Effects of plant densities on the performance of common bean varieties in multiple environments of northwestern Tanzania

A study was carried out at two sites in Tanzania to assess the effect of different planting densities on growth and yield of five recently released bush bean varieties. The experiment was laid out in a split-plot design in a factorial arrangement with three replications during long and short rainy seasons of 2019/20 and 2020/21. The treatments comprised five bean varieties; TARIBEAN 1, 2, 3, 4 and 5 and five plant population densities; 200000, 222222, 250000, 266666 and 333333 plants/ha. Variables evaluated were plant height, angular leaf spot and common bacterial blight disease scores in leaves, number of pods per plant, number of seeds per pod, hundred seed weight and grain yield. The variables were subjected to ANOVA and means of statistically significant variables to plant density, variety, and environment were analyzed by Tukey HSD test and “which-won-where” view of the GGE biplot. The interaction of factors only affected significantly plant height and yield. Highest grain yield of 1,353 and 1,607 kg/ha were recorded by plant density of 200,000 plants/ha and TARIBEAN 1 variety at Maruku site during short rainy seasons (E2). Therefore, a plant density of 200,000 plants/ha and TARIBEAN 1 variety are recommended in all four environments

Gain and performance in yield and micronutrient concentration in common bean improvement

Common bean (Phaseolus vulgaris L.) is a staple and nutritious leguminous food crop for all income categories in Africa. Efforts to improve its yield performance and nutritional components, especially Iron and zinc have resulted in the release of several varieties in the sub-Saharan African region. The objective of this study was to assess genetic progress in varieties released in 12 African countries through the Pan African Bean Research Alliance (PABRA) from 1973 to 2017, to inform current breeding decisions. A total of 214 released varieties, land races and breeding lines, of bush and climbing beans were evaluated for yield, micronutrient (Fe and Zn) concentration, and phenology in three locations (Kawanda and Kachwekano in Uganda, and Kitengule in Tanzania) in 2017–2018. There were significant differences (P 0.01) among genotypes for all traits except days to maturity (DPM). Genotype x environment interaction was also significant (P<0.05) for all assessed traits, except for iron in climbing beans. Across environments, repeatability (H2) was greater than 0.50 for all traits, except for DPM in climbing beans. Annual rates of genetic yield gains were 4.41 and 4.57 kg ha-1 for large and small seed bush beans, and -2.74 and 21.6 kg ha-1 for large and small seeded climbers. Similarly, gains in seed iron (FESEED) were 0.40 and 0.17 ppm for bush and climbing beans, respectively. These represented an annual relative gain over the oldest varieties of 0.6 and 0.7% kg ha-1 for yield of large and small seeded bush beans, -0.3 and 1.6% kg ha-1 for yield of large and small seeded climbers, 0.6 and 0.2% ppm for FESEED of bush and climbers. Overall, genetic progress was slow for both yield and FESEED

Multivariate genomic analysis and optimal contributions selection predicts high genetic gains in cooking time, iron, zinc, and grain yield in common beans in East Africa

Common bean (Phaseolus vulgaris L.) is important in African diets for protein, iron (Fe), and zinc (Zn), but traditional cultivars have long cooking time (CKT), which increases the time, energy, and health costs of cooking. Genomic selection was used to predict genomic estimated breeding values (GEBV) for grain yield (GY), CKT, Fe, and Zn in an African bean panel of 358 genotypes in a two-stage analysis. In Stage 1, best linear unbiased estimates (BLUE) for each trait were obtained from 898 genotypes across 33 field trials in East Africa. In Stage 2, BLUE in a training population of 141 genotypes were used in a multivariate genomic analysis with genome-wide single nucleotide polymorphism data from the African bean panel. Moderate to high genomic heritability was found for GY (0.45 ± 0.10), CKT (0.50 ± 0.15), Fe (0.57 ± 0.12), and Zn (0.61 ± 0.13). There were significant favorable genetic correlations between Fe and Zn (0.91 ± 0.06), GY and Fe (0.66 ± 0.17), GY and Zn (0.44 ± 0.19), CKT and Fe (−0.57 ± 0.21), and CKT and Zn (−0.67 ± 0.20). Optimal contributions selection (OCS), based on economic index of weighted GEBV for each trait, was used to design crossing within four market groups relevant to East Africa. Progeny were predicted by OCS to increase in mean GY by 12.4%, decrease in mean CKT by 9.3%, and increase in mean Fe and Zn content by 6.9 and 4.6%, respectively, with low achieved coancestry of 0.032. Genomic selection with OCS will accelerate breeding of high-yielding, biofortified, and rapid cooking African common bean cultivars

Improving association studies and genomic predictions for climbing beans with data from bush bean populations

Common bean (Phaseolus vulgaris L.) has two major origins of domestication, Andean and Mesoamerican, which contribute to the high diversity of growth type, pod and seed characteristics. The climbing growth habit is associated with increased days to flowering (DF), seed iron concentration (SdFe), nitrogen fixation, and yield. However, breeding efforts in climbing beans have been limited and independent from bush type beans. To advance climbing bean breeding, we carried out genome-wide association studies and genomic predictions using 1,869 common bean lines belonging to five breeding panels representing both gene pools and all growth types. The phenotypic data were collected from 17 field trials and were complemented with 16 previously published trials. Overall, 38 significant marker-trait associations were identified for growth habit, 14 for DF, 13 for 100 seed weight, three for SdFe, and one for yield. Except for DF, the results suggest a common genetic basis for traits across all panels and growth types. Seven QTL associated with growth habits were confirmed from earlier studies and four plausible candidate genes for SdFe and 100 seed weight were newly identified. Furthermore, the genomic prediction accuracy for SdFe and yield in climbing beans improved up to 8.8% when bush-type bean lines were included in the training population. In conclusion, a large population from different gene pools and growth types across multiple breeding panels increased the power of genomic analyses and provides a solid and diverse germplasm base for genetic improvement of common bean

Accelerated variety turnover for open-pollinated crops in Tanzania - Phase 1 Key Findings

Open-pollinated varieties (OPVs), such as beans, sorghum, and groundnuts, are important for increased income, job creation, food security, and nutrition of both urban and rural households in sub-Saharan Africa (SSA). However, the main constraint is underdeveloped seed systems, which contribute substantially to dwindling productivity among small-scale farmers due to limited access to reliable and quality planting materials. ACCELERATE is expected to accelerate varietal adoption and turnover in Tanzania by tapping into the power of large/small-scale or marketplace traders, and institutional seed buyers

Farm to plate: School feeding catalysing investments in high iron bean value chain in Tanzania

Adequate nutrition is essential for schoolchildren’s health and wellbeing. Most children who benefit from school feeding programmes could already be nutrient deficient, vulnerable or at risk. These children rely heavily on such programmes because these could either be the only meal they consume in the day. In response to the high prevalence rates of malnutrition, to maximize the impact of investments on negative nutrition outcomes for women and children, multi-sectoral interventions are proposed as long-term sustainable approaches to address malnutrition in Africa (Garrett et al., 2011). Anticipating the release of HIB varieties in 2018, by the Tanzania Agriculture Research Institute (TARI) in collaboration with PABRA, the two organizations co-developed an approach to promote use and consumption of high iron beans (HIBs) in schools and surrounding communities. The approached used a multi-stakeholder approach consisting of: Local Government Authorities (LGAs), schools, entrepreneurs (grain traders, food processors), inputs suppliers (seeds and agro inputs) and end-users

Replication data for: Improving association studies and genomic predictions for climbing beans with data from bush bean populations

Genomic predictions for climbing beans were established. The climbing bean panel (VEC) was phenotypically and genotypically characterized. To improve association studies and predictions, contrasting bush type bean data, i.e., publicly available data as well as data from new field trials, were added to the data set

Improving Association Studies and Genomic Predictions for Climbing Beans With Data From Bush Bean Populations

Common bean (Phaseolus vulgaris L.) has two major origins of domestication, Andean and Mesoamerican, which contribute to the high diversity of growth type, pod and seed characteristics. The climbing growth habit is associated with increased days to flowering (DF), seed iron concentration (SdFe), nitrogen fixation, and yield. However, breeding efforts in climbing beans have been limited and independent from bush type beans. To advance climbing bean breeding, we carried out genome-wide association studies and genomic predictions using 1,869 common bean lines belonging to five breeding panels representing both gene pools and all growth types. The phenotypic data were collected from 17 field trials and were complemented with 16 previously published trials. Overall, 38 significant marker-trait associations were identified for growth habit, 14 for DF, 13 for 100 seed weight, three for SdFe, and one for yield. Except for DF, the results suggest a common genetic basis for traits across all panels and growth types. Seven QTL associated with growth habits were confirmed from earlier studies and four plausible candidate genes for SdFe and 100 seed weight were newly identified. Furthermore, the genomic prediction accuracy for SdFe and yield in climbing beans improved up to 8.8% when bush-type bean lines were included in the training population. In conclusion, a large population from different gene pools and growth types across multiple breeding panels increased the power of genomic analyses and provides a solid and diverse germplasm base for genetic improvement of common bean.ISSN:1664-462

Planteome/CO_335-common-bean-traits: 1st release

&lt;p&gt;This is the first release of the Common Bean repository&lt;/p&gt