Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2008
Publication Date: 2/10/2009
Citation: Blair, M.W., Astudillo, C., Grusak, M.A., Graham, R., Beebe, S.E. 2009. Inheritance of seed iron and zinc concentrations in common bean (Phaseolus vulgaris L.). Molecular Breeding. 23:197-207. Interpretive Summary: Micronutrients, such as iron and zinc, are essential elements needed in small amounts for adequate human nutrition. Both of these minerals are critical to human well-being, and an adequate supply of iron and zinc helps to prevent iron deficiency anemia and zinc deficiency, two prevalent health concerns of the developing world. Beans are an important staple food in certain world regions, including areas where human iron and/or zinc deficiency are found. Because of this, we are interested in being able to improve the iron and zinc concentrations of bean varieties, in order to enhance human dietary consumption of these elements. Thus, the objective of this study was to determine the genetic inheritance of seed iron and zinc accumulation in common bean, such that we would have new tools for future cultivar improvements in this crop. We used a special population of beans that was derived from a cross between two parent lines that were low or high for seed iron and zinc concentrations. The population was grown over two trial sites; iron and zinc concentrations were determined in the seed harvested from these trials. Statistical tests using these data, along with genetic information on each of the lines in the population, helped us to identify 26 regions within the bean genome that contributed to enhanced levels of iron or zinc in bean seeds. Genetic markers associated with these regions can now be used in bean breeding programs to develop nutritionally improved varieties. Once developed, these varieties should help to improve micronutrient status in at-risk populations in bean-consuming regions throughout the world.
Technical Abstract: Micronutrients are essential elements needed in small amounts for adequate human nutrition and include the elements iron and zinc. Both of these minerals are essential to human well-being, and an adequate supply of iron and zinc helps to prevent iron deficiency anemia and zinc deficiency, two prevalent health concerns of the developing world. The objective of this study was to determine the inheritance of seed iron and zinc accumulation in a recombinant inbred line population of common beans from a cross of low x high mineral genotypes (DOR364 x G19833) using a quantitative trait locus (QTL) mapping approach. The population was grown over two trial sites, and two analytical methods were used to determine iron and zinc concentration in the seed harvested from these trials. A total of 26 QTL were identified for the mineral x trial x method combinations of which half were for iron concentration and half for zinc concentration. Many of the QTL (11) for both iron (5) and zinc (6) clustered on the upper half of linkage group B11, explaining up to 47.9% of phenotypic variance, suggesting an important locus useful for marker assisted selection. Other QTL were identified on linkage groups B3, B6, B7, and B9 for zinc and B4, B6, B7, and B8 for iron. The relevance of these results for breeding common beans is discussed especially in light of crop improvement for micronutrient concentration as part of a biofortification program.