Physiological bases in wheat selection influencing nitrogen nutrition efficiency

Abstract

On the basis of relevant references and the author’s own data, this paper deals with analyzing physiological parameters for determining the nitrogen nutrition efficiency of wheat. The nitrogen fertilization efficiency (NFE) presents the activity of N unit from fertilizer and soil in forming yield. The nitrogen fertilization efficiency depends on the N uptake efficiency from the fertilizer or soil (NUpE) and the efficiency of N utilization in the plant (NUtE) in forming yield. So, it represents their product, (NFE = NUpE x NUtE). This efficiency was measured by the amounts of yield per N fertilizer unit. In addition to these two, the other possible parameters were also analyzed, such as: biological yield, followed by grain yield and harvest index, the activity and growth of the root system, N concentration in the plant, grain and straw, its accumulation in the plant before and after fertilizing, N harvest index, as well as by the efficiency of nitrate reduction and nitrogen re-utilization efficiency in the plant.

Significant genotypic variations in NUpE and NUtE in the plant render basis for wheat selection to be managed towards an improved N nutrition efficiency in its initial’ stage and to be obtained from uniting peaks of both parameters in one genotype. Genotypes in the hybrid progeny would be selected according to the groups with peaks of either one, or of the other parameter, or by increased , but balanced values of both parameters. The first two groups of genotypes would be used as gene sources for further selection to increase the values of either one or of the other parameter, while the third group would be used for developing lines and breeding new varieties.