Evaluation Of Aroma Substances Of Strawberry Germplasm Resources And Cross Breeding

Strawberries are perennial herbs,rich in nutrients and aroma.Studying the aromatic substances in strawberry fruits is valuable for the breeding and quality evaluation of new strawberry varieties.Japanese strawberry varieties have good flavor but poor disease resistance,while European and American strawberry varieties are sour but have strong disease resistance.Breeders in China are committed to synthesizing the dominant traits of these two types of strawberries,and have selected some varieties suitable for cultivation in China.At present,conventional hybrid breeding is still one of the effective methods for breeding new varieties.In this work,50 strawberry varieties cultivated in the strawberry resource nursery in Changfeng County,Hefei were sampled.The aroma components were extracted by headspace solid phase microextraction,and analyzed by GC/MS,the strawberry aroma components were analyzed,,and different varieties were selected.Comparison of aroma substances;the selection of two varieties of strawberry of ‘Benihoppe’ and‘Albion’ for cross breeding,the quality identification of the hybrid offspring fruit,laid the foundation for the future variety breeding.The main results are as follows:1.The volatile substances of the fruit of 50 strawberry varieties during the mature period were analyzed by GC-MS.A total of 344 substances were detected,including135 esters,31 alcohols,24 ketones and 12 kinds of acid,25 kinds of aldehydes,and117 kinds of other substances.2.The content and type of volatile substances in different varieties are different,and the relative content of the same volatile substance in different varieties is also different.Esters are basically the main components of all volatile substances in strawberries.For example,the relative content of esters in ‘Tokun’ is 83.93%,‘Sachinoka’(53.72%),‘Yuefeng’(84.08%),‘Snow White’(77.93%),et..3.Among the 50 strawberry varieties,ethyl caproate,methyl caproate,etc.are the most important esters,such as the relative content of ethyl caproate in ‘Tokun’ is22.79%,the relative content of methyl caproate in ‘Sachinoka’ is 21.75%;Hexanal,(E)-2-hexenal are the most important aldehydes,such as the relative content of hexanal in ‘Jingquanxiang’ is 36.70%,the relative content of(E)-2-hexenal in‘Shenyang’ is 39.70%.4.Among the 50 strawberry varieties,2,5-dimethyl-4-hydroxy-3(2H)-furanone and γ-decalactone are the most important ketones,such as the relative content of2,5-dimethyl-4-hydroxy-3(2H)-furanone in ‘Benihoppe’ is 1.54%,the relative content of 2,5-dimethyl-4-hydroxy-3(2H)-furanone in ‘Yanli’ is 6.90%,γ-decalactone(25.59%);5.Among the 50 strawberry varieties,linalool,L-α-terpineol,nerolidol,etc.are the most important alcohols.For example,the relative content of linalool in ‘Suizhu’ is28.33%,and L-α-terpineol content is 3.12%,nerolidol content is 3.14%;the relative content of linalool in‘Yanli’ is 17.66%,L-α-terpineol content is 3.21%,nerolidol content is 9.52%;Caproic acid,valeric acid,etc.are the most important acid substances,such as the relative content of ‘Ningfeng’ caproic acid is 22.15%.The valeric acid(6.20%)in ‘Yanli’ is the main acid substance.6.Divide strawberry varieties into four groups based on differences in volatile substances: cluster A had only one strawberry cultivar,‘Zhaoyue,’ the major components of which were ethyl hexanoate and methyl hexanoate.Cluster B contained ‘Maehyang’ and ‘Sophie,’ which also mostly consisted of ethyl hexanoate but at lower concentrations than that in cluster A,as well as ethyl octanoate and he×anoic acid.Cluster C grouped 15 strawberry cultivars: ‘Snow White,’ ‘R12,’‘Jingyao,’ ‘Kalina,’ ‘xiaobai,’ ‘Yuelan’ ‘Redchief,’ ‘Danshui,’ ‘Zhaofeng,’ ‘Earliglow,’‘Danmei 1,’ ‘Wanxiang,’ ‘Roman,’ ‘Kaorino,’ and ‘Ssanta.’ These cultivars contained(E)-2-hexenal,methyl hexanoate,linalool,and(E)-2-hexen-1-ol as major compounds.The other 32 strawberry cultivars belonged to cluster D,and volatiles were too diverse and difficult to determine.Therefore,no consistent major compounds were identified for this group.7.Carry out forward and reverse hybridization with ‘Benihoppe’ and ‘Albion’ as parents,and obtain a total of 862 hybrid seedlings.And evaluate the fruit quality of the hybrid offspring.The single fruit weight of the hybrid strawberry offspring is7.2-60.32 g,the soluble solid content ranges from 4.80 to 12.60%,and the soluble sugar content ranges from 2.89 to 8.48%.The titratable acid content range is0.53-1.31%.The aspect ratio of hybrid strawberry progeny fruit is 1-2.11,and the fruit shape ranges from nearly spherical to conical to long conical.8.Analyze the fruit quality of the hybrid progeny and select two plants with better traits,‘H56’ and ‘H166’.The maximum single fruit weight of ‘H56’ is 60 g,which can be used for breeding new varieties of large fruit strawberry.The maximum single fruit weight of ‘H166’ is 21 g,with strong aroma,large fruit shape index,and beautiful appearance.It can be used for breeding new varieties of ornamental and picking strawberries.