Genetic basis of leaf curl virus resistance in double cross F1 chilli: A monogenic dominant trait

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Chilli is a vital crop in Indian agriculture, serving as a major cash crop and export commodity, with substantial contributions to farmers’ livelihoods and the national economy. Its significance extends beyond agriculture to nutrition, health and cultural heritage. However, chilli cultivation faces considerable challenges due to susceptibility to pests and diseases, particularly the chilli leaf curl virus (ChLCV), which has emerged as a significant threat in recent years. ChLCV can cause up to 100% crop loss, with widespread damage occurring at all growth stages, jeopardizing the sustainability of chilli cultivation. This underscores the urgent need for effective management strategies, including integrated pest management and the deployment of resistant planting materials. To develop resistant hybrids, understanding the genetic basis of resistance is critical. A study aimed at developing combined resistant lines to chilli leaf curl virus (ChLCV), cucumber mosaic virus (CMV) and chilli veinal mottle virus (ChVMV) employed a double-cross breeding strategy: [(MS?B × IHR 2451) × (MS?B × IHR 4597)]. Segregation of double-cross F? individuals under natural epiphytotic conditions revealed a 1:1 ratio of resistant to susceptible plants, indicating that resistance to ChLCV is governed by a single dominant gene. The virus associated with this study was identified as the chilli leaf curl virus (Raichur isolate). Chi-square analysis confirmed a good fit to the expected segregation ratio, supporting the hypothesis of monogenic dominant inheritance. The resistant source, IHR 4597, identified in this study, can be effectively utilized for transferring the resistance gene into higher-yielding genotypes. Furthermore, this source offers potential for mapping the resistance gene, facilitating future breeding efforts to enhance ChLCV resistance in chilli.