| Cucumber is a major vegetable crop in protected cultivation.Parthenocarpy is an important trait affecting both yield and quality in protected cucumber production.Genetic analysis of parthenocarpy and its QTL mapping are of great significance for enriching the molecular mechanism of cucumber fruit development and promoting cucumber breeding.Based on three-year phenotypic data,the genetic linkage map of cucumber was constructed using SSR molecular markers obtained from cucumber genome sequencing,and the QTL-Seq analysis was used to map the parthenocarpy of cucumber,using recombinant inbred line F2:8:8 constructed from strong parthenocarpic inbred line‘6457’and weak parthenocarpic inbred line‘6426’.The main results are as follows:1.The average parthenocarpic fruit setting rate of RIL(F2:8)of cucumber was continuous distribution,and parthenocarpic trait accorded with quantitative genetic characteristics.2.A total of 169 pairs of SSR primers with clear bands were obtained from1220 pairs of SSR primers,and the polymorphism was 13.9%.A genetic map containing 11 linkage groups was constructed by removing 87 pairs of segregated maker primers,covering 555.0 cM of the genome with an average distance of 6.8 cM.In spring 2016 and spring 2017,a single QTL locus related to parthenocarpy was commonly detected between SSR19430 and SSR15419 markers（3.33Mbp-5.57Mbp）on chromosome 3,and the genetic distance was 6.6 cM,with 11%,12.5%and 6.3%contribution rate,respectively.3.Genome-wide re-sequencing of highly parthenogenetic pool,weak parthenogenetic pool and parent pools of cucumber yielded 23.567G of valid data.By QTL-Seq analysis,four QTLs related to parthenocarpy were identified on chromosome1（4.38Mbp-11.00Mbp）,3（2.24Mbp-10.66Mbp）and6（15.67Mbp-17.93Mbp;26.33Mbp-27.49Mbp）;the QTL on chromosome 3 overlapped with that detected by Map QTL approach.Csa3G047740,Csa3G073810,Csa3G043910 and Csa6G362930 were proposed to be candidate genes associated with parthenocarpic trait in cucumber. |
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