Agronomic characteristics of common bean genotypes influenced by the use of boron.

Boron is an indispensable micronutrient for common bean culture, requiring careful studies in relation to the need and time of application since it presents a narrow range between deficiency and toxicity. The objective of this study was to evaluate the effect of boron application at different times in common bean culture. An experiment was carried out in Gurupi-Tocantins, with four replicates in a factorial scheme 7 x 4, with seven cultivars (Aporé, Diplomata, IPR-Corujinha, IPR-Chopim, IPR-Gralha, CNFC 10467 and Sapphire) and four application times (T1- absence of boron application, T2- application of boron at 15 DAE -days after emergence-, T3- application of boron at 25 DAE, T4- Application of boron at 35 DAE). There was a significant interaction between the time of application of boron and genotypes for the characteristics of one hundred grains and grain yield. There is a difference between genotypes regarding the efficiency and use of boron. The most appropriate times for boron application, taking into account productivity, are 15 DAE for cultivars CNFC 10467 and Diplomata, and 25 DAE for Aporé and IPR-Chopim. Boron fertilization at 35 DAE is not recommended due to the non-responsiveness of the crop