Growth and Nutrient Composition of Maize Genotypes in Acid Nutrient Solutions

Abstract

AbstractCrop production in acid soils may be limited by several factors, including low pH. Development of acid‐tolerant cultivars requires information about differences in tolerance to low pH among crop genotypes. To determine whether differential responses to nutrient solution pH occurred among seven maize (Zea mays L.) genotypes, seedlings were grown in a growth chamber in flowing solutions at pH levels ranging from 3.3 to 6.7. Top weights, root lengths and weights, and concentrations of Ca, Mg, Fe, Zn, and Mn in plant tops were determined after 12 d. All genotypes grew well with pH of 4.0 to 5.5, with maximum dry weights of plant tops at pH 4.6 for most of the genotypes. However, all genotypes had necrotic root tips and decreased root lengths at pH 3.3, with relative root lengths (length at pH 3.3/maximum length) ranging from 0.26 to 0.55. Root weights were relatively unaffected by solution pH, but top weights decreased markedly at both pH extremes. Iron concentrations of all genotypes were decreased at pH 6.7, and interveinal chlorosis, resembling Fe deficiency, appeared in the younger leaves. Relative top weights (weight at pH 3.3/maximum weight) averaged 0.79 for Trinidad Grpl&2 and ‘PDMR Comp 1’ and 0.58 for ‘UPCA Varl’, ‘PDMR3’, Kalimpos, and Dikit at pH 3.3, and relative top weights among genotypes were positively correlated (r = 0.85) with Mn concentrations in tops. Based on relative top weight at pH 3.3, the former two genotypes were relatively more tolerant of extremely low pH than those in the latter group.