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Abstract
Four field experiments were carried out at Agricultural Experimental Station Farm, Agricultural Research Center, Giza during the period extended -#102;-#114;-#111;-#109; 2003 to 2007. The study began by collecting seeds of 23 alfalfa populations. These population and the three check verities (Sewa1, Ismailia1 and Ismailia94) were evaluate for forage yield and seed yield and its composition as well as chemical compositions(experiment I). On the basis of performance of these populations as compared with three check varieties, the best twelve populations were selected as well as two check varieties. The best populations were evaluated for forage and seed yield and its components (experiment II) during two years (2004/2005 and 2005/2006) and two growing seasons (spring and summer seasons).Other two experiments were carried out to study the performance of So, S1, S2 and OPSo as well as estimate some genetic parameters i.e GCA, heritability and inbreeding depression. The main results can be summarized as follows:-The first experiment:- Forage seed yield and its components. Significant differences were appeared among the 26 alfalfa populations for all traits. Population number 17 surpassed the three check varieties in plant height and fresh weight of leaves, population number 20 yielded the highest value for dry forage yield and population number 18 had the highest values of number of tillers and fresh weight of stem. Also, population number 9 gave the highest number of inflorescences and number of seeds/plant. Chemical compositions, insignificant differences were obtained among the studied alfalfa populations in crude protein, crude fiber, ether extract. and ash content.The second experiment:- Forage seed yield and its components: The main effects of populations (P), years(Y) and growing seasons(S) were significant for all traits and their interactions expect 100-seed weight. For most traits, average of populations, growing in the second year was higher than its average in the the first year and its average of summer season than spring season. Results in path coefficient analysis indicate that both plant height and dry weight of leaves had the most prominent and can be considered as the most sources of dry yield variation, followed by number of tillers through, 100-seed weight and seed less important on yield variation. Broad sense heritability were high for plant height, 100-seed weight and seed yield while its values were low for dry weight of leaves, number of tillers and forage yield.