Tomato Bacterial Spot Resistance Derived from PI 114490; Inheritance of Resistance to Race T2 and Relationship across Three Pathogen Races
Tomato Bacterial Spot Resistance Derived from PI 114490; Inheritance of Resistance to Race T2 and Relationship across Three Pathogen Races
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DOI：
10.21273/jashs.128.5.0698
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发表时间：
2003-09
影响因子：
1.9
通讯作者：
J. Scott;D. Francis;S. Miller;G. Somodi;Jeffrey B. Jones
中科院分区：
文献类型：
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作者：
J. Scott;D. Francis;S. Miller;G. Somodi;Jeffrey B. Jones
摘要。利用番茄（Lycopersicon esculentum Mill.） T2和T3小种对细菌斑疹（黄斑单胞菌）和油菜黄单胞菌（Xanthomonas campestris pv.）易感的自交系进行杂交。对T1、T2和T3小种均有抗性的稻种PI 114490。利用其中一个杂交的亲本、f1代和f2代对T2小种的抗性进行分析。f1在疾病严重程度上介于亲本之间，提示加性基因作用。f2后代的分离符合2位点模型（χ 2 = 0.96, P = 0.9 ~ 0.5），其中高抗性需要4个抗性等位基因，中等抗性需要2个或3个抗性等位基因，易感性需要0个或1个抗性等位基因。根据f2 - f3亲代回归，估计T2菌株的狭义遗传力为0.37±0.1。利用二交发展成近交系回交（IBC）群体，以方便多品种的多地点重复试验。在自交系回交群体中，T2抗性的分离也表明控制是由两个基因座控制的，这支持了基于f2分离的双基因座模型的假设。为了确定相同的位点是否赋予其他小种抗性，在f2和f3代中选择T2小种抗性，在f2到f4代中选择T3小种抗性。然后对6个T3品种（f5）、13个T2品种（f4品种与7个f2品种不同）和对照品系在两个季节内对T1、T2和T3品系的疾病严重程度进行评估。利用线性相关估计了以单种接种为基础的苗圃对多小种的抗性选择效率。比赛T1和比赛T2的疾病严重程度在年内和年之间相关（r≥0.80,P < 0.001），而比赛T3和年份均不相关。这些结果表明，在PI 114490杂交后代中选择抗T2小种可能是在被试群体中获得对T1和T2小种的抗性的有效策略。相比之下，选择种族T3或T2将不太可能产生对其他种族有抗性的系。pi114490对T3的抗性低于T2和T1。来自pi114490的IBC群体中T2和T3抗性的独立分离表明，T3抗性与T2抗性不是由同一基因控制的，支持线性相关数据。
A BSTRACT . Crosses were made between tomato ( Lycopersicon esculentum Mill.) inbreds susceptible to races T2 and T3 of bacterial spot ( Xanthomonas vesicatoria and Xanthomonas campestris pv. vesicatoria , respectively) and accession PI 114490 with resistance to races T1, T2, and T3. Resistance to race T2 was analyzed using the parents, F 1 , and F 2 generations from one of the crosses. The F 1 was intermediate between the parents for disease severity suggesting additive gene action. The segregation of F 2 progeny fi t a two-locus model ( χ 2 = 0.96, P = 0.9-0.5) where four resistance alleles are required for a high resistance level, two or three resistance alleles provide intermediate resistance, and zero or one resistance allele results in susceptibility. The narrow sense heritability of resistance to T2 strains was estimated to be 0.37 ± 0.1 based on F 2 to F 3 parent-offspring regression. A second cross was developed into an inbred backcross (IBC) population to facilitate multilocation replicated testing with multiple races. Segregation for T2 resistance in the inbred backcross population also suggested control was by two loci, lending support to the two-locus model hypothesized based on the F 2 segregation. To determine if the same loci conferred resistance to the other races, selections for race T2 resistance were made in the F 2 and F 3 generations and for race T3 resistance in the F 2 through F 4 generations. Six T3 selections (F 5 ), 13 T2 selections (F 4 ʼ s that diverged from seven F 2 selections), and control lines were then evaluated for disease severity to races T1, T2, and T3 over two seasons. Linear correlations were used to estimate the ef fi ciency of selecting for resistance to multiple races based on a disease nursery inoculated with a single race. Race T1 and race T2 disease severities were correlated ( r ≥ 0.80, P < 0.001) within and between years while neither was correlated to race T3 either year. These results suggest that selecting for race T2 resistance in progeny derived from crosses to PI 114490 would be an effective strategy to obtain resistance to both race T1 and T2 in the populations tested. In contrast, selection for race T3 or T2 will be less likely to result in lines with resistance to the other race. PI 114490 had less resistance to T3 than to T2 or T1. Independent segregation of T2 and T3 resistance from the IBC population derived from PI 114490 suggests that T3 resistance is not controlled by the same genes as T2 resistance, supporting the linear correlation data.