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Abstract The objective of this work was to estimate the repeatability coefficients of variables related to fruit and nut production, the minimum number of crops required for genotype selection, and the permanent phenotypic correlation coefficients between variables in a cultivated population of Amazon nut. A total of 40 genotypes from seeds, belonging to an agroforestry system implemented in 1995, in the state of Roraima, Brazil, were evaluated during ten years for six variables related to fruit and nut production. The genetic-statistical analyses were performed using the maximum restricted likelihood and best linear unbiased prediction (REML/BLUP) method, based on the basic model of repeatability, without an experimental design, of the Selegen-REML/BLUP software. Genetic variability between genotypes and a moderate regularity in the repetition of the studied variables between different harvests were detected. The number of harvests required to reach a coefficient of determination of 80% ranged from seven, for the variables average nut weight per fruit and number of fruits per plant, to nine, for average nut weight. The correlation results indicate the possibility of indirect selection for nut production through the evaluation of the number and weight of fruits per plant.

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ABSTRACT Cowpea is a species used for various purposes, including green grain production. New cowpea cultivars should be developed to answer the growing market demands for green gains, which can be achieved via breeding programs. In this scenario, diallel cross is a breeding method that allows researchers to select the most suitable parents for hybridization. From this perspective, this study aimed to identify cowpea parents and hybrids with good combining abilities to initiate a breeding program aimed at green grain production. The experiment was developed at the Plant Science Department of the Federal University of Ceará. Fifteen treatments (five parents and ten hybrids) were set up in a randomized block design with ten replications. The variables of green pod length, green pod mass, number of grains, grain mass per green pod, and green grain length were studied in this experiment. The data were subjected to analysis of variance, test of means, and diallel analysis. The parents and hybrids showed variations for the evaluated traits. Both additive and non-additive effects influence the behavior of inherited traits. The parent CE0002 and hybrid combinations BRS Juruá x CE1002 and CE0957 x CE0002 are recommended for selection, showing desirable aspects for green grain production.

The correlation estimation and its partition into cause and effect is seen as a valuable tool in obtaining gains from selection in plant breeding. This allows the anticipation of choosing the best genotypes. Thus, the objective of this study was to consider indirect selection for simultaneous improvement of root and aboveground traits in segregating common bean populations. The experiment was carried out in the 2021/22 season, considering six common bean genotypes, two parents and four segregating generations (F2, F3, F4 and F5), under a lattice design. Root system traits were measured by two phenotyping methods, called Shovelomics and WinRHIZO. The aerial part traits evaluated were chlorophyll content, plant height, stem diameter, first pod height insertion and yield components (number of pods, number of grains and weight of grains per plant). Correlation analysis and cause and effect analysis (path analysis) were performed. Significant correlation estimates (t) were found between root and aerial traits, with emphasis on chlorophyll B content with left horizontal length (t = -0.22) and chlorophyll A content with total root length (t = 0.24). The unfolding of these estimates by path analysis indicated that the chlorophyll A content has a correlation and a high direct effect on the total length of roots and that the total chlorophyll content indirectly influences the left and right horizontal root lengths. This fact makes it possible to obtain gains with the selection of improved common bean plants for root system based on the direct and indirect evaluation of chlorophyll contents, easily measured in the aerial part of the plants. This allows the optimization of time and resources in breeding programs, aiming at obtaining agronomically superior plants. [ABSTRACT FROM AUTHOR]

ABSTRACT: Due to the economic importance of maize, it is essential to evaluate the performance of genotypes under environmental variations (years, locations, and seasons). Consequently, researchers have scrutinized genotype-environment (G×E) interactions to ensure reliability in genotype recommendations. Furthermore, when a G×E interaction exists, adaptability and stability analysis can be performed. This analysis enables one to identify genotypes with predictable responses and adaptability to environmental variability. Hence, this study sought to determine if there is a G×E interaction and evaluate the response of 16 maize genotypes across seven environments through adaptability and stability analyses. Seven experiments were conducted with 16 maize genotypes using a randomized complete block design with three replications. Tassel length (TL), tassel branch number (TBN), tassel dry matter (TDM), and grain yield (GY) were evaluated. Individual and joint variance analyses were performed, along with the F-test at a 5% significance level. The complex parts of the interaction between genotypes and pairs of environments were estimated, followed by adaptability and stability analyses using the Eberhart and Russell method. A genotype-environment interaction was found for TL, TBN, TDM, and GY, indicating that genotypes respond differently in various environments. However, considering all four traits, there is no indication of the ideal genotype.

ABSTRACT Watermelon has great importance due to its nutritional properties. The aim of this work was to study accessions classified as resistant to fusariosis. Twelve accessions and two cultivars, Sugar Baby and Charleston Gray (controls), were characterized for watermelon fruit quality descriptors. The experiment was conducted in Petrolina-PE, over two production cycles in a randomized complete block design, with three repetitions and five plants per plot. Two fruits per plot were sampled for characterization. Ten quantitative and seven qualitative descriptors were evaluated. For the qualitative traits, dissimilarity measures were determined by a matrix of Euclidean distance. At the second harvest, most accessions had higher organic acid and vitamin C content in the pulp and higher soluble solids (°Brix) content. The accessions were divided into four groups according to the Tocher method. There is variability among the evaluated accessions, and the accessions BGH-Univasf 40, BGH-Univasf 169, and BGH-Univasf 177 are potential sources for use in watermelon breeding programs. Accessions BGH-UNIVASF 76, BGH-UNIVASF 128, and BGH-UNIVASF 185 (Citrullus lanatus var. citroides) performed well in terms of total production, fruit mass, and vitamin C content.

ABSTRACT: This study carried out early selection of soybean progenies that are productive and resilient to environmental conditions. The experiment took place at the Genetic Breeding Program of UNIJUI (University of the Northwest of the State of Rio Grande do Sul), located in Ijuí - RS, Brazil. The experiment used augmented blocks design with interim checks. The regular treatments correspond to 24 soybean F2 populations and the common treatments were 18 commercial checks, arranged in four replications. At full physiological maturity, in each experimental unit, five plants were randomly collected to obtain seed weight per plant (SWP, g). The Jinks and Pooni methodology was used to calculate the probability of extracting superior lineages from the evaluated populations. The best control and promising cultivars to compose the parent bank are BMX FORÇA RR, FUNDACEP 66 RR and TMG 7062 IPRO. Jinks and Pooni’s methodology identified populations IRC001, IRC002, IRC017, IRC019, IRC028, IRC030, IRC032, IRC033, IRC035, IRC036, IRC039 and IRC040 as having high potential for extraction of superior lineages.