A Study On The Relationship Between Nectarine (Prunus Persica Var. Nectarina Maxim) Fruit Development And Dehiscence Of Nectarine Fruit

Nectarine(Prunus persica var.nectarina Maxim) has been growing all over China in recent years; it, however, suffers from dehiscent fruit easily, especially when managed inappropriately. Dehiscent fruit in nectarine growing commonly exists in China; this has turned out to be a serious problem that needs solving urgently. In this study, "Huaguang" Nectarine that is prone to have dehiscent fruit is chosen as experimental material, and was compared with "Shuguang", a nectarine variety that maturates the same time as Huaguang but has much less dehiscent fruit. The causes of dehiscent fruit has been revealed through observing the regular patterns of dehiscent fruit, the alteration of inclusions, the features of pericarp texture as well as bagging young fruit under different cultivation conditions in the course of upgrowth of nectarine. This study is targeted at working out theoretical foundations for prevention of dehiscent nectarines.The results of the experiment are as the following. 1) Dehiscent fruit appear the most rapidly in the early stage of intumescence period; dehiscence is greatly related to the fruit setting place, with more dehiscent fruit in the outer part of the crown than the inner part of the tree. Dehiscent fruit rate of large fruit is higher than that of smaller ones. Dehiscence will occur severely if the fruit are caught in a heavy rain. 2)Dehiscence degree varies with different varieties, different maturation periods and different cultivation conditions of the same variety. Generally, dehiscence occurs less with extra-early and early varieties than middle and late ones. Dehiscence occurs easily when the cultivation soil has bad permeability and sharp change of humidity. Cultivation in greenhouse can effectively prevent dehiscence. 3)The relation between the inclusion of nectarine fruit and dehiscence of fruit shows that the changes of inclusion is closely related to dehiscence. The inclusion of nectarine fruit in the course of growing is closely related to dehiscence of fruit. The SOD activity in the course of the fruit development is negatively correlated to MDA content and cell membrane permeability. Fruit with high SOD activity suffer less from dehiscence. 4)The pericarp texture of nectarine has something to do with the degree of dehiscence resistance. The differences in the shape and size of pericarp cells are the important reason for the dehiscence variations. Pericarp texture can be used as anatomic foundation to scale the dehiscence resistance. 5) The dehiscence rate was reduced remarkably when the fruit had been bagged; bagging greatly improves the appearances of the nectarine. When debagged, the fruit looks clean and smooth and take up color quickly. Bagging, however, affects the accumulation of photosynthetic product, which causes the reduction of inner quality of the fruit.