Construction Of InDel Genetic Map Of Bitter Gourd And Analysis Of QTLs For Node And Quantity Of Male Flowers

Bitter gourd is not only an important vegetable,but also has good health functions.Bitter gourd is cultivated in many places including Asia,Africa and South America.Compared with the popular cucurbit crops,the research on the genetics and breeding of bitter gourd is still relatively rare.The InDel marker is a novel molecular marker developed based on genomic sequences.It is widely distributed in the genome and is one of the best choices for constructing genetic maps.In this study,the bitter gourd cultivars‘04-17’and’47-2-1-1-3’were crossed to obtain F₁ generations.F₁generations were strictly pollinated and F₂ generations were obtained.Using 113 F₂individuals as the mapping population,the first InDel genetic map of bitter gourd was constructed based on InDel markers to identify the QTL of several traits in bitter gourd.The results are as follows:1.The genomic DNAs of’04-17’and’47-2-1-1-3’were used as amplification templates,and there were 2,466 primers that could amplify clear bands among the2,502 InDel primers.For the primers,the specific amplification rate was 98.56%,of which 2,230 primers（89.13%）obtained a single amplified band;and 212 pairs of primers（8.47%）that showed polymorphism between the two parents were used for F2 generation genotyping analysis.An InDel genetic map of bitter gourd was obtained through the software joinmap 4.0 analysis.The total length of the map was 1,279.59cM,including 164 InDel markers,distributed on 15 linkage groups,and the average distance between markers was 7.80 cM.2.Based on this map,combined with field survey data,we used MapQTL 6software for the first branching node,the first male flower node,the number of male flowers in ten nodes,the length of the fruit stalk,the fruit shoulder width,the fruit length,the fruit diameter,the fruit weight,the fruit surface rib width,flesh thickness 1,flesh thickness 2,seed length,seed width,seed number（14 traits in total）QTL analysis.The first male flower node regulatory site was located on the linkage group LG8 with an LOD value of 10.04（threshold value of 5.20）and explained 34.80%of phenotype variation.The genetic range is from 111.94 to 119.87 cM,and the additive effect was 2.52 while dominant effect was-1.32.The control loci of male flower number within 10 nodes was located on the linkage group LG8 with a LOD value of9.23（threshold value of 4.50）and explained 33.60%of phenotype variation.The genetic range was from 107.43 to 111.94 cM,and the additive effect was-1.62 while the dominant effect was 0.83.