AUTHOR=Devi Shilpa , Sharma Parva Kumar , Behera Tusar Kanti , Jaiswal Sarika , Boopalakrishnan G. , Kumari Khushboo , Mandal Neha Kumari , Iquebal Mir Asif , Gopala Krishnan S. , Bharti  , Ghosal Chandrika , Munshi Anilabha Das , Dey Shyam Sundar 

TITLE=Identification of a major QTL, Parth6.1 associated with parthenocarpic fruit development in slicing cucumber genotype, Pusa Parthenocarpic Cucumber-6

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1064556

DOI=10.3389/fpls.2022.1064556

ISSN=1664-462X

ABSTRACT=<p>Parthenocarpy is an extremely important trait that revolutionized the worldwide cultivation of cucumber under protected conditions. Pusa Parthenocarpic Cucumber-6 (PPC-6) is one of the important commercially cultivated varieties under protected conditions in India. Understanding the genetics of parthenocarpy, molecular mapping and the development of molecular markers closely associated with the trait will facilitate the introgression of parthenocarpic traits into non-conventional germplasm and elite varieties. The F<sub>1</sub>, F<sub>2</sub> and back-crosses progenies with a non-parthenocarpic genotype, Pusa Uday indicated a single incomplete dominant gene controlling parthenocarpy in PPC-6. QTL-seq comprising of the early parthenocarpy and non-parthenocarpic bulks along with the parental lines identified two major genomic regions, one each in chromosome 3 and chromosome 6 spanning over a region of 2.7 Mb and 7.8 Mb, respectively. Conventional mapping using F<sub>2:3</sub> population also identified two QTLs, <italic>Parth6.1</italic> and <italic>Parth6.2</italic> in chromosome 6 which indicated the presence of a major effect QTL in chromosome 6 determining parthenocarpy in PPC-6. The flanking markers, SSR01148 and SSR 01012 for <italic>Parth6.1</italic> locus and SSR10476 and SSR 19174 for <italic>Parth6.2</italic> locus were identified and can be used for introgression of parthenocarpy through the marker-assisted back-crossing programme. Functional annotation of the QTL-region identified two major genes, <italic>Csa_6G396640</italic> and <italic>Csa_6G405890</italic> designated as probable indole-3-pyruvate monooxygenase YUCCA11 and Auxin response factor 16, respectively associated with auxin biosynthesis as potential candidate genes. <italic>Csa_6G396640</italic> showed only one insertion at position 2179 in the non-parthenocarpic parent. In the case of <italic>Csa_6G405890</italic>, more variations were observed between the two parents in the form of SNPs and InDels. The study provides insight about genomic regions, closely associated markers and possible candidate genes associated with parthenocarpy in PPC-6 which will be instrumental for functional genomics study and better understanding of parthenocarpy in cucumber.</p>