Study On The On-Tree Storage Technique For Newhall Navel Nranage In Gannan South Of Jiangxi

Citrus is the central industries in south of Jiangxi province which is one of the most important navel orange(Citrus sinensis Osbeck) production base in China. However, the main cultivars of navel orange in south of Jiangxi is single and come into the markets in the same stage, which decrease the benefit of Citrus industry. On-tree storage is one of the effective way to solve these problems which can extend the period of the fruit supply and improve economic benefits.In this research, Newhall navel orange (Citrus sinensis Osbeck cv. Newhall) was used as experiment materials. The tree nutrition and fruit quality changes of on-tree storage in different amount fruits remained on tree was studied to determine the applicable date of on-tree storage and the appropriate fruit remained number per tree. The main results were as follows:1. The influence on fruit quality and nutrition by different amount fruits remained on tree: three treatments of different amount fruits remained on tree (100%, 75%, 50%) were used in this research. In the early on-tree storage stage (in 60 day), fruit inner quality change of each treatments were the same. However, in the late stage, the indexes such as TTS (the total soluble solid content), titratable acidity content, Vc content and fruit juice rate of 50% treatment were higher than 100% and 75% treatments. According to the influence on fruit set rate of next year by on-tree storage, the next year fruit set rate of 100% and 75% treatments was much lower than comparison, but this index of 50% treatment was close to comparison.2. The influence on tree nutrition by different amount fruits remained on tree: there was less difference of leaf N, P, K content among three treatments, the N, K contents of 50% treatment were higher than others. The change current of leaf organic nutrition among three treatments was different, but the difference become small in the late stage of on-tree storage(100 day).The appropriate number of fruit remained on tree could not deduced by tree nutrition. However, because the more fruits remained , the more fruits dropped in the late stage, so the number of fruits remained on tree could not be too much. In summary, the appropriate fruit remained number of Newhall was 50%.3. The applicable date of on-tree storage: according to the change of fruit quality, the TTS of Newhall was raised in the early stage of on-tree storage and reach the climax in 60 day. The titratable acidity content was raised slightly in 20 day and then decreased slowly, it was remained high level in the early stage (60 day) of on-tree storage. After this stage, titratable acidity content was decreased evidently due to the increase of respiration. Vc content was always decreased in 40 day. However, it was raised in 60 day and then decreased. In the on-tree storage stage, the change of fruit juice rate was disordered, but the total current was decreased. In summary, the applicable date of on-tree storage of Newhall was 60 day, of which the fruit quality was better than comparison.All in all, the appropriate fruit remained number and applicable date of Newhall was 50% and 60-80 day which could not influence the fruit quality and tree nutrition. Though this treatment, the fruit drop rate was low and the next year fruit set rate was close to comparison, so the yield of next year was not influenced.