Evaluation Of Genetic Diversity And Excellent Single Plant Selection Of Malus ‘Red Jewel’ Hybrid Offspring

In order to produce ornamental crabapple with phenotypic characteristics different from those currently available on the market,this experiment was carried out on 48hybrid offspring of Malus‘Red Jewel’,an ornamental crabapple variety with excellent winter fruiting characteristics,and Malus spectabilis var.albiplena,an ornamental crabapple variety with spring flowering effects.The results of the study were as follows.The qualitative traits of the fruit,flowers and leaves of the offspring were observed and recorded,and their quantitative traits were measured.The results showed that the phenotypic traits differed extremely significantly between the different samples of the offspring ornamental crabapple,with coefficients of variation ranging from 15.3%to63.70%,and single fruit weight was the trait with the largest coefficient of variation.The principal component analysis showed that the main factors causing variation in phenotypic traits among the offspring samples were fruit size and leaf size,indicating that fruit traits were more variable and segregated in the offspring population.Cluster analysis of the offspring phenotypic traits allowed the classification of the offspring samples into four categories:the first category was characterised by moderate leaf size;a separate category for number 23,which had a much larger leaf area than the other samples at 57.79 cm~2;the third category failed to set fruit;and the fourth failed to flower.A total of 98 alleles were detected in the 22 primer pairs,with an average of 4.45alleles amplified per primer,and a mean major allele frequency of 0.5150.Among the22 primer pairs,four pairs with clear bands and high polymorphism were selected for fingerprinting of the offspring samples.UPGMA clustering analysis was performed on the offspring samples and the 48 offspring samples could be classified into four categories based on 0.02.The first group had yellow-green leaves,poor growth and no fruit;the second group had more yellow-green leaves and red-yellow fruits,with better growth than the first group;the third group had light pink flowers,lighter leaves and red-yellow fruits;the fourth group had rich flower and fruit colours and the best growth.The samples selected by phenotypic analysis and molecular identification were No.22 and No.48,which were white heavy petals and dark pink single petals,respectively;No.48,which was selected by leaf phenotype and had variegated leaves with purplish-red new leaves and dark green adult leaves;and No.17,which was selected by fruit phenotype and had red spherical fruits.The fingerprints confirm the selection of the best plants as hybrid live offspring.