Pissard Audrey, Arbizu Carlos, Ghislain Marc, Faux Anne-Michèle, Paulet Sébastien, Bertin Pierre
Département de Biologie Appliquée et Productions Agricoles, Ecophysiologie et Amélioration Végétale, Université Catholique de Louvain, Place Croix du Sud, 2 bte 11, 1348 Louvain-La-Neuve, Belgium.
Genetica. 2008 Jan;132(1):71-85. doi: 10.1007/s10709-007-9150-9. Epub 2007 Apr 19.
Oxalis tuberosa is an important crop cultivated in the highest Andean zones. A germplasm collection is maintained ex situ by CIP, which has developed a morphological markers system to classify the accessions into morphotypes, i.e. groups of morphologically identical accessions. However, their genetic uniformity is currently unknown. The ISSR technique was used in two experiments to determine the relationships between both morphological and molecular markers systems. The intra-morphotype genetic diversity, the spatial structures of the diversity and the congruence between both markers systems were determined. In the first experience, 44 accessions representing five morphotypes, clearly distinct from each other, were analyzed. At the molecular level, the accessions exactly clustered according to their morphotypes. However, a genetic variability was observed inside each morphotype. In the second experiment, 34 accessions gradually differing from each other on morphological base were analyzed. The morphological clustering showed no geographical structure. On the opposite, the molecular analysis showed that the genetic structure was slightly related to the collection site. The correlation between both markers systems was weak but significant. The lack of perfect congruence between morphological and molecular data suggests that the morphological system may be useful for the morphotypes management but is not appropriate to study the genetic structure of the oca. The spatial structure of the genetic diversity can be related to the evolution of the species and the discordance between the morphological and molecular structures may result from similar selection pressures at different places leading to similar forms with a different genetic background.
块茎酢浆草是安第斯山脉最高区域种植的一种重要作物。国际马铃薯中心（CIP）在异地保存了一份种质资源库，该中心已开发出一种形态学标记系统，用于将种质分类为形态型，即形态相同的种质组。然而，目前尚不清楚它们的遗传一致性。在两项实验中使用了ISSR技术来确定形态学和分子标记系统之间的关系。测定了形态型内的遗传多样性、多样性的空间结构以及两个标记系统之间的一致性。在第一个实验中，分析了代表五个形态型的44份种质，这些形态型彼此明显不同。在分子水平上，种质根据其形态型精确聚类。然而，在每个形态型内部都观察到了遗传变异。在第二个实验中，分析了34份在形态基础上逐渐不同的种质。形态学聚类没有显示出地理结构。相反，分子分析表明遗传结构与收集地点略有相关。两个标记系统之间的相关性较弱但显著。形态学和分子数据之间缺乏完美的一致性表明，形态学系统可能对形态型管理有用，但不适用于研究块茎酢浆草的遗传结构。遗传多样性的空间结构可能与物种的进化有关，形态学和分子结构之间的不一致可能是由于不同地方相似的选择压力导致具有不同遗传背景的相似形态。
