Variation And Selection Of Representative Traits In F₂ Generation Of Soft-endocarp Hawthorn Fruit

Soft-endocarp hawthorn is a unique Chinese hawthorn germplasm resource,and it is important for germplasm innovation to use it as the parent for cross breeding and to select lines with excellent traits from the F₂ generation.In order to obtain high quality Soft-endocarp hawthorn germplasm resources,this experiment selected the natural self-progeny F₂ of the F₁ generation of the cross of’Shandong Da Mian Gou’×’Xinbin Soft Seed’as the test material,and a total of 60 plants of the F₂ population were used to determine the appearance quality and inner quality of the fruits.A total of 20 traits were measured and analyzed,with the aim of selecting and breeding soft hawthorn strains with large single fruits and excellent traits,and obtaining new soft hawthorn strains to lay the foundation for variety validation.The main results of the study are as follows:1.Among the 60 strains of soft-endocarp hawthorn fruits,18-27 had the largest single fruit weight of 5.27g;16-1 had the longest longitudinal diameter of 22.97mm;18-41 had the largest fruit shape index of 1.07;25-42 had the largest peel color L^*value and h value of 72.96 and 70.52°,respectively,and the peel color was earthy yellow,which was significantly different from the fruits of other strains;14-56 had the largest peel color a^*value and c^*values were the largest,46.01 and 53.80,respectively;22-27had the largest b^*value of 40.88;15-38 had the longest longitudinal diameter of 21.78mm and yellow-red flesh color,6-34 and 6-28 had light red flesh color,while the rest of the strains had white flesh color;2-44 had the largest hardness,29.17 N with skin and 23.25 N with peel.17-17 had the highest edibility of 91.04%;16-35 had the highest soluble solids content with 21.50%;24-41 had the highest water content of 83.95%;3-27 had the highest soluble sugar content of 31.50%;7-49 had the highest titratable acid content of 5.92%;22-36 had the highest soluble protein content of 20.97mg/g;7-49had the highest vitamin C content with 130.99mg/100g.2.For the traits of 60 soft-endocarp hawthorn fruit,soluble sugar,soluble protein,and vitamin C had the highest degree of variation with coefficients of variation of42.96%,63.71%,and 42.77%,respectively;longitudinal diameter,peel color c^*,transverse diameter,fruit shape index,edibility,and water content had the lowest degree of variation with 9.64%,9.06%,8.89%,6.59%,4.68%,and 4.40%;the remaining traits showed average variability.3.The single fruit weight of 60 soft-endocarp hawthorn fruit was most strongly correlated with longitudinal diameter and transverse diameter,with correlation coefficients of 0.796 and 0.914,respectively,both with highly significant positive correlations（P<0.01）;skin color L^*was most strongly correlated with skin color b^*and h,with correlation coefficients of 0.854 and 0.918,respectively,both with highly significant positive correlations（P<0.01）;skin color b^*was most strongly correlated with The strongest correlation was found between peel color b^*and peel color h,with a correlation coefficient of 0.881 and a highly significant positive correlation（P<0.01）;the strongest correlation was found between peel hardness and peel hardness,with a correlation coefficient of 0.954 and a highly significant positive correlation（P<0.01）.4.60 soft-endocarp hawthorn strains were analyzed by principal component analysis,and seven principal component factors were proposed with a cumulative contribution of 82.482%.The top 5 strains were ranked from highest to lowest:20-9,15-38,18-45,22-22,25-37.60 soft-endocarp hawthorn plants were divided into 4major categories using cluster analysis,and the results were similar to those of principal component analysis.In conclusion,after statistical analysis,five strains,20-9,15-38,18-45,22-22,and25-37,were the top 5 strains in terms of overall ranking.Their fruit size,color,intrinsic quality and other traits were superior to other strains at significant or highly significant levels by ANOVA.