Relationship of Seed Germination and Respiration during Stratification with Cultivar Chilling Requirement in Peach

Abstract

Abstract Seed germination and respiration of peach [Prunus persica (L.) Batsch] were evaluated as potential preselection indices for predicting bud chilling requirement. Low chilling lines (Ã650 hours) germinated significantly earlier than high chilling lines, with an average r of 0.91 between cultivar chilling requirement and mean days to 80% germination at 4°C in 2 experiments. Based on germination behavior, differentiation between lines exhibiting small differences in chilling requirement was not feasible but separation into low and high chilling categories was possible. Removal of the testa resulted in earlier germination among all lines, but the order of germination remained consistent. An r of 0.84 was obtained between cultivar chilling requirement and mean days to 80% germination at 4°C using seeds with the testa removed. Respiration rate of seeds from 4 lines varying in bud chilling requirement with intact testa rose gradually during stratification. Seeds with the testa removed exhibited a rapidly increasing respiration rate during stratification. Respiration rate of seeds from low chilling lines exhibited a higher mean respiration rate than seeds from high chilling lines in seeds with the testa removed.