Wheat cultivars evaluation by agronomic traits, application of three nitrogen levels and nitrogen efficiency parameters

Abstract

          Ten wheat cultivars (cv.) and three nitrogen levels were used in thisfield experiment which was conducted at the Universityof Kufa, Facultyof Agriculture, during the winter season of 2013.. The aim of this experiment was to compare ten wheat cv. toward agronomic traits, nitrogen levels application andnitrogen efficiency parameters. The fertilizer   levels were Zero (control) ,200 kg  . h̅¹ and 400  kg . h.̄ ^{1 .} The wheat cv. were selected  to represent the experimental materials and they are listed in Table 1. All agronomic traits values (  plant height PLH, spike length (SL), tillers number (TN), life tillers  number (LTN), stem dry weight (SDW), leafdry weight (LDW), grain dry weight (GDW) and total weight(TW) were increased as the nitrogen application levels increased. Root dry weight RDW behaved differentlyin which RDW increased with decreasing nitrogen availability in soil. 

 Results revealed that total dry matter produced per unit nitrogen absorbed NE ₁averaged over the ten wheat cv. increased where ever the availability of nitrogen in soilreduced.The NE₁ values was60.91, 50.03 and 45.39 under nitrogen levels of Zero, 200 kg .h̄¹ and400  kg  . h̄ ¹, respectively.  Similar trends were observed toward total grain yield per unit nitrogen absorbed NE₂ andNE₃, which was the product of the ratio of grain nitrogen to stover nitrogen, times NE₂. The ratio of grain nitrogen to stovernitrogen TEFF was represented transfer efficiency. TEFF value behavior wasdifferent, in which its value increased as nitrogen level increased in soil.

Results also showed significant differences among wheat cv. toward NE₁, NE₂, NE₃ and TEFF. . Sham 9 cv.  had the highest NE₁ value (61.518) while Tamous 2 gave the lowest (47.173).  Sham 9 and Tamous 2 behaved in the same manner toward NE₂ and NE₃ . The ranking of wheat cv. toward TEFF was different and sham 9 which was one of the highest in NE₁, NE₂, and NE₃ came the last in TEFF. It could be concluded that cv. with low values of NE₁, NE₂ and NE₃ are not necessarily have low grain yield.