Variability among common bean lines for maximum dry matter accumulation in the grains

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.