الفهرس 
INTRODUCTION
Genetic variability in Egyptian cloverOnly 14 pages are availabe for public view
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Abstract
The present study aims were; a) to evaluate the genetic variability among nineteen local ecotypes and a check cultivar (Fahl) of monocut Egyptian clover for forage and seed yields, b) to estimate the efficiency of recurrent selection and synthetic population in improving forage and seed yields. The genetic materials were nineteen accessions and one check variety. Three separate experiments were carried out during the successive seasons of 2010/2011 and 2011/2012 for evaluation, 2011/2012, 2012/2013 and 2013/2014 for recurrent selection and synthetic population procedures at Shandaweel Agricultural Research Station, Agricultural Research Center, Ministry of Agricultural.
The obtained results could be summarized in four main topics as following:
I- Evaluation of twenty accessions of Fahl Egyptian clover for forage and seed yields.
A- Forage yield and its components
1- The separate and combined analyses of variance showed significant genetic differences among the twenty accessions of monocut Fahl berseem clover for all studied forage traits i.e. plant height, leaf/stem ratio, fresh forage yield, dry forage yield, protein forage yield and dry matter percentage. Moreover, the accessions x year interactions were only significant for fresh forage yield and protein yield.
2- Three accessions (No. 1, 6 and 19) were significantly taller than the check over the two seasons by 5.24, 7.80 and 7.45%, respectively.
3- The genotypic variance relative to environmental variance was larger in magnitude for plant height in both seasons.
4- The accessions No. 3, 6, 11, 15 and 19 were exceeded significantly the check cultivar for leaf/stem ratio over the two seasons.
5- Generally genotypic variance was close to the phenotypic variance for leaf/stem ratio reaching 16.76 and 16.52% over the two seasons, respectively.
6- Four accessions (no. 3, 6, 15 and 19) had significantly surpassed the check cultivar for fresh forage yield over the two seasons.
7- The influence of environment on fresh forage yield were 20.3, 15.58 and 18.97% in first, second season and over the two seasons, respectively.
8- Five accessions No. 3, 6, 13, 15 and 19 had significantly surpassed the check cultivar for dry forage yield over the two seasons.
9- The values of genotypic and phenotypic variances coupled with heritability revealed that approximately more than 80 percent of the effects for the dry forage yield were due to genetic factors.
10- The average of protein yield over the two seasons revealed that six accessions (no. 2, 6, 11, 13, 15 and 19) significantly surpassed the check cultivar by 39.67, 53.26, 17.43, 24.67, 43.75 and 45.17%, respectively.
11- The genotypic variance was very close to the phenotypic and revealed less effect for environment on protein yield. Heritability estimate was 96.5% over the two seasons. That means more than 95% of the effect for protein yield was due to genetic factors.
12- Two accessions (No. 13 & 15) were significantly higher in dry matter percentage than the check cultivar over the two seasons by 14.5 and 11.51%, respectively.
13- The influences of environment on the dry matter percentage were 28.35, 14.21 and 10.45% in first, second and over the two seasons, respectively. The phenotypic, genotypic coefficients of variations and heritability values were 8.78, 7.42 and 71.5; 10.72, 9.93 and 85.7 and 9.33, 8.82 and 89.5%, respectively.
B- Seed yield and its components
1- The separate and combined analyses of variance showed highly significant genetic differences among the twenty accessions of monocut Fahl berseem clover for all studied seed yield traits i.e.; number of inflorescences/plant, number of seeds/inflorescence, seed yield/plant, seed yield/m2 and 1000-seed weight. Meanwhile, the accessions x year interactions were significant only for seed yield/plant, seed yield/m2 and 1000-seed weight.
2- Five accessions No. 3, 8, 11, 13 and 18 were significantly higher than the check cultivar for number of inflorescences/plant over the two seasons by 11.42, 11.42, 18.22, 16.36 and 14.25%, respectively.
3- The influences of environment on the number of inflorescences/plant were 44.1, 32.03 and 42.31% in the first, second and over the two seasons, respectively. This means that approximately 40% of the effect for the number of inflorescences/plant due to environmental factors.
4- Only one accession (No. 13) was significantly higher than the check cultivar by 11.56% for number of seeds/inflorescence over the two seasons.
5- The phenotypic, genotypic coefficients of variation and heritability estimates were 15.77 and 15.06 and 91.2% over the two seasons, respectively. This means that the genetic factors control approximately 90% of the effect for number of seeds/ inflorescences.
6- Seed yield/plant ranged from 1.25 (No. 4) to 1.94 (No. 13) with an average of 1.58 g/plant over the two seasons. Only three accessions No. 3, 13 and 15 were significantly surpassed the check cultivar over the two seasons by 12.43, 14.79 and 12.4 %, respectively.
7- Seed yield/m2 over the two seasons ranged from 100.17 (No. 4) to 133.92 (No. 13) with an average of 113.29 g/m2. Only three genotypes (No. 11, 13 and 15) were significantly exceeding the check cultivar over the two seasons by 14.32, 15.55 and 11.73%, respectively.
8- The P.C.V., G.C.V. and heritability values were 13.12 and 12.17 and 86.0% for seed yield/plant and 8.13, 7.40 and 82.8% for the seed yield/m2 over the two seasons, respectively.
9- regarding 1000-seed weight over the two seasons, five accessions (No. 3, 6, 11, 13 and 15) were significantly heavier than the check cultivar by 7.83, 13.32, 18.54, 17.44 and 9.92%, respectively.
10- Heritability estimates were as high as 97.0, 96.8 and 96.85% in first, second and over the two seasons, respectively, indicating that 1000-seeds weight influenced by the genetic factors.
C- Path coefficient analysis
1- The path coefficient analysis revealed that fresh forage yield had most direct contribution (0.517) and indirect effect (0.409 and 0.468) followed by mean protein percentage (0.283) and dry matter percentage (0.249). This may indicate that these three variables had the major effects in direct and indirect contributions toward protein yield.
2- Among seed yield components, the number of seeds/inflorescence had the highest direct effect on seed yield/plant (0.485). While its indirect effect via number of inflorescences/plant and 1000-seed weight was small (0.113) and intermediate (0.324) respectively. Less importance of other seed yield components was found on seed yield.
II- Recurrent selection stem
A- Forage yield and its components
1- Significant differences were obtained among the three tested populations (recurrent selection, base population and the check cultivar) for all forage yield traits i.e.; plant height, leaf stem/ratio, fresh forage yield, dry forage yield and protein yield.
2- Recurrent selection significantly surpassed the base population and the check cultivar for plant height, dry forage yield and protein yield, while, only surpassed the check cultivar for leaf /stem ratio and fresh forage yield.
3- The realized gains due to recurrent selection relative to base population and the check cultivar for plant height, leaf stem/ratio, fresh forage yield, dry forage yield and protein forage yield were 10.0 and 11.4, 18.6 and 42.1, 11.7 and 29.9, 14.61 and 44.66, and 27.6 and 44.7%, respectively.
B- Seed yield and its components
1- Significant differences were detected among the three tested populations (recurrent selection, base population and the check cultivar) for all seed yield traits i.e.; number of inflorescences/plant, number of seeds/inflorescence, seed yield/m2 and 1000-seed weight.
2- Recurrent selection significantly surpassed the base population and the check cultivar for number of seeds/inflorescence, seed yield/m2 and 1000-seed weight and only the check cultivar for number of inflorescences/plant.
3- The realized gains due to the recurrent selection over the base population and check cultivar for number of inflorescences/plant, number of seeds/inflorescence, seed yield/m2 and 1000-seed weight were 14.39 and 25.83, 19.2 and 26.6, 13.1 and 23.0, and 16.9 and 28.8%, respectively.
III- Synthetic population procedure
A- Forage yield and its components
1- Significant differences were obtained among the eight tested populations (synthetic population, base population and the check cultivar) for all forage yield traits i.e. plant height, leaf stem/ratio, fresh forage yield, dry forage yield, protein forage yield and dry matter percentage.
2- Synthetic population significantly surpassed the check cultivar for all studied traits.
3- The realized gains due to the synthetic population compared to the check cultivar and parents mean for plant height, leaf stem/ratio, fresh forage yield, dry forage yield, protein forage yield and dry matter percentage were 6.0 and 2.5, 15.2 and 3.2, 13.1 and 2.7, 20.39 and 4.2, 23.0 and 3.2 , and 7.0 and 1.0 %, respectively.
B- Seed yield and its components
1- Significant differences were obtained among the eight tested populations (synthetic population, base population and the check cultivar) for all seed yield traits i.e. number of inflorescences/plant, number of seeds/inflorescence, seed yield/m2 and 1000-seed weight.
2- Synthetic population significantly surpassed the check cultivar for all studied traits.
3- The realized gains due to the synthetic population comparing to the check cultivar and parents mean for number of inflorescences/plant, number of seeds/inflorescence, seed yield/m2 and 1000-seed weight were 13.3 and 4.4, 16.7 and 4.7, 15.7 and 2.8, and 14.3 and 3.9 %, respectively.
IV- Synthetic vs. recurrent selections overview
1- There are significant differences among the three genotypes (recurrent selection, synthetic population and check cultivar) for all forage and seed yields and their components, reflecting the genetic variations among genotype resulted from synthetic and recurrent procedures.
2- The recurrent selection significantly surpassed the synthetic population for forage yield and its components i.e.; plant height, leaf stem ratio, fresh forage yield/m2, dry forage yield/m2, protein/plot and dry matter percentage by 23.31, 5.17, 14.96, 20.16, 39.96 and 6.57%, respectively. In the meantime, similar results were found for seed yield traits such as no. of inflorescences/plant and 1000-seed weight by 11.0 and 13.0%, respectively. But, insignificantly increase for no. of seeds/inflorescence and seed yield/m2 by 8.5 and 6.28%, respectively.
3- Moreover, the recurrent selection significantly exceeded the check cultivar for all forage yield and its components such as plant height, leaf/stem ratio, fresh forage yield/m2, dry forage yield/m2, protein m2 and dry matter percentage by 11.44, 42.05, 29.96, 44.66, 77.44 and 12.23%, respectively. The same was true for seed yield traits such as no. of inflorescences/plant, no. of seed/inflorescence, seed yield/m2 and 1000-seed weight by 25.83, 26.62, 23.0 and 28.84%, respectively.
4- Significantly increasing values were obtained for synthetic population over the check cultivar for all studied characters in a range of 5.32-26.78%.
4- The superiority of the recurrent selection over the synthetic population and the check cultivar might be due to selecting the best selfed plants from the best parent (P6) evaluated for forage. On the other hand, synthetic cultivar was developed through selection of open-pollinated progenies.
Finally, the obtained populations, i.e. from recurrent stem and synthetic variety, could be used as new populations with improved forage and seed yields of monocot Egyptian clover.