Study On Genetic Characteristics Of Volatile Compounds In Apple Fruit

Aroma is an important trait of apple fruit,which directly affects the flavor quality of the fruit.Fruit aroma is usually composed of many volatile compounds.The genetic analysis of volatile compounds can provide scientific basis for apple flavor improvement and genetic breeding.In this study,‘Ruixue’,‘Ruixianghong’,‘Qinyun’,‘Huaguan’and their parents were used as plant materials to analyze the differences of volatile compounds in fruits.Moreover,to investigate the genetic characteristics of the crucial volatile compounds in apples,the F₁hybrid population of‘Fuji’בGolden Delicious’was utilized.The main findings are as follows:1.‘Ruixue’,‘Ruixianghong’,‘Qinfu 1’and‘Cripps Lady’were detected 37,40,38 and37 types of volatile compounds with the total content of 12646.89μg/kg,35645.18μg/kg,4183.16μg/kg and 14457.98μg/kg,respectively.The esters,aldehydes,alcohols,terpenes and others volatile compounds in‘Ruixue’apple were 41.15%、22.26%、1.54%、34.17%and 0.87%,respectively.The percentage of aldehydes,alcohols,and terpenes of‘Ruixue’apple were higher than those of‘Qinfu 1’and‘Cripps Lady’,and esters and other volatile compounds were lower than those of‘Qinfu 1’and‘Cripps Lady’.The percentage of esters,aldehydes,alcohols,terpenes and others volatile compounds in‘Ruixianghong’apple were62.71%,8.99%,0.24%,26.89%and 1.18%,respectively.The esters and terpenes of‘Ruixianghong’apple were higher than‘Qinfu 1’and‘Cripps Lady’,while aldehydes and alcohols were lower than‘Qin Fu 1’and‘Cripps Lady’,other volatile compounds were between‘Qin Fu 1’and‘Cripps Lady’.The proportions of aldehydes and terpenes in apples of‘Ruixue’were higher than those of‘Ruixianghong’,but the volatile compounds of esters were lower than those of‘Ruixianghong’,indicating that these two new apple varieties have different aroma characteristics.2.The determination of volatile compounds in‘Qinyun’,‘Fuji’and‘Gala’were performed,with the total content were 17414.30μg/kg,7920.68μg/kg and 5227.60μg/kg,respectively.The esters,aldehydes,alcohols,terpenes and others volatile compounds in‘Qinyun’apple were 42.44%,8.91%,3.25%,42.05%and 3.35%,respectively.The percentage of esters and alcohols of‘Qinyun’apple were between‘Fuji’and‘Gala’,and terpenes were higher than those of‘Fuji’and‘Gala’,and aldehydes were lower than those of‘Fuji’and‘Gala’.The proportion of various volatile compounds in the apple of‘Qinyun’was similar to that of the female parent‘Fuji’.3.The determination of volatile compounds in‘Huaguan’,‘Fuji’and‘Golden Delicious’were performed,with the total content were 15522.62μg/kg,7920.68μg/kg and12598.74μg/kg,respectively.The esters,aldehydes,alcohols,terpenes and other volatile compounds in‘Huaguan’apple were 50.19%,19.08%,4.71%,23.87%and 2.16%,respectively.The percentage of alcohols of‘Qinyun’apple were higher than those of‘Fuji’and‘Golden Delicious’,and esters,aldehydes and terpenes were between‘Fuji’and‘Golden Delicious’.The proportion of various volatile compounds in the apple of‘Huaguan’was similar to that of the female parent‘Golden Delicious’.4.A total of 12 common volatile compounds were detected in‘Ruixue’,‘Ruixianghong’,‘Qinyun’,‘Huaguan’and their parents:8 esters:,2 aldehydes:,1 kind of alcohol,1 terpenes,which can be considered as representative volatile compounds of apple fruit in this study.5.The analysis of volatile compounds in the F₁hybrid population of‘Fuji’בGolden Delicious’found that in the progeny population,the content of volatile compounds in esters were the highest,and the content of volatile compounds in alcohols were the lowest.The volatile compounds were shared by both parents and did not separate in the offspring were higher than the parental median value,and there were continuous variation in the hybrid population,showing the typical genetic characteristics of quantitative traits.There were 49kinds of volatile compounds with different separation ratios.Most of the volatile compounds were distributed continuously in the progeny,showing the heritability of quantitative traits.Only 4 kinds of volatile compounds conformed to the heritability of mendelian qualitative traits.Esters volatile compounds had large coefficients of variation,while aldehydes volatile compounds had small coefficients of variation.These findings showed that it was more advantageous to select apple varieties with prominent esters in this hybrid population,but it is difficult to select apple varieties with prominent aldehydes.