QTL Analysis for Surrogate Traits of Water use Efficiency, Yield and Yield Related Traits in Tomato Developed from Inter Specific Cross Solanum Lycopersicum × Solanum Penellii
Tomato is one of the most important vegetable crops valued for its nutritional properties and antioxidants. However it is extremely sensitive to water stress resulting in yield losses. Water use efficient genotypes themselves establish water use efficiency under water stress environments. Hence the present study was envisaged to identify QTLs for surrogate traits related to WUE namely SPAD chlorophyll meter reading (SCMR), Specific leaf area (SLA), Δ13C and fruit yield and yield related traits. A mapping population was developed from an inter-specific cross involving high fruit yield and drought susceptible S. lycopersicum (EC-771612) with low fruit yield and drought tolerant accession S. penellii (LA-2657). The parents were found polymorphic for 206 primers out of 410 SSR primers that were used for genotyping 112 F2 segregants. Among 206 polymorphic primers 146 amplified. Ninety of the 146 primers were found linked and mapped onto 12 linkage groups comprising of a total map length of 1247.73 cM with an average interval of 13.86 cM. Five major and two minor QTLs for SCMR, two major and three minor QTLs for SLA were detected. One minor QTL for ∆13C was detected at a LOD threshold of 2.03 and 8.08% phenotypic variation explained. Four QTL each governing fruits cluster-1 and clusters plant-1 were detected. The identified QTLs need to be validated before they are used in marker assisted selection for water use efficiency, fruit yield and yield related traits.
Keywords - Tomato, Quantitative trait Loci, specific leaf area, SCMR, Yield