Stability and inheritance of storage-induced hardening in 20 common bean cultivars

Storage of common bean (Phaseolus vulgaris L.) in elevated temperature and/or humidity conditions leads to a textural defect where the beans harden and fail to soften upon soaking and cooking. The objectives of this study were to determine the stability of 20 common bean cultivars grown in three environments for initial hardness, final hardness following storage and hardening ratio, and to estimate the heritability of these hardening parameters. Cultivar × environment interaction was highly significant for the hardening parameters. When stability was examined by plotting hardness against coefficient of variation across environments, three cultivars, GN-77135B, ICA Pijao and T39 Black Turtle, were marginally below the mean for both final hardness and coefficient of variation. While the coefficients of variation for the red kidney bean cultivars Redkloud and Montcalm were high, the maximum compression forces were only slightly (< 20%) greater than the maximum acceptable hardness level as determined by a sensory panel. Fiesta Pinto had the lowest coefficient of variation and near mean values for both final hardness and hardening ratio making it arguably the cultivar with best combination of texture and stability. Heritability estimates were low (0–0.24) with high standard error and estimates of the proportion of phenotypic variance due to G × E were moderate to high (0.29–0.69). Initial cultivar improvement efforts should focus on developing cultivars with greater stability across environments for the hardening parameters. Key words: Phaseolus vulgaris L., storage-induced hardening, stability, broad sense heritability, bean (common)