U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska

 

Date of this Version

3-2017

Citation

ANNUAL REPORT OF THE BEAN IMPROVEMENT COOPERATIVE, No. 60, March 2017. Published by USDA.

Comments

U.S. government work.

Abstract

INTRODUCTION Dry edible beans (Phaseolus vulgaris L.) provide an economical, nutritious food source for millions of people around the world and are grown in a diverse variety of sizes, colors, shapes, and agronomic traits. In the United States, dry beans are commonly consumed as readyto- eat canned products, which makes canning quality important to industry standards and consumer preferences. When black beans are processed for canning, they dramatically lose their dark coloration, which results in an undesirable, faded-brown, canned product. Although phenotyping is time and labor-intensive, genotypes with superior color retention have been identified that can enable genetic improvement of this key trait. This research seeks to improve color retention and canning quality via complementary improvements in genotyping and phenotyping, bypassing the current onerous phenotyping procedures. Mapping color retention and canning quality traits to the dry bean genome may allow marker assisted selection, while refining predictive models may be able to efficiently screen dry seed.

MATERIALS AND METHODS Several recombinant inbred line (RIL) populations were developed from parental genotypes that showed extreme differences in color retention (Table 1). Once canned, breeding line B14311 has abysmal color retention, resulting in light brown beans, while B12724 and B10244 ‘Zenith’ have outstanding color retention, resulting in dark black beans. Color and appearance scores of canned beans are determined by a trained sensory panel using separate 1-5 hedonic scales, where 1 is very unfavorable (light brown color or split beans, respectively) and 5 is very favorable (dark black color or fully intact beans, respectively). B14311 was selected as a parent common to both populations due to the combination of poor color score and relatively high appearance score. The high appearance scores reflect good seed coat integrity, demonstrating that color loss in this genotype is not necessarily due to mechanical breakdown of the seed coat. Recurrent parents B12724 and ‘Zenith’ have good appearance scores and excellent color scores, despite having different genetic backgrounds and potentially different mechanisms of color retention. Selecting only parents with similar appearance scores minimizes any potential confounding effect between color and appearance ratings.

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