EVALUATION OF CARNAUBA PROGENIES AND ESTIMATES OF GENETIC PARAMETERS IN THE JUVENILE PHASE

ABSTRACT Carnauba (Copernicia prunifera) is a forest species with multiple uses, and is of great economic and social importance for several communities involved in extractive agriculture in northeastern Brazil. However, there are few studies on genetic variability in this species. Thus, this work aimed to produce information about the genetic characterization of C. prunifera seeds and seedlings, using provenance and progeny evaluations. A progeny test was performed in a plant nursery, using seeds of 36 matrices sampled in the municipalities of Mossoró and Apodi (Rio Grande do Norte State), and Russas and Icapuí (Ceará State). Three groups were derived according to the spatial distance between the collected matrices. Biometric analyses of the seeds were performed, adopting a completely randomized experimental design, with four replicates of 25 seeds in each analysis. A randomized block design (five replicates and five plants per plot) was used at the seedling production phase. The data evaluated included the emergence speed index, emergence percentage, leaf size, leaf base diameter, and survival (at 30, 60, and 90 days after sowing). The restricted maximum likelihood method was used in the statistical analysis, with the aid of SELEGEN software. In order to evaluate genetic variability in the C. prunifera population samples, it was verified that the juvenile characters presented a moderate genetic control. The three groups of spatially delimited matrices presented no significant genetic differences. This information may assist in the development of forestry practice for this species.

摘要：巴西蜡棕（Copernicia prunifera）是一种多用途森林树种，对巴西东北部参与采撷农业的诸多社区而言具有重要的经济与社会价值。然而当前针对该物种的遗传变异研究相对匮乏。为此，本研究通过种源与子代评价，旨在获取巴西蜡棕种子及幼苗的遗传特征相关信息。本研究于苗圃内开展子代测定试验，所用种子采自北里奥格兰德州莫索罗市、阿波迪市以及塞阿拉州鲁萨斯市、伊卡普伊市的36株母树，根据采集母树间的空间距离划分为3个组群。种子生物测量分析采用完全随机试验设计，每次分析设置4个重复，每个重复包含25粒种子；幼苗培育阶段则采用随机区组试验设计，设置5个重复，每小区种植5株幼苗。评估指标涵盖出苗速率指数、出苗率、叶面积、叶基直径以及播种后30、60、90天的幼苗存活率。统计分析采用约束极大似然法，并借助SELEGEN软件完成。为评估巴西蜡棕种群样本的遗传变异，本研究证实其幼龄性状存在中等水平的遗传调控，且按空间距离划分的3组母树群未表现出显著遗传差异。本研究结果可为该树种的林业生产实践提供参考依据。