ACCUMULATION CHARACTERISTICS OF FRUIT WEIGHT, DIAMETER AND MAIN NUTRIENT COMPOSITION INDICES IN GROWING 'BOYSENBERRY' FRUIT

In this study, the dynamic accumulation characteristics of the fruit weight, fruit diameter, and nutrient composition indices including total sugar, total acid and vitamin C of blackberry (Rubus L. subgenus Rubus) ‘Boysenberry’ were investigated respectively. All the indices accumulated at the late stages of fruit development and exhibited an incomplete single S-shaped curve. Complete single S-shaped curves were uniformly observed for accumulation rate of fruit weight, total sugar and vitamin C, while total acid showed a horizontal double S-shaped curve and the average diameter an upward and basic symmetrical parabola trend. The accumula¬tion acceleration of fruit weight, total sugar and vitamin C exhibited an upward and asymmetrical parabola pattern, while the total acid and average diameter showed a horizontal single S-shaped curve and a straight line respectively. The growth models of the fruit parameters accurately fitted the blackberry growth patterns and provided reference for better understanding of blackberry development with the days after fruit-setting.