Cover

Abstract

On the cover

Tomatoes (Solanum lycopersicum) are one of the most important vegetable crops worldwide, but domestication has greatly reduced their genetic diversity. Their wild relatives, such as Solanum pennellii, harbor traits valuable for improving fruit quality, yield, and stress tolerance. Introgression lines (ILs), developed from crosses between the cultivar ‘M82’ and S. pennellii accession LA716, serve as powerful genetic resources for dissecting quantitative trait loci (QTLs) underlying complex traits. This review highlights key IL-based studies focusing on fruit development and quality. IL5-4 and IL8-3 exhibit elevated Brix values compared with ‘M82’, making them useful models for studying sugar accumulation and blossom-end rot, a serious physiological disorder in tomato. IL12-1-1 produces substantially larger fruits due to enhanced cell division and hormonal regulation during early development, and candidate genes for these traits have been identified in its introgressed region. By integrating genetic and physiological insights from ILs, researchers have uncovered fundamental mechanisms underlying fruit traits. These findings deepen our understanding of tomato biology and provide valuable resources for future breeding programs aimed at improving fruit quality and resilience.

(Provided by H. Ikeda: Utsunomiya University)