Construction Of SRAP Genetic Linkage Map And QTL Analysis In Walnut(Juglans Regia)

Walnut(Juglans regia) is an important economic tree.The fruit and growth traits are typically controlled by multiple quantitative genes,which are susceptible to the influence of environment.Constructing linkage map of J.regia by DNA markers and locating the QTL of mainly economic traits are the basic link of developing molecular-design-breeding for J.regia. In this research,a genetic linkage map of Juglans regia was constructed with SRAP markers in 110 F1 progeny derived from the cross of'Yuanlin'and'Qinglin'walnut .The QTL of tree height,sprouting ability,vertical diameter nuts,horizontal diameter nuts and nut weight for the population were analysised.The main research results were as follows:1. The DNA of'Yuanlin'and'Qinglin'were used to select the primers,as a result,25 pairs of primers were selected from 100 SRAP primers,which could amplify rich polymorphism and steady bands.2.By the SRAP analysis of the F1 population,180 polymorphic markers were obtained. Joinmap3.0 were used to analysis the 180 markers and a genetic map was constructed.The genetic map was composed of 18 linkage groups,128 loci .The whole length of linkage map was 1153.1cM,and the average distance between adjacent loci was 9.01cM. Every group was consisted with 2~15 loci,and the length of linkage group was between 8.2 ~ 90.7 cM.3. The quantitative traits were analysised with winqtlcart2.5 software using composite interval mapping method.Two QTLs"sg-1"and"sg-2"for tree height were detected,all of which were located in Lg11,the additive effect of"sg-1"was -57.35,and the phenotypic variance explained of it was 7.31% . The additive effect of"sg-2"was -47.42,and the phenotypic variance explained of it was 5% .One QTL"myl-1"for sprouting ability was detected,it was located in Lg4,it's additive effect was -3.55,and the phenotypic variance explained of it was 3.58% . Three QTLs"zj-1","zj-2","zj-3"for vertical diameter nuts were detected,they were located in Lg4,Lg4 and Lg8,the additive effect of them were 0.32,-0.31and -0.91,and the phenotypic variance explained of them were 10.59%,9.87% and 6.93%; One QTL"hj-1"for horizontal diameter nuts was detected,it was located in Lg7,it's additive effect was -0.12,and the phenotypic variance explained of it was 4.53%.Two QTLs"gz-1"and"gz-2"for nut weight were detected,they were located in Lg5 and Lg8,the additive effect of them were 3.76 and -1.26,and the phenotypic variance explained of them were 63.77% and 5.81%.