Abstract The objective of this work was to verify if there is variability in the dry matter accumulation rate of grains of the carioca-type common bean, as well as to identify the success of selection for this trait and the best time for harvest. Sixteen lines with carioca-type grains were evaluated in three sowing seasons through samples of five plants obtained at regular intervals. A quadratic equation was used to estimate the number of days to obtain the maximum dry matter in the grains. A low variability was observed among the lines, discouraging selection for this trait. The ideal moment for harvesting is when 100% of the grains present the typical stripes of carioca common bean, which may vary among and within pods of the same plant. If the harvest is carried out before complete physiological maturation is reached, the dry matter in the grains decreases, on average, 2.75% per day.

Resumo O objetivo deste trabalho foi verificar se há variabilidade na taxa de acúmulo de matéria seca nos grãos de feijão comum do tipo carioca, bem como identificar o sucesso na seleção para este caráter e a melhor época para colheita. Dezesseis linhagens com grãos do tipo carioca foram avaliadas em três épocas de semeadura, por meio de amostras de cinco plantas, obtidas em intervalos regulares. Utilizou-se equação quadrática para estimar o número de dias para obtenção do máximo de matéria seca nos grãos. Observou-se baixa variabilidade entre as linhagens, o que desestimula a seleção para esse caráter. O momento ideal para a colheita é quando 100% dos grãos apresentam as listras típicas do feijão carioca, o que pode variar entre e dentro das vagens da mesma planta. Se a colheita for realizada antes da maturação fisiológica completa ser atingida, a matéria seca nos grãos é reduzida, em média, 2,75% por dia.

ABSTRACT. In Brazil, there is an increasing demand for common bean (Phaseolus vulgaris L.) cultivars having Carioca-type (cream-colored seed coat with brown stripes) beans which have a light color that persists for a longer time combined with the most possible upright plant architecture. However, plant breeders are finding it difficult to combine these two traits in the same cultivar. The aim of this study was to compare success in the selection of new common bean lines that combine the two traits in segregating populations with 25%, 50%, or 75% of the alleles from the parents contrasting in upright plant architecture or in bean grains with persistent light color. A biparental cross was performed between a parent with light-colored beans (P1) and another with upright plants (P2). Three populations were obtained from the F1 seeds, with allelic frequencies of 75%, 50%, and 25% of P1. Subsequently, progenies were evaluated in a similar number in each population in the F2:3, F2:4, F2:5, and F2:6 generations. The plant architecture (PA) and grain darkening (GD) traits were visually evaluated using a scoring scale. Genetic and phenotypic parameters were estimated for all generations. There was no expressive advantage in using populations with a greater allele proportion of the parent favorable to upright plant architecture or slow grain darkening either in releasing of variability or in the occurrence of progenies with favorable phenotypes for the two traits.

RESUMO A mancha angular, causada pelo fungo Pseudocercospora griseola, é uma das doenças mais importantes do feijoeiro. A utilização de cultivares resistentes é uma das estratégias mais eficaz para o controle de ALS. O controle genético é quantitativo e envolve desde genes maiores como genes de pequeno efeito. Uma estratégia para a obtenção de linhas com resistência durável é a seleção recorrente, que visa aumentar gradativamente a frequência de alelos favoráveis. Neste estudo, avaliou-se a eficiência da inoculação artificial de P. griseola em feijão comum cultivado em casa de vegetação em um programa de seleção recorrente visando à resistência à mancha angular, com o objetivo de acelerar os programas de melhoramento. A partir da população inicial, três ciclos de avaliação, seleção e cruzamento foram realizados em casa de vegetação e as plantas mais resistentes foram selecionadas fenotipicamente. Plantas no estágio V2 foram inoculadas usando um isolado de P. griseola raça 63-63. As plantas selecionadas foram transplantadas para vasos e intercruzadas para formar o próximo ciclo de seleção. As progênies obtidas da população base (C0) e dos ciclos subsequentes (CI, CII e CIII) da geração S0: 2 foram avaliadas quanto à severidade da mancha angular em casa de vegetação e campo. As estimativas dos ganhos genéticos obtidos foram de -14,8% e -5,3%, para casa de vegetação e campo, respectivamente. A inoculação artificial com P. griseola permitiu três ciclos de seleção recorrentes por ano, representando um método promissor para a obtenção de linhagens de feijão resistentes a ALS em curto período.

ABSTRACT The angular leaf spot (ALS), caused by the fungus Pseudocercospora griseola, is one of the most notable diseases of common beans (Phaseolus vulgaris). The most effective strategy to control ALS is quantitative disease resistance provided by major and minor genes. One breeding strategy for obtaining lines with durable resistance to P. griseola is a recurrent selection that aims to gradually assemble favorable alleles. In this study, common beans were artificially inoculated with P. griseola and grown in a greenhouse under a recurrent selection program that aims to accelerate the breeding cycle and assimilate resistant conferring genes per generation. From the initial population, three cycles of evaluation, selection, and intercross were carried out in a greenhouse and the most resistant plants were phenotypically selected. Plants at the V2 stage were inoculated with an isolate of P. griseola, race 63-63. Selected plants were transplanted into pots and intercrossed to reap the next cycle of selection. Progenies obtained from the base population (C0) and subsequent cycles (CI, CII, and CIII) were assessed for the degree of the symptoms for ALS under greenhouse and field conditions. The rate of genetic progress per breeding cycle was - 14.8% and - 5.3% for the plants grown in greenhouse and field, respectively. Artificial inoculation with P. griseola allowed three recurrent selection cycles per year, signifying a promising method to obtain ALS-resistant common bean lines in a short period.

Abstract The success of bean (Phaseolus vulgaris L.) crops in Brazil is due to the development of new cultivars. The aim of the present study was to critically analyze the fifty years of a bean breeding program at the Universidade Federal de Lavras (UFLA) and estimate the genetic progress (GP) achieved for grain yield. The estimated genetic progress for grain yield was 0.35% per year, which is associated with visible improvement in plant architecture, resistance to some pathogens, and better carioca bean grain quality. The program was found to be efficient, generating 119 theses and 43 dissertations during the period under study. In addition, hundreds of articles have been published, especially studies aimed at improving the efficiency of genetic breeding programs. Over the past few years, partnerships with other public institutions in performing Value for Cultivation and Use tests have resulted in 12 recommended cultivars.

Abstract Our aim in this study was to evaluate common bean progenies for water use efficiency (WUE) and verify if selection carried out under conditions without water limitation reflects the selection carried out under stress conditions. Eighty progenies from the BRSMG Talismã x G4280 cross and 80 from the BRSMG Talismã x G6492 cross were evaluated with high water availability (HWA) and low water availability (LWA) in two locations and two years. Genetic variance, heritability, accuracy, expected gain from selection, correlated response to selection, genetic correlation between HWA and LWA and between the two traits evaluated, and risk index in the recommendation (RI) were estimated. Some progenies had a RI close to zero, were tolerant in LWA, and were responsive in HWA. Progenies with high grain yield and WUE could be identified. The two conditions of evaluation were equally efficient for selection, as verified by estimates of expected gains from selection.

ABSTRACT: When breeding the common bean in Brazil, the best progenies are chosen, normally, from solely the generation under analysis at the conclusion of the evaluation, without considering what occurred in the past. However, a number of recently published studies show that if an evaluation were to consider all relevant generations, the gain from selection could be higher, especially when an index that involves information from the population that gave rise to the progenies is used. Thus, the aim of this study was to compare three selection procedures in the evaluation of successive generations and to discuss the implications of the progeny × environment interaction in terms of success of selection. Cycle XV progenies from a bean recurrent selection program were used. The traits evaluated were grain yield, plant architecture and grain type. Analysis of variance was carried out and the variance components and heritabilities were estimated. The same analyses were made using mixed models. A selection index weighted by the effect of populations and progenies within populations (WSI) was also obtained. We estimated the correlations between the classification of the progenies using the three procedures and the coincidence of the best progenies evaluated in S0:4 with the progenies in the previous generations. We found that the classification of the progenies by the BLUP's and WSI did not expressively differ from that obtained when using only the mean, even when a number of generations were considered in the selection. None of the procedures used effectively mitigated the effect of the progeny × environment interaction.

ABSTRACT: Phenotyping for severity of angular leaf spot (ALS) in common bean is important to identify new sources of resistance and select progenies in conventional and molecular marker-assisted breeding. In this study, three phenotyping methods for ALS severity were assessed and its implications in breeding for resistance to Pseudocercospora griseola are discussed. Reaction of 144 common bean lines to P. griseola was evaluated. Three different experiments were conducted in the greenhouse (V2 and V3 stages) and in the field. Common bean lines were inoculated with a mixture of spores of pathogen races 63-63 and 63-23. We observed that 31 %, 7 % and 10 % of lines were resistant in stages V2, V3 and in the field, respectively. Estimates of coincidence index V2-V3, V2-field and V3-field were 68 %, 69 % and 88 %, respectively. Evaluations in V3 stage and in the field were the phenotyping methods more efficient for ALS severity. However, evaluation in V3 stage is impracticable to assess routinely many genotypes in breeding programs. Evaluation in V2 stage may be used to carry out a first screening, especially in the early stages of breeding programs. Moreover, this methodology may be used in association with evaluation of plants in the field to increase genetic gain.

Abstract BRS Sublime is a common bean cultivar with carioca grains, high nutritional grain quality, and high yield potential (4667 kg ha-1). It has a normal cycle, upright growth, low loss rates in the mechanical harvest, and is recommended for planting in 19 Brazilian states, in the three main common bean cultivation regions. It is the first cultivar developed in the world with angular leaf spot resistance.

Abstract The aim of this study was to verify if the harvest index (HI) of common bean is higher in modern lines, to verify if its estimate varies with the cycle of the plant and environmental conditions, and to obtain information concerning its genetic control (through diallel crossing). For this purpose, six lines were crossed in a diallel. Evaluations were carried out in three crop seasons/generations - F2, F3, and F4. A receptacle was used to collect leaves, pods, and other plant parts that fell before harvest. Diallel analysis was performed using Griffing's method II. It found that the HI was higher in modern lines and was not affected by the cycle; the estimated HI heterosis was negative, indicating the occurrence of dominance in order to reduce trait expression.

ABSTRACT: In common bean (Phaseolus vulgaris) harvesting is carried out in the field. It is therefore necessary that cultivars be tolerant to viviparity, i.e., germination of grains still in the pods. Study of the percentage of germination of beans in the pods under laboratory conditions, where humidity content is high, has been proposed. Furthermore, under question is whether the thickness of the pod wall affects water uptake by the pods and, consequently, viviparity. Thus, the aim of the present study was to verify if there is variance among progenies for viviparity and if it is influenced by pod thickness. We assessed the parents, Pérola and ESAL 686, the F1, and a number of segregating generations in two crop seasons, in relation to the percentage of germination of seeds in the pods (PGSP) and pod wall thickness (PWT), and data on individual plants were obtained. The same traits were also assessed using the F2:3, F3:4 and F4:5 progenies. Taking into account the genetic and phenotypic parameters estimates, especially the level of high heritability, selection to less viviparity in common bean has to be carried out to evaluate PGSP in progenies.

Abstract The methodology available for evaluating the cooking quality of dry beans is impractical for assessing a large number of progenies. The aims of this study were to propose a new strategy for evaluating cooking quality of grains and to estimate genetic and phenotypic parameters using a selection index. A total of 256 progenies of the 13thcycle of a recurrent selection program were evaluated at three locations for yield, grain type, and cooked grains. Samples of grains from each progeny were placing in a cooker and the percentage of cooked grains was assessed. The new strategy for evaluating cooking quality was efficient because it allowed a nine-fold increase in the number of progenies evaluated per unit time in comparison to available methods. The absence of association between grain yield and percentage of cooked grains or grain type indicated that it is possible to select high yielding lines with excellent grain aspect and good cooking properties using a selection index.

Abstract The common bean cultivar with carioca grain type, BRSMG Uai, is recommended for cultivation in Minas Gerais and stands out for its upright plant architecture, which facilitates cultivation and mechanical harvesting. This cultivar has high yield potential and is resistant to the major races of anthracnose that occur in region.

Abstract BRS Ártico is a common bean cultivar with white grains with international standard size (62 g per 100 seeds), appropriate for cultivation in the Central region of Brazil and the state of Paraná. The cycle is semi-early, the yield potential 2677 kg ha-1 and BRS Ártico has moderate resistance to rust and curtobacterium wilt.

É questionável se a seleção precoce para resistência ao Colletotrichum lindemuthianum reduz a eficiência da seleção para produtividade de grãos no feijoeiro comum. Para responder esta questão foi utilizada a população segregante do cruzamento entre duas linhagens de feijão: CI107 (suscetível) x BRSMG Madrepérola (resistente). A seleção para resistência foi realizada em F2e F3, obtendo-se três tipos de progênies: não selecionadas (A), selecionadas somente em F2(B), e selecionadas em F2e F3(C). As progênies obtidas foram avaliadas para produtividade de grãos e ocorrência do patógeno em experimentos. Na F3:5 foram utilizados 289 tratamentos (96 progênies A, 96 B, 95 C e 2 testemunhas (T)); na F3:6, 196 tratamentos (64 A, 64 B, 64 C e 4 T); na F3:7, 81 tratamentos (26 A, 26 B, 26 C e 3 T). A seleção de plantas resistentes à antracnose em gerações precoces aumenta o sucesso com a seleção para produtividade de grãos em gerações avançadas.

It is questionable if early selection for resistance to Colletotrichum lindemuthianum reduces the efficiency of selection for grain yield in common beans. For this, it was used the segregating population of the cross between two common bean lines: CI107 (susceptible) x BRSMG Madrepérola (resistant). Selection for resistance was carried out in F2and F3, obtaining three types of progenies: not selected (A), selected only in F2(B), and selected in F2and F3(C). The progenies obtained were evaluated for grain yield and pathogen occurrence in experiments. In F3:5, it was used 289 treatments (96 progenies A, 96 B, 95 C and 2 checks (T)); in F3:6, 196 treatments (64 A, 64 B, 64 C and 4 T); in F3:7, 81 treatments (26 A, 26 B, 26 C and 3 T). Selection of plants resistant to anthracnose in early generations increases the successful selection for grain yield in later generations.

A common bean (Phaseolus vulgarisL.) cultivar must combine desirable genotypes for several traits in order to be accepted by producers and consumers. This study aimed to evaluate selection efficiency when segregating bean populations for traits, by means of a selection index, in order to obtain superior progenies for traits considered. A total of 16 populations from the F4 and F5generations were evaluated in 2011 and 2012, respectively. The traits evaluated were plant architecture, plant disease, grain type and yield. Using standard scores (Z), the sum of the four traits (∑Z) was obtained and, based on this information, the best populations were identified. The evaluation of selection effectiveness was performed on 31 progenies from each population. The 496 progenies plus eight controls were evaluated in the F5:6and F5:7 generations for the same traits in July and November 2012, respectively. The selection, using the index based on the sum of standardized variables (∑Z), was efficient for identifying populations with superior progenies for all the traits considered.