Study on quality development of naval orange (Citrus sinensis Osb.) during storage of fruit kept on tree.

The quality change of 'Roberson' navel orange fruit kept on tree during December to the next April was studied.The acid content of juice decreased significantly with the time and the decreased range was finally 37.5 %.The total soluble solids(TSS) and sugar content of juice increased slightly,and the ratio of TSS/acid and sugar/acid increased greatly.Few change was observed with Vitamin C content,percentage of edible parts and percentage of juice during the whole period.After one month kept fruits on tree since mid-December,the fruit taste and the key quality factors were improved markedly,and reached or exceeded the indexes of high-quality fresh fruits.The chief reason for sugar/acid and TSS/ acid increasing as well as fruit taste improving was the large-ranged decrease of acid content.The experimental result showed that the storage method by keeping fruit on tree for months can really improve the fruit quality of navel orange,and the ability of market competition for fresh fruits can also enhance when harvested at a proper time.