High fiber quality is one of the most desired traits in the upland cotton breeding. To this end, breeding programs have developed hybrids with high heterotic effect, which provide genetic combinations and segregating populations from which superior genotypes can be selected. The objectives of this study were: (1) to identify superior genitors based on the general combining ability (GCA), (2) to indicate the best crossbreeds through the specific combining ability (SCA), and (3) to estimate phenotypic and genotypic correlations for the following fiber traits: length, uniformity, short fiber index, strength, elongation, micronaire, maturity, reflectance, degree of yellowing, and spinning index. The experiments were carried out in two environments in the semi-arid region of Brazil and two harvests (2015 and 2019) to evaluate six parents and fifteen F₁’s hybrids obtained by diallel crossings. The design used was random blocks with three replicates. The following traits were evaluated: length, uniformity, short fiber index, strength, elongation, micronaire, maturity, reflectance, degree of yellowing, and spinning index. Analysis of variance, diallel analysis and genetic correlations were performed. The parents with higher GCA were: TAMB 139-17, PSC 355, IAC 26, and FM 993. The crossings with highest SCA were: TAMB 139-17 × TAMCOT CAMD-E, CNPA 04 2080 × PSC 355, TAMB 139-17 × IAC 26, FM 993 × CNPA 04 2080. Positive genetic correlations were found between length, uniformity, strength, and spinning index. Micronaire had positive correlations with maturity. The short fiber index showed negative correlations with length, uniformity, strength, elongation, degree of yellowing, and spinning index.

高纤维品质是陆地棉育种中最需要的特性之一。为此，育种计划开发了具有高杂种优势效应的杂种，它们提供了可以从中选择优良基因型的遗传组合和分离种群。本研究的目的是：(1) 根据一般配合力 (GCA) 确定优良生殖细胞，(2) 通过特定配合力 (SCA) 指示最佳杂交品种，以及 (3) 估计表型和基因型以下纤维特性的相关性：长度、均匀度、短纤维指数、强度、伸长率、马克隆值、成熟度、反射率、黄化程度和纺纱指数。实验在巴西半干旱地区的两种环境和两次收获（2015 年和 2019 年）中进行，以评估 6 个亲本和 15 个 F₁通过双列交叉获得的杂种。使用的设计是具有三个重复的随机区组。评价以下特性：长度、均匀度、短纤维指数、强度、伸长率、马克隆值、成熟度、反射率、泛黄程度和纺丝指数。进行了方差分析、双列分析和遗传相关性分析。GCA 较高的亲本为：TAMB 139-17、PSC 355、IAC 26 和 FM 993。SCA 最高的杂交为：TAMB 139-17 × TAMCOT CAMD-E、CNPA 04 2080 × PSC 355、TAMB 139-17 × IAC 26, FM 993 × CNPA 04 2080。在长度、均匀度、强度和纺纱指数之间发现了正的遗传相关性。马克隆值与成熟度呈正相关。短纤维指数与长度、均匀度、强度、伸长率、黄变程度和纺丝指数呈负相关。