تقييم بعض المؤشرات الفيزيولوجية لعدة طرز من الذرة البيضاء Sorghumbicolor L. Moench لتحمل الإجهاد المائي خلال الإزهار

الملخص EN

An experiment was conducted in Kharabo station which belongs to the faculty of agriculture, Damascus university during the growing season 2009 ـ!ـ 2010, to evaluate the response of seventeen sorghum genotypes under water stress conditions during the flowering stage according to the randomized complete block design (RCBD), with three replicates.

Results indicated to the existence of genetic variability (p < 0.01) in the response of studied genotypes to water stress.

Water stress caused a decline in studied traits, compared with irrigated conditions.

The genotypes KHARABO-238, KHARABO-232, LOCAL-26 maintained the lowest rates of reduction in the leaf area index (1.41, 2.65, 11.48%, respectively) compared with GIZA-123 (41.25%).

The genotype KHARABO-238 recorded the highest average percentage of leaf area (32.04 cm2 .g-1) under water stress conditions while the lowest average of this trait appeared in IZRAA-3 (15.03 cm2 .g-1).

The genotypes of LOCAL-26, KHARABO-238 achieved the highest net assimilation rates (0.49, 0.91%, respectively) and thus classified as drought-tolerant, which are advised to be planted in the areas suffering from the the availablity of water resources .While genotypes IZRAA-3, KHARABO-245, SC# 246 had achieved the highest reduction percentage in that trait nearly (19.26, 22.13, 40.46%) compared with the control.

Thus, they were classified as the most sensitive to drought.

This study showed the importance of leaf area index, leaf area ratio because of its positive and significant correlation with net assimilation rate, hence they are considerd as important physiological parameters to screen the genotypes of this crop under dry conditions.