Development of common bean genotypes with high iron and zinc seed concentrations and superior canning and agronomic quality traits

Abstract

Iron deficiency anemia is prevalent worldwide but mainly affects children under five years of age and women of reproductive age. One of the main causes of anemia in these groups is diet incapable of meeting daily iron requirements. Biofortification of staple foods is an approach aimed at contributing to reduction of anemia in Africa, and common bean (Phaseolus vulgaris L.), one of the leading staple foods in East and Central Africa, has gained attention as a valuable source of iron (Fe) and zinc (Zn). Its usefulness in improving iron status of iron anemic women and children is documented. Natural variation in iron and associated micronutrients like zinc exists in beans but their concentrations are below the target levels to meet daily requirements. This study aimed to develop and identify potential bean genotypes that surpass the HarvestPlus threshold of 90 ppm seed iron for possible promotion as high iron and zinc beans, and utilization in hybridization programs targeting these minerals, productivity and market traits. Advanced 578 genotypes were evaluated in five genotype groups planted in three locations from 2016 to 2018. Genotypes significantly differed (P≤0.05) in Fe, Zn, cooking time, canning quality and yield. Iron and Zn varied highly, ranging between 44-118 and 25-50 ppm, respectively, across the five-genotype groups. Cooking time ranged from 29-118 minutes and majority of the genotypes expressed good to excellent canning quality based on visual assessment (4-5) and hydration coefficients (2.1-2.2). Mean yields for bush beans and climbers were 1674-1977 kg ha-1 and 2204-3160 kg ha-1, respectively. The most outstanding genotypes that combined above average yield with high Fe/Zn were CMKN1109 (96/ 43 ppm), SMR103 (92/ 43 ppm), SMC12 (90/ 43 ppm), and NUS16 (91/ 48 ppm). In addition, NUA127 (84/ 42 ppm), SMR53 (84/ 42 ppm), SMC160 (84/ 43 ppm) and NUA595 (83/ 42 ppm) yielded above average and expressed high canning quality. The genotypes that combined high Fe/ Zn, canning quality, and yield are potential genotypes for further improvement or evaluation for possible release.

Phenotype based clustering, and diversity of common bean genotypes in seed iron concentration and cooking time

“…The small red bean market class generally reflected the poorest soaking ability even though some hydrated well and cooked fast. Similar soaking ability like observed in this study was previously reported [ 10 , 42 ]. The high swelling capacity of beans was largely a trait for the canning industry that is used to reflect a higher can weight [ 43 ].…”

“…The mean concentration of 64 ppm for FESEED was low compared to other populations described in literature. The mean FESEED has increased from 65 ppm in the first regional nutrition nursery for East African bush beans [ 37 ] to 75–78 ppm in some recently improved varieties [ 10 , 36 , 38 ]. The low mean FESEED in this study is attributed to the nature of the population that was assembled for multiple traits.…”

“…Thus, a daily consumption of iron-rich beans with the full target level of 94 ppm of Fe was estimated to provide 127% and 80% daily average requirements of children aged 6–7 years and women of reproductive age, respectively [ 9 ]. However, not many such genotypes exist on the market despite the realization of 94 ppm through breeding [ 9 , 10 ]. Increasing the diversity of iron concentration in different market classes, and targeted breeding could increase availability and access to full target level iron-rich beans.…”

Elucidating the Effect of Genotype x Environment Interaction and Storage Period on Cooking Time of Selected Common Bean (Phaseolus vulgaris L.) Genotypes

“…In Tanzania, the crop is primarily produced in mid to high-altitude areas that experience cooler temperatures and reliable rainfall (Ngowi et al, 2007). Common bean is among the well-known crops because it is affordable in terms of price, palatable and has a long shelf life which ensures food security in the community (Amongi et al, 2021). Also, common beans have been reported to minimize the risk of some diseases including cancer (breast and colon cancer) and heart diseases to potential consumers hence uplifting their health security (Campos-Vega et al, 2013) Consumption of common beans is enduring to be constrained by the tendency to take a long time to cook.…”