الفهرس 
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Abstract
The present investigation was carried out at Sids Agric. Res. Station, ARC during the period from 2001 to 2005 aimed to estimate the variation among some ecotypes of Egyptian clover (Trifolium alexandrunum L.), the response of selection among and within these ecotypes and to obtain
a composite from the selected populations based on the estimated.
Seventy one populations were collected from three governorates (Beni-Suif, El-Minia and El Fayoum) and evaluated in complete block design trial with 4 replications in 2001/2002 seasons to assess the following traits: plant height (cm), number of tillers/plant, number of leaves/plant, leaf/stem ratio, fresh yield t fed-1 and dry yield t fed-1
The obtained results could be summarized as follow:
I- Variation among and within populations:
Highly significant differences were detected among populations under study and ranged from 65.31 to 75.38 cm for plant height with mean of 70.35cm, from 1.37 to 2.42 with mean of 2.11 for tillers number plant-1, from 7.23 to 10.10 with mean of 8.29 for number of leave plant-1, from 38% to 54% with mean of 44% for leaf/stem ratio, from 44.89 to 64.40
t fed-1 with mean of 55.54 for fresh yield and from 5.65 to 8.28 t fed-1 with mean of 7.42 t fed-1 for dry yield.
A wide range of variation among and within the populations was found as a result of the significant differences among the evaluated populations.
1- Genetic parameters:
1- Phenotypic variation:
High values of variability were observed between the studied traits where the fresh forage yield showed the highest value followed by plant height, while, number of leaves plant-1, dry forage yield, number of tillers plant-1 and leaf/stem ratio showed the least values.
2- Genetic variation:
Almost the same trend was found with respect to genetic variation which influenced the importance for selection of fresh forage yield and plant height traits when selection process is carried out to improve the productivity of Egyptian clover.
3- Heritability in broad sense:
The calculated H2% values were 85.59, 77.78, 81.21, 80.00, 84.39 and 83.93 for plant height, number of tillers plant-1, and number of leaves plant-1, leaf/stem ratio, fresh forage yield and dry forage yield, respectively.
4- Genetic advance:
The obtained values of genetic advance were 3.96, 8.50, 8.06, 8.07, 5.99 and 6.49 for plant height, number of tillers plant-1, and number of leaves plant-1, leaf/stem ratio, fresh forage yield and dry forage yield, respectively.
5- Correlation:
Significant positive correlations were found between fresh yield and either dry yield or plant height for both phenotypic and genotypic correlations. Positive genetic correlation was found between fresh yield and number of leaves plant-1.
Positive phenotypic and genotypic correlations were obtained between dry yield and plant height.