Analysis of dry matter and protein contents in fresh yam bean tubers by near-infrared reflectance spectroscopy

Fast screening methods are needed for plant breeding. The objective of this research was to evaluate the potential of near-infrared reflectance spectr oscopy (NIRS) for the simultaneous analysis of dry matter and protein conte nts in intact discs of fresh yam bean (Pachyrhizus spp.) tubers. Discs from 210 tubers were extracted with a punch few hours after harvesting and scan ned by NIRS using a specially designed adapter. External validation reveale d a close relationship between NIRS and reference methods for dry matter co ntent (r(2)=0.94; standard error of performance, SEP=1.2%) and protein cont ent (r(2)=0.87; SEP=1.94%). The calibration for protein content was compare d with another one developed using dried-ground tuber samples (r(2)=0.97; S EP=0.97%). These results suggested that NIRS can be used to determine dry m atter and protein contents in fresh tuber samples of yam beans with accepta ble accuracy. Further research will have to determine if additional traits can be incorporated into this scheme.