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首页> 外文期刊>Genetic Resources and Crop Evolution >Sources of resistance to Phytophthora pod rot at the International Cocoa Genebank, Trinidad.
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Sources of resistance to Phytophthora pod rot at the International Cocoa Genebank, Trinidad.

机译：特立尼达国际可可种质库对疫霉菌腐烂的抗性来源。

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The International Cocoa Genebank, Trinidad (ICG,T) contains about 2000 cacao (Theobroma cacao L.) accessions. The purpose of the collection is to provide a source of genes for the genetic improvement of cacao through breeding. In fulfilling this objective, it is imperative that this collection be evaluated to identify major sources of genes for the genetic improvement of important agronomic-economic traits. In this study, 816 cacao accessions were evaluated for resistance to Phytophthora pod rot (black pod disease), which causes enormous loss of yield in cocoa production throughout the world. The study identifies promising resistant genotypes that could be exploited in cacao breeding programmes. It further compares the levels of resistance to Phytophthora pod rot among two cacao types (wild and cultivated types), three major groups (Forastero, Trinitario and Refractario) and 11 accession groups (B, AM, CL, ICS, IMC, JA, LP, MOQ, NA, PA and TRD). The distribution of scores for the 816 accessions showed skewness towards the susceptible end of the disease rating scale, indicating that a large proportion (68.9%) of the sample was susceptible (disease rating 6-8) to Phytophthora pod rot. However, 12.9% of the sample population was found to be resistant (disease rating 1-3) and 18.2% moderately resistant (disease rating 4-5). Significant differences were observed between the wild and cultivated accessions and among the Forastero, Refractario and Trinitario groups. Marked differences were also observed among 11 accession groups, each of which was represented by at least 20 genotypes. Higher proportions of resistant (17.7%) and moderately resistant (22.6%) genotypes were observed in the wild accessions than in the cultivated varieties (9.4% resistant and 14.4% moderately resistant). The Forastero group, consisting of many wild accessions, was found to contain more resistant (18.0%) and moderately resistant (23.1%) genotypes than either the Trinitario (4.8% resistant and 13.6% moderately resistant) or Refractario (11.3% resistant and 15.4% moderately resistant). Among 11 accession groups, the largest percentage of resistant (24.2%) and moderately resistant (28.8%) genotypes were found in the PA (Forastero). Different accession groups had varying proportions of resistant and moderately resistant genotypes. This is not unexpected in an out-breeding crop such as cacao with a high level of heterogeneity. This finding reinforces the idea of a pre-breeding programme (germplasm enhancement) to accumulate resistance genes over several populations as a strategy for improving the genetic base of resistance in national cacao breeding programmes. One hundred and five promising resistant genotypes were identified among the 816 accessions evaluated. These accessions are potential sources of resistance genes for the development of high-yielding resistant varieties in cacao..
机译：特立尼达国际可可种质库（ICG，T）包含约2000种可可（Theobroma cacao L.）保藏。收集的目的是通过繁殖为可可的遗传改良提供基因来源。为了实现这一目标，必须对这一收藏进行评估，以鉴定重要农艺经济性状遗传改良的主要基因来源。在这项研究中，评估了816种可可成分对疫霉（Phytophthora）荚腐病（黑荚病）的抵抗力，这在全世界范围内导致可可生产中的巨大产量损失。该研究确定了可可育种计划中可以利用的有希望的抗性基因型。它进一步比较了两种可可类型（野生和栽培类型），三个主要组（Forastero，Trinitario和Refractario）和11个登录组（B，AM，CL，ICS，IMC，JA，LP）之间对疫霉的腐烂的抗性水平。 ，最小起订量，NA，PA和TRD）。 816个种质的分数分布显示出朝向疾病等级量表的易感末端偏斜，表明大部分样本（68.9％）对马铃薯疫霉菌腐烂很敏感（疾病等级为6-8）。但是，发现12.9％的样本人群具有抗药性（疾病等级1-3）和18.2％的中度抗药性（疾病等级4-5）。在野生和栽培种之间以及Forastero，Refractario和Trinitario组之间观察到显着差异。在11个登录组之间也观察到显着差异，每个登录组均由至少20个基因型代表。在野生种中观察到的抗性（17.7％）和中度抗性（22.6％）基因型比例要比栽培品种更高（9.4％的抗性和14.4％的中度抗性）。与三针线虫（4.8％的抗性和13.6％的中度抗性）或耐火线虫（11.3％的抗性和15.4）相比，由许多野生种组成的Forastero组具有更高的抗性（18.0％）和中度抗性（23.1％）基因型。 ％中等抵抗力）。在11个入组中，在PA（Forastero）中发现了最大百分比的抗性（24.2％）和中度抗性（28.8％）基因型。不同的登录组具有不同比例的抗性和中度抗性基因型。这在异种程度高的可可作物（如可可）中并不意外。这一发现加强了预育计划（种质增强）的构想，以在多个种群上积累抗性基因，以此作为改善国家可可育种计划中抗性遗传基础的策略。在所评估的816个种质中鉴定出一百零五个有希望的抗性基因型。这些种质是可可中高产抗性品种发展的抗性基因的潜在来源。

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