Seed development and maturation in edible dry bean (Phaseolus vulgaris L.) cv. Teebus

Abstract

A study of seed development and maturation in edible dry bean cv. Teebus was conducted on field-grown plants. Mass maturity (maximum seed dry mass) occured 43 days after flowering (DAF) when seed moisture content was 52%. Harvest maturity (at a seed moisture content of 12.7%) was reached 15 days after mass maturity (58 DAF). Fresh seeds produced 90.5% normal seedlings at 30 DAF (13 days before mass maturity), when they had acquired only 48% of their maximum dry mass. Only 3% of rapidly dried seeds produced normal seedlings at this stage. Maximum seed quality (as determined by normal germination and conductivity of steep water), as well as maximum desiccation tolerance, were attained 5 days after mass maturity when seed moisture content was 34%. Respiration initially increased sharply, followed by a relatively constant high level for several days, after which it diminished to near zero levels when moisture content was 16.8% (5 days before harvest maturity). ATP content followed much the same pattern, but the seeds still contained a relatively large amount of this compound (39 nmol seed ⁻¹) when respiration had declined to a negligible value.