Genetic Analysis Of Main Agronomic Traits And Gene Localization Of Seed Coat Color In Luffa Spp.

Content：Luffa is one of the most important economic and garden crop speciesworldwide. In our county, the breeding of luffa had begun relatively late, and had fewstudy on breeding basic theory, especially on marker-assisted selection.In order to revealthe genetic effect of main agronomic Characters, a joint analysis of multi-generations fromthe6generations （P₁、P₂、F₁、F₂、BC₁、BC₂） of the crosses between Yueyoudarou andZhuzabai No2. was carried out to investigate the inheritance of the5agronomic traits forcomposite analyze. Besides, in this study, a luffa COS genetic map was constructed usingthe BC2pouulation. Based on this COS map, gene loci analysis was conducted for luffaseed testa color traits.Thereby afford theoretical guide to luffa breeding. The main resultsare as followe:1. The color of luffa seed coat were quality character determined by the1gene, theblack seed coat was dominant to white, have cytoplasmic inheritance.The fruit ridge waspartially dominant and controlled by one major gene with other minor genes. The traits offruit peel color, carpopodium shape and flower opening time were all quantitativelyinherited and fit the pattern of additive-dominance mode. The minimum gene numbers forthree traits were2,1and3, respectively. General inheritabilities and narrow inheritabilitiesfor three traits were all very high, indicating that the selection in breeding can be carriedout in early generations. There existed no cytoplasmic inheritance for four trait studied.2.322COS markers developed from cucumber whole genome sequences wereemployed for polymorphism screening and the development of luffa linkage map, fromwhich172（53.4%） were polymorphic between Yue You Da Rou and Zhu Za No.2. A57BC2plants were employed to conduct luffa linkage mapping experiments used122polymorphic COS markers, which polymorphism is obviously, zone zype is clear, and wereselected from174polymorphic COS markers. This map contained114COS markers in17linkage groups, with a mean marker interval of5.57cM, spanning634.96cM. Syntenicrelationships between cucumber and chromosomes were inferred based on their COS map,the syntenic and co-linearity relationships of their chromosomes were preliminarilyanalysised.3. With the software of JoinMap3.0, a BC2generation was used to gene loci analysisof luffa seed coat color traits. Furthermore, the population of F2reciprocal crosser was usedto verify this loci. In finally, the gene loci of luffa seed coat color traits was located in LG6,between COS213and COS212, named Ws（white seed）.The density of Ws gene andCOS213,COS212were3.06cM and1.95cM, respectively.4. Used the part genomic microcolinearity relationship among luffa, cucumber andwatermelon, developed10COS markers based on the cucumber, watermelon’sconservative sequence between COS213and COS212. After mapping and positioningagain,4COS markers were finally placed on LG6, and COS233was located in betweenCOS213and COS212, which was only1.83cM away from Ws gene.