DEVELOPMENT OF THE 'AURORA' PEACH AND 'SUNRAYCER' NECTARINE FRUITS IN SOUTHERN SANTA CATARINA, BRAZIL

The peach fruit development is a result of the differentiation and growth of the ovary wall after fertilization. The persistency and the growth of the fruit on the plant depend on the exact relationships among auxin, gibberelin and cytokinin hormones, which condition the development of the fruits, characterized by a double sigmoid curve with three distinct stages. This study aimed to understand the performance of fruits and seeds of the Aurora peach and Sunraycer nectarine throughout their development cycle. Fruits and seeds growth was evaluated weekly by collecting 30 fruits from previously identified branches of ten different plants. The seeds were separated from the fruit for the determination of the fresh weight (FW) and the dry weight (DW). The growth of the Sunraycer fruits variety is continuous and accelerated from flowering to maturity, which suggests a short period or absence of the growth Stage II. For the Aurora variety, the growth curve is differentiated during the three stages (I, II and III). The fruits thinning must be done until the beginning of stage II for both varieties, Aurora and Sunraycer. Their seeds reach their maximum size at stage I of fruit growth. The increase in the dry weight of the Sunraycer variety was practically absent on stage III, whereas it increased significantly in the Aurora variety until the fruit maturation.