The status of ongoing research to use near infrared reflectance spectroscopy (NIRS) to measure cottonseed oil content is summarized. A data set of 36 seed samples consisting of a single replication of six entries grown at two locations for 3 yr was used to generate prediction equations for oil content of cottonseed (Gossypium hirsutum L.). The equations were generated with NIRS based on seed-oil contents from continuous wave nuclear magnetic resonance (NMR) analysis. The results in predicting the remaining four replications in the tests, 144 samples, demonstrate the ability to develop prediction equations capable of identifying differences in seed-oil content within specified populations (r2 = 0.89–0.92). However, these prediction equations were not as successful when tested on the National Cotton Variety Test entries (r2 = 0.00-0.84). A universal prediction of seed-oil content will require a larger sample base to eliminate spectral variability that might interfere with calibration.
