A visual indicator of the physiological maturity stage of indeterminate dry beans

Abstract

Two indeterminate breeding lines, L-227 and RAB 205, were planted during two growing seasons for the purpose of identifying a visual indicator of physiological maturity of dry beans which could be used in the field. Ten-plant samples were taken at 2-day intervals beginning approximately 8 weeks after emergence to determine seed dry weight accumulation and number of green, yellow, and brown pods. In order to identify a stage of pod development which coincided with maximum accumulation of seed dry weight, the number of green, yellow and brown pods per plant was estimated with polinomial regression equations. Coefficients of determination for the number of yellow pods were relatively low, ranging from 0.52 to 0.77, whereas the coefficients of determination for most equations for green and brown pod numbers were near 0.9, indicating that the number of both green and brown pods may be useful as indicators of the occurrence of physiological maturity. Physiological maturity of L-227 occurred when plants had developed 1 to 2 green pods and 12 to T4 brown pods, whereas physiological maturity of RAB 205 occurred when 2 green pods and 8 brown pods were present on each plant. In the field, the number of green pods would be a better visual indicator of physiological maturity than the number of brown pods because fewer green pods have to be counted and because the green pods are on top of the plant.