Comparison of some local durum wheat cultivars from Southeastern Anatolia in uptake and harvest index of nitrogen

N-uptake and partitioning of N to grain (NHI) is an important determinant of N-use efficiency in durum wheat (Triticum turgidum L. var. durum). Local durum wheat genotypes may be used as germplasm in this respect. Three field experiments were conducted during 1993/94, 1994/95 and 1995/96 crop years in Balcah/ Adana to examine genotypic differences tor N-uptake and NHI. Seven local genotypes from Southeastern Anatolia and five cultivars were grown under N fertilizer rates of 80 and 160 kg N ha~l before booting and 0 and 60 kg N ha~l rates as additive to these applications at anthesis. Differences were not remarkable in the first year. In the second and third year however, earlier, shorter and high yielding cultivars showed generally higher total-N and grain-N at maturity with greater differences as "N fertilizer rates increased. Likewise, NHI was found to be greater in cultivars than in local genotypes. NHI values decreased with increased N rates. N application at anthesis, especially in combination with lower preanthesis N increased NHI. Key Words : Durum wheat, biological yield, grain yield, nitrogen uptake, Nitrogen Harvest Index.