2024, Vol. 4, Issue 1, Part B
Mapping Quantitative Traits in Cherry Tomato: A Comprehensive Genetic Analysis of F2 Populations
Author(s): Lucia M Baptiste
Abstract: Cherry tomato (Solanum lycopersicum var. cerasiforme) improvement requires translation of quantitative genetic insights into breeder-ready tools. We evaluated biparental F2 populations derived from contrasting cherry parents to dissect the genetic basis of fruit weight (FW), total soluble solids (TSS), locule number (LOC), pericarp thickness (PT), and earliness (EAR). Standardized, replicated phenotyping across two seasons followed internationally accepted tomato descriptors. Genome-anchored genotyping employed a high-density SNP platform or reduced-representation sequencing. After rigorous marker QC (call rate, minor allele frequency, segregation distortion) and genetic map construction, we performed interval and composite interval mapping with permutation-derived genome-wide thresholds. Traits displayed broad phenotypic ranges and moderate-to-high broad-sense heritabilities (H² ≈ 0.46-0.62). FW exhibited an approximately normal distribution and a modest negative correlation with TSS, indicating potential trade-offs between size and sweetness. Six significant QTL surpassed empirical thresholds: two for FW (including a major signal on chromosome 2), one each for TSS (chromosome 10), PT (chromosome 2), LOC (chromosome 11), and EAR (chromosome 3). Co-localizations with canonical regions reinforced biological plausibility: the leading FW signal overlapped the fw2.2 interval; LOC mapped near the OVATE/sov cluster; and the TSS signal lay close to the lc vicinity. Individual QTL explained ~6-14% of phenotypic variance, consistent with a mixed architecture featuring a few moderate effects atop a polygenic background. Practically, these findings support a dual strategy: marker-assisted selection to fix the largest, stable loci (e.g., fw2.2 and OVATE/sov-linked intervals) coupled with multi-trait indices or genomic selection to capture diffuse small effects and manage correlations among FW, TSS, and LOC. Fine-mapping of priority intervals and validation across seasons and locations are recommended to secure robust, transferable markers. This integrated framework provides actionable paths to develop cherry tomato cultivars that combine attractive architecture with elevated sweetness, firmness, and timely maturity.
Pages: 147-154 | Views: 105 | Downloads: 64
Download Full Article: Click Here
How to cite this article:
Lucia M Baptiste. Mapping Quantitative Traits in Cherry Tomato: A Comprehensive Genetic Analysis of F2 Populations. Zool Entomol Lett 2024;4(1):147-154.
