engleski

Estimation of quantitative genetic parameters for grain yield and quality in winter wheat under optimal and reduced nitrogen fertilization

Information on the performance of wheat genotypes under a range of nitrogen (N) levels in multi-environment tests is expected to be helpful in identification of genotypes better adapted to low N environments. The objectives of the present study were to (1) investigate the effect of two N levels on grain yield and grain quality traits, and (2) estimate variance compo¬nents and heritability for these traits under high and low N levels in a selection of winter wheat varieties differing in yield potential and grain quality. Field trials including 19 winter wheat varieties were conducted during three successive growing seasons under optimal (180kg Nha-1) and reduced (80kg Nha-1) N fertilization in total of eight environments (location-year combinations). Other cultural practices including fertilization with phosphorus and potassium were equal for both fertilization levels. Mean values, components of variance and heritability were estimated under each N level as well as across N levels for grain yield (GY), grain N yield (GNY), grain quality traits such as grain protein content (GPC), Zeleny sedimentation value (SED), wet gluten content (WGC), gluten index (GI) and falling number (FN) as well as for rheological dough properties. The results of the present study showed that testing genotypes under optimal N fertilization can give good prediction of their performances in low N environments. In order to cost-effective use of resources selection of superior wheat genotypes, aimed at growing under both high and low N conditions, can be conducted through conventional breeding programs using optimal N fertilization. To check for specific adaptation of a genotype to N stress conditions, a range of N levels can be applied in the final test including smaller number of previously selected genotypes.

winter wheat; fertilization; grain yield; quality; heritability

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