Study On The Comparison Of Fruit Characters And The Difference Of Storage In Two High Flavonoid Apple Strains

In order to provide the fundamental information for the utilization and conservation of Malus sieversii germplasm resources and the theoretical and technical system of functional apple breeding,we used 2 high flavonoid apple strains ‘Hongxin 7' and ‘Hongxin 9' as experimental materials,and investigated volatile components,firmness,cell wall-modifying enzyme activities and gene expression related to aroma and firmness.Moreover,We used above-mentioned functional apple strains as the materials while ‘Gala' was employed as the control.And then,We measured and analyzed the relevant indicators of flavor substances,such as the composition and contents of flavonoids,sugar and acid components,contents of calcium,iron and zinc,etc.The main results were as follows:1)The firmness,contents of calcium,iron,zinc,anthocyanin and antioxidant power of ‘Hongxin 7' and ‘Hongxin 9' were very significantly or significantly higher than those of ‘Gala';Four sugars and seven organic acids were detected from 3 materials,and the contents of fructose and malic acid were the highest among three tested materials;The categories of aroma components and characteristic aroma components in ‘Hongxin 9' were the highest,while the contents of those in ‘Gala' were the highest,meanwhile,the categories and contents of those in ‘Hongxin 7' were the lowest;The content of flavonoids in ‘Hongxin 9' and ‘Hongxin 7' was 3.1 and 2.3 times higher than that of ‘Gala' respectively,but ‘Hongxin 9' tasted sour while the taste evaluation of ‘Hongxin 7' is sweet and sour as the same as ‘Gala';2)‘Hongxin 7' was hard-crisp and juicy,and it tasted sweet and sour.Meanwhile,the contents of flavonoids,anthocyanin,calcium,iron,zinc and antioxidant power of ‘Hongxin 7' were very significantly or significantly higher than those of ‘Gala'.Therefore,we could select functional apple cultivars with excellent comprehensive quality from hybrid or backcross progeny segregating populations of Malus sieversii f.neidzwetzkyana;3)During fruit storage,the firmness in ‘Hongxin 9' was significantly lower than in ‘Hongxin 7' while the ethylene production rate in ‘Hongxin 9' was significantly higher than in ‘Hongxin 7'.The contents of ester and total aroma as well as the expression of AAT1,AAT2,LOX in ‘Hongxin 9' were significantly higher than in ‘Hongxin 7' during fruit storage,however,in the later period of storage(90-120 d),the contents of alcohols and aldehydes and the expression of HPL and ADH in ‘Hongxin 9' were significantly lower than in ‘Hongxin 7'.The cell wall-modifying enzyme activities and related-gene expression of PG,XET,PME,AM,?-L-Af and ?-Gal in ‘Hongxin 9' were significantly higher than in ‘Hongxin 7' during fruit storage;4)All results indicated that the main reason causing the firmness in ‘Hongxin 9' was lower than in ‘Hongxin 7' during fruit storage was of a high level in the ethylene production rate and ester content and the up-regulated expression of ester biosynthesis related genes and cell wall related genes.Meanwhile,the change,types,content of aroma compounds can be used as one of the evaluation indicators of fruit quality during storage.