LEAF AND STEM CHARACTERISTICS IN MAIZE STRAINS DIFFERING IN STEM LEAFNUMBER

Better logic is needed for predicting genetic and environmental effect s on canopy leaf expansion and stem extension. We measured leaf area a nd internode lengths and dry masses for 19 strains of Zea mays L., wit h mature leaf numbers ranging from 10 to 27, at a uniform population d ensity. Similar measurements were made on plants growing in four diffe rent plant densities for one of the cultivars (Pioneer 3344). The numb er of the ear nodes correlated well with total leaf number. In general , area per ear-node leaf increased up to 20 total leaves, with conside rable variability among strains having roughly the same total leaf num ber. Other general relationships were found between total leaf number and (a) the nodal position of the leaf with maximum area, as well as ( b) the two positions above and below the ear node for 1/2 maximum area , (c) internode lengths, and (d) internode dry masses. Such informatio n can be used for developing better maize production management models , as well as better selection methods for increased productivity.