ملخص
Abstract
This research was conducted in Agriculture Faculty Research Center/ El-Fatah University, Tripoli, Libya during 2006/2007 growing season. The objective was to study some morphological, physiological and anatomical characters associated with grain yield and drought resistance in some varieties and lines of barley developed by crossing and hybridization in Agriculture Research Center in Great Jamahiriya. Statistical analysis of the data showed significant differences between varieties and lines in main spikes length and number of spikes/plant .Moreover the differences between varieties and lines in length of main stem spike, total tiller number /plant and spike number/ plant were significant. Statistical analysis of data also showed that differences between varieties and lines in grain number of main spike, grain number of lateral spike, and mean grain weight /spike were significant. Data also showed that differences between varieties and lines in grain weight of main spike were not significant. However, differences between them in grain weight of lateral spike, and mean grain weight /spike were significant. This data also indicated that that there were significant differences in weight of 100 grains /plant, grain weight/plant and straw. In addition to this, harvest index for this varieties and lines was significantly different, and its value ranged between 59.9% and 70.9%. These results also showed that number of spikes/plant was the main grain yield component (r =0.76 p <0.01), followed in importance by number of grain /spike(r= 0.28 p <0.05).However, the relationship between grain yield and 100 grain weight was highly significant (r= 0.36 Harvest index was significantly and highly correlated with grain yield. .(0.01 Results indicated that there was a significant difference between varieties and lines of barley in flag leaf area and its specific leaf weight. Specific flag leaf weight ranged between 2.2 mg/cm2 and 7.2 mg/cm2, and its water content ranged between 61.9 and 80.0% Flag leaf area was not significantly correlated neither with its water content, nor with its specific leaf weight. However, specific flag leaf weight was significantly and negatively correlated with its water content. Statistical analysis showed that there was a significant between varieties and lines of barley in characters associated with drought resistance , which include stomata resistance and transpiration rate .Moreover, there was a significant difference between these varieties and lines of barley in stomata frequency and size in upper flag leaf surface. In general, these results showed that stomata resistance was associated with stomata frequency and size and transpiration rate. Results of this study indicated that increasing stomata frequency in variety Seffit 9 by about 1%above the overall mean of all varieties and lines in this character, decreased transpiration rate by 2.67 %. This results indicated that barley production is highly dependent on grain yield components and flag leaf area, and since the main objective in cereal breeding program is increasing yield genetic potential of cereal crops and improving its quality, therefore, results of this study indicated that there are additional bases that can help plant breeders in selecting high yielding varieties. Moreover, genetic variation between varieties and lines in their morphological and physiological characters which were studied and associated with drought resistance and its yield, indicated the possibility of its utilization s in breeding program for selecting drought resistant varieties and lines.Additional Index Words; Barley, flag leaf, Stamata, transpiration, drought resistance.