Employment of flanking codominant STS markers to estimate allelic substitution effects of a nematode resistance locus in carrot
Employment of flanking codominant STS markers to estimate allelic substitution effects of a nematode resistance locus in carrot
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DOI：
10.1023/b:euph.0000019508.78153.dd
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发表时间：
2004-01-01
期刊：
影响因子：
1.9
通讯作者：
Simon, PW
中科院分区：
文献类型：
--
作者：
Boiteux, LS;Hyman, JR;Simon, PW
在胡萝卜中，两个共显性序列标记位点 (STS) 标记位于爪哇根结线虫抗性 (Mj-1) 基因座的紧密连锁侧翼，用于研究抗性表达与基因座剂量之间的关联。纯合抗性(R)的表型表达；杂合子；来自'Brasilia-1252'（R）x'B6274'（S）的396株F-2植物的F-2种群中的纯合易感（S）个体根据三个抗性标准进行估计：每株植物的总产蛋量（TEP）、每克须根产蛋量（EPG）和根瘿指数（RGI）。纯合抗性类别的 TEP 平均值为 403.9； EPG 为 147.5，RGI 为 0.8。杂合子类有 1,673 个； 477.3；和 0.16，而纯合易感人群有 68,604 人； 11,877；和2.54，分别。显性比（d/a）表明，源自抗性亲本的基因组区域包含对 RGI 几乎完全显性的遗传因子（d/a = 0.93-0.94），对转化的（TEP）（0.25）和（EPG）（0.25）（d/a = 0.63-0.65）不完全显性。广义遗传力很高，从 (EPG)(0.25) 的 72.9% 到 RGI 的 86.0%。狭义遗传力值范围从 RGI 的 55.9% 到 (TEP)(0.25) 的 64.3%。在 (TEP) 0.25 和 (EPG) 0.25 的纯合抗性与杂合子之间观察到高度显着的正交对比。标记辅助选择可以极大地促进Mj-1等位基因并入雄性可育和雄性不育对应品系中，以获得具有最有效抗性水平的F-1杂种。
In carrot, two codominant sequence-tagged site (STS) markers, flanking in tight linkage the Meloidogyne javanica resistance (Mj-1) locus, were employed to investigate the association between expression of resistance and locus dosage. Phenotypic expression of homozygous resistant (R); heterozygous; and homozygous susceptible (S) individuals in an F-2 population of 396 F-2 plants from 'Brasilia-1252' (R) x 'B6274' (S) was estimated for three resistance criteria: total egg production per plant (TEP), egg production per gram of fibrous root (EPG) and root gall index (RGI). The homozygous resistant class had average values of 403.9 for TEP; 147.5 for EPG and 0.8 for RGI. The heterozygous class had 1,673; 477.3; and 0.16 whereas the homozygous susceptible class had 68,604; 11,877; and 2.54, respectively. The dominance ratio (d/a) indicated that genomic region(s) derived from the resistant parent encompass genetic factor(s) with almost complete dominance for RGI (d/a = 0.93-0.94) and incomplete dominance for transformed (TEP)(0.25) and (EPG)(0.25) (d/a = 0.63-0.65). Broad sense heritabilities were high varying from 72.9% for (EPG)(0.25) to 86.0% for RGI. Narrow sense heritability values ranged from 55.9% for RGI to 64.3% for (TEP)(0.25). Highly significant orthogonal contrasts were observed between homozygous resistant vs. heterozygous for ( TEP) 0.25 and ( EPG) 0.25. Marker-assisted selection could greatly facilitate the incorporation of the Mj-1 allele in both male-fertile and male-sterile counterpart lines in order to obtain F-1 hybrids with the most effective levels of resistance.