Number of Leaves and Maturity Classification in Zea mays L. 1

To test the constancy and predictive value for maturity classification of number of leaves developed on the main stalk in maize, 21 double crosses were studied in three replicated trials. The plantings were made on May 15, 1965, in Illinois and on September 10 and November 22, 1965, in lqorida. Eighteen of the hybrids were commercial dents selected to represent the range of kinds and maturities grown in the United States and Canada. Three later maturity experimental flint/dent double crosses were added to extend the range of maturities studied. Highly significant positive correlations were obtained between number of leaves per hybrid and days to anthesis in each planting. Leaves per plant were fewer in the winter plantings than in the summer. Fewer days were required for anthesis in the September planting than in the other two. Highly significant positive correlations were obtained among plantings for number of leaves per hybrid and for number of days from planting to anthesis. Number of leaves per hybrid was in these trials a highly reliable index of maturity class.