Flower Thinning Improves Fruit Quality and Oil Composition in Camellia oleifera Abel

Abstract

Camellia oleifera is a woody oil tree with overlapping flower bud differentiation and fruit maturation. Therefore, mechanical harvesting of fruits leads to flower abscission. The present study investigated the effects of flower number per tree on fruit growth, yield, nutrient accumulation, and oil fatty acid composition in C. oleifera. Here, we set different flower numbers per tree by thinning flowers. Heavy flower thinning (T2 and T3) significantly reduced fruit yield and the proportion of palmitic, palmitoleic, linoleic, and linolenic acid in fatty acids compared with other treatments. However, heavy thinning favored an increase in fruit size and weight, seed and dry kernel rate of fresh fruit, soluble protein and oil accumulation in seeds, and the proportion of oleic acid and stearic acid in fatty acids, and it had no significant effect on oil yield per tree compared with light thinning (T1) and control (T0). T2 and T3 decreased soluble sugar content in the kernels at the later stage of fruit development (260–320 days after full bloom (DAFB)) in contrast to the rapid fruit growth period (200–230 DAFB). As the crop load decreased, fruit ABA content increased continuously during 260–320 DAFB, while fruit IAA content increased during 260–300 DAFB and then decreased during 310–320 DAFB. These data suggest that the abscission of a few flowers during mechanical harvesting will not affect fruit production efficiency in C. oleifera.