Cotton yield is determined by the number of bolls per unit area, number of seeds per boll, number of fibers per seed, and average weight per fiber. Improvements in fiber number per seed may result in increased yields. The objective of this study was to determine the genetic variation and combining ability for initial ovule fiber cells in modern cotton cultivars. A seven-parent full diallel study was repeated for two years. Initial ovule fiber cell numbers were counted at 2-d post-anthesis. There was a 20% variation in ovule fiber cell numbers among the seven parents. There were significant year effects but no year–genotype interactions. This trait was controlled primarily by additive gene effects. Two cultivars, Georgia King and Sure Grow 125, contributed positively in hybrid combinations.
