Commercial, technological and nutritional quality of bean cultivars (Phaseolus vulgaris L.) recommended in Brazil

O feijão tem grande importância nacional e o desenvolvimento de novas cultivares com melhor qualidade tecnológica e nutricional dos grãos, além das características agronômicas, pode representar uma alternativa para solucionar problemas alimentares, sociais e econômicos. Assim, os objetivos com este trabalho foram avaliar a variabilidade genética de 105 cultivares de feijão, recomendadas no Brasil nos últimos 60 anos, quanto a qualidade tecnológica e nutricional de seus grãos, além de determinar o tamanho de amostras para avaliação acurada destes caracteres. Em sementes destas cultivares, multiplicadas em quatro experimentos conduzidos nas safras das águas de 2018, seca e inverno de 2019 e águas de 2020, foram determinadas a concentração dos minerais ferro, zinco e cobre, teor de proteína bruta e quantificado o grau de achatamento, formato e tempo de cozimento dos grãos. Observou-se que há variabilidade genética para a concentração destes minerais (ferro, zinco, cobre e proteína bruta) e para os caracteres que determinam a qualidade tecnológica dos grãos nestas 105 cultivares de feijão. Com acurácia de 0,90, amostras constituídas de 10 grãos são suficientes para quantificar o tamanho e grau de achatamento, e de 7 grãos para determinar o tempo de cozimento. Houve interação cultivares x safras de natureza complexa para o tempo de cozimento, indicando que a determinação deste caráter deve ser realizado nas diferentes safras. A partir do germoplasma de feijão avaliado, é possível desenvolver novas linhagens, tanto do tipo carioca quanto preto, que associem alta concentração dos minerais ferro, zinco e cobre, alto teor de proteína bruta, além de produtivas e com massa de 100 grãos e aspecto de grãos que atendam ao mercado consumidor. Palavras-chave: Concentração de minerais. Análise de repetibilidade. Tempo de cozimento. Melhoramento do feijoeiro.Beans hold significant national importance, and the development of new cultivars with improved technological and nutritional grain quality, in addition to agronomic characteristics, can provide an alternative to address food, social, and economic challenges. Therefore, the objectives of this study were to assess the genetic variability of 105 bean cultivars recommended in Brazil over the past 60 years regarding the technological and nutritional quality of their grains and to determine sample sizes for the accurate evaluation of these traits. For seeds of these cultivars, multiplied in four experiments conducted during the 2018 rainy season, 2019 dry and winter seasons, and 2020 rainy season, the concentrations of the minerals iron, zinc, and copper, crude protein content, as well as the degree of flattening, shape, and cooking time of the grains were determined. It was observed that there is genetic variability in the concentration of these minerals (iron, zinc, copper, and crude protein) and in the traits determining the technological quality of the grains among these 105 bean cultivars. With an accuracy of 0,90, samples consisting of 10 grains are sufficient to quantify size and flattening degree, and 7 grains to determine cooking time. There was a complex interaction between cultivars and crop seasons regarding cooking time, indicating that this trait should be assessed in different crop seasons. Based on the evaluated bean germplasm, it is possible to develop new lines, both of the 'carioca' and 'preto' types, that combine high concentrations of the minerals iron, zinc, and copper, high crude protein content, as well as being productive with a mass of 100 grains and having grain characteristics that meet consumer demand. Keywords: Mineral concentration. Repeatability analysis. Cooking time. Bean improvement

PHENOLOGICAL, PLANT ARCHITECTURE, AND GRAIN YIELD TRAITS ON COMMON BEAN LINES SELECTION

The development of common bean cultivars with early cycle, upright plant architecture, and high grain yield represents marketing advantages to bean farmers. This study aimed to evaluate whether common bean inbred lines differ for phenological, plant architecture, and grain yield traits; analyze the correlations between these traits; and select early and upright common bean lines with high grain yield. To this end, 14 common bean inbred lines were evaluated in two growing seasons in Santa Maria - RS, Brazil. Common bean inbred lines showed significant differences for all traits, except for insertion of the first pod and length of the fourth and fifth internodes. The four superior common bean lines selected by the multiplicative index were CNFP 10794, CNFC 10762, DF 06-09, and BRS Valente. CNFP 10794 presents earliness (flowering and cycle), upright plant architecture (lower values of general adaptation score, lodging, and stay-green phenotype) and high grain yield (higher values of number of pods per plant, number of grains per plant, mass of 100 grains, and grain yield). Mass of 100 grains showed a positive correlation with grain yield (r= 0.68). The indirect selection using mass of 100 grains is of intermediate efficiency to increase grain yield in common bean. CNFP 10794 presents earliness, upright plant architecture, and high grain yield and will be selected for the breeding program

Adaptability and stability analyses of plants using random regression models.

The evaluation of cultivars using multi-environment trials (MET) is an important step in plant breeding programs. One of the objectives of these evaluations is to understand the genotype by environment interaction (GEI). A method of determining the effect of GEI on the performance of cultivars is based on studies of adaptability and stability. Initial studies were based on linear regression; however, these methodologies have limitations, mainly in trials with genetic or statistical unbalanced, heterogeneity of residual variances, and genetic covariance. An alternative would be the use of random regression models (RRM), in which the behavior of the genotypes is characterized as a reaction norm using longitudinal data or repeated measurements and information regarding a covariance function. The objective of this work was the application of RRM in the study of the behavior of common bean cultivars using a MET, based on Legendre polynomials and genotype-ideotype distances. We used a set of 13 trials, which were classified as unfavorable or favorable environments. The results revealed that RRM enables the prediction of the genotypic values of cultivars in environments where they were not evaluated with high accuracy values, thereby circumventing the unbalanced of the experiments. From these values, it was possible to measure the genotypic adaptability according to ideotypes, according to their reaction norms. In addition, the stability of the cultivars can be interpreted as variation in the behavior of the ideotype. The use of ideotypes based on real data allowed a better comparison of the performance of cultivars across environments. The use of RRM in plant breeding is a good alternative to understand the behavior of cultivars in a MET, especially when we want to quantify the adaptability and stability of genotypes