Evaluation Effects of Different Planting Systems on Water Use Efficiency, Relative Water Content and some Plant Growth Parameters in Onion (Allium cepa L.)

To evaluate the effect of different sowing methods on water use efficiency, relative water content and some vegetative growth parameters of onion a study was carried out in the Agriculturalr research Center of East Azarbayjan in 2007-2008 cropping season. The experiment was a factorial by using the randomized complete block design with 4 treaments and 4 replications. The first factor was consistting of two sowing methods, dirct sowing (DS) and the transplanting method (TM), the second factor was including two onion cultivars Azarshahr (red hull and later maturing) and Gooli-Ghesseh Zanjan (bright-red, early maturing). Analysis of variance for the measured traits indicated that except for the relative water content (RWC), other traits were significant influenced by the sowing methods. TM had higher values of water use efficiency (WUE), bulbing ratio (BR), aerial leaves length (ALL), leaf area (LA), leaf area index (LAI), leaves dry weight (LDW), leaves fresh weight (LFW) and leaves saturation weight (LSW) than the DS methods. Maximum WUE (6.07 kg m3) and minimum WU (9381 m3 ha-1) were obtained in TM. However, the lowest WUE (4.19 kg m3) and the highest WU (115921 m3 ha-1) was obtained with DS. In other words, in TM water economizing was 1.5 tim, amount of yield was increased up 15% (in comparison with DS). Also among the cultivars except for the RWC, WUE and BR other traits were significantly. The sowing method x cultivar interaction were not significant. For the studied traits, TM and red Azarshahr cv. were better than the DS and Gooli-Ghesseh Zanjan, thus thy were identified the best treatments for experiment therefore it is recommended for the places with the same environmental conditions of this experiment