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Assessing agro-morphological variation is important for crop improvement strategies in cultivated species. Bambara groundnut (Vigna subterranea(L.) Verdc.) is a neglected crop that requires extensive agro-morphological characterisation to design suitable agronomic and crop improvement strategies. Nineteen Bambara groundnut lines were evaluated at two sites for agro-morphological traits in 2017 and 2018. The experiments were laid out as a split-split plot completely randomised design with three replications. The lines showed significant differences (p < 0.05) for all the traits except chlorophyll content and stomatal conductance. The observed genotypic differences would be useful for Bambara groundnut improvement if they are underpinned by genetic differences for recombination. Principal components 1 and 2 accounted for 52.31% of the variation showing that agro-morphological traits alone could not adequately discriminate between the Bambara groundnut lines. The most useful traits were root and shoot mass, plant height and leaf number. The negative and unfavourable correlations between seedling emergency and chlorophyll would complicate simultaneous selection for these traits during Bambara groundnut improvement. However, genetic dissimilarity indices indicated that there was genetic variation within the germplasm, which is important for Bambara groundnut improvement. Lines Kenya Capstone, Uniswa-Red-G, Uniswa-Red-R and KANO2 were selected for breeding and recommended for production due to their high performance in several key traits.

Combining ability effects for yield related traits can serve as selection criteria to pursue breeding for optimal biomass allocation in wheat (Triticum aestivum). The objective of this paper is to provide information based on a retrospective quantitative genetic analysis on combining ability studies of wheat for yield and yield‐related traits to predict potential genetic gains achievable in improving biomass allocation for drought tolerance and soil carbon storage. The study compares data on the general combining ability and specific combining ability effects of wheat for yield and related traits under optimum and drought stressed conditions from 40 studies around the world. Days to heading (DTH), plant height (PH), number of tillers per plant (TN), kernels per spike (KPS), 1,000‐kernel weight (TKW), shoot biomass (SB), and grain yield (GY) exhibited wide variation for general combining ability (GCA) and specific combining ability effects. Progeny performance increased by 14.30 and 4.04% for SB and GY, respectively, compared with parental values under optimum water conditions. Number of tillers and SB exhibited positive associations with GY (.45 ≤ r≤ .85, p< .05) under both water conditions. Meta effect sizes for drought stress were negative. The highest meta‐effect sizes were calculated for DTH (−4.5) followed by SB (−2.0), whereas KPS (−1.25) had the lowest. The genetic gains for PH, SB, and other yield components showed that divergent crosses involving complementary parents could enhance biomass allocation patterns in wheat. This could be used as a basis for improving biomass allocation to roots. There is sufficient genetic variation in wheat genotypes for manipulating biomass allocation.The number of kernels per spike is stable under varying moisture conditions.Shoot biomass and grain yield expression are severely confounded by drought.Aboveground traits are important for indirect selection of root traits.

Pigeonpea Cajanus cajan(L.) Millsp. is the most important legume cash crop grown in Malawi. However, productivity is low due to biotic and abiotic stresses and socioeconomic constraints. The objectives of this study were to determine farmers’ perceived constraints to pigeonpea production and to identify the varieties and traits preferred by farmers in Malawi. A participatory rural appraisal was conducted in four major pigeonpea growing districts (viz. Chiradzulu, Mulanje, Thyolo and Zomba) in Malawi. Data were collected using a semi-structured questionnaire, focus group discussions and transect walks. ‘Mthawajuni’ was the most preferred variety grown by 45% of the respondents, due to its palatability and resistance to pod borers. The farmers identified insects, diseases, late-maturing varieties and small land holdings as the most important constraints to pigeonpea production in Malawi. Short cooking time, palatability, high yield, early maturity, long shelf-life, pest and disease resistance, large seeds and cream colour were the most preferred traits of the pigeonpea. The constraints experienced by farmers and their preferences for the identified traits should be considered as selection criteria during the breeding of new pigeonpea varieties in Malawi.

Drought is a major cause of reduced yields in dryland wheat production. This study aimed to determine the combining ability effects of selected bread wheat genotypes (Triticum aestivumL.) for yield and yield-related traits. Eight parental lines were selected and crossed using a half-diallel mating design. The parents and 28 crosses were evaluated at two sites in Ethiopia, representing drought-stressed and non-stressed conditions, using a 6 x 6 simple lattice design. The parental line ETW17302 was the best general combiner for the growth indices: days to heading, days to maturity, grain-filling period, and 1 000-kernel weight, thereby enabling direct selection for improved grain yield under a drought-stressed condition. Parent ETW17377 could also be used for improving grain yield under a drought-stress condition owing to its positive and significant general combining ability effect on grain yield. The families ETW17302 × ETW17377, ETW17396 × ETW17374, and ETW17396 × ETW17385 were the best specific combiners for improving grain yield under the drought-stressed condition. The selected parents and families are desirable genetic resources to enhance yield and yield-related traits under both drought-stressed and non-stressed conditions.

Systematic genetic profiling of the genetic pool is fundamental to select desirable parents for conventional and genomic-assisted breeding. The objective of this study was to assess genetic variation and population structure in a diverse population of sorghum (Sorghum bicolor(L.) Moench) accessions collected from various regions of Ethiopia. Using single nucleotide polymorphism (SNP) markers, potential breeding parents were then selected. In all, 342 sorghum accessions were genotyped using diversity array technology sequence-derived 5060 SNPs with > 5% minor allele frequency. Population structure, clustering, PCA, and analysis of molecular variance (AMOVA) were conducted to deduce variability within the germplasm. The AMOVA results revealed a higher percentage (58.8%) of variation among the populations followed by variation within accessions (40.4%). Polymorphic information content (PIC) values ranged from 0.184 for accessions collected from the Somali to 0.260 for the Oromia and Southern Nations, Nationalities, and Peoples (SNNP) regions. Higher genetic variation was detected among sorghum collections from Oromia followed by those of the SNNP region. The selected SNP markers were the most powerful in discriminating the tested sorghum accessions. Population structure analysis revealed the presence of two main distinct genetic clusters in which accessions were grouped based on area of collection. The present findings indicated abundant genetic variability among Ethiopian sorghum accessions, confirming that they will be useful for breeding, germplasm conservation and genomic selection.

Correlation and path coefficient analyses of economic traits is important in identifying traits that can be used to simplify selection of complex traits such as grain yield. The aim of this study was to determine the degree of association between yield and yield components of drought-tolerant wheat populations using correlation and path analyses. Twelve selected parents and 66 of their F3families were evaluated under drought-stressed and non-stressed conditions in two sites using a 6 × 13 alpha-lattice design with two replications. Partitioning of correlation coefficients into direct and indirect effects revealed strong positive direct effects of kernels per spike and fresh biomass on grain yield under the drought-stressed condition. Among the assessed traits, fresh biomass had high significant simple correlation coefficients of 0.75 and 0.90, and strong direct effects of 0.76 and 0.98 with grain yield under drought-stressed and non-stressed conditions, respectively. The high-yielding genotypes, LM02 × LM05, LM02 × LM23 and LM13 × LM45, showed high mean values for kernels per spike, thousand-kernel weight and fresh biomass. The overall association analyses indicated that the latter three traits had significant influence on grain yield performance and are useful for selection of drought-tolerant breeding populations of wheat.

Narrow genetic variation limits the success of crop improvement programs. Mutagenesis using ethyl methane- sulphonate (EMS) provides an opportunity to increase genetic variation to enhance selection in wheat improvement. This study aimed at establishing the optimum dosage and treatment conditions for EMS to induce genetic variation for drought tolerance and enhanced carbon sequestration in wheat. Seeds of three genotypes (LM29, LM43 and LM75) were treated with four EMS dosages (0, 0.1, 0.4 and 0.7% v/v) at three temperatures (25, 30 and 35 °C) for three exposure periods (1, 1.5 and 2 h) using three replicates. The ideal treatment conditions for effective mutagenesis were 0.7% EMS for 2 h at 35 °C for genotypes LM29 and LM43 and 0.4% EMS for 2 h at 25 °C for LM75. The estimated EMS dosages for LM43, LM29 and LM75 were 0.32%, 1.07% and 1.81% v/v EMS, respectively. This information can be used for large-scale mutation induction, exploration of new genetic variation, evaluation for genetic improvement and selection of mutant individuals for drought tolerance, high root–shoot biomass and carbon sequestration.