Genetic analysis of grain yield and yield-attributing traits in navy bean (Phaseolus vulgaris L.) under drought and optimal environments

Knowledge of the genetic basis of navy bean (Phaseolus vulgaris L.) performance under drought stress (DS) is important for planning appropriate breeding and selection strategies in DS environments. Twenty-eight F2 progenies generated from an 8 x 8 half-diallel mating design were evaluated to determine combining ability effects and mode of gene action of grain yield (GYD) and yield attributing traits in navy bean under DS and non-stressed (NS) conditions. The experiments were conducted in two locations in a 6 x 6 square lattice design with two replications during the 2020 dry season. There were significant (p < 0.001; p < 0.05) positive correlations for number of pods per plant (NPPP), number of seeds per plant (NSPP) and 100-seed weight (SW) with GYD under both DS and NS. General and specific combining ability (GCA; SCA) effects were significant (p < 0.05) under both DS and NS for most traits indicating the importance of both additive and non-additive gene effects in the expression of the traits. Parents with best combining ability for most of the studied traits were G1, G7, G6 and G8 under NS, and G3, G4, G7 and G8 under DS. The most promising progenies with high values for GYD and its component traits under DS were G2 X G3, G2 X G8, G4 X G5, G4 X G8, and G6 X G8. Good general and specific combiners with high significant positive effects under DS should be used further in breeding for moisture stress tolerance.

NUTRACEUTICAL PROPERTIES OF GLUTEN-FREE CUPCAKES PREPARED BY GLUTEN-FREE COMPOSITE FLOUR

Objective: The present study was aimed to evaluate the nutritional, phytochemical and antioxidant properties of all ratios of gluten-free composite flour-based cupcakes. Methods: Composite flour was the blend of teff millet flour (TF), navy bean flour (NF) and watermelon seeds flour (WF). The variations of three composite flours were prepared as, A being (TF: NF: WF=45:45:10), B being (TF: NF: WF=55:35:10) and C being (TF: NF: WF=65:25:10) respectively. Moisture, ash, fat, fiber, protein and carbohydrate were analyzed in this study. Minerals like calcium, iron, phosphorus and zinc were also analyzed. Results: The result of macronutrient and micronutrient of C ratio was moisture (28.1±0.2), ash (2.5±0.0), protein (12.2±0.3), fat (24.5±0.0), fiber (2.8±0.1) and carbohydrate (32.2±0.1 g/100g) respectively. Calcium (36.9±0.1), iron (7.5±0.0), zinc (3.8±0.2) and phosphorus (235.0±0.4 mg/100g) were also present in gluten-free Cupcakes. On the basis of the present study, it was found that gluten-free cupcakes contain different macro as well as micronutrients. It also has some phytochemicals such as flavonoids, saponins, tannin, glycocides and steroids. Conclusion: The study result revealed that gluten-free Cupcakes had higher phenols content as well as antioxidant activity. The overall good amount of all nutrients found in the C ratio. The sensory evaluation of Cupcakes on a 9 point hedonic scale revealed that a ratio was more acceptable than the B and C ratio. Therefore, it can be beneficial for celiac diseases, hypertension, anemia, diabetes and cancer condition.

Farmers’ perceptions of navy bean (Phaseolus vulgaris L.) production constraints, preferred traits and farming systems and their implications on bean breeding: a case study from South East Lowveld region of Zimbabwe

Background Navy bean is an important legume crop in Zimbabwe. Although its production in Zimbabwe is limited by multiple constraints including biotic, abiotic and socio-economic, there is no documented evidence. Thus, this study aimed at identifying farmers’ production constraints, preferred traits and cultivars of navy bean, and strategies used to mitigate some of these constraints. Methods A Participatory Rural Appraisal approach involving transect walks, focus group discussions (FGDs), and formal surveys with semi-structured questionnaires was conducted in four villages of the Lowveld region of Zimbabwe. In each of the four villages, two FGDs (one for men and one for women) were conducted. A total of 176 (75 males and 101 females) navy bean-growing households were interviewed. Data from household interviews and FGDs was analysed using the Statistical Package for Social Scientists computer package. Results The most important constraints to navy bean production were drought stress (Females—86%, Males—73%), heat stress (Females—58%, Males—55%), power outages (Females—46%, Males—54%), poor soil fertility (Females—32%; Males—33%) and susceptibility to pod shattering (Females—32%, Males—43%). Mitigation strategies included mulching (18%), ridges (12%), reduced acreage (11%), and cultivating to retain more soil moisture (11%) for drought stress, while irrigating at night (32%), and adjusting planting dates (29%) were used to manage heat stress. Farmer-preferred traits included tolerance to drought and heat, early maturing varieties and disease resistance. Marketing constraints included non-payment for produce in hard currency, lack of diversity in terms of off-takers, high inflation, low grain producer price, delayed payment and breach of contract by contractors. Conclusion There will be increased adoption of improved navy bean cultivars if breeding programs address the aforementioned constraints and consider farmer-preferred traits when developing new cultivars. Breeders should work closely with extension officers to ensure that cultivars released are cultivated with appropriate agronomic packages for increased productivity and high adoption.

Navy Bean Supplementation in Established High-Fat Diet-Induced Obesity Attenuates the Severity of the Obese Inflammatory Phenotype

Cooked common beans (Phaseolus vulgaris) improve intestinal health in lean mice and attenuate intestinal dysbiosis and inflammation when consumed concurrent with obesity development. We determined the effects of a high-fat (HF) bean supplemented diet in mice with established obesity (induced by 12 weeks of HF diet (60% fat as kcal)) compared to obese mice consuming a HF or low-fat (LF) weight loss control diet. Obese C57BL/6 male mice remained consuming HF for eight weeks or were randomly switched from HF to an isocaloric HF with 15.7% cooked navy bean powder diet (HFàHFB) or LF (11% fat as kcal; HFàLF) (n = 12/group). HFàHFB improved the obese phenotype, including (i) fecal microbiome (increased Prevotella, Akkermansia muciniphila, and short-chain fatty acid levels), (ii) intestinal health (increased ZO-1, claudin-2, Muc2, Relmβ, and Reg3γ expression), and (iii) reduced adipose tissue (AT) inflammatory proteins (NFκBp65, STAT3, IL-6, MCP-1, and MIP-1α), versus HF (p < 0.05). Conversely, HFàLF reduced body weight and circulating hormones (leptin, resistin, and PAI-1) versus HF and HFàHFB (p < 0.05); however, AT inflammation and intestinal health markers were not improved to the same degree as HFàHFB (p < 0.05). Despite remaining on a HF obesogenic diet, introducing beans in established obesity improved the obese phenotype (intestinal health and adipose inflammation) more substantially than weight loss alone.

Farmers’ perceptions of navy bean (Phaseolus vulgaris L.) production constraints, preferred traits, farming systems and their implications on bean breeding: A case study from South East Lowveld region of Zimbabwe

Background: Navy bean is an important legume crop in Zimbabwe. Its production is limited by multiple constraints including biotic, abiotic and socio-economic. However, in the major navy bean-production regions of Zimbabwe, there is no recent study documenting biotic stress management strategies, farmers’ perceived production, and marketing constraints, and cultivar trait preferences. Thus, this study aimed at identifying farmers’ production constraints, preferred traits and cultivars of navy bean, and strategies used to mitigate some of these constraints.Methods: A Participatory Rural Appraisal approach involving transect walks, focus group discussions (FGDs), and formal surveys with semi-structured questionnaires was conducted in four villages of the Lowveld region of Zimbabwe. In each of the four villages, two FGDs (one for men and one for women) were conducted. A total of 176 (75 males and 101 females) navy bean growing households were interviewed. Data from household interviews and FGDs was analysed using the Statistical Package for Social Scientists computer package.Results: The most important constraints to navy bean production were drought stress (Females – 86 %, Males – 73 %), heat stress (Females – 58 %, Males – 55 %), power outages (Females – 46 %, Males – 54 %), poor soil fertility (Females – 32 %; Males – 33 %) and susceptibility to pod shattering (Females – 32 %, Males – 43 %). Mitigation strategies included mulching (18 %), ridges (12 %), reduced acreage (11 %), and cultivating to retain more soil moisture (11 %) for drought stress, while irrigating at night (32 %), and adjusting planting dates (29 %) were used to manage heat stress. Farmer-preferred traits included tolerance to drought and heat, early maturing varieties and disease resistance. Marketing constraints included non-payment for produce in hard currency, lack of diversity in terms of off-takers, high inflation, low grain producer price, delayed payment and breach of contract by contractors. Conclusion: There will be increased adoption of improved navy bean cultivars if breeding programs address the aforementioned constraints and consider farmer-preferred traits when developing new cultivars. Breeders should work closely with extension officers to ensure that cultivars released are cultivated with appropriate agronomic packages for increased productivity and high adoption.