Abstract

The delay of maize harvest may affect the stem and grain sanity. This work was carried out aiming to evaluate the effects of harvest time on the incidence of stem rots and rotten grains of maize hybrids with contrasting growth cycles. The experiment was set in Lages, SC, during the 2012/2013 and 2013/2014 growing seasons. A randomized block design, disposed in split plots was used. Five single-cross hybrids were tested in the main plots: P1630H and P32R22H (hipper early cycle), P2530 (super early cycle) and P30F53YH and P30R50YH (early cycle).  Five harvest times were assessed in the split plots: 0 (grain physiological maturity), 10, 20, 30 and 40 days after physiological maturity. The incidence of stem rots increased proportionally to the delay in harvest time, regardless of hybrid growth cycle. More than 60% of the stems presented rot symptoms when harvest was performed 30 and 40 days after physiological maturity. Such behavior enhanced the percentage of lodged and broken stems when harvest was postponed. Harvest time did not affect the percentage of rotten grains, which was higher for hybrid P32R22H due to its poor ear husk coverage. Harvest delay affected more significantly the stem than grain sanity of maize hybrids.

Key words: Zea mays, stalk rots, rotten grains, harvest delay.