SEEDLING CHARACTERISTICS IN HYDROPONIC CULTURE AND FIELD PERFORMANCE OF MAIZE GENOTYPES WITH DIFFERENT RESISTANCE TO ROOT LODGING

Root lodging resistance in maize (Zen mays L.) is difficult to improve due to the effects of unpredictable meteorological events, this empha sizes the interest in utilizing other traits as indirect selection cri teria. The objective of this study was to identify seedling traits in hydroponic culture and plant traits in the field related to root lodgi ng resistance. Nine-hundred and ninety test-crosses (TC) were obtained by crossing an inbred line related to Stiff Stalk Synthetic with F5 l ines derived from the cross between two elite non-Stiff Stalk inbred l ines. TC were evaluated in 19 environments (seven locations in 1994 an d 12 in 1995) with root lodging occurring in only eight. The 20 TC wit h the greatest resistance (R) to root lodging and the 20 TC with the g reatest susceptibility (S) were selected and examined in hydroponic cu lture. In field trials, the R group showed significantly lower means t han the S for plant height (268 vs. 273 cm) and ear height (125 vs. 12 9 cm). In hydroponic culture, the R group was characterized by a large r diameter (1.13 vs. 1.11 mm) and a higher weight (16.7 vs. 15.5 mg) o f the primary root, by a greater tendency to curve the primary root, a nd by a shorter shoot as measured from the kernel to the first ligule (3.82 vs. 3.94 cm). Grain yield was positively correlated with plant a nd ear height, suggesting that selection for low values of such traits could lead to some yield reduction. No correlation was found between grain yield and seedling traits: indicating that selection for these t rails should nor be detrimental to grain yield. Results indicate some plant and seedling traits that may be used to screen materials under s election for root lodging resistance.