Differences in Mycorrhizal Colonization of Maize Selections for High and Low Ear Leaf Phosphorus

Abstract

Mycorrhizal colonization may contribute to the uptake of P in crop plants, particularly under nutrient limited conditions. This study was done to evaluate the hypothesis that inbreds of maize (Zea mays L.) previously selected for differences in ear leaf P at silking, may differ in degree of mycorrhizal colonization. Roots of up to six inbreds (three high P and three low P) were assayed for mycorrhizae after 10 weeks growth under field conditions. A positive rank correlation was observed between ear leaf P content of the inbreds and their percent mycorrhizal colonization. The high P inbreds were more mycorrhizal (18% mean colonization) than the low P inbreds (10% mean colonization). The same six maize inbreds were also grown in the greenhouse under nonmycorrhizal conditions in 1983. Neither tops or roots showed growth or P content characteristics under nonmycorrhizal conditions which would explain the differences observed in the field in ear leaf P content or mycorrhizal colonization. These data suggest mycorrhizal colonization may be a significant component of the genetic differences expressed as ear leaf P content in these maize lines.