Identification Of Inbred Lines And Screening Of Crosses Of Red Fruit Tomato Resistant To Grey Leaf Spot

Tomato gray leaf spot is a disease caused by Stemphylium solani Weber.The yield and quality of tomato affected by this disease are severely damaged,which has an important impact on agricultural production.Breeding new varieties of tomato resistant to tomato gray leaf spot is the fundamental way to solve the harm of this disease.In this study,Marker Assisted Selection and field performance were used to identify the inbred lines of highgeneration red fruit tomato screened in the laboratory,and the inbred lines with good comprehensive disease resistance and economic characteristics were screened out.A new tomato cross with resistance to grey leaf spot disease and yellow leaf curl virus disease,strong growth,good fruit shape,high yield and tolerance,storage and transportation was bred through comparison test.The main results are as follows:Inbred lines identification: using Marker Assisted Selection,77 materials resistant to leaf spot disease were identified from 123 materials screened in the laboratory(79 highgeneration inbred lines and 44 newly collected materials).After field observation and MAS,the high-generation inbred lines were mixed and kept seeds and newly collected materials prefer to retain seeds per plant.In the autumn of 2020,five inbred lines with homozygous resistance to grey leaf spot were selected as hybrid fathers,which were 20RA022,20RA087,20RA168,20RA169 and 20RA171.In the spring of 2021,four excellent inbred lines,21RS009,21RS019,21RS059 and 21RS060,were selected,which could be used as hybrid parent selection for the current season or the next season.Crosses screening: a total of 72 crosses were prepared by using the male hybrids with pure resistance to grey leaf spot disease recommended in the autumn of 2020 and other excellent inbred lines.These crosses were involved in the variety comparison test in the spring of 2021.The botanical characters,appearance quality,nutritional quality,field resistance and other key traits of the crosses were observed and evaluated.Finally,eight combinations with excellent economic traits and resistance to grey leaf spot were screened,which were 21HS030,21HS032,21HS044,21HS048,21HS055,21HS056,21HS070 and21HS072,respectively.