The major objective of our cotton breeding investigations is to develop improved Acala cottons for production in the One-Quality District which is the San Joaquin Valley of California. The Acala Cotton Board (ACB) was established in 1979 to administer the law, tests, and approve new strains for release and production. The ACB established a cotton for the breeders to use as a standard. A new cotton has to exceed the performance of the standard cotton to be considered for release. Fiber quality traits are very important considerations by the ACB because of the market reputation of San Joaquin fiber.

Acala SJC-1 was established as a standard cotton. Fiber strength was 7-10% stronger than Acala SJ-2 as measured by stelometer and spinning tests. Fiber quality tests conducted by Dr. Dick Bassett, Agronomist, U. C. Davis, who conducts the ACB tests, had found the same results independently of CPCSD. The 986 fiber quality results obtained from the HVI line at the Textile Research Center (TRC), Texas Tech University, showed no difference in fiber strength. The HVI T(1) gm/tex pressley was 28.6 for Acalas SJ-2 and SJC-L. Subsequently, Dr. Bassett released T(1) stelometer and 22 yarn test data showing significant differences between these cottons.

The stelometer has served the cotton breeder for many years for testing fiber strength of plant selections, new strains, and varieties. Fiber testing by this method is slow, expensive, and requires carefully trained employees. The strength index obtained by using the 1/8 inch gauge was found to correlate with yarn strength to a high degree. This estimate of fiber strength was a better estimator of yarn strength than the pressley strength index.

We have observed the development and testing of the HVI over the years and viewed it as a way of reducing the cost and time of evaluation per sample. Dr. Bassett's report raised the question as to what level of difference in fiber strength could be detected by HVI strength test.