Analysis Of Fruit Quality And Molecular Markers Of Middle Late Ripening Plum In Chongqing

Chongqing has favorable climatic and geographical conditions,with 63%of the mountainous areas under its jurisdiction,which is suitable for the development of fruit industry.At present,fruit industry has become one of the backbone industries in the revitalization of Chongqing's rural economy.In recent years,the plum industry in Chongqing has developed rapidly.By the end of 2018,the planting area of plum in Chongqing is 64500 hm~2,the output is 476000 t,and the output value is about 4 billion yuan.It has become the second largest fruit industry in Chongqing.From the perspective of planting situation,the characteristics of single variety and concentrated maturity are common.In order to better develop the plum industry in Chongqing,it is necessary to continuously explore new resources and cultivate new varieties.In this experiment,117 crisp plum fruits and 179 crisp plum leaves(including the other plum varieties)were collected from 12 regions in Chongqing,including Bailong village,Chaoyang village,Quchi village,Quanfa village,Huatai Township,Jiuquan village,Pulian Township,Changgui village,Xiaoheba village,Yuanxing village,Wanzhou and Yongfeng Village,and they were used for fruit quality analysis.Meanwhile,genetic distance and genetic relationship were analyzed by SSR and ISSR markers.The main results are as follows:1.The fruit quality of 117 crisp plum materials was different according to the region and variety.Wuxi late crisp plum and Jiuquan late crisp plum have the largest single fruit weight;Jinshan late crisp plum has yellow peel and pulp,good glossiness,lower total acid content and higher sugar and acid content than other regions,among which Yuanxing village has lower soluble solid content and Xiaoheba village has higher soluble solid content.The results of principal component analysis showed that the fruit quality of Changshou Yongfeng Village was superior,followed by Yuanxing village in Nanchuan,Huatai village in Wuxi and Quchi village in Wushan.On the premise of little difference in comprehensive quality,Jinshan late crisp plum ripened later,and matured in the middle and late September.It can be used as the key to develop late mature plum varieties,but its suitable extension area needs further experimental observation.2.179 samples of plum leaves were extracted by DNA and amplified by SSR-PCR to screen crisp plum materials with obvious genetic differences.The results showed that 24 pairs of polymorphic primers were screened from 343 pairs of SSR primers,and 137 bands were amplified,including 124 polymorphic bands,and the ratio of polymorphic bands was 90.51%.However,the polymorphic bands were only found in Guofeng plum,Yueguang plum and other red or yellow skinned plum varieties.The reason may be that all of the tested lines are green crisp plum selected in Chongqing,the genetic basis is narrow,and the difference is very small.The number of marker loci screened in this study is small,so no genetic difference can be found.3.ISSR labeling of 179 samples.The results showed that 18 polymorphic primers were selected from 100 universal primers,134 bands were amplified,90 of which were polymorphic.Except for the genetic similarity coefficient between Guofeng plum and other materials of 0.5941-0.6066,the genetic similarity coefficient between other lines is 0.9763-1.0000,and the genetic relationship is very close.As a control,the genetic distance between Wushan crisp plum and other crisp plum strains was between0.0220-0.0226.The genetic distance of each strain in Jiuquan crisp plum mother garden was slightly larger than that in other regions.The above results show that there are weak differences among the strains of crisp plum in different regions,and there are very weak genetic differences among Yongfeng Village,Quchi village and Yuanxing village with better comprehensive fruit quality.Based on the above results,it is considered that Jinshan late crisp plum(Yuanxing village,Nanchuan)has the best comprehensive quality and is the latest mature variety in Chongqing at present.It can be used as a good late ripening variety to be popularized in the middle altitude area,but the mature period in different altitude areas remains to be observed.Wuxi late crisp plum(Wuxi Changgui Village)and Jiuquan crisp plum(Wuxi Jiuquan Village)have the characteristics of big fruit and high quality,which can be appropriately promoted as new varieties in middle and high altitude areas.All the above three varieties have passed the crop variety identification in Chongqing and can be popularized in the main planting area of plum in Chongqing.