Strategies of selection of bean plant lines efficient in nitrogen use / EstratÃgias de seleÃÃo de linhagens de feijoeiro eficientes no uso de nitrogÃnio

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The development of high-yielding bean plant cultivars adapted to both the high and low use of inputs, is essential to the reduction of the production costs and sustainability of the different cropping systems existing in Brazil. The understanding of mechanisms which account for the differential behavior of those lines in relation to efficiency of the use of N could aid in the genetic breeding of the bean plant aiming at the selection for such traits. In this context, 12 bean plant lines were studied in the presence and absence of N in three environments with the objective of evaluating the effect of the nitrogen fraction in the leaves of these lines differing in the efficiency of the nitrogen use. In each environment, two distinct experiments were conducted, with and without N, in the randomized block design (DBC), the plot being made up of a three-meter long row. 15 to 20 leaves per plot were collected from the medium part of the plant at half-blooming of the bean plant for determination of the contents of total N (Kjeldahl), soluble-N, N-NO3-, soluble organic-N and insoluble N. Also, the average grain yield was evaluated and, by means of that, estimated the index of efficiency of nitrogen use. In the average of the three environments, grain yield obtained from N was 63.7% above the one obtained without N. The nitrate contents were higher without the application of N, while the contents of the other fractions of N and total-N in the leaf and grain were higher with the application of N. No correlation among the contents of total-N, N fractions in the leaves and EUN among the studied lines. However, in the lines ESAL 629 and MA-I-2.5 there was a trend that the fractions of N and total-N in the leaf could account for the highest EUN. These lines also stood out in grain yield and EUN.

ASSUNTO(S)

feijÃo eficiÃncia nutricional fractions of nitrogen phaseolus vulgaris nutrient efficiency seleÃÃo ciencia do solo fraÃÃes de nitrogÃnio

ACESSO AO ARTIGO

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