Effect of drought stress in different growth stages on yield and some physiological properties of sugar beet

For determination of water stress effects in different growth stages of sugar beet and optimum water usage on quantity and quality of sugar beet, this study was performed using randomized complete blocks design in factorial experiment with 12 treatments and 4 replications from 1999 to 2001 in Agricultural Research Center of Hamadan. The first factor was non-irrigation in 3 stages of growth (S1-S3) and the second was non- irrigation with 4 levels (I1-I4). Experiment was performed with 12 treatments and a control without drought stress. The combined analysis results showed that there was significant difference among root yield, sugar yield and white sugar yield in interaction of different growth stages and year levels. There was significant difference (P≤ %1) in interaction of treatments and year on relative water content and soil moisture percent. There was significant difference in interaction of different growth stages and year on water use efficiency for root yield, sugar yield and white sugar yield. Maximum water use efficiency obtained from S1I2 (not-irrigated for two times in the leaf growth stage) and the minimum obtained from S2I4 (not-irrigated for four times in the root growth stage).Non-irrigation for more than one time in sugar beet different grail stages cause damage on qualitative and quantitative characters. In general, drought stress in relation of the time and stress intensity decreased yield and quality of sugar beet. Reduction of root and sugar yield root growth and sugar accumulation stages was more severe.