Response of Wheat to Cycocei (CCC) Application - II. Effects of nitrogen level and CCC concentration on yield components of dwarf and tall wheat (triticum aestivum).

الملخص

The effect of nitrogen level at the rate of 40, 80, and 120 kg N/ha and the foliar spray of the growth retardant CCC at the rate of 0.0, 2.5 and 6.0 kg a.i./ha on grain yield and its components were studied using the short-straw variety ‘sidi misri 1’ and the tall-straw variety ‘florence aurora'. Nitrogen application at 80 and 120 kg N/ha significantly increased grain yield (44 and 23%) and number of grains per spike (14.3 and 8%) of ‘sidi misri 1'. Grain size was significantly decreased (5.7 %) only with 80 kg N/ha. Slight, but not significant, increase of number of tillers and weight of grains/spike was found due to nitrogen application. Cycocel application at the rate of 2.5 and 6.0 kg a.i./ha increased grain yield of‘sidi misri 1’ by 14% and 21 %, respectively. Number of grains/ spike was significantly increased (10% and 6%) by CCC treatments; whereas grain size was significantly decreased (7.8% and 5.8%). Number of tillers and weight of grains/ spike were slightly increased by CCC treatments.
With the tall-straw variety ‘florence aurora', no significant increase in grain yield due to nitrogen and CCC treatments was observed except at 80 kg N/ha (there was 24 % increase). The number of tillers, the number of grains/spike, weight of grains/spike and the grain size were not significantly affected by nitrogen application with the only excep-tion of 8% significant increase in number of grains/spike at 120 kg N/ha. No significant response to CCC treatments was observed in regard to grain yield, number of tillers, number of grains/spike, weight of grains/spike and size of grain. Only at 2.5 a.i. CCC/ha the grain size of ‘florence aurora' was significantly reduced by 4 %.