Genetic Analysis of Tomato Leaf Curl New Delhi Virus ToL CNDV Resistance in Sponge Gourd Luffa cylindrica L Roem

Abstract

The present experiment entitled, Genetic Analysis of Tomato Leaf Curl New Delhi Virus (ToLCNDV) Resistance in Sponge Gourd [Luffa cylindrica (L.) Roem.] was conducted at the Indian Institute of Vegetable Research at Varanasi from kharif 2022 to zaid 2024. The primary objectives included screening sponge gourd germplasms for resistance under natural and artificial conditions, confirming the biochemical basis of resistance, and examining inheritance pattern of ToLCNDV. Twenty-two promising sponge gourd genotypes were evaluated for disease resistance, out of them five lines viz., DSG-6, DSG-7, VRSG-3-21, VRSG-17-16, and Kashi Kalyani) revealed as resistant under field conditions. Under challenge conditions, only DSG-6 and DSG-7 remained resistant. Hybridization program was done through 15 lines (10 lines viz. VRSG - 17-6, VRSG 17-15, VRSG 17- 17, VRSG - 17- 18, VRSG - 17-22, VRSG - 17- 26 VRSG 17-27, VRSG 17-28, VRSG 17-29 and VRSG -17-31 and 5 testers viz. DSG-6, DSG-7, VRSG-3-21, VRSG-17-16, and Kashi Kalyani) using line × Tester mating design and resulted 50 hybrids. The line VRSG-17-28 crossed with DSG-6 and DSG-7 identified as most promising for horticultural quality and disease resistance comparatively than others. Analysis of general combining ability indicated favourable traits were found in lines VRSG-17-28, VRSG-17-6, VRSG-17-27, and VRSG-17-31, from tester in DSG-6 and DSG-7. Biochemical assessments demonstrated that increased enzyme activities (e.g., peroxidase, phenylalanine ammonia lyase) correlated negatively with defence against ToLCNDV, suggesting resistance is governed by a single dominant gene. This research not only identifies potential sponge gourd genotypes for breeding programs but also enhances understanding of the genetic mechanisms underlying disease resistance. newline