Marker and CKX2 gene expression-based selection of high yielding tomato (Lycopersicon esculentum Mill.) germplasms

Abstract

Tomatoes are an important agricultural crop grown for food, industrial, and pharmaceutical needs. Identification of high-yielding tomato germplasms is crucial to achieving the goal of doubling farmer's income. Our study aimed to select the germplasm with a smaller number of fruits and high weight so that, in a single harvest, maximum yield could be achieved. In the present study, tomato germplasms were evaluated based on agro-morphological traits, molecular markers and Cytokinin Oxidase/Dehydrogenase 2 (CKX2) gene expression. Inter simple sequence repeat markers (ISSRs) harbouring multiple allelic variations were used to study the genetic diversity. Among the markers used, UBC 820 exhibited the highest polymorphism, with eight alleles, an amplicon size range of 650–1800 bp and a polymorphic information content (PIC) value of 0.3001. Based on morphological observation and CKX2 gene expression analysis by qRTPCR, the genotype KS-8105 was found to be the best performer. The mean number of fruits/plants was 79, while the mean weight of fruits/plants was 3.2 kg/plant in the tomato germplasm KS-8105. In future, introgression of desirable traits like weight of fruits/plants may be introgressed from KS-8105 to the elite cultivars with the help of molecular markers.