Genetic diversity in round gourd [Praecitrullus fistulosus (Stocks) Pangalo] accessions introduced from USDA for various qualitative and quantitative traits

ABSTRACT

Assessment of genetic variability in available germplasm, identification of genetically diverse genotypes for developing F₁ hybrids, and to generate further variability are prerequisites for any crop improvement program. Here, 15 accessions, including 5 released varieties, of round gourd were used to estimate genetic variability for 6 qualitative and 9 quantitative traits. Most accessions had round, shining, and light green fruits. Degree of secondary lobing of leaf blade was the most diverse qualitative trait. The 15 accessions were grouped into four clusters, of which two were solitary. Cluster II had eight accessions, followed by cluster I with five accessions. The grouping pattern revealed that geographical diversity might or might not be correlated with genetic diversity. The principal component analysis indicated that the first three components accounted for 85.73% of the total variation, with principal component 1 (PC1) accounting for 37.21%, PC2 for 36.35%, and PC3 for 12.16% of the total variation. Of nine traits studied, early yield contributed 55.24% toward genetic divergence, followed by vine length (21.90%) and number of primary branches per vine (14.29%). The highest broad-sense heritability (95.60%) and genetic advance (123.06%) were recorded by early yield followed by vine length and number of primary branches. Crossing between genotypes belonging to clusters I, III, and IV with those belonging to cluster II, and between clusters I and III has been advocated to develop F₁ hybrids, and to search for transgressive segregants with new combinations of genes to bring necessary improvement in the crop.

KEYWORDS:

• Benincasa
• cluster analysis
• earliness
• germplasm
• principal component analysis

Acknowledgments

The author is grateful to Plant Genetic Resources Conservation Unit (PGRCU), United States Department of Agriculture, Agricultural Research Service, 1109, Experiment Street, Griffin, Georgia, for providing the accessions of round gourd for study. The author is also thankful to National Bureau of Plant Genetic Resources, New Delhi, India, for facilitating the process of import of accessions. Thanks are also due to the Director, Indian Institute of Horticultural Research, Bengaluru, India and the Head, Department of Vegetable Science, Choudhary Charan Singh Haryana Agricultural University, Hisar, India, for kindly providing the seeds of “Arka Tinda” and “Hisar Tinda,” respectively. The financial help received from the State Government of Punjab for conducting this research work is duly acknowledged. Thanks are also due to Dr. Raj Kumar Pal, Assistant Agrometeorologist, Punjab Agricultural University, Regional Research Station, Bathinda, for sharing weather parameters recorded at the observatory. Sincere thanks are due to Prof. Manjit Singh Kang, Editor-in-Chief, Journal of Crop Improvement, and two anonymous reviewers for reviewing the manuscript and giving useful suggestions for improving the article.

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