The long process of producing a sterile 'A'-line for hybrid production has prompted the need to develop a method for predicting the performance of a sterile cytoplasm hybrid. The combining ability and potential hybrid vigor of cotton cultivars might be determined by crossing into the fertile cytoplasm and assuming the results will be similar to those obtained utilizing sterile cytoplasm. Paired 'A'and 'B'-lines pollinated by selected 'R'-lines were observed to determine similarities in yield, picked lint percent, boll size, boll set, and earliness.

Six paired 'A'-and 'B'-lines and 6 'R' lines of diverse origin from across the Cotton Belt were hand crossed to produce F₁ hybrids to be grown out for observation. White bloom counts were recorded and open bolls were harvested on a periodic basis for yield and earliness determinations.

Half of the thirty-six hybrid pairs produced yields using the sterile cytoplasm hybrid that were within plus or minus 10% of the fertile cytoplasm hybrid. Most of the agronomic properties observed were significantly similar for the 'B' X 'R' hybrid and its corresponding 'A' X 'R' hybrid. Some exceptions that did not show similar results in yields were also different for earliness and boll set percent. Picked lint percent and boll size showed the most consistent similarities within the paired hybrids.