Simultaneous Improvement of Yield, Fiber Quality, and Yarn Stregth in Upland Cotton

Abstract

A five‐parent half diallel mating design was utilized to determine the potential for the simultaneous improvement in yield, fiber quality, and yarn strength in upland cotton (Gossypium hirsutum L.). In addition, fiber traits were measured by standard laboratory instrumentation (SLI) and high volume instrumentation (HVI) to compare their usefulness to breeders in population improvement. The 10 FI populations plus the parental lines were grown in a randomized complete‐block design in 1983 at two locations each with a different soil type at the Pee Dee Research and Education Center, Florence, SC. Significant general combining ability (GCA), which may approximate additive genetic effects, was detected for 2.5 and 50% fiber span length (SLI measurement), uniformity (SLI measurement), yarn strength, yield, and lint percentage. Therefore, progress from early generation selection could be expected in these populations. There were no significant GCA effects for any of the HVI fiber measurements, and it was concluded that HVI is not as useful to breeders in detecting small genetic differences as HVI is to the textile industry for which it was developed. There was some evidence of nonadditive genetic effects for some of the fiber traits by a general test of heterosis, although it was not detected by the test for specific combining ability. No single parent exhibited high GCA effects for yield and all fiber traits, thus simultaneous improvement in multiple fiber traits and yield probably will require intermating of several parental lines. However, simultaneous improvements in yield and yarn strength could be expected from crosses with PD 3249 and SC‐1, thus providing further evidence of the breakup of unfavorable linkages.