A Study On The Genetic Diversity And Cold Resistance Of 'Shuanggan' Aprioct

The'Shushanggan'apricot is good endemic apricot variety in Yili Xinjiang, China, which has a high economic development value, because of the fruit can be eaten fresh or preserved and the almond also can be eaten. There were serious floral organ freeze injuries during florescence and big differences on biological characteristics and fruit qualities, so industrial large-scale production of'Shushanggan'apricot facing enormous difficulties in Yili Xinjiang. Our research aimed at these questions and get some results through the investigation of'Shushanggan'apricot germplasm resources, the appraisal as well as the RAPD analysis, established the molecular genetic map, we have also evaluated floral organ hardiness using principal component analysis. All these results provide the basis for the'Shushanggan'apricot heredity relationship and the kiwifruit germplasm resources appraisal and the new variety's protection. The main results were as follows:1. Through the observations of the phenophase of blossom of different strains, it was found that from the flower bud enlargement period to blossom falling time it lasted 20 to 30 days overall, which is only 8 to 11 individually. The flower bud germinated earliest in S5 and latest in S1 and S6, and the phenophase of blossom lasted longest in S5. The percentage of imperfect flower among different tree speices is remarkly different, which is from 10.9% to 28.6% among 6 strains'Shushanggan'apricot. Experiment on pollination methods demonstrated that the fruit set percentage of natural pollination was better one among the others, which canobtained 15.4%.2. The clustering analysis displayed that the genetic similarity of the 6 Shushanggan materials was from 0.831 to 0.938, and it can be gathered into three classes, S1, S2, S3, and S6 of classⅠand S5 of classⅡa nd S4 of classⅢ. (3) The biggest similarity(0.802)shows between Shushanggan apricot group and Liguang apricot in Xinjiang. It shows that Liguang apricot is most closely related to the Shushanggan Apricot.3. To determine cold hardiness of'Shushanggan'apricot cultivars, seven indexes of flower organs was observed in the study, including browning rate, LT50, proline contents, MDA, SOD, POD and CAT enzyme activity of buds, using principal component analysis after artificial freezing test (0,-2,-4,-6,-8,-10 degrees C). The result shows that order of frost tolerance is S6>S2>S1>S3>S4>S5, which provides theoretical basis for the breeding and production of'Shushanggan'apricot in Xinjiang. Plant prevention'libby'could improve frost resistance abilities and fruit set percentage of'Shushanggan'apricot. Cold-resistant agent'Bihu'could decrease the semilet hal temperatures and enhance the cold resistance effectively.4. Strains S6 is the best in the terms of fruit quality and chillness-tolerance ability, which is suitable for choosing as excellent promotion materials for'Shushanggan'apricot breeding.