Construction Of A SRAP-based Genetic Linkage Map Using F₂ Population Derived From A Cross Between C.var.chinensis And C.var.ameri

A molecular map of melo(Cucumis melo L.)was constructed with SRAP(Sequence-related Amplified Polymorphism)markers using a population consisting of 114 F2 individuals derived from the cross of 4G21(C.var.chinensis)and 3A832(C.var.ameri).184 SRAP primer pairs were used to detect the polymorphisms between 4G21(sp,dudaim) and 3A832(Cucumis melo L.) and showed 176 primer pairs generated 614 polymorphic bands with an average of 3.34 polymorphic bands per primer pair. The primer pairs showing polymorphism produced 1～15 polymorphic bands.The result showed that SRAP marker has high polymorphism to mapping parents of melon.29 primer pairs were used and produced 187 polymorphic loci with an average of 6.45 polymorphic bands per primer pair. A single primer combination could generated 1~15. The frequency of the 4G21 and 3A832 alleles at all the loci studied was 48.7%(96) and 51.3%(91) respectively, fitting a 1:1 ratio(p=0.796).Skewed markers did not show systemic bias towards either parent.The map consists of 12 linkage groups include 152 genetic markers.The total length of map is 2077.1cM,covering 63.9~91.2% of the whole melon genome and the average genetic distance of 13.67cM.Every linkage group has 6~32 genetic markers and average genetic distance is 9.72~19.19cM.The length of linkage group is 85.3~496.1cM.Chi-square test indicated only 7(4.6%)markers exhibited distorted segregation and they indicate significance levels at 5% or 1%.This is the first linkage map of melon in China.It provide a important base of information in quantitive trait loci(QTL), marker-assisted selection , map-based cloning , comparative genetic et.al..