Genetic Improvement of Chilli (Capsicum spp.): Integrating Conventional Breeding and Modern Biotechnology

Abstract

Chilli (Capsicum spp.) is an economically important spice and vegetable crop with wide variation in fruit morphology, pungency, quality attributes, and adaptation to environmental conditions. This review examines the genetic improvement of chilli by integrating conventional breeding approaches with modern biotechnological tools. Conventional methods discussed include plant introduction, mass and pure-line selection, pedigree breeding, single-seed descent, backcross breeding, heterosis breeding, wide hybridisation, mutation breeding, and polyploidy breeding. These approaches have supported the development of cultivars and breeding materials with improved yield, fruit quality, disease resistance, and stress tolerance. The review also considers tissue culture, genetic transformation, RNA interference, and CRISPR/Cas9-based genome editing as complementary strategies for accelerating targeted improvement. Emphasis is placed on the use of diverse Capsicum germplasm, male-sterility systems, interspecific hybridisation, marker-assisted approaches, and gene-editing technologies to address major breeding objectives. Specific attention is given to disease resistance, tolerance to drought and heat, pungency and capsaicinoid-related quality, and the prospects of pangenomes and artificial intelligence. The synthesis highlights the importance of combining established breeding methods with emerging genomic and biotechnological approaches while conserving wild accessions and landraces. Continued improvement in regeneration efficiency, stress-resilience breeding, and the integration of genomic selection with advanced analytical approaches may strengthen future chilli improvement programmes and support the development of productive, resilient, and quality-oriented cultivars.