Study On The Identification Of Pummelo Resources In Majiayou Production Areas And The Effects Of Pollination Treatments On Fruit Quality Of Majiayou

Majiayou is an excellent local pummelo variety in China.The main planting area is Shangrao City,Jiangxi Province.As of 2019,the planting area of Majiayou in Shangrao City exceeded 25,300 hectares,the fruit yield exceeded 50,000 tons,and the industry developed rapidly.With the continuous growth of Majiayou industry,problems such as mixed seedlings,low yield and unstable quality have become increasingly prominent.The present study was conducted on Majiayou,and the prominent industrial problems of Majiayou were studied.The local pummelo resources in Majiayou producing areas were sorted out and systematically analyzed from the aspects of genomic data,and the specific molecular markers of Majiayou were developed.The aim is to accurately identify Majiayou from its local pummelo resources and carry out early rapid screening of Majiayou seedlings.Meanwhile,the effects of different pollination combinations on the yield and quality of Majiayou fruit were analyzed by using local pummelo and tetraploid Grapefruit to configure pollination combinations with Majiayou,and the effect of liquid pollination technology on Majiayou industry was explored.The results are shown below.1.Identification of pummelo resources in Majiayou producing areaMajiayou is the main cultivated variety in Majiayou producing area,accompanied by coarse Majiayou,Xinmuyou and local pummelo which has not been identified.Through the results,it was found that there was no significant difference in leaf morphology between Majiayou and other pummelo resources,and it could not be distinguished by leaf shape.In terms of fruit appearance characteristics,Shatianyou has obvious long fruit handles.Xinmuyou and Tuyou 3 belong to medium-sized fruits,while others belong to medium-sized fruits.Compared with other pummelo,the oil cells of Majiayou and coarse Majiayou peel were larger and less distributed,and the oil cells of coarse Majiayou were convex,and the oil cells of Majiayou were flat and concave.In terms of fruit quality indicators,Significant differences in single fruit weight between Majiayou and Xinmuyou,Tuyou 1 and Tuyou 3.The difference in fruit shape index between Shatianyou and Tuyou 2 is significant,and the average peel thickness was as high as 2.58 cm.Except for Tuyou 2,there were significant differences with other pummelo species.The average content of soluble solids in Majiayou was 17.57%,significantly higher than that in Guanxi pummelo,Xinmuyou,and Tuyou 2.The average content of titratable acid was1.35%,Significantly higher than that in Xinmuyou and significantly lower than that of Tuyou 2 and Tuyou 3.The comprehensive solid-acid ratio is 13.00,which belongs to a higher level in pummelo.Based on genome resequencing,8 pairs of CAPS molecular markers were developed to distinguish Majiayou from common local pummelo.2.Effects of pollination treatment on fruit yield and quality of MajiayouIn order to explore the difference of fruit yield and quality among different pollination treatments and the application effect of liquid pollination on Majiayou,different pollination combinations were configured with different paternal pollen and Majiayou under the treatment of artificial point pollination and liquid pollination.The results showed that the pollen viability of coarse Majiayou,Xinmuyou and tetraploid Grapefruit were 94.5%,94.3% and 93.8%,respectively.The fruit setting rate of coarse Majiayou,Grapefruit and Xinmuyou was significantly higher after artificial pollination than natural pollination.among which coarse Majiayou > Grapefruit > Xinmuyou.Compared with natural conditions,liquid pollination can also significantly increase the number of fruit sets in Majiayou.Under artificial pollination treatment,the single fruit weight of coarse Majiayou and Xinmuyou pollinated fruits was larger than that of Grapefruit pollinated and natural pollinated fruits,and the single fruit weight of Grapefruit pollinated fruits was slightly lower than that of natural pollinated fruits.The average peel thickness of Grapefruit pollinated in Jiandiyuan was 2.06 cm,Which was lower than that of naturally pollinated.Pollination of tetraploid Grapefruit could significantly reduce the seed weight of pollinated fruit compared with natural pollination,while pollination of coarse Majiayou and Xinmuyou could significantly increase the seed weight of pollinated fruit compared with tetraploid Grapefruit.Pollination of Grapefruit and Xinmuyou can reduce the soluble solids and titratable acid content of the fruit,but the overall solid acid ratio is higher than that of natural pollination.The primary metabolites of different pollinated fruits were mainly organic acids and sugars.The citric acid content of Grapefruit pollinated fruit was the highest,which was significantly higher than that of other pollinated combinations.The volatile substances in the peels of different pollinated fruits and parents were mainly terpenes,among which the content of limonene was the highest.In the pollination combination of Xinmuyou,21 volatile substances showed obvious pollen xenia effect,including most terpenes.The limonene content of Majiayou peel was 25822.76±951.39 μg/g,and the limonene content of Xinmuyou peel was154583.28±6566.76 μg/g.After pollination,the limonene content of Majiayou fruit reached 84271.06±14187.77 μg/g,which was 3 times higher than that of Majiayou female parent,and the fruit aroma was significantly improved.In summary,the specific molecular markers of Majiayou developed in this study are expected to be applied to the rapid screening of Majiayou seedlings,exploring different pollination combinations of Majiayou can provide a basis for the selection of pollination combinations in Majiayou production,and the application of liquid pollination in Majiayou can prove that it can improve fruit yield and improve fruit quality,which can provide new technologies and ideas for the production of Majiayou assisted pollination.