EFFECTS OF DIFFERENT ENVIRONMENTS ON LEAF NUMBER AND DURATION TO FLOWERING IN CORN

Abstract

The effects of diverse geographic environments on leaf number and duration to 50% flowering were investigated in a number of corn hybrids and genotypes. The relationships between leaf number and duration to 50% flowering within these environments were also examined. In the study, involving 25 hybrids at six locations, ranging from Beltsville, Maryland (38°N) to La Pocatière, Quebec (48°N), leaf number was highly significantly correlated with days to 50% flowering. Mean leaf number was least at Beltsville and highest at La Pocatière. Days to 50% flowering showed a consistent rise from the lowest value at Beltsville to the highest values at Macdonald College and La Pocatière. Leaf number did not vary appreciably within locations, and was more stable than days to 50% flowering and the agrometeorological indices of maturity. The study, involving 23 genotypes in 26 environments, embraced the widest geographical range ever used for this type of study. The environments ranged from Rocque, Mexico (21°N) to Morden, Manitoba (49°N). In general, genotypes planted progressively farther north took longer to flower, grew taller, and tended to develop more leaves. High positive linear relationships between leaf number and duration to flowering (0.699–0.959) were obtained.