV indicating the influence of environmental variations is less and prevalence of additive gene action. Similarly, high magnitude of heritability (>80%) combined with a strong genetic advance as per cent of mean (>20%) was established for most of the growth and yield attributing traits including caffeine content and per cent ‘A’ grade bean (100%) during both the years of study 2020–2021 and 2021–2022, respectively indicated better scope for genetic improvement in these character through simple selection. The variability observed among the genotypes should be further confirmed by using the molecular markers.

Nested association mapping (NAM) captures the best features of both linkage and association mapping and enables the high power and high resolution of quantitative trait locus mapping through joint linkage-association analysis. In the current study, NAM population was developed by hybridizing JS 335, a popular variety of central India with 20 diverse soybean genotypes. The parents used in the study have various traits of economic importance such as drought and water-logging tolerance, bacterial pustule and yellow mosaic virus resistance, wider adaptability, resistance to mechanical damage and higher yield potential. High variability in the F2 populations of 20 crosses for grain yield and days to maturity indicated scope for development of high-yielding varieties. Genetic variability studies, correlation, regression, principal component analysis (PCA) and genetic diversity analyses were carried out in 900 NAM-recombinant inbred lines (RILs) derived from 11 crosses. Correlation and regression analysis indicated a significant positive effect of biomass, pods/plant, harvest index, branches/plant, nodes/plant and plant height on grain yield. Genetic diversity analysis grouped 900 NAM-RILs into 10 clusters. PCA revealed first two principal components to explain 63.78% of total variation mostly contributed by grain yield, biomass and number of pods. The inbred lines developed in this study will serve as an elite soybean genetic resource in understanding the genetic architecture underlying different traits of economic significance.

Genetic variation of resistance and tolerance to stem-borer, Chilo partellus, was studied in three sorghum crosses. Parents, F1 and F2 progenies were evaluated for per cent foliar damage and stem tunnelling as a measure of resistance or susceptibility. The parental cultivars involved in the crosses represented a fairly distinct range of character expression for plant height, foliar damage, stem tunnelling, stem lodging and grain yield. Means, degrees of dominance in F1 and inbreeding depression in F2 suggested that susceptibility was dominant over resistance in crosses susceptible x resistant and susceptible × tolerant, while resistance was dominant over susceptibility in the cross tolerant × resistant. The variation patterns of foliar damage and stem tunnelling in parents, F1 and F2 progenies suggested that they are different and are independently inherited. Both resistance and tolerance mechanisms are operating in sorghum resistance to stem-borers and these mechanisms are independently inherited. Estimates of heritability (broad-sense), genetic coefficient of variation and expected genetic advance, indicated that the cross Serena (tolerant) x IS 2146 (resistant) provides maximum chances of selecting resistant and tolerant plants in the segregating populations. Recurrent selection (population breeding) is suggested to improve the level of stem-borer resistance and tolerance and yield in sorghum.