Inheritance of resistance to Fusarium oxysporum f. sp. phaseoli Brazilian race 2 in common bean

Com o objetivo de obter informações a respeito do controle genético da resistência do feijoeiro (Phaseolus vulgaris L.) ao fungo Fusarium oxysporum f. sp. phaseoli, foram realizados seis cruzamentos envolvendo três linhagens resistentes (Carioca MG, ESAL 583 e ESAL 566) e quatro suscetíveis ao fungo (Carioca, CNFC 10443, Uirapuru e ESAL 522). As plantas dos genitores, das testemunhas (Carioca MG e Carioca) e das gerações F1, F2 e F3 foram avaliadas quanto à reação à murcha-de-fusarium utilizando a metodologia de inoculação de imersão de raízes na suspensão de esporos, com o corte do sistema radicular. As avaliações foram realizadas aos 21 dias após a inoculação, por meio de escala de notas variando de 1,0 (plantas sem sintomas) a 9,0 (plantas mortas). Com os dados obtidos, foram estimados parâmetros genéticos e fenotípicos. A herdabilidade no sentido restrito variou de 0,34 a 0,42 e no sentido amplo de 0,76 a 0,97, podendo considerar o caráter como de fácil seleção, desde que se adotem critérios eficientes de inoculação e avaliação das plantas. O grau médio de dominância foi próximo de 1,0 evidenciando a presença de dominância no controle do caráter, embora a presença de efeitos aditivos também seja expressiva.Aiming to obtain information concerning the genetic control of the resistance of the bean (Phaseolus vulgaris L.) to the fungus Fusarium oxysporum f. sp. phaseoli, six crosses involving three resistant lines (Carioca MG, Esal 583 and Esal 566) and four susceptible to the fungus (Carioca, CNFC 10443, Uirapuru and Esal 522) were developed. The parental lines, the controls (Carioca MG and Carioca) and the F1, F2 and F3 generations were evaluated for reaction to Fusarium. For inoculation, root cuttings were immersed in a spore suspension. The evaluations were performed at 21 days after inoculation, by scale of notes ranging from 1.0, to 9.0 and genetic and phenotypic parameters were estimated. The heritability in the narrow sense ranged from 0.34 to 0.42 and in the broad sense of 0.76 to 0.97, showing that selection should be easy, since efficient inoculation and selection methods are used. The average degree of dominance was around 1.0 indicating the presence of dominance in the control of the character, although additive effects are also expressive

Phenotypic recurrent selection for early flowering of 'Carioca' common bean

O objetivo deste trabalho foi avaliar a eficiência da seleção recorrente fenotípica em relação ao número de dias para o início do florescimento em feijoeiro e verificar se a seleção afeta outros caracteres. Utilizou-se uma população proveniente da mistura das populações F2 (S0) de 11 combinações híbridas, avaliadas para a precocidade. As plantas S0 (ciclo 0), que floresceram mais precocemente, foram intercruzadas para a obtenção do ciclo I. As sementes obtidas foram utilizadas para a continuidade da seleção, e o processo foi repetido até o quinto ciclo seletivo. O progresso genético foi avaliado com cinqüenta e três progênies, provenientes da mistura das sementes das plantas S0 após uma autofecundação (S1:2) de cada ciclo. Os caracteres avaliados foram: número de dias para o florescimento, severidade da mancha-angular (Phaeoisariopsis griseola), número de dias para a maturação, produtividade e tipo de grãos. Constatou-se que o progresso com a seleção foi de 2,2% ao ano, o que indica que a seleção recorrente fenotípica foi efetiva em reduzir o número de dias para o florescimento. Não houve resposta correlacionada à seleção quanto ao número de dias para o florescimento nos demais caracteres avaliados, do que se depreende ser possível a seleção de progênies que associem florescimento precoce à expressão fenotípica dos demais caracteres, conforme o interesse dos melhoristas.The objective of this work was to evaluate the efficiency of phenotypic recurrent selection for the number of days until blooming in common bean, and to verify if this selection affected other traits. One S0 population derived from the mixture of the F2 populations of 11 hybrid combinations evaluated for earliness was used. The plants of the S0 (cycle 0) which bloomed first were crossed to obtain cycle I. To go on with the selection the obtained seeds were used. The process was repeated until the fifth selection cycle. Fifty-three S1:2 progenies of each cycle were used for evaluation of the genetic progress. The number of days to flowering, severity of angular leaf spot (Phaeoisariopsis griseola), number of days to maturation, yield and grain type were evaluated. A selection gain of 2.2% per year was observed, which indicates that phenotypic recurrent selection reduced the number of days to flowering. The selection for the number of days to flowering had no correlated response with other evaluated traits, indicating that progeny selection for early flowering can be associated with the phenotypic expression of other traits, according to the breeder's interest

Associação entre o porte da planta do feijoeiro e o tamanho dos grãos

The widest use of technology in bean culture in Brazil has required cultivars to present more upright architecture. However, every available cultivated material which showed that sort of architecture, possesses small seeds which have less commercial acceptance. For this reason, this work was conducted over the period from February 1993 to November 1994, to verify whether there is any association between these two traits. For this goal, the F2, F3, F4 and F5 generations from the crosses Milionário x Flor de Mayo, EMGOPA 201-Ouro x Manteigão Fosco 11 and Rio Vermelho x Roxo PV were used. The screening experiments of the F3, F4 and F5 families were carried out at the Universidade Federal de Lavras, in Lavras, MG, Brazil. This latter generation was also evaluated at Patos de Minas, MG, Brazil. The results obtained showed that the existence of correlation between the score of architecture and yield was not found, but a general bias of positive association between the weight of 100 seeds and yield was verified. In an overall way, no association between the architecture score and the seed weight was observed, showing to be possible to select upright plants with any seed size. However, the frequency of upright architecture families (score inferior to 3) and 100 seeds weight above 25 grams was very low.O maior emprego de tecnologia na cultura do feijoeiro no Brasil tem exigido que as cultivares apresentem porte mais ereto. Contudo, todos os materiais cultivados disponíveis que apresentam porte ereto possuem sementes pequenas, e por isso têm menor aceitação comercial. Foi realizado este trabalho no período de fevereiro de 1993 a novembro de 1994, para verificar se existe associação entre o porte do feijoeiro e o tamanho de suas sementes. Foram utilizadas, para isso, as gerações F2, F3, F4 e F5 dos seguintes cruzamentos: Milionário x Flor de Mayo, EMGOPA 201-Ouro x Manteigão Fosco 11 e Rio Vermelho x Roxo PV. Os experimentos de avaliação das famílias F3, F4 e F5, foram conduzidos na Universidade Federal de Lavras, em Lavras, MG. Esta última geração foi também avaliada em Patos de Minas, MG. A correlação entre a nota do porte da planta e a produção de grãos é inexpressiva. Já a correlação entre o peso de 100 sementes e a produção de grãos é positiva. Não há associação entre a nota do porte e o peso de 100 sementes, o que indica ser possível selecionar plantas eretas com qualquer tamanho de sementes. Contudo, a freqüência de famílias com porte ereto (nota inferior a 3) e peso de 100 sementes acima de 25 gramas, foi muito pequena

Genetic control of viviparity in common bean

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

Genetic control of the number of days to flowering in common bean

The aim of this study was to investigate the genetic control of early flowering in common bean. Crosses weremade between the parents Pérola and BRS Radiante and between ESAL 506 and Preto 60 dias. The segregating generations,F3, F2BC11 and F2BC12 of each cross were evaluated in experiments with two replications. F3 plants of both crosses wererandomly taken, and F3:4 progenies evaluated for the trait number of days to flowering. There was good adjustment to theadditive-dominant model of both crosses. The dominance effect was lower than the additive effect in the trait control and, whenpresent, it reduced the number of days to flowering. The value of realized heritability (h2R) was similar in both crosses andlower than the h2 estimated for selection among F3:4 progenies. There were indications that aside from the environmental effecton the trait expression, the genotype-environment interaction was also significant

Nine‑hole system efficiency in selection of carioca‑type common bean progenies for erect architecture

O objetivo deste trabalho foi verificar a eficiência do sistema de nove covas na avaliação de progênies de feijoeiro (Phaseolus vulgaris) tipo carioca quanto à arquitetura da planta. Foram avaliadas 97 progênies nas gerações F2:3 e F2:4, em delineamento de blocos ao acaso, com 20 repetições e nove plantas por parcela, em que a planta central foi avaliada, e as oito vizinhas foram consideradas conjuntamente como controle. Avaliaram-se os caracteres: produção de grãos por planta, porte e acamamento. O índice de seleção conjunta, para as três características (Zij), foi obtido pelo somatório dos valores padronizados por parcela. Os dados foram submetidos à análise de variância e, a partir das esperanças dos quadrados médios, foram estimados os componentes de variância. É possível identificar plantas mais eretas em populações segregantes do feijoeiro, utilizando-se o sistema de nove covas. Este sistema possibilita a obtenção de elevadas estimativas de acurácia experimental e herdabilidade.The objective of this work was to verify the nine-hole system efficiency in the evaluation of common bean (Phaseolus vulgaris) carioca-type progenies for plant architecture. Ninety-seven progenies were evaluated in the F2:3 and F2:4 generations in an randomized block design, with 20 replicates, and nine plants per plot, in which the central plant was evaluated, and the eight neighbor ones were considered together as the control. The evaluated traits were: grain yield per plant, architecture and lodging. The joint selection index (Zij) for the three characters was obtained through the sum of the standardized values per plot. Data were submitted to the analysis of variance, and from the mean square expected values, the components of variance were estimated. It is possible to identify more upright plants using the nine-hole system, in segregating common bean populations. This system allows for high estimates of experimental accuracy and heritability.

Performance of common bean families after different generations under natural selection

ABSTRACT: A segregant bulk population derived from a single cross between the Carioca MG cultivar and the ESAL 686 line was used to investigate whether the action of natural selection in the direction required by the breeders and the delaying line extraction would increase the chance of obtaining families with greater grain yield. The populations were advanced from F2 to F24 and obtained families F2, F8 and F24 from the plants. These families and their parents were assessed for grain yield (kg/ha) in Lavras-MG in three sowing seasons (July 2001, November 2001 and March 2002) in an 18 x 18 lattice design with two replications in the first sowing and three in the other two. The largest mean yield, regardless of sowing season, was among the families derived from the F24 plants. The frequency of superior families increased when line extraction was delayed to more advanced generations

Selection of common bean families resistant to anthracnose and angular leaf spot

O objetivo deste trabalho foi identificar famílias de feijoeiro com resistência a Colletotrichum lindemuthianum e Phaeoisariopsis griseola e com outros fenótipos agronômicos desejáveis. As famílias utilizadas foram obtidas do cruzamento entre a linhagem H91, portadora de três alelos de resistência à antracnose, com três famílias F2:5 resistentes à mancha-angular, derivadas da cultivar Jalo EEP 558. Foi utilizado o delineamento látice quadrado em todos os experimentos. Inicialmente, foram avaliadas 144 famílias F2:3, no inverno de 2004, em Lavras, MG, com base no tipo de grão. Foram selecionadas 80 famílias F2:4 e avaliadas com a testemunha BRSMG Talismã, no período das águas de 2004/2005, no mesmo local. Considerando-se o tipo de grão e a resistência à mancha-angular e antracnose, foram mantidas 48 famílias F2:5, que foram avaliadas na seca de 2005, em Lavras e Lambari, MG. Essas 48 famílias passaram por inoculação das raças 2047, 73 e 1545 de C. lindemuthianum, para verificação da presença dos alelos de resistência Co-42, Co-5 e Co-7, respectivamente. Foram identificados genótipos da maioria das 48 famílias, quanto à reação à antracnose, das quais se destacaram quatro, em relação ao tipo de grão semelhante ao 'Carioca', de porte ereto, produtividade elevada e resistência à mancha-angular.The objective of this work was to select common bean families resistant to Colletotrichum lindemuthianum and Phaeoisariopsis griseola and, also, with superior agronomical traits. Families used were obtained from crosses of H91 lineage, bearer of three alleles resistant to anthracnose, and F2;5 families derived from the cultivar Jalo EEP 558, which is resistant to angular leaf spot. Square lattice design was used in all experiments. Initially the F2:3 families (144) were evaluated in the winter of 2004, in Lavras county, MG, Brazil, based on grain type. Eighty families (F2:4) were selected and evaluated with the check BRSMG Talismã, in the wet periods of 2004/2005, in the same place. Considering grain type, anthracnose and angular leaf spot resistances, 48 families (F2:5) were selected and evaluated in the dry period of 2005, in two places, Lavras and Lambari, MG. These 48 families were also inoculated with the 2047, 73 and 1545 races of C. lindemuthianum, in order to verify the presence of alleles of resitance Co-42, Co-5 and Co-7, respectively. Genotypes with anthracnose resistance were identified in most families, four of which are outstanding for their ideal 'Carioca'-like grain, with upright plant, high grain yield and resistance to angular leaf spot