Abstract
Pumpkins (Cucurbita moschata) are one of the most important economic crops in genus Cucurbita worldwide. They are a popular food resource and an important rootstock resource for various Cucurbitaceae. Especially, C. moschata is widely used as a rootstock for the commercial production of bloomless cucumbers in East Asia. Since the genetic diversity of the commercial rootstock varieties is narrow, there has been an increasing demand for the trait development of abiotic and biotic stress tolerance breeding. In this study, 2071 high-quality SNPs that were distributed evenly across 20 chromosomes of pumpkins were discovered through the genotyping-by-sequencing (GBS) analysis of 610 accessions of C. moschata germplasm with a global origin. Using these SNPs, various analyses of the genetic diversity and the population structure were performed. Three subgroups were clustered from the germplasm collection, which included East Asia, Africa, and America, and these areas were included the most in each subgroup. Among those groups, accessions from Africa and South Asia showed the highest genetic diversity, which was followed by the Mexico accessions. This result reflected that large gene pools that consist of various native landraces have been conserved in those of countries. Based on the genetic diversity, we finally constructed the C. moschata core collection, which included 67 representative accessions from the 610 germplasms. Five morphological traits that are important in commercial grafting and rootstock seed production, which include the cotyledon length, the cotyledon width, the hypocotyl length, the internode length, and the number of female flowers, were investigated for three years and used to confirm the validity of the core collection selection. The results are expected to provide valuable information about the genetic structure of the worldwide C. moschata germplasm and help to create new gene pools to develop genetically diverse rootstock breeding materials.
Highlights
The genus Cucurbita (Cucurbitaceae) has five major domesticated species, which include C. argyrosperma, C. ficifolia, C. maxima, C. moschata, and C. pepo, which have been cultivated globally as an economic crop [1,2]
All the high quality SNPs were evenly distributed among the 20 pumpkin chromosomes, and 52 SNPs from the scaffolds within the unidentified chromosome were gathered in chromosome number 00 (Figure 1 and Table S1)
We confirmed that all of the accessions used in this study were highly fixed in the genotype that fit for the genetic diversity study
Summary
The genus Cucurbita (Cucurbitaceae) has five major domesticated species, which include C. argyrosperma, C. ficifolia, C. maxima, C. moschata, and C. pepo, which have been cultivated globally as an economic crop [1,2]. Fig leaf gourds (C. ficifolia), pumpkins (C. moschata), and Shintoza (C. maxima × C. moschata) are mainly used [9]. Pumpkins are used as bloomless rootstock, because they inhibit the formation of blooms on the fruit’s surface, which makes it possible to produce high quality cucumbers with a shiny fruit skin [10]. Bloomless rootstocks are preferred in China even in the cold season, because the blooms are visible on the fruit’s skin of the long-type Chinese cucumbers, which have a uniform dark green color. It is required to understand the genetic structure and the diversity of the C. moschata germplasm for this
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
