Evaluation relationships between seed number, used water in evapotranspiration and leaf relative water content with canola seed weight

To study the effects of used water in evapotranspiration، seed number per unit area and leaf relative water content on seed weight of canola (Brassica napus L.)، an experiment was conducted as a randomized complete block design، arranged in a split-plot under two conditions، i. e. supplemental irrigation and rainfed in 2005-7. Two cultivars of canola (‘Hyola401’ and ‘RGS003’) as subplots were grown at five sowing dates as main plots، spaced 30 days apart. There was a linear relationship between seed weight and used water in evapotranspiration. Irrigation increased seed weight and seed yield significantly. The mean 1000- seed weight under irrigation and rainfed conditions was 3. 2 and 2. 7g in 2005-6، and 4. 2 and 3. 7g in 2006-7. There was a strong linear relationship between seed weight and leaf relative water content، explaining 92 and 84 percent of the variation for ‘Hyola401’ and ‘RGS003’، respectively. For an each percent increase in leaf relative water content، 1000-seed weight of ‘Hyola401’ and ‘RGS003’ increased 0. 191 and 0. 146g، respectively. The strong relationships of seed weight with used water in evapotranspiration and leaf relative water content، over different environmental conditions and cultivars، showed these variables to be generally applicable in canola seed weight determination