Labeyrie Vanesse, Deu Monique, Barnaud Adeline, Calatayud Caroline, Buiron Marylène, Wambugu Peterson, Manel Stéphanie, Glaszmann Jean-Christophe, Leclerc Christian
UMR AGAP, CIRAD, Montpellier, France.
UMR DIADE, IRD, Montpellier, France.
PLoS One. 2014 Mar 17;9(3):e92178. doi: 10.1371/journal.pone.0092178. eCollection 2014.
Understanding the effects of actions undertaken by human societies on crop evolution processes is a major challenge for the conservation of genetic resources. This study investigated the mechanisms whereby social boundaries associated with patterns of ethnolinguistic diversity have influenced the on-farm distribution of sorghum diversity. Social boundaries limit the diffusion of planting material, practices and knowledge, thus shaping crop diversity in situ. To assess the effect of social boundaries, this study was conducted in the contact zone between the Chuka, Mbeere and Tharaka ethnolinguistic groups in eastern Kenya. Sorghum varieties were inventoried and samples collected in 130 households. In all, 297 individual plants derived from seeds collected under sixteen variety names were characterized using a set of 18 SSR molecular markers and 15 morphological descriptors. The genetic structure was investigated using both a Bayesian assignment method and distance-based clustering. Principal Coordinates Analysis was used to describe the structure of the morphological diversity of the panicles. The distribution of the varieties and the main genetic clusters across ethnolinguistic groups was described using a non-parametric MANOVA and pairwise Fisher tests. The spatial distribution of landrace names and the overall genetic spatial patterns were significantly correlated with ethnolinguistic partition. However, the genetic structure inferred from molecular makers did not discriminate the short-cycle landraces despite their morphological distinctness. The cases of two improved varieties highlighted possible fates of improved materials. The most recent one was often given the name of local landraces. The second one, that was introduced a dozen years ago, displays traces of admixture with local landraces with differential intensity among ethnic groups. The patterns of congruence or discordance between the nomenclature of farmers' varieties and the structure of both genetic and morphological diversity highlight the effects of the social organization of communities on the diffusion of seed, practices, and variety nomenclature.
了解人类社会行为对作物进化过程的影响是遗传资源保护面临的一项重大挑战。本研究调查了与民族语言多样性模式相关的社会边界影响高粱多样性田间分布的机制。社会边界限制了种植材料、种植方式和知识的传播，从而在原地塑造了作物多样性。为评估社会边界的影响，本研究在肯尼亚东部楚卡、姆贝雷和塔拉卡民族语言群体的接触区开展。对130户家庭的高粱品种进行了编目并采集了样本。总共对从16个品种名称下收集的种子培育出的297株单株植物，使用一组18个SSR分子标记和15个形态学描述符进行了特征分析。采用贝叶斯分配法和基于距离的聚类法对遗传结构进行了研究。主坐标分析用于描述圆锥花序形态多样性的结构。使用非参数多变量方差分析和成对费舍尔检验描述了各民族语言群体中品种和主要遗传簇群的分布情况。地方品种名称的空间分布和总体遗传空间模式与民族语言划分显著相关。然而，从分子标记推断出的遗传结构并未区分短周期地方品种，尽管它们在形态上有明显差异。两个改良品种的案例突出了改良材料可能的命运。最新的改良品种通常采用当地地方品种的名称。另一个是十几年前引进的，显示出与当地地方品种有不同程度的混合痕迹，不同族群的混合强度有所差异。农民品种命名与遗传和形态多样性结构之间的一致或不一致模式，突出了社区社会组织对种子、种植方式和品种命名传播的影响。
