Development of begomovirus resistant hybrid(s) using KASP markers in pumpkin (Cucurbita moschata Duchesne)
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Date
2023
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Punjab Agricultural University
Abstract
The present investigation entitled, “Development of begomovirus resistant hybrid(s) using KASP markers in pumpkin (Cucurbita moschata Duchesne)” was conducted in the Department of Vegetable
Science, Punjab Agricultural University, Ludhiana with the objectives to screen pumpkin genotypes using Cmo4018182 KASP marker against mixed infection of squash leaf curl China virus and tomato
leaf curl New Delhi virus (MI-Sq/To) and to develop begomovirus resistant hybrids for year-round cultivation of pumpkin. Forty genotypes of pumpkin were screened in spring season 2022, genotypically with Cmo4018182 KASP marker for resistance against MI-Sq/To. Based on KASP marker analysis, nineteen genotypes were selected and randomly hybridized to develop twenty-nine F1
hybrids. In rainy season 2022, the forty genotypes and twenty-nine F1 hybrids were subjected to whitefly mediated artificial mass screening for resistance against MI-Sq/To at nursery stage and 75
days after sowing (DAS). Among forty genotypes, four genotypes were observed as resistant, thirteen as moderately resistant, three as moderately susceptible and twenty genotypes as susceptible at nursery stage. Most of the genotypes showed same disease reaction in nursery stage and 75 DAS except P-37 which later on shifted its reaction from moderately resistant to moderately susceptible. Among 29 hybrids, two hybrids were found resistant, sixteen were moderately resistant, two were moderately susceptible while nine were susceptible at nursery stage. Likewise parents, hybrids retained their disease reaction from nursery to 75 DAS except H9. However, marker trait association of Cmo4018182 KASP marker against resistance to MI-Sq/To was found to be 75% in the diverse panel of 40 genotypes while it was 86.20% in case of hybrids, suggesting further exploration of the identified genomic region for the development of gene-linked markers. In addition to assessing begomovirus resistance, the hybrids underwent evaluation concerning morphological, yield and yield-attributing traits. Significant differences among hybrids for all horticultural traits were observed during both rainy and spring seasons as shown by the analysis of variance. In terms of individual performance, the majority of hybrids displayed substantial improvements in favorable directions for all traits compared to their parents. High genetic variability among genotypes for majority of traits offers an opportunity to develop heterotic hybrids because of their high heritability and genetic advance. Traits such as days to 1st male flower, days to 1st female flower and days to 50% female flower exhibited low genetic variation indicating that hybridization of divergent genotypes could be beneficial in generating diversity in these traits. The significant positive correlation of traits viz, average fruit weight, vine length, number of fruits per plant, fruit diameter, peduncle length, petiole length and flesh thickness with fruit yield indicates the potential for enhancing yield by focusing on these specific traits. Among the 29 hybrids, H8, H18, H20, H24 and H27 were found as the most optimal hybrids based on their resistance to begomovirus, earliness and yield. However, conducting multi-location trials is imperative to affirm the commercial potential of these hybrids. Conclusively, this study showcased the pragmatic value of employing marker assisted breeding in the introgression of begomovirus resistance and expedited the development of begomovirus-resistant hybrids in a shorter duration, conserving both labour and resources.
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Sood, Anushka (2023). Development of begomovirus resistant hybrid(s) using KASP markers in pumpkin (Cucurbita moschata Duchesne) (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.