Selection among and within full-sib families of elephant grass for energy purposes

Abstract Pennisetum purpureum Schum. has been a key alternative as an energy source in Brazil because of its higher dry matter accumulation and fiber content. This research aimed to select superior individuals of P. purpureum for energy purposes using among-and-within family selection. The study was carried out in Campos dos Goytacazes- RJ (Brazil), using eight full-sib families. Plants were individually assessed during two pasture cuttings, one in 2014, and another in 2015. The dry matter production (DMP) was correlated with the number of tillers, stem diameter, plant height, and neutral detergent fiber content. Plant selection criteria in both cuts were through direct and indirect selections, and Smith and Hazel index. A joint analysis of variance showed significant differences for all five traits assessed in both cuts. The results achieved with Smith and Hazel index were promising for simultaneous selection of the evaluated traits, favoring selection of superior families and individuals them.

摘要 象草（Pennisetum purpureum Schum.）因干物质积累量与纤维含量较高，是巴西关键的能源替代作物。本研究旨在采用家系间与家系内选择法，筛选出适配能源用途的优良象草单株。本试验于巴西里约热内卢州坎波斯多斯戈亚塔卡泽斯（Campos dos Goytacazes-RJ）开展，共使用8个全同胞家系。分别于2014年与2015年的两次牧草刈割期对单株进行性状考察。干物质产量（DMP）与分蘖数、茎粗、株高及中性洗涤纤维含量存在相关性。两次刈割期的单株选择均采用直接选择、间接选择以及史密斯-黑兹尔指数（Smith and Hazel index）法。联合方差分析结果显示，两次刈割期考察的全部5个性状均存在极显著差异。采用史密斯-黑兹尔指数得到的结果对同时选择考察性状颇具应用前景，有利于筛选出优良家系及单株。