This investigation aimed to evaluate some three-way crosses of Egyptian
cotton for combining ability and further partition of genotypic variance to its
components for fiber properties. The genetic materials used in the present study
included six cotton varieties and their 60 three-way crosses. These genotypes were
evaluated during two successive growing seasons at Sakha Agricultural Research
Station, Kafr EI-Sheikh Governorate for the following traits: fiber fineness , fiber
strength, 50% span length, 2.5% span length and uniformity ratio. The results revealed that partition of the three-way crosses mean squares to
its components predicted Hie significant contribution of additive, dominance end
epistatic variances in the genetic expression of fiber properties. These parameters
were stable at different years for the studied fiber properties except for 2.5% span
length. Giza 87 variety was the best general combiners as a parent andlor grand
parent in the three-way crosses for yield and yield components. Therefore, this variety
could be utilized in a breeding program for improving these traits to pass favorable
genes for improving hybrid and subsequently producing improved genotypes through
the selection in segregating generations. The best three-way combination for fiber
properties resulted from the crossing the single cross (Giza 76 x Giza 87) by Giza 85
as parent. In addition, the results showed that fiber properties were mainly contrclled
by additive variance as well as additive x dominance variances, while the other
components play the minor role in the inheritance of these traits. Thus, the selection
within the advanced generations of the previous three-way cross may be effective for
improving fiber properties.