Near infrared reflectance spectroscopy prediction and heritability of neutral detergent-soluble fiber in alfalfa

Increasing neutral detergent-soluble fiber (NDSF) concentration has been co nsidered a strategy for breeding alfalfa (Medicago sativa L.) with improved quality. Pectin is the main component of NDSF and is highly digestible, bu t the assay for NDSF is time-consuming. The objectives were (i) to determin e the potential use of near infrared reflectance spectroscopy (NIRS) to pre dict NDSF concentration in alfalfa and (ii) to estimate NDSF heritability a nd gain from selection. Herbage was sampled five times across 2 yr from two populations of half-sib (HS) progeny tested at Ithaca, NY. Calibration equ ations were developed by multiple linear regression of laboratory values of NDSF on NIBS spectra. Samples from one harvest were assayed twice to compa re extraction methods. Means of NDSF from 90- and 80%-ethanol extractions w ere 213.1 +/- 7.21 and 179.5 +/- 5.89 g kg(-1), respectively. Assay standar d deviations were low for both ethanol concentrations. Because a better cal ibration equation was obtained with the 80%-ethanol assay, all remaining sa mples were assayed by that technique. Standard errors of calibration were s mall, ranging from 4.71 to 7.54 g kg(-1). Coefficients of multiple determin ation (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 o n HS progeny ranged from 4.6 to 19.0 g kg(-1) and averaged 10.3 g kg(-1) Se lecting parents with higher NDSF concentrations predicted by NIRS evaluatio ns of HS progenies may improve forage quality of alfalfa.