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AN EVALUATION OF GRAIN SORGHUM (SORGHUM BICOLOR (L.) MOENCH) HYBRIDS FOR EFFICIENCY OF NITROGEN USE
Abstract
The ability to select grain sorghum genotypes for efficient utilization of N would lead to incorporation of high N efficiency in commercial hybrids and a better understanding of plant N metabolism. Field and greenhouse studies were conducted on plant utilization of absorbed N to identify genotypic differences in N use efficiency, examine parental influence on hybrid performance, and determine the effects of N fertility and irrigation on hybrid N efficiency. Hybrids were tested as seedlings in the greenhouse to identify morphological or physiological characteristics associated with their N utilization efficiency at maturity. Hybrid efficiency of N utilization was evaluated by the ratios of plant dry weight to the amount or concentration of N in the plant. In a field experiment, 36 F1 hybrids produced from six female and six male inbreds were grown under dryland or irrigated conditions with zero or 112 kg N/ha. At physiological maturity, the aboveground dry matter of plot subsamples were analyzed for reduced N. Significant differences were found among the hybrids and their common parent averages for each of the N use efficiency variables. Irrigation had little effect on hybrid efficiency of N utilization and produced no significant change in the relationship among hybrids for N efficiency. The range of N efficiency values was larger, and hybrids utilized N more efficiently in the zero N treatment. Significant hybrid x N fertility interactions occurred for each of the N efficiency variables. In the greenhouse experiments, plants were grown in nutrient solutions with different growth-limiting supplies of N. Two hybrids that differed widely in N use efficiency at maturity were compared for seedling efficiency of N utilization. Plants were harvested after they exhausted solution N supplies and divided into shoot and root samples which were analyzed for reduced N. Hybrid differences for N use efficiency measured at maturity in field experiments were not detected in the seedling stage. None of the traits measured, including pattern of fresh weight accumulation, predicted the N utilization efficiency of mature plants.
Subject Area
Agronomy
Recommended Citation
ZWEIFEL, THOMAS ROBERT, "AN EVALUATION OF GRAIN SORGHUM (SORGHUM BICOLOR (L.) MOENCH) HYBRIDS FOR EFFICIENCY OF NITROGEN USE" (1982). ETD collection for University of Nebraska-Lincoln. AAI8227046.
https://digitalcommons.unl.edu/dissertations/AAI8227046