'Plant Breeding: Sustaining the Future' Abstracts of the XVIth EUCARPIA Congress, Edinburgh, Scotland, 10-14 September 2001 BREEDING NITROGEN-EFFICIENT WHEAT GENOTYPES M. KRALJEVIC-BALALIC Faculty of Agriculture, Institute of Field and Vegetable Crops, 21000 Novi Sad, Yugoslavia

Increasing costs of fertilisers and the need to protect the environment have recently made clear the importance of recognising the efficiency rate with which wheat cultivars utilise the available N to form grain yield. The aim of this study was to provide information on combining ability and gene effects for grain N concentration (GNC) in the F₁ and F₂ generations in wheat. In a 4x4 half diallel, the GNC was evaluated at full maturity. N concentration was measured following the Kjeldahl method. The combining ability analysis was made according to Griffing (1956), method 1, model I. The mode of inheritance of GNC in F₁ and F₂ was intermediate, dominant or superdominant. Highly significant GCA and SCA variances in F₁ and F₂ indicated the presence of genes with both additive and non-additive effects. NS Rana 2, the most effective N-efficient genotype on the basis of the GCA value, is recommended as a potential parent in hybridisation programs for developing new N-efficient cultivars.