GROWTH TRAITS AND MINERAL CONCENTRATIONS OF MAIZE HYBRIDS GROWN ON UNLIMED AND LIMED ACID SOIL

Growing crop plants tolerant to acid soils is an alternative for succe ssful production on acid soils with limited inputs, especially lime. A cid soil- or aluminum (Al)-tolerant plants offer considerable protecti on against soil acidity problems. Thirteen maize (Zea mays L.) hybrids developed for production under various environmental conditions were grown (greenhouse) on two acid soils (unlimed and limed) to determine differences among hybrids for growth traits, mineral acquisition, and relative tolerance to acid soil. Porters soil induced greater acid soi l stress on maize than did Lily soil, although shoot/root dry matter ( DM) ratios were affected more in plants grown on Lily than on Porters soil. Shoot and root DM and total root length (RL) over all hybrids fo llowed sequences of Limed Lily greater than or equal to Limed Porters > Unlimed Lily > Unlimed Porters, and the trait with the greatest vari ation among hybrids was total RL. Specific RL (total RL/root DM) over all hybrids followed a sequence of Limed Lily = Limed Porters = Unlime d Lily>Unlimed Porters, with relatively small variations among hybrids . Shoot DM/RL among hybrids followed a sequence of Unlimed Porters gre ater than or equal to Unlimed Lily > Limed Lily Limed Porters, and had the least variation among hybrids. Two Brazilian hybrids (HD 91102 an d HD 9176) had highest DM and total RL to indicate relatively high tol erance to acid soil stresses, while other hybrids (ten from the United States rand one from Brazil) had relatively small differences for gro wth traits to indicate moderate to low tolerance to acid soils. Althou gh genotypes differed widely for mineral element concentrations, no si gnificant differences in mineral elements between more and less tolera nt genotypes were noted.