PREDICTION OF STARCH, MOISTURE, AND SUGAR IN SWEET-POTATO BY NEAR-INFRARED TRANSMITTANCE

Near infrared analysis,vas used to predict the starch, moisture, and s ugar content in sliced fresh sweetpotato [Ipomoea batatas (L.) Lam,] s torage roots, Samples were collected in each of three growing years, T he best calibration equation for starch from combined samples (1989 to 1991) showed a multiple correlation coefficient (R) of 0.949, a stand ard error of calibration (sec) of 2.01, and a standard error of predic tion (SEP) Of 1.91, The R, sec, and SEP for moisture and sugar were 0. 930, 1.85, end 2.00, and 0.837, 1.30, and 1.21, respectively, Calibrat ions based on samples from a given year adequately predicted the varia bles but could not account for variances introduced by samples from ot her years, Multiyear calibrations based on several years of data adequ ately predicted starch and moisture content in root slices, Thus, mult iyear calibrations with annual bias adjustments can be applied to scre ening sweetpotato breeding germplasm for these two variables.