Near infrared reflectance spectroscopy (NIRS) for large scale screening of fatty acid profile in peanut (Arachis hypogaea L.)

Breeding programmes dealing with the modifications of the fatty acid profile in oilseed crops require large number of chromatographic analysis. This study was conducted to characterize the potential of near infrared reflectance spectroscopy (NIRS) for the fatty acid analysis of intact single seeds of peanut. The material consisted of 1000 mutant entries of M₄ with varying fatty acid profile determined by gas chromatography (GC). Spectra from intact single seeds of the mutant entries were collected with a specially designed adapter using standard monochromator instrument. Calibration equations were developed for the calibration set of 800 mutant entries and were further validated with cross-validation and external-validation set consisting each of 100 mutant entries. Among the three regression models, the spectra with modified partial least square regression model (mPLS) after second derivative pretreatment with SNV and detrend scatter correction had the best calibration and satisfactory prediction abilities. The r² between NIRS and GC was 0.79 (palmitic acid), 0.91 (oleic acid) and 0.89 (linoleic acid) in cross validation, demonstrating the high reliability of NIRS in determining these fatty acid concentrations in intact single seeds. NIRS permitted analysis of about 40 samples per hour as against 1–2 samples in GC. Research clearly indicated that NIRS prediction of fatty acid profile using intact seeds was non-destructive, accurate, rapid and should be especially useful for early generation selection.