و مقاومت روزنه اي در مقاومت به خشكي در گندم و ارتباط آنها با عملكرد دانه در شرايط مزرعه و گلخانه RWC بررسي نقش مقدار نسبي آب

Evaluation of relative water content (RWC) and stomatol resistance in wheat as drought resistance indicators in the field and greenhouse

Effective screening techniques for drought resistance would be beneficial in wheat (Triticum aestivum L.) breeding programs. Two drought resistance criteria, consisting of relative water content (RWC) and stomatal resistance were evaluated in field and greenhouse to investigate drought resistance in five wheat cultivars reputed to differ in drought resistance: Alvand and B. C. Roshan (resistance), Zarrin and C-73-5 (moderate and Navid (susceptible). In both experiments, RWC decreased with progressing in pheno Logical stages. There was a significant difference in RWC among caltivars (excpet at stem elongation stage in the field) but drought resistant genotypes has not superiorty to susceptible ones. In greenhouse a significant linear relationship was obtained between RWC and yield reduction ratio as determined by Yr=1-(Ys/Yp)(Ys and Yp=yield under stress and non-stess conditions, respectively). In stress conditions, stomatal resistance in the greenhouse was higher than in the field. Siomatal resistance and yield reduction ratio in greenhouse showed a significant correlation. It seems that there is a relationship between RWC and stomatal resistance and these criteria were recognized as benifical drought resistance indicator but the time of drought stress is an important factor in this subject.