Importance and correlations of characters for cowpea diversity in traditional varieties

ABSTRACT Cowpea is a legume with ample plasticity, versatility and nutritional potential. It is a species widely used as a source of income and subsistence for small farmers in several Brazilian states, among them Acre. Due to the different varieties found in the State, it is the target of studies aiming at its genetic improvement. Thus, as one of the first stages of its improvement, it was aimed to determine the importance and correlations of characters for diversity and selection in traditional varieties of cowpea. The experiment was carried in completely randomized design, with plots consisting of four vase with capacity to 15.7 L, with one plant each and two replicates. The characteristics evaluated were: days for emergence, flowering (days), plant vigor (note), number of main stem nodes, apical leaflet length (mm), apical leaflet width (mm), length of pod (cm) and width of the pod (cm). The correlation coefficients (phenotypic, genotypic and environmental) were obtained, and the principal components analysis and the importance of the characters by the method proposed by Singh were carried out. The Singh method and principal components analysis were partially concordant in the distinction of the evaluated characters. The days for emergence, width of the apical leaflet, flowering and length of the apical leaflet were the main determinants for quantification of the genotypes and those that contributed the most to the variability of cowpea. The least discriminant characteristic by principal component analysis and recommended for discarding was plant vigor.

摘要：豇豆（cowpea）是一类兼具优异可塑性、广泛适用性与较高营养潜力的豆科作物。在巴西多个州（其中包括阿克里州），豇豆是小农重要的收入来源与生计依托物种，应用广泛。鉴于该州境内存在丰富多样的豇豆品种，其已成为遗传改良研究的重点目标。作为该作物遗传改良的首批阶段之一，本研究旨在明确传统豇豆品种的多样性评价与选育过程中，各性状的重要性及其相关性。本试验采用完全随机设计，每个试验单元包含4个容量为15.7 L的花盆，每盆定植1株植株，设置2次重复。本研究评估的性状包括：出苗天数、开花天数、植株活力（评分）、主茎节数、顶生小叶长度（mm）、顶生小叶宽度（mm）、豆荚长度（cm）与豆荚宽度（cm）。本研究计算了相关系数（包括表型、基因型及环境相关系数），并开展了主成分分析（principal components analysis）与基于辛格（Singh）提出方法的性状重要性评估。辛格法与主成分分析在对所评估性状的区分结果上存在部分一致性。出苗天数、顶生小叶宽度、开花天数与顶生小叶长度，是量化豇豆基因型的核心决定因素，同时也是对豇豆遗传变异度贡献最大的性状。通过主成分分析得出的判别能力最弱、建议予以剔除的性状为植株活力。