hrvatski

Assessment of stability of grain yield and grain protein content of winter wheat at two nitrogen fertilization levels

Grain yield (GY) and grain protein content (GPC) of winter wheat (Triticum aestivum L.) were determined by genotypic and environmental factors. To completely understand the genetic potential of selected genotypes, it necessary to know how individual genotype responds to environmental conditions. The study included 19 winter wheat genotypes. Field experiments were set over three growing seasons at eight environments (eight combinations of location-years) at reduced (N80) and optimal (N180) nitrogen fertilization levels. The stability of the traits was estimated by the coefficient of linear regression (b), variance of the mean square deviations from regression (MS-DEV) and the AMMI model for each level of nitrogen fertilization. The results show a wide range of value of b for GY (N80 0.79 to 1.22 ; N180 0.55 to 1.53) and for GPC (N80 0.74 to 1.37 ; N180 0.62 to 1.28), indicating different stability of the studied genotypes. Genotype Liberta proved as the most stable genotype for GY because of the value for b about 1 and because of the below average MS-DEV value. Genotype Aura proved as the most stable genotype for GPC. The biplot of the first two PCA axes showed different influence of the environment on the studied traits of individual genotypes at both levels of fertilization. Correlation for b between optimal and reduced fertilization levels for GY and GPC was r=0.57* and r=0.49*, indicating a significant impact of nitrogen fertilization on estimates of the genotypes stability.

winter wheat ; fertilization ; grain yield ; proteins ; stability

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