Genetic analysis and BSA-QTL mapping of tomato leaf area

LI Shanshan; LIANG Pan; MENG Fanyi; MA Mengqiu; HU Tixu; LIANG Yan; CAI Yiyong; ZHAN Xiangqiang

doi:10.16861/j.cnki.zggc.2024.0634

Abstract：Leaf area is one of the important agronomic traits in tomato that directly influences photosynthetic efficiency and material accumulation,thus significantly affecting plant growth and productivity.Studying the inheritance patterns of tomato leaf area and performing gene mapping through BSA-seq can provide a theoretical foundation for understanding the genetic and molecular mechanisms of leaf area in tomato.In this study,two parental lines with significant differences in leaf area,21GA04(P1)and 19GA13(P2),were selected to construct a population comprising six generations:P1,P2,F1,F2,BCP1 and BCP2.ImageJ software was used to measure the leaf area across these six generations.Genetic analysis of tomato leaf area was performed using a mixed genetic model combining major genes and polygenes.Additionally,bulked segregation analysis(BSA)was employed to assess the genotypes of extreme materials and parents,while QTL-seq(SNP-index association analysis)was used for preliminary localization of leaf area associated genes.The leaf area in the F2,BCP1 and BCP2 populations showed a skewed normal distribution.The most suitable genetic model for tomato leaf area is MX2-ADI-AD,indicating that this trait is controlled by two pairs of additive-dominant epistatic major genes and additive-dominant polygenes.SNP-index association analysis identified three QTL intervals,located on chromosome 1(89.0-89.8 Mb),chromosome 8(2.1-4.5 Mb),and chromosome 9(63.9-64.8 Mb).These results suggest that tomato leaf area is governed by both major genes and polygenes,with three associated regions located on chromosomes 1,8 and 9,and SlSAUR20 and SlSAUR21 are proposed as candidate genes associated with leaf area trait.