Genetic divergence among accessions of Manihot spp.

ABSTRACT. The aim of this study was to perform a morphological and morphoagronomic analysis of wild Manihot species from a Brazilian semiarid region for inclusion in the collection at the Center for Agricultural Sciences, Federal University of Paraíba. To characterize the 55 accessions, 12 quantitative and 18 qualitative descriptors were used. A dissimilarity matrix was generated by Mahalanobis generalized distance (D²), and clusters were identified by the UPGMA method. It was possible to verify the formation of 8 dissimilar groups based on morphological characters and 5 groups based on morphometric characters, indicating the presence of genetic diversity among accessions. The evaluated morphometric variable with the greatest relative contribution was the length between the central lobe. Based on the dissimilarity matrix, the accessions 16 x 48 were the most genetically distant accessions, followed by 47 x 49. The accessions 4 Monteiro, 16 Soledad, 38 Boa Vista, 3 Pedra Lavrada, 7 Junco, 10 Barra de Santa Rosa, 21 Monteiro, and 39 Junco are the most promising and can be used as parents in breeding programs for this forage species.

摘要。本研究旨在对巴西半干旱地区的野生木薯属（Manihot）物种开展形态学及形态农艺学分析，以将其收录至帕拉伊巴联邦大学农业科学中心的种质资源库。本研究采用12个数量性状描述符与18个质量性状描述符，对55份种质材料进行表型鉴定。通过马哈拉诺比斯广义距离（Mahalanobis generalized distance, D²）构建差异矩阵，并采用非加权组平均法（UPGMA）进行聚类分析。结果表明，基于形态性状可划分为8个差异类群，基于形态计量性状则可划分为5个类群，证实供试种质间存在遗传多样性。相对贡献率最高的形态计量性状为中央裂片间距。基于差异矩阵分析，种质16与48间的遗传距离最远，其次为47与49。其中，4 Monteiro、16 Soledad、38 Boa Vista、3 Pedra Lavrada、7 Junco、10 Barra de Santa Rosa、21 Monteiro及39 Junco这8份种质表现最为优异，可作为该饲用木薯属物种育种项目的亲本材料。