Four common bean (Phaseolus vulgaris L.) varieties, Kawanda (K)131, K132, NABE4 and NABE11, were evaluated for the relationship between development of the hard-to-cook (HTC) defect and changes in nutritional quality during 6-month storage under ambient conditions. All varieties developed the HTC defect, but the extent was found to vary with variety. Cooking time increased by 113% in K131, 95.3% in K132, 56.4% in NABE4 and 42.93% in NABE11 after 6 months. The development of the HTC defect was found to be associated with a reduction in phytic acid content (r2 = -0.802), in vitro protein digestibility (r2 = -0.872) and in vitro starch digestibility (r2 = -0.729). The susceptibility to the HTC defect during storage could be attributed to a phytic acid interaction with proteins and carbohydrates, and is also associated with small seed size. Breeding for large seed size could therefore help reduce the development of the HTC defect.

No abstract

Background: Common bean one of the grain legumes that was traditionally considered a subsistence crop and therefore a woman's crop in Uganda was prioritized for commercialization. This has transformed the crop from being a subsistence crop (food security crop) to a commercial crop with more men engaged in its production. Little is known about the possibility of gender conflicts in production activities as the crop finds market. Methods:The study uses gender-disaggregated survey data from 500 men and 625 women in central Uganda. Both bivariate and multivariate methods were used to access the notion of bean being a women's crop based on gender participation intensities (a pairwise t test and Tobit regression model).Results: Seventy-three percent male-headed and 87% female-headed households had membership in farmers groups. Bean crop was majorly owned by women. Seventy-five percent of the studied bean plots were intercropped with other crops. On average, both men and women operated at one bean plot per season estimated. Winnowing (4.26), post-harvest handling and storage (4.25), sorting (4.22), planting (4.04) and weeding (4.00) were the five top most activities that rural women heavily participated in. The following are the top most five activities that men participated in: site selection (3.94), spraying against pests and diseases (3.81), bush clearing (3.77), fertilizer application (3.73) and harvesting beans (3.73). Bean consumption (1.3%), marketability (17.5%), distance to plot (8.1%), education (1.3%) and color (18.1%) had significant influence on women participation intensities. Household size (5.8%), farming as primary occupation (42.7%) and bean color (30.8%) had significant influence on men bean participation intensities. Conclusions:The study revealed there was significantly no bean production activity that was purely done by only men or only done by women. Thus, bean cannot be classified as a women's crop based on participation intensities since men offered support in a number of activities. In order to close the gender gap in bean production, there is need to target both men and women with gendered interventions and address issues of traditional norms.

Background: This study investigated consumer demand heterogeneity and valuation of a processed bean product-"precooked beans" with substantially reduced cooking time. Common bean is the most important source of protein for low-and middle-income households in Uganda. Its consumption is, however, constrained by long cooking time, high cooking energy and water requirements. As consumption dynamics change due to a rapid expansion of urban populations, rising incomes and high costs of energy, demand for fast-cooking processed foods is rising. An affordable, on-the-shelf bean product that requires less time, fuel and water to cook is thus inevitable.Methods: A choice experiment was used to elicit consumer choices and willingness to pay for precooked beans. Data used were collected from 558 households from urban, peri-urban and rural parts of central Uganda and analyzed using a latent class model which is suitable when consumer preferences for product attributes are heterogeneous. Results:Study results revealed three homogeneous consumer segments with one accounting for 44.3% comprising precooked bean enthusiasts. Consumers derive high utility from a processed bean product with improved nutrition quality, reduced cooking time and hence save water and fuel. The demand for the processed bean is driven by cost saving and preference for convenience, which are reflected in willingness to pay a premium to consume it. Heterogeneity in attribute demand is explained by sex and education of the respondents, volumes of beans consumed, location and sufficiency in own bean supply. Conclusions:Our findings suggest that exploring avenues for nutritionally enhancing while optimizing processing protocols to make precooked beans affordable will increase consumer demand. These results have implications for market targeting, product design and pricing of precooked beans.

Productivity of dry bean is constrained by the competition with weeds for scarce nutrients and water in eastern Africa. Trials were conducted at Cornell University in 1996 and in central Uganda during the two seasons of 1997 to test the hypothesis that bean crop nutrition can be improved while increasing the relative competitiveness of bean with annual weed species. Soil levels of available N, P, and K were varied in the main plots. Subplots consisted of bean and two weed species in pure stands and bean mixed with each of the weed species. The weed species were black nightshade and smallflower galinsoga at Cornell and smallflower galinsoga and hairy beggarticks in Uganda. Bean yield was the most suppressed by hairy beggarticks with a mean reduction of 48%. Bean nutrient uptake and growth decreased relative to the weed nutrient uptake and growth when N and P were applied, but the relative competitiveness of bean increased with K application. The K effect on bean yield was greater than the P effect in two out of three trials. Alternative practices for the supply of N and P need to be evaluated for increasing bean yields while reducing the relative benefit to weeds.

Germplasm of common beans from the Mesoamerican gene pool races: Durango, Jalisco, Mesoamerica and Guatemala have highest genetic variation for the crop's improvement. The objective was to assign 50 common bean germplasm in Uganda into its gene pool races based on analyses of population structure. Secondly, to estimate heritability and effects of genotype × environment (GXE) interaction on common bean agronomic and yield traits in space and time. Sample genomic DNA was amplified in 2011 with 22 Simple sequence repeat markers (SSRs) and alleles separated using capillary electrophoresis. Field evaluations were conducted in 2010 and 2011 at NaCRRI and 2015 at CIAT – Kawanda. Multivariate analyses of SSRs data identified four subgroups within the germplasm: K4.1–K4.4, with corresponding Wrights fixation indices (FST) as 0.1829 for K4.1, 0.1585 for K4.4, 0.1579 for K4.2 and least for K4.3 at 0.0678. Gene pool race admixtures in the population (14%) were notable and attributed to gene flow. Four superior parents currently used in improving resistance to major diseases grouped as; Jalisco for MLB49-89A; Mesoamerica for MCM5001 and G2333; Durango for MEXICO 54. Heritability values for yield traits estimated using phenotypic data from above fixed parents, was above 0.81. Season and location had significant effect (P < 0.05) on numbers of: flower buds per inflorescence, pod formation and weight of 100 seeds. The findings will improve understanding of co-evolutionary relationships between bean hosts and pathogens for better disease management and will broaden the germplasm base for improving other tropical production constraints.

Snap bean (Phaseolus vulgaris L.) farmers rely mostly on insecticides to manage pests and to satisfy the stringent market requirements for insect and blemish-free pods. However, the cost of these pesticides lowers farm incomes. In addition, heavy and wrong use of pesticides could result in residue accumulation, which reduces market access by the farmers. To identify optimal pest control with lower economic risks to farmers, we investigated the effectiveness and profitability of different insecticides and insecticide formulations against bean fly (Ophiomyia spp.) and bean flower thrips (Megalurothrips sjostedtii). Two separate experiments were conducted during 2009 to 2012. The first experiment targeted bean fly and bean flower thrips, comprising the treatments: seed dressings, soil drenches, foliar sprays and an untreated control. We used randomised complete block design, with four replicates. All the seed dressing and soil drenching insecticides, except Apron, significantly lowered bean fly infestation by two to 60 fold when compared with control. These insecticides, however, did not control flower thrips. Confidor® resulted in a marginal returns of 0.89 and Actara® -0.11 compared to seed dressings, which ranged from 0.47 to 1.82. The second experiment laid in a randomised complete block design involved the foliar application of Roket® under different spray regimes. Application of Roket® reduced infestation of thrips, and resulted in positive MRR in all the seasons.

No abstract