Department of Agriculture Technology, Faculty of Agriculture, Universiti Putra Malaysia (UPM), Malaysia.
Gene. 2012 Aug 15;505(1):23-36. doi: 10.1016/j.gene.2012.05.056. Epub 2012 Jun 6.
Andrographis paniculata (AP) has been stated as a low-diverse, endangered and red-listed plant species. Self-pollinated mating system, being an introduced species and experiencing a bottleneck as well as over exploitation cause such a consequence. Inter and intra-specific hybridizations have been suggested as essential techniques for generating genetic diversity. To test the effect of intra-specific hybridization on diversification and heterosis of AP, seven accessions were outcrossed manually in all 21 possible combinations. Three types of markers including morphological, phytochemical and RAPD markers were employed to evaluate the mentioned hypothesis. The results revealed that hybridization acted as a powerful engine for diversification of AP as it caused heterotic expression of the studied traits, simultaneously. Initially, it seems that additive and non-additive gene effects both can be considered as the genetic basis of heterosis in AP for the investigated traits. Agronomic and morphological traits were differentiated from each other, while positive heterosis was recorded mainly for agronomic traits but not for the morphological traits. Intra-specific hybridization increased the genetic diversity in AP population. Nevertheless, a part of this variation could also be attributed to the negative heterosis. The current exploration demonstrated the first ever conducted manual intra-specific hybridization among AP accessions in a mass scale. However, the 17 RAPD primers produced a monomorph pattern, but perhaps increasing the number of markers can feature a new genetic profile in this plant.
穿心莲（AP）被认为是一种低多样性、濒危和红色名录植物物种。自交交配系统、作为引入物种以及经历瓶颈和过度开发是导致这种结果的原因。种间和种内杂交被认为是产生遗传多样性的重要技术。为了测试种内杂交对 AP 多样化和杂种优势的影响，将 7 个品系以 21 种可能的组合全部进行了人工异交。采用三种类型的标记，包括形态学、植物化学和 RAPD 标记来评估上述假设。结果表明，杂交是 AP 多样化的强大动力，因为它同时导致了所研究性状的杂种优势表达。最初，杂种优势的遗传基础似乎可以同时考虑加性和非加性基因效应。农艺和形态性状彼此不同，而正杂种优势主要记录在农艺性状上，但不是在形态性状上。种内杂交增加了 AP 群体的遗传多样性。然而，一部分这种变异也可能归因于负杂种优势。目前的研究表明，这是首次在大规模范围内对 AP 品系进行人工种内杂交。然而，17 个 RAPD 引物产生了单一模式，但也许增加标记的数量可以在这种植物中呈现出新的遗传特征。
