Near Infrared Reflectance Spectroscopy Prediction And Heritability Of Neutral Detergent-Soluble Fiber In Alfalfa

Increasing neutral detergent-soluble fiber (NDSF) concentration has been considered a strategy for breeding alfalfa (Medicago sativa L.) with improved quality. Pectin is the main component of NDSF and is highly digestible, but the assay for NDSF is time-consuming. The objectives were (i) to determine the potential use of near infrared reflectance spectroscopy (NIRS) to predict NDSF concentration in alfalfa and (ii) to estimate NDSF heritability and gain from selection. Herbage was sampled five times across 2 yr from two populations of half-sib (HS) progeny tested at Ithaca, NY. Calibration equations were developed by multiple linear regression of laboratory values of NDSF on NIBS spectra. Samples from one harvest were assayed twice to compare extraction methods. Means of NDSF from 90- and 80%-ethanol extractions were 213.1 +/- 7.21 and 179.5 +/- 5.89 g kg(-1), respectively. Assay standard deviations were low for both ethanol concentrations. Because a better calibration equation was obtained with the 80%-ethanol assay, all remaining samples were assayed by that technique. Standard errors of calibration were small, ranging from 4.71 to 7.54 g kg(-1). Coefficients of multiple determination (R-2) ranged from 0.72 to 0.97. Most heritability estimates for NDSF were significantly greater than zero, ranging from -0.03 +/- 0.20 to 0.56 +/- 0.17 and averaging 0.41. Expected gain from selection of parents based on HS progeny ranged from 4.6 to 19.0 g kg(-1) and averaged 10.3 g kg(-1) Selecting parents with higher NDSF concentrations predicted by NIRS evaluations of HS progenies may improve forage quality of alfalfa.