Tomato (Solanum lycopersicum) is the most important vegetable crop globally; however, its production is often hindered by soil-borne biotic and abiotic stresses. The use of rootstocks provides an effective strategy to mitigate these soil-related challenges. Hence, the development of new rootstock cultivars remains crucial to meet the demands of rapidly changing environmental conditions. Wild tomato species represent valuable genetic resources for rootstock improvement and are increasingly utilized in rootstock breeding programs. Nevertheless, the genetic mechanisms, particularly quantitative trait loci (QTL), underlying rootstock–scion interaction, remain poorly understood. In this study, 38 introgression lines (ILs) derived from S. lycopersicoides were used as rootstock and grafted with the commercial cultivar ‘Torry F₁’ to evaluate their effects on morphological and fruit quality traits under greenhouse conditions. The evaluations included assessments of morphological and fruit quality traits for QTL analysis. A total of 19 QTLs were identified, associated with 11 traits such as yield, antioxidant capacity, flavonoid content, and fruit color parameters (L*, a*, b*, C*, h°), with the phenotypic variance explained ranging from 12% to 61%. Of these QTLs, seven favorable alleles originated from S. lycopersicoides, notably including a major yield-associated locus (Fy5.1). In addition, the identification of a QTL for scion stem thickness (Tsc3.1) highlights the genetic contribution of the rootstock to scion development. This study represents the first evaluation of the rootstock potential of S. lycopersicoides ILs and provides novel insights into the genetic basis of rootstock–scion interaction in tomato. The identified QTLs offer valuable information for future breeding efforts aimed at developing improved rootstock cultivars for sustainable tomato production.

Potato, Solanum tuberosum, the most important non-grain food crop and essential crop globally, has been widely cultivated around the world for centuries. The significance of this plant is increasing due to high nutritional value of the tubers combined with the simplicity of its propagation. As a plant organ, tuber of potato, is mainly edible part of it and popular as nutrient for almost all nations. Tuberization in potato is a very complex biological occurrence affected by numerous ecological signals, genetics, plant nutrition and several different hormones. Many pests including nematodes limit potato tuber development that plant hormones play roles in nematode feeding cell formation. Parasitic nematodes, important pests which cause damage to plants, tubers, suck up nutrients from plants and weaken plant development and yield losses. Many genes involve in tuber development and plant response nematodes. The aim of this chapter is to demonstrate the new advances in the field of molecular host-nematode interactions and tuber development.