Foolad M R, Chen F Q
Department of Horticulture, The Pennsylvania State University, 103 Tyson Building, University Park, PA 16802, USA, , , , , , US.
Plant Cell Rep. 1998 Feb;17(4):306-312. doi: 10.1007/s002990050398.
This study was conducted to identify randomly amplified polymorphic DNA (RAPD) markers associated with quantitative trait loci (QTLs) conferring salt tolerance during germination in tomato. Germination response of an F population (2000 individuals) of a cross between UCT5 (Lycopersicon esculentum, salt-sensitive) and LA716 (L. pennellii, salt-tolerant) was evaluated at a salt-stress level of 175 mM NaCl+17.5 mM CaCl (water potential ca. -9.5 bars). Germination was scored visually as radicle protrusion at 6-h intervals for 30 consecutive days. Individuals at both extremes of the response distribution (i.e., salt-tolerants and salt-sensitives) were selected. The selected individuals were genotyped for 53 RAPD markers and allele frequencies at each marker locus were determined. The linkage association among the markers was determined using a "MAPMAKER" program. Trait-based marker analysis (TBA) identified 13 RAPD markers at eight genomic regions that were associated with QTLs affecting salt tolerance during germination in tomato. Of these genomic regions, five included favorable QTL alleles from LA716, and three included favorable alleles from UCT5. The approximate effects of individual QTLs ranged from 0.46 to 0.82 phenotypic standard deviation. The results support our previous suggestion that salt tolerance during germination in tomato is polygenically controlled. The identification of favorable QTLs in both parents suggests the likelihood of recovering transgressive segregants in progeny derived from these genotypes. Results from this study are discussed in relation to using marker-assisted selection in breeding for salt tolerance.
本研究旨在鉴定与番茄萌发期耐盐数量性状基因座（QTL）相关的随机扩增多态性DNA（RAPD）标记。对UCT5（盐敏感的普通番茄）和LA716（耐盐的潘那利番茄）杂交的F群体（2000个个体）在175 mM NaCl + 17.5 mM CaCl（水势约为 -9.5巴）的盐胁迫水平下的萌发反应进行了评估。连续30天每隔6小时对胚根突出情况进行肉眼评分以记录萌发情况。选择了反应分布两端的个体（即耐盐个体和盐敏感个体）。对所选个体进行53个RAPD标记的基因分型，并确定每个标记位点的等位基因频率。使用“MAPMAKER”程序确定标记之间的连锁关联。基于性状的标记分析（TBA）在八个基因组区域鉴定出13个与影响番茄萌发期耐盐性的QTL相关的RAPD标记。在这些基因组区域中，五个包含来自LA716的有利QTL等位基因，三个包含来自UCT5的有利等位基因。单个QTL的近似效应范围为0.46至0.82个表型标准差。结果支持我们之前的观点，即番茄萌发期的耐盐性受多基因控制。在两个亲本中鉴定出有利的QTL表明有可能在这些基因型的后代中获得超亲分离株。本文结合利用标记辅助选择进行耐盐育种对本研究结果进行了讨论。
