Exploring novel resistant sources for chilli leaf curl disease in Capsicum annuum L. germplasm for genetic enhancement

Chilli, as a vegetable and spice, is an important constituent of Indian food. The major constraint that hampers chilli production is Chilli leaf curl disease (ChiLCD). It often leads to heavy yield losses as a result of which the farmers do not prefer chilli cultivation. Therefore, the present investigation has been undertaken to screen and evaluate chilli germplasm conserved in National genebank of India and identify lines resistant to ChiLCD. We screened 500 chilli accessions for four consecutive years (2021-2024) to identify the resistant lines. In the 2021 screening, 16 accessions were found highly resistant, 40 resistant, 33 moderately susceptible, 23 susceptible, and 388 highly susceptible. Accessions showing symptoms of Chilli leaf curl disease in each season were discarded, whereas resistant accessions were retained for repeated screening. From the advanced screening and validation during 2022-2024, some promising accessions were identified as EC771555, IC643853, EC772795, EC787119, EC769427, and IC607252 which maintained low disease incidence (≤ 5% PDI) and severity score one. Another 28 accessions were found resistant to ChiLCD. Quantitative PCR also confirmed very low viral titres (0.1-0.3-fold) in resistance accessions. The identified promising accessions can be used as donors in chilli improvement programs to develop resilient varieties that express good yield and quality under high disease pressure, reducing reliance on chemical controls. They also offer genetic resources for studying resistance mechanisms and molecular markers development for sustainable agriculture which leads to reduced production costs.