Screening Of New Superior Lines Of ’Changfu 2’ Apple High-quality And Efficient Pollination Trees

The apple is a self-incompatibility fruit tree of apple in Rosaceae,and its self flowering seed setting rate is low‘Fuji’is an important main variety in China’s apple producing areas.In orchard production,selecting efficient superior pollination line（high ornamental value,high pollen vitality and high pollination quality）is of great significance to improve the yield and quality of orchards and increase economic benefits.This study takes the‘Hongli’seedling population as the test material,selects the high-efficiency pollination trees as the goal,and gradually determines the S-genotype of the superior pollination line,so as to better configure the pollination trees for the main varieties in the orchard.The research results are as follows:1.56 varieties of crabapple were preliminarily selected from the first 700 plants of ornamental crabapple under the comparison of resistance and plant type,and the flowers,leaves,fruits and tree shapes of the preliminarily selected strain were investigated and counted in their phenological period.The superior line of crabapple with high ornamental value were selected through cluster analysis.Combined with the pollen germination rate,7new pollination trees with pollen germination rate of more than 85%were finally selected,and‘Yingyu’,‘Yingxiang’,‘Yinglan’,‘Yingxing’,‘Yingxue’,‘Yinghuang’and‘Yinglv’are named.2.According to the results of fruit setting rate,internal and external quality,volatile substances and mineral elements content of‘Changfu 2’apple pollinated by 7 superior pollination lines and control（Gala）,there are certain differences between varieties and control,and the phenomenon of pollen directness is obvious.The results showed that different superior lines of crabapple pollen pollinated‘Changfu 2’could significantly improve the external quality of fruit,such as fruit setting rate,single fruit weight,fruit shape index,hardness and anthocyanin content in pericarp.Soluble solids,soluble sugar,sugar acid ratio to solid acid ratio,fruit vitamin C and flavonoids and other fruit internal indexes were improved compared with the control after crabapple pollination,and most of them were significantly higher than the control.The content of titratable acid was significantly lower than that of the control,which realized the purpose of increasing sugar and reducing acid and improved the fruit quality.The mineral elements of N,P,K,Ca,Mg and Fe in fruit were determined.The results showed that the content of mineral elements in fruit was affected by pollination combinations.The total volatile substances of different crabapple superior lines after pollination were higher than the control,in which esters accounted for the largest proportion,and the types of volatile substances were also richer than the control.3.Through correlation analysis,the fruit quality indexes of‘Changfu 2’after pollination were analyzed.There is a significant or positive correlation between the indicators.7 fruit quality indexes were selected to rank 8 pollination combinations.The results showed that‘Yinghuang’had the best fruit quality.4.7 superior pollination lines were amplified,cloned and sequenced by PCR using the universal primer sequences’FTQQYQ’and’anti-1/MIWPNV’of Rosaceae.The S-genotype of’Yingxiang’crabapple was successfully identified.Its S-genotype was S₁₇S₃₄.Its nucleotide sequence and amino acid sequence had 99.73%and 98.72%homology with S-RNase of Malus,respectively.The genome structure had high similarity.‘Md S₂₆Sp F’and‘Md S₂₆Sp R’specific primers were used to amplify,clone and sequence the other 6 superior lines.An S-haplotype shared by the 5 superior lines‘Yingyu’,‘Yinglan’,‘Yingxing’,‘Yinghuang’and‘Yinglv’was successfully identified.The homology with S₂₆-RNase was 100%,which was S₂₆;‘Yingxue’was amplified,cloned and sequenced with‘Pycom C1F’and‘S₅₀R-2’specific primers.One S-haplotype of‘Yingxue’was identified,and its homology with S₅₀-RNase was100%,which was S₅₀.