General and specific combining abilities and RAPD marker-trait
associations in cotton genotypes
A.E.M. Eissa2 and El-A. Y. El-Samman2
of Genetics, Faculty of Agriculture, Sohag University, 82786 Sohag, Egypt.
Research Institute, Agriculture Research Centre, Giza, Egypt.
*Corresponding author (e-mail:
Gene action, heritabilities, and genetic variability were studied in seven
promising genotypes of cotton.
The results indicated that estimates of h2b.s % were
larger than those h2n.s% for yield and its component
traits which ranged from 59.15 to 98.77% for lint index and boll weight
traits, respectively. While, estimates of h2n.s% ranged from
8.68 to 58.33% for lint index and number of bolls per plant traits,
respectively. For fiber quality traits, the values of h2b.s%
also were larger than those h2n.s%, which were
63.08, 92.42, 94.01 and 95.25 % for fiber fineness, fiber strength and
length, and uniformity ratio, respectively.
The percent of polymorphism among genotypes ranged from 16.67% to 75.00%
with an average of 47.21%.
The PIC values for the 10 RAPD primers varied from 0.07 to 0.33 with an
average of 0.20. The Marker index values ranged from 0.07 to 1.32 for
primer OPA-10 and OPAT-08, respectively with an average of 0.54.
The results of RAPD markers, revealed similarity
coefficient values ranged from 60.8% (P2 and T3) to 91.1% (P4 and T1) with
an average of 75.7%. The UPGMA cluster analysis based on the RAPD markers
separated the studied genotypes into four different clusters, but the
dendrogram based on phenotypic data separated the cotton genotypes into 2
Correlation between the morphological traits and RAPD markers was negative
and significant (r = -0.36434 at α=0.05).
Twenty five polymorphic RAPDs were screened using single marker analysis,
and 2 markers of them were significant associated with 3 phenotypic
Additive, Dominance, RAPD markers, Correlation
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