CARTHAMUS TINCTORIOUS اثر فصل كاشت و تراكم بوته بر كارآيي مصرف آب در ارقام و لاين هاي مختلف گلرنگ

Effects of growing season and plant densities on water use efficiency in safflower (Carthamus tinctarious L.) cultivars and lines

In order to study effects of plant density on water use efficiency (WUE) in spring and summer groltiing seasons in Esfahan region, five safflower genotypes including two selected lines from Esfahan landraces and three improved cultivars (Arak 2811, Gilla and Kooseh) were compared in two growing season (sown on April. 4 and July. 6) and three plant densities (40 , 20 and 13 plants per m2) using split-split plots experimental design in Isfahan in 2000. The results showed that differences in water use efficiency between two growing season was significant (P<0.01). Water use efficiency in summer growing season better than spring growing season by 17%. Summer growing season produced 474.6 kg/ha less grain yield than spring growing season, however, WUE in summer growing season was higher than spring growing season, Plant density effects were also significant on water use efficiency. The highest and the lowest of WUE were 0.481 kg/mʹ and (1.308 kg/m^3 40 and 13 plants per m2, respectively. The main factor that contributed to higher WUE was higher plant in density which increased grain yield. Arak 2811 in spring growing season and line 1 in summer growing season had the highest WUE.