International Journal of Horticulture, 2024, Vol.14, No.4, 250-262 http://hortherbpublisher.com/index.php/ijh 256 Traditional cultivation methods, selection and breeding techniques, and the impact of agricultural practices on genetic diversity have all played significant roles in the domestication and improvement of pumpkins. These practices have shaped the genetic landscape of pumpkins, leading to the development of a wide array of varieties that are well-suited to different growing conditions and consumer preferences. 7 Modern Genetic Techniques in Pumpkin Research 7.1 Genomic sequencing and analysis Genomic sequencing has revolutionized our understanding of pumpkin domestication by providing detailed insights into the genetic variations between wild and domesticated species. For instance, targeted sequencing of approximately 15,000 SNPs in Cucurbita argyrosperma and Cucurbita maxima revealed significant differences in genetic diversity and structure between domesticated and wild progenitors. This study highlighted that only 1.5% of domestication features were shared between the two species, suggesting unique domestication pathways (Kates et al., 2021). Additionally, the genome of wild Cucurbita argyrosperma was sequenced, uncovering structural variants and candidate domestication genes involved in growth regulation, plant defense, and seed development. This genomic data indicated a monophyletic origin and gene flow between domesticated and wild subspecies, which likely mitigated the effects of domestication bottlenecks (Barrera-Redondo et al., 2021). 7.2 CRISPR and gene editing applications CRISPR/Cas9 technology has emerged as a powerful tool for precision breeding in pumpkins, enabling targeted modifications to enhance desirable traits. The application of CRISPR/Cas9 in plant genome editing has been extensively reviewed, showcasing its potential to accelerate crop improvement by enabling targeted nucleotide substitutions and fine-tuning gene regulation (Chen et al., 2019). Although specific studies on pumpkins are limited, the successful de novo domestication of wild tomato using CRISPR/Cas9 demonstrates the potential of this technology. By editing six loci important for yield and productivity, researchers significantly improved fruit size, number, and nutritional value, paving the way for similar applications in pumpkins (Zsögön et al., 2018). 7.3 Future directions in genetic research of pumpkins Future research in pumpkin genetics is poised to leverage advanced genomic and gene-editing technologies to further enhance crop traits and resilience. Expanding genomic sequencing efforts to include more wild and domesticated Cucurbita species will provide a comprehensive understanding of genetic diversity and evolutionary history (Kates et al., 2017). Additionally, integrating CRISPR/Cas9 with high-throughput mutant libraries and advanced delivery systems will facilitate the development of pumpkins with improved disease resistance, stress tolerance, and nutritional value (Chen et al., 2019). Continued exploration of gene flow between wild and domesticated species will also be crucial in maintaining genetic diversity and mitigating the effects of domestication bottlenecks (Barrera-Redondo et al., 2021). These advancements will not only enhance pumpkin breeding programs but also contribute to global food security by increasing the availability of nutritious and resilient crops. 8 Case Studies 8.1 Domestication of Cucurbita pepo The domestication of Cucurbita pepo is one of the earliest examples of plant domestication in the Americas, with archaeological evidence indicating its cultivation history dates back to around 10,000 years ago in the region of Mexico. Castellanos-Morales et al. (2019) analyzed the genetic variation and structure of Mexican Cucurbita pepo ssp. pepo using two chloroplast regions and nine nuclear microsatellite loci to explore its domestication history. The study revealed that Cucurbita pepo ssp. pepo exhibits high genetic diversity, and C. pepo ssp. fraterna is likely its wild ancestor (Figure 2), although hybridization between the two complicates the definition of its ancestor.
RkJQdWJsaXNoZXIy MjQ4ODYzNA==