Abstract Carioca grains are the most cultivated commercial group of common bean and Fusarium oxysporum f. sp. phaseoli (Fop) is an important disease under field conditions. Genetic resistance is the most effective control strategy. Thus, our objective was to study the inheritance of Fop resistance in the carioca grain type common bean. Lines CNFC 11965 (S) and CVIII 8511 (R) were crossed to obtain F1 and F2 generations and backcrosses, inoculated with the isolate FOP UFV 01, and severity grades used to estimate genetic parameters. Segregation of resistant and susceptible plants in the F2 generations and backcrosses resulted in dominant monogenic inheritance of Fop resistance. The high values of heritability emphasized the probability of success in the selection processes because environmental factors were not significant. The carioca grain line CVIII 8511 is promising, and its Fop resistance gene can be transferred to commercial cultivars of this group using the backcross method.

Abstract In breeding programs, understanding the potential of parents should be a way to spend significantly less time and costs to obtain new cultivars. For this, the objective of this study was to estimate the general and specific combining ability of parents aiming common bean breeding for resistance to Fusarium wilt (FW) based on disease severity and reduction in plant growth. Eight common bean genotypes were crossed in a 3 x 5 partial diallel mating scheme to obtain F1 hybrids. The parents and their 15 F1 hybrids were evaluated for severity of Fusarium wilt, area under the disease progress curve, percentage of plant height reduction and plant shoot fresh weight reduction and grain yield. The resistance of common bean to FW is controlled by a few dominant genes. The reduction in plant growth is controlled by a different set of genes that can increase the selection efficiency of parents for common bean breeding.

Este trabalho foi realizado com o objetivo de avaliar a resposta da cultura do feijoeiro (Phaseolus vulgaris L), cv. Carioca Precoce, à adubação com nitrogênio (N) e fósforo (P), cultivado no norte de Minas Gerais. O experimento foi realizado na safra do inverno-primavera de 2008, com delineamento experimental de blocos casualizados e três repetições. Os tratamentos foram organizados segundo esquema fatorial 4x4, sendo quatro doses de N: 0, 70, 140 e 210 kg ha-1 e quatro doses de P: 0, 100, 200 e 300 kg ha-1 de P2O5. A ureia e o superfosfato simples foram utilizados como fontes de N e P, respectivamente. O incremento das doses do fertilizante nitrogenado reduziu linearmente o estande inicial de plantas de feijão, sem influência das doses de fósforo. O número de vagens por planta foi o único componente de rendimento influenciado pela aplicação dos fertilizantes, unicamente para doses de N, com número máximo na dose de 108 kg ha-1 de N. Houve resposta quadrática da produtividade de grãos às diferentes doses de N e P, sendo a máxima produtividade (1.528 kg ha-1) alcançada com 98 kg ha-1 de N e 201 kg ha-1 de P, sem haver interação entre eles.

This work was carried out to evaluate the common bean (Phaseolus vulgaris L.) cv. Carioca Precoce response to nitrogen (N) and phosphorous (P) fertilization, in the North Region of Minas Gerais. The trial was carried out in the winter-spring season, 2008, using a randomized block design with three replicates. Treatments were arranged in a 4x4 factorial scheme, with four N rates: 0, 70, 140 and 210 kg ha-1; and four P rates : 0, 100, 200 and 300 kg ha-1 of P2O5. Urea and simple superphosphate were used as N and P sources, respectively. Increasing N rates linearly reduced the initial stand of common bean, without influence of P rates. The number of pods per plant was the only yield component affected by fertilizer application, only for N rates, with the maximum number achieved at the rate of 108 kg ha-1. The quadratic yield response was adjusted to the different rates of N and P, with maximum yield (1.528 kg ha-1) achieved with 98 kg ha-1 of N and 201 kg ha-1 of P, without interaction between them.