Volatile Profiling Of ’Honeycrisp’ And ’Modi’ And Their Hybrid Offspring

Aroma is a very important commodity trait of apple fruit,and it is also one of the focuses of apple breeding work.The aroma is multiplied Changes in the composition,type and content of volatile substances will cause changes in traits,and aroma traits are multigenetic Control,highly heterozygous,easy to separate.Therefore,the study of the genetic law of aroma substances is conducive to the quality improvement and product of apples Seed selection.In this experiment,’Honeycrisp’,’Gala’,’Modi’ and Fupingqiuzi as wild species and the F1 generation hybrid population of ’Honeycrisp’ × ’Modi’ as research materials,the apple aroma material and its genetic characteristics were analyzed,and A hypospectral technique was tried for aroma substance detection,while focusing on the ralationship between amino acid and branched-chain aliphatic aroma and between fatty acid and straight-chain aliphatic aroma.The main findings are as follows:(1)A total of 61 aroma substances were detected in ’Honeycrisp’,including 27 esters,10 aldehydes,9 alcohols,4 ketones and 27 esters 4 hydrocarbons and 1 olefineterpene,the total volatiles(peel)was 22189.98 μg/kg.’Modi’ detected 44 aroma substances,Contains 28 esters,6 aldehydes,4 alcohols,3 ketones and 2 eneterpenes,and the total volatiles(peel)is 4423.46μg/kg.’Gala’ contains 56 aroma substances,also dominated by esters(24 types).The aroma characteristics of Fupingqiuzi are more special,only Contains 4 esters,8 aldehydes,3 alcohols,3 ketones,2 alkanes and 3 olepenes,volatilized the total amount is also significantly lower than that of cultivars,which is only 323.61μg/kg(peel).A total of 127 species were detected in the fruits of the F1 offspring Aroma substances,of which the peel contains 106 and the pulp contains 99.The aroma composition is 49 esters,18 aldehydes,20 alcohols,8 ketones,6 alkanes,1 ether and 8 oleterpenes.The offspring contain all the aroma substances of the parents and are produced 63 aroma substances that parents do not have.Fupingqiuzi has 2 unique aromatic substances,(+)-alfalfone and docosane.Among all varieties and F1 offspring,except for Fupingquizi,the main aroma substance of aroma peel and pulp is an ester,and the number of type and content of peel aroma substances are higher than that of pulp.In addition,expect for Fupingqiuzi,the peel and fruit are also relatively close in the types of aroma substances,with about 1/3 of the substances coinciding.In the F1 generation,the overall aroma super-kinship phenomenon emerges The present frequency is higher than that of low-parental phenomena.(2)The differential accumulation substances were screened in the form of a scatter plot,33 species were screened in the peel,and the pulp was sifted 18 species were selected.The peel differential accumulation contains 19 esters,8 aldehydes,3 ketones,2 alcohols,and α-farnesene.Base on differential accumulation of substances,the hierarchical clustering algorithm(HCA)classifies the F1 generation into 2 groups.Then by partial least squaresdiscriminant points The PLS-DA method classifies F1 offspring and calculates the VIP value of the variance accumulation substance.Eventually at high VIP values of substances are screened for potential markers.The potential marker for group 2 of the final F1 generation peel isα-farnesene.The differential accumulation substance in plup contains 8 esters,5 aldehydes,3 alcohols,and 1 olenoterpene(Artemisia sinensis).On the same technical route,the potential markers in the 3 groups of F1 generation pulp were n-hexanol,anipetol and amyl acetate.use"Aroma Office" software retrieves the aroma characteristics of each volatile and counts the frequency of each flavor.Compared cultivars and wild species(Fupingqiuzi),there are obvious differences in the flavor.The cultivated varieties are mainly apple-flavored,supplemented by aromatic and oily flavors.Fupingqiuzi is dominated by grass and green apple.According to the grouping of peel and pulp in the F1 generation,the flavor characteristics of each group were analyzed and it was found that the F1 generation was basically the same as the parent in the apple and aromatic taste,but at the same time,the green apple flavor and grass flavor increased,and the aroma characteristics tended to be inclined to wild species.(3)By modeling the aroma of apple peel through hyperspectra,it is found that the most suitable pretreatment method for this experiment is Standard normal variate(SNV).The hyperspectral image shows that the characteristic bands of esters are 413,493,512,551,592,600,721,727,729 and 733 nm,alcohols are 519,562,570,571,660,676,700,737 and 738 nm.R2 of esters,aldehydes,alcohols,and ketone models are 0.90,0.92,0.92,and 0.91,respectively.Modeling aroma types is better than modeling individual compounds.Select the best modeled alcohols for model-based visualization of alcohol content.The visualization results show that the distribution of alcohols in the fruit is high in the edge and low in the middle.But the visualization effect is clearly boundary,not three-dimensional,perhaps related to the spatial background and model effect,and needs to be further optimized.(4)The literature indicates that branched-chain aliphatic aroma precursors are alanine(Ala),valine(Val),leucine(Leu),isoleucine(Ile),and phenylpropionine(Phe).The linear aliphatic aroma precursors are linoleic acid(linoleic acid and trans-linoleic acid)and linolenic acid(γ-linolenic acid and α-linolenic acid).The highest content amino acid in the peel is isoleucine,and the pulp is alanine.F1 generation related amino acid flat the distribution of the means coincides with the 4 selected species.8 ubiquitous branched-chain aromas and amino acids were screened from peel aromas to construct a grid search algorithm model,which was used to calculate the importance of each amino acid to branched-chain aromas.The model results showed that isoleucine,alanine,valine,tyrosine,and glycine were significantly more important than other amino acids,with explanations exceeding 0.1,with isoleucine up to 1.7.In the peel and pulp,the fatty acids associated with the chain aroma are linoleic acid,translinoleic acid is only found in the ’Honeycrisp’ peel,and α-linolenic acid is only found in’Gala’ peel.The peel and pulp of the F1 generation are also dominated by linoleic acid.33 straight-chain aromas were screened from peel aromas and PLS-R models were constructed with related fatty acids.It can be seen from the correlation load matrix that the content of trans-linoleic acid is significantly negatively correlated with the content of 13 straight-chain aromas.Other fatty acids did not show significant correlation.