Genetic analysis and QTL mapping of fruit length and diameter in a cucumber (Cucumber sativus L.) recombinant inbred line (RIL) population

Abstract

Fruit length and diameter are very important appearance quality which affects preference of consumers and quality of fruit. To improve the genetic mechanisms of cucumber fruit shape and size, an F2:5 recombinant inbred line (RIL)-population was derived from a cross between Q16 inbred lines which had slender fruit and Q24 inbred lines which had round fruit to screen fruit shape QTLs locus. 85 RILs, 15 F1 and 15 of each parental line were grown in the spring of 2016 and 2017 respectively. The length and diameter of ovary, immature fruit and mature fruit were measured at blooming day, 12 days after pollination and 35 days after pollination respectively. The RIL population was screened basing on the data related fruit using 89 SSR markers and 1 InDel marker. Twenty-one QTLs loci were totally identified for fruit shape traits from RIL population. Comparing the flanking markers of 21 QTL loci allowed to 5 consensus QTLs FS1.1, FS1.2, FS2.1, FS3.1 and FS6.1 loci, in which FS3.1 played a role in fruit elongation, FS6.1 was important for the increase of fruit diameter, and the else 3 QTLs acted in both fruit elongation and diameter. The results from this study may increase the understanding of the genetic basis control of fruit shape and size and provide support for marker-assisted selection in cucumber with ideal fruit shape.