The objective of this work was to determine the genetic effects that control the inheritance of characters associated with the phosphorus utilization efficiency (PUE) in maize, and to determine the relationship among them. A diallel between six maize cultivars was performed and 15 hybrid combinations were obtained from it. These cultivars were evaluated in high and low phosphorus availability in the greenhouse and field. Plant response to nutrient availability (RU) and traits associated to utilization and translocation efficiency were measured. There were significant interactions between hybrid combinations and phosphorus availability for plant dry matter mass (MSP), P concentration in plants (PAP), and the ratio between shoot and root dry matter masses (RMS). The interaction between general combining ability and P availability was significant for RMS and PAP, and the one between specific combining ability and P availability, for MSP and PAP. The PUE in low and high P were correlated with each other and with RU. The PUE at low P availability was not correlated to grain yield. However, in high soil P availability these parameters were correlated. Non additive effects are more important for traits related to PUE, so that selection should be carried out on hybrid combinations.
Zea mays; combining ability; abiotic stress; plant breeding; mineral nutrition
