FRUIT AND SEED DEVELOPMENT OF Jatropha curcas L. AND PHYSIOLOGICAL INDICATORS OF SEED MATURITY

Abstract

Physiological seed maturity is attained at maximum dry matter accumulation, and it is related to maximum yield and physiological seed quality. In this study the kinetics of variables related to fruit and seed development of an edible ecotype of Jatropha curcas L. were recorded; from these data seed physiological maturity was determined, as well as its relationship to fruit color. In a four-year-old plantation, two fruiting periods were evaluated under a complete block experimental design with three replications. Female flowers were labeled at anthesis and were harvested every day, twice per week for the first and second fruiting periods, until fruit dehiscence. In fruit and seed, diameter, length, diameter/length ratio, and fresh weight were quantified. Dry matter and moisture content were recorded in seed, and volumetric seed weight as well as 1000-seeds weight for shade-dried seed were measured. Changes in fruit color were recorded also. Physiological seed maturity or maximum dry matter (654.1 and 639.2 mg/seed) occurred at 75 and 78 days after anthesis (daa), with 42.7 and 36.4 % seed moisture content, for the first and second fruiting period. In fruits maximum values of diameter were reached at 68 and 57 daa; maximum length occurred at 75 and 64 daa; and maximum fresh weight accumulated at 75 and 68 daa. Maximum values for seeds occurred at 75 and 64 daa for diameter; 75 and 68 daa for length, fresh weight and 1000-seeds weight; and 75 daa, for volumetric weight. Maximum values for seed characteristics coincided with yellow fruits; so this trait is considered a reliable and practical visual indicator of seed physiological maturity for this species.