Genetic diversity in the orange subfamily Aurantioideae .1. Intraspecies and intragenus genetic variability
Genetic diversity in the orange subfamily Aurantioideae .1. Intraspecies and intragenus genetic variability
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DOI：
10.1007/bf00224564
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发表时间：
1996-04-01
影响因子：
5.4
通讯作者：
Navarro, L
中科院分区：
文献类型：
--
作者：
Herrero, R;Asins, MJ;Navarro, L
尽管柑橘具有重要的经济价值，但其系统发育和分类仍然存在争议。此外，致病性增强的病原体以及剧烈的环境变化目前正在蔓延或出现。本文的目的是测量遗传变异性并研究其分布模式，这是在大量柑橘及柑橘近缘物种中优化采样策略以寻找耐受或抵抗这些威胁因素的基因型的关键步骤。通过10种酶系统并使用8种不同的测量方法对其种内和属内变异性进行了比较研究。对10种酶系统的分析使我们能够区分所有物种以及除一种人工杂交种之外的所有物种。基因型变异性最低的物种是香桃木叶橘（C. myrtifolia）、克里迈丁橘（C. deliciosa，柳叶橘）、葡萄柚（C. paradisi）、柠檬（C. limon）和甜橙（C. sinensis），而酒饼簕（Severinia buxifolia）的值最高。在收集的样本中发现了广泛的杂合度值。柠檬（C. limon、C. meyeri、C. karna、C. volkameriana）、酸橙（C. aurantifolia、C. limettioides、C. lattifolia）和香柠檬（C. bergamia）显示出非常高的杂合度百分比，这表明它们是通过种间杂交起源的。有两个主要因素限制了种内遗传变异性：无融合生殖，其中珠心胚比合子胚更有活力；以及苗圃经营者在砧木幼苗阶段或营养繁殖接穗品种时对变异性进行筛选。此外，一些主要用作砧木的物种中出现自花授粉，这可以解释它们杂合度值较低的原因。物种和属之间的遗传差异通常较大，这表明适应性可能在柑橘亚科的进化过程中起到了重要作用。
Despite the great economic importance of citrus, its phylogeny and taxonomy remain a matter of controversy. Moreover pathogens of increased virulence and dramatic environmental changes are currently spreading or emerging. The objectives of the present paper, measuring genetic variability and studying its pattern of distribution, are crucial steps to optimize sampling strategies in the search of genotypes that tolerate or resist these threatening factors within the huge array of Citrus and Citrus related species. Their intraspecific and intrageneric variability was studied comparatively by means of ten enzymatic systems using eight different measures. The analysis of ten enzymatic systems allowed us to distinguish all the species and all but one artificial hybrid. The species with the lowest genotypic variability are C. myrtifolia, C. deliciosa (willow leaf mandarin), C. paradisi (grapefruit), C. limon (lemon) and C. sinensis (sweet orange), while Severinia buxifolia shows the highest value. A broad spectrum of heterozygosity values was found in the collection. Lemons (C. limon, C. meyeri, C. karna, C. volkameriana), limes (C. aurantifolia, C. limettioides, C. lattifolia) and C. bergamia show a very high percentage of heterozygosity which indicates an origin through interspecific hybridization. Two main factors limit genetic intraspecific variability: apomictic reproduction: where nucellar embryos are much more vigorous than the zygotic ones, and nursery-men selecting against variability in the seedling stage of the rootstocks or in propagating the scion cultivars vegetatively. Additionally, self-pollination appears in some species mainly used as rootstocks which would explain their low heterozygosity values. Genetic differences between species and genera are in general high, which suggests that adaptation might have played an important role during the evolution of the orange subfamily.