Utilizing Hypocotyl Color as a Phenotypic Marker for Enhancing Disease Resistance and Fruit Quality in Solanum lycopersicum F3 Generation: A Pedigree Selection Study Focused on Phytophthora infestans and Alternaria solani.

Abstract

Tomato is one of the most important crops in agriculture; hence, optimization of its breeding program for the development of better cultivars and improved disease resistance is a key target. The present study tries to facilitate the selection of elite varieties from the large breeding program by easily identifiable phenotypic markers like hypocotyl color, associated with the disease resistant trait. The present work implements the use of phenotypic markers for disease resistance and improvement of fruit quality in Solanum lycopersicum F3 generation pedigree selection. A hybrid of the BAX247 variety of tomatoes derived from PGRC in Sri Lanka was intercrossed to derive the progeny possessing the RR gene allele linked to the dominant R gene responsible for providing resistance against Phytophthora infestans and Alternaria solani. In other words, it means that the major role of a resistance gene is to recognize a pathogen and subsequently trigger plant defenses. All 26 breeding lines were phenotype evaluated at RARDC Bandarawela, and a strong association of purple hypocotyls with the RR allele was observed, verified by Chi-square analysis. The purple and green hypocotyl traits were proved to be a reliable marker for selecting disease resistance. These findings emphasize that hypocotyl color can be used as an efficient phenotypic marker in breeding programs, which is essential for further advances in tomato production through the development of cultivars with increased resistance and superior agronomic traits. Improved breeding techniques via such markers can meet important challenges in tomato cultivation and thus increase yield stability and quality.