Abstract

Six faba bean parents and their F₁ and F₂ generations were used in this investigation to study the genetic system controlling resistance of faba bean (Vicia faba L.) to broomrape (Orobanche crenata). Most of the F₁ hybrids were tolerant to broomrape. In the F₂ generation, the population P₅ × P₆ (Assiut 125 × Romy 12) gave the highest value of relative yield and tolerance index. Heterosis and inbreeding depression were only positive in number of tillers/plant and seed yield/plant characters. The results indicated that the additive effect was more important than the dominance one (D > H₁) only for No. of pods/plant in the F₁ generation. Moreover, the narrow-sense heritability was low for most of the studied traits. Three molecular marker systems, namely RAPD, ISSR and SRAP were used for identification and estimation of the genetic diversity among the six faba bean genotypes. The three molecular markers generated DNA unique bands for all genotypes. Only, eight DNA fragments were related to Orobanche tolerance. Clearly and reproducible polymorphic markers were subjected to QTL analysis. The linkage analysis showed that, out of 34 marker loci segregated in the F₂ population, 29 (85.29%) were mapped on three linkage groups. QTL analysis using SIM method performed for the 29 markers assigned to LG-1, LG-2 and LG-3 with the eight traits, number of tillers/plant, plant height, number of pods/plant, seed yield/plant, number of broomrape spikes per plant, height of broomrape spikes, relative yield and tolerance index, showing 12 putative QTLs for all traits except number of tillers/plant. From this study, it is clear that P₅ × P₆ (Assiut 125 × Romy12) population could be considered promising for selection for resistance to broomrape infestation.

中文翻译：

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蚕豆对B帚的抗性遗传，遗传多样性和QTL作图分析

摘要

本研究使用六个蚕豆亲本及其F ₁和F ₂代来研究控制蚕豆对帚柄（Orobanche crenata）抗性的遗传系统。大多数F ₁杂种都能耐受扫帚。在F ₂代中，群体P ₅  ×P ₆（Assiut 125×Romy 12）的相对产量和耐受指数最高。杂种优势和近交抑制仅在分ers /植物数量和种子产量/植物特征方面为阳性。结果表明，加性效应比优势度更重要（D> H ₁）仅适用于F ₁代中的豆荚/植物数量。而且，大多数研究性状的狭义遗传力很低。三种分子标记系统，分别为RAPD，ISSR和SRAP，用于鉴定和评估6种蚕豆基因型之间的遗传多样性。这三种分子标记为所有基因型产生了DNA独特的条带。只有八个DNA片段与Orobanche耐受性有关。对清晰可重复的多态性标记进行QTL分析。连锁分析显示，在F _2中分离的34个标记基因座中人口，29个（85.29％）被映射到三个链接组。使用SIM方法对分配给LG-1，LG-2和LG-3的29个标记进行QTL分析，具有八个特征，分，/株数，株高，豆荚/株数，种子产量/株数，每株植物的扫帚穗数，扫帚穗数的高度，相对产量和耐受指数，除分12数/植物数外，所有性状均显示12个假定的QTL。从这项研究中可以清楚地看出，P ₅  ×P ₆（Assiut 125×Romy12）种群可被认为对选择扫帚rap侵染具有抗性。