Construction Of Permanent Genetic Map And Mapping Agronomic Traits In Hami Melon [Cucumis Melo L.ssp. Melo. Convar. Ameri (Pang.) Greb.]

Melon (Cucumis melon L.) is a widely grown economic and garden crop species,belonging to the family of Cucurbitaceae. Xinjiang Hami melon, with independent and different genetic background of cantaloupe, is unique cultivars in China. A set of 107 recombinant inbred lines (RIL7) was developed from a cross between the cantaloupe (Cucumis melo L. ssp. melo.convar. cantalupa (Pang.) Greb.) and the Xinjiang Hami melon(Cucumis melo L. ssp. melo. convar. ameri (Pang.) Greb.). Simple sequence repeat (SSR) markers,coming from published papers and ICuGI Web site, was used to construct permanent genetic map with the RIL7 populations. And comparative analysis of melon map with genetic background of cantaloupe. And then Identification Quantitative Trait Loci and analysis genetic effect for important agronomic traits . Therefore the research laid foundation to integrate and comparative analysis for international common melon genetic map, fine mapping and clone gene of melon QTL, and molecular maker-assisted breeding.My research has led to the following results:1) Analysis genotype of RIL7 population, the results showed that homozygous genotype accounted for 96.68%, Heterozygous genotype accounted for 3.32% in the whole population. So the RIL7 population we got was large variation between strains and stability in strain, and parents genotype (A:B) segregation ratio in line with theoretical ratio (1:1).2) 258 SSR primers showed stable polymorphism (13.37%). The polymorphism rate of gSSR primers was 10.22%, EST-SSR was 15.62%.And the polymorphism rate coming from melon primers was 16.25%, coming from cucumber was 2.26%, coming from watermelon was 2.29%.3) The map consisted of 22 linkage groups, contained 201 SSR markers and 1 morphological traits, it spanned a total genetic distance of 977.153cM with an average map interval of 4.837cM/marker. The length of 22 linkage groups was between 2.895～90.021cM,the locus number were between 3～20 loci, Marker density was between 0.965～8.319cM. LG3 contained the most markers (20 SSR markers),LG18 contained the least markers(3 SSR markers). LG19 was the maximum in average distance between markers (8.319cM), LG18 was the minimum (0.965cM).The distance between MU5035 and MU3494 was the maximum (22.206cM).4) 47 SSR makers (18.22%) showed the genetic distortion (p<0.05) among 258 polymorphic makers. Of total segregation distortion makers, 34 makers (72.34%) showed significant distortion.38 markers (80.85%) deviated toward female parent, K7-2; while 9 markers (19.15%) deviated toward male parent, K7-1. 40 markers located 12 linkage groups, and screed 8 SDRs. In the same SDR, all of markers deviated toward the same direction. Among 8 SDRs, 7 SDRs deviated toward female parent, K7-2; SDR-6 deviated toward male parent,K7-1. Segregation distortion makers accounted for 75% and 87.5% separately on LG13 and LG15. Distortion makers of SDR-4 and SDR-7 showed significant level.5) According to international standards for gene functional classification, 90 SSR-ESTs mapping in the map were classified. The molecular function of ESTs were the catalytic activity and binding function mainly, for example zinc finger binding protein, protein binding, RNA binding, DNA binding, ion binding, transcriptional regulation, and enzyme activity regulation; involved in biological processes, including regulation, development, biological interaction, various stimulus-response, metabolism and signal transduction.6) Comparative analysis between hami melon map and cantaloupe map of Fernandez-Silva et al(2008), 59 SSR markers coming from Fernandez-Silva et al(2008) showed polymorphism in our parents K7-1 and K7-2, 46 SSR markers were common in two maps. 17 linkage groups in the map were collinear with cantaloupe genetic map. 3 linkage groups (LG5,LG7,LG16) were corresponding with cantaloupe genetic map(Ⅶ,Ⅷ,Ⅱ)one-on-one;14 linkage groups in the map were corresponding with 7 linkage groups of cantaloupe genetic map(37 common markers).7) Using multiple QTL model method, 16 QTLs were detected distributed in 6 linkage groups. Except flesh thickness didn't detected, other traits detected 1~4 QTLs separately. Some QTLs (qFSC-3 and qRSC-3) were co-location on one linkage group, indicated that the traits of similar function or correlation usually locate the same or near position in the same linkage group.