Özet:

The intensive use of nitrogenous fertilizers in agricultural fields causes significant environmental and health issues along with increasing production costs. The objective of the study was to evaluate nitrogen use efficiency of 6x6 half diallel durum wheat (Triticum turgidum L.) F2 progenies and their parental lines at N0 (zero N fertilizer), N1 (120 kg N ha-1) and N2 (240 kg N ha−1) nitrogen levels. Significant differences were found among genotypes and nitrogen applications for grain nitrogen yield (GNY), N use efficiency for grain yield (NUEgy) and N use efficiency for grain N yield (NUEgn). N use efficiency (NUE) significantly decreased with increasing nitrogen doses. General combining ability of parents (GCA) was significant for all studied traits. GCA/SCA ratio ≥1 for GNY, NUEgy and NUEgn at different N conditions showed that it dominated by additive gene effects. GNY gradually increased depending on N increase while NUEgy and NUEgn decreased. Among the parents ‘Mersiniye’ genotype showed positive GCA effects and was the best general combiner for GNY, NUEgy and NUEgn. The best specific combining ability (SCA) for NUEgy was obtained from ‘Mersiniye x Spagetti’ hybrid. The GCA effects of each parent were generally stable for all traits and nitrogen levels. Our results revealed that it is possible to select promising lines which have high nitrogen use efficiency from the segregating progenies obtained by crossing of high nitrogen use efficiency parents.

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