CHANGES IN PHYSIOLOGICAL QUALITY AND THEIR RELATIONSHIPS WITH MATURITY DURING SEED DEVELOPMENT IN MAIZE

Abstract

Changes in germination rate and vigor during seed development in corn (Zea mays L.) were studied to determine the development stage at which seed maturity and maximum quality is obtained. Four open pollinated varieties were evaluated at Montecillo, Méx., across two years. Moisture content (g H₂O g^-1 fresh weight), dry weight, black layer, milk line, germination test and could test were measured in freshly harvested seeds in seven sampling dates (175 to 217 days after planting, DAP) in 1995, and in ten sampling dates (123 to 186 DAP) in 1996. Maximum germinability varied among genotypes according to their precocity, and between years; the rest of the indicators varied too. The visual indicator most closely associated with maximum germination was the black layer, in the four varieties and the two years of evaluation.