Adriano-Anaya María de Lourdes, Pérez-Castillo Edilma, Salvador-Figueroa Miguel, Ruiz-González Sonia, Vázquez-Ovando Alfredo, Grajales-Conesa Julieta, Ovando-Medina Isidro
Instituto de Biociencias, Universidad Autónoma de Chiapas , Tapachula, Chiapas , Mexico.
PeerJ. 2016 May 24;4:e2071. doi: 10.7717/peerj.2071. eCollection 2016.
Sex expression and floral morphology studies are central to understand breeding behavior and to define the productive potential of plant genotypes. In particular, the new bioenergy crop Jatropha curcas L. has been classified as a monoecious species. Nonetheless, there is no information about its reproductive diversity in the Mesoamerican region, which is considered its center of origin and diversification. Thus, we determined sex expression and floral morphology in J. curcas populations from southern Mexico and Guatemala. Our results showed that most of J. curcas specimens had typical inflorescences with separate sexes (monoecious); meanwhile, the rest were atypical (gynoecious, androecious, andromonoecious, androgynomonoecious). The most important variables to group these populations, based on a discriminant analysis, were: male flower diameter, female petal length and male nectary length. From southern Mexico "Guerrero" was the most diverse population, and "Centro" had the highest variability among the populations from Chiapas. A cluster analysis showed that the accessions from southern Mexico were grouped without showing any correlation with the geographical origin, while those accessions with atypical sexuality were grouped together. To answer the question of how informative are floral morphological traits compared to molecular markers, we perform a Mantel correlation test between the distance matrix generated in this study and the genetic distance matrix (AFLP) previously reported for the same accessions. We found significant correlation between data at the level of accessions. Our results contribute to design genetic improvement programs by using sexually and morphologically contrasting plants from the center of origin.
性别表达和花形态学研究对于理解育种行为以及界定植物基因型的生产潜力至关重要。特别是，新型生物能源作物麻疯树已被归类为雌雄同株物种。然而，在被认为是其起源和多样化中心的中美洲地区，尚无关于其生殖多样性的信息。因此，我们测定了来自墨西哥南部和危地马拉的麻疯树种群的性别表达和花形态。我们的结果表明，大多数麻疯树标本具有典型的雌雄异花（雌雄同株）花序；与此同时，其余的则是非典型的（雌株、雄株、雄全同株、雄雌同株）。基于判别分析，对这些种群进行分组的最重要变量是：雄花直径、雌花花瓣长度和雄花花蜜腺长度。在来自墨西哥南部的种群中，“格雷罗”种群最为多样，而在恰帕斯州的种群中，“中心”种群具有最高的变异性。聚类分析表明，来自墨西哥南部的种质被归为一组，与地理起源没有任何相关性，而那些具有非典型性别的种质则被归在一起。为了回答与分子标记相比花形态特征的信息量有多大这一问题，我们对本研究中生成的距离矩阵与先前报道的相同种质的遗传距离矩阵（AFLP）进行了Mantel相关性检验。我们发现在种质水平上数据之间存在显著相关性。我们的结果有助于通过使用来自起源中心的具有性别和形态差异的植物来设计遗传改良计划。
