Identification of New Sources of Tolerance to Leaf Curl-mosaic Complex Disease in Chilli Pepper (Capsicum spp.)

Abstract

The identification of disease-tolerant genotypes is a necessity for sustainable management of chilli leaf curl-mosaic complex disease (ChiLCMC) that usually causes upto hundred percent yield loss in chilli. This study aimed to screen chilli genotypes for ChiLCMC tolerance through natural infection, graft transmission and molecular validation of resistance markers. Sixty-four genotypes from three Capsicum species were evaluated under natural epiphytotic conditions, and thirty promising genotypes were subjected to artificial screening via graft transmission. Virus titre estimation using polymerase chain reaction (PCR) with virus-specific primers was conducted to assess infection levels. The degenerate Deng primer and virus coat protein specific CLA 7F/CLA 8R and AVF9/AVR10 were used to study the presence of leaf curl virus. RsCMV primer was used to study the presence of chilli mosaic virus. Six genotypes (Venjaramood Local II, KD-2, Unda Chilli, AP-1, IC-208580, and IC-570376) remained symptomless post-grafting, indicating potential tolerance. PCR analysis revealed the presence of Geminiviruses and Bromoviruses in some asymptomatic genotypes, suggesting their ability to suppress symptom expression despite viral replication. These findings identify novel sources of ChiLCMC tolerance, which can be integrated into breeding programs to develop high-yielding, disease-resistant hybrids/varieties. Such approaches contribute to sustainable chilli cultivation by reducing reliance on chemical controls and promoting eco-friendly farming practices.