Title: Genetic diversity and selection of genotypes to enhance Zn and Fe content in common bean Authors
|Talukder, Z -|
|Anderson, E -|
|Blair, M -|
|Osorno, J -|
|Dilawari, M -|
|Hossain, K -|
Submitted to: Canadian Journal of Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2009
Publication Date: February 1, 2010
Citation: Talukder, Z.I., Anderson, E., Miklas, P.N., Blair, M.W., Osorno, J., Dilawari, M., Hossain, K.G. 2010. Genetic diversity and selection of genotypes to enhance Zn and Fe content in common bean. Canadian Journal of Plant Science. 90: 49-60. Interpretive Summary: Common bean is a staple food crop representing 50% of all grain legumes consumed worldwide. Beans are a rich source of protein, energy, vitamins, fiber, and minerals including zinc (Zn) and iron (Fe). The study was conducted to identify beans with greater concentrations of Zn and Fe for use in genetic studies geared toward improving mineral content of common bean. Significant differences in Zn and Fe content were observed among the accessions. Vista navy bean had ten times more Fe content in the seeds than Jalo EEP558 dry bean from Brazil. The difference in Zn content was less pronounced. Crosses made between parents with low and high Zn and Fe content will be made based on the results obtained from this study. Ultimately, developing beans with higher mineral content will benefit human nutrition in developing countries, and is a goal of many bean breeding programs.
Technical Abstract: Common bean (Phaseolus vulgaris L.) is an important source of dietary protein and minerals worldwide. Genes conditioning variability for mineral contents are not clearly understood. Our ultimate goal is to identify genes conditioning genetic variation for Zn and Fe content. To establish mapping populations for this objective, we tested mineral content of 29 common bean genotypes. Chemical analyses revealed significant genetic variability for seed Zn and Fe contents among the genotypes. Genetic diversity was evaluated with 49 primer pairs, of which 23 were simple sequence repeats (SSR), 16 were developed from tentative consensus (TC) sequences, and 10were generated from common bean NBS-LRR gene sequences. The discriminatory ability of molecular markers for identifying allelic variation among genotypes was estimated by polymorphism information content (PIC) and the genetic diversity was measured from genetic similarities between genotypes. Primers developed from NBS-LRR gene sequences were highly polymorphic in both PIC values and number of alleles (0.82 and 5.3), followed by SSRs (0.56 and 3.0), and markers developed from TC (0.39 and 2.0). genetic similarity values between genotypes ranged from 14.0 (JaloEEP558 and DOR364) to 91.4 (MIB152 and MIB465). Cluster analysis clearly discriminated the genotypes into Mesoamerican and Andean gene pools. Common bean genotypes were selected to include in crossing to enhance seed Zn and Fe content based on genetic diversity and seed mineral contents of the genotypes.