Chemical imaging of intact seeds with NIR focal plane array assists plant breeding

Abstract

Early generation identification of desirable or undesirable traits of kernels of grain is useful to the breeding program to assist in selection of the best seeds to carry forward and to eliminate the inferior ones. In the case of wheat, resistance to premature sprouting (germination) in the field, before harvest under high moisture conditions is desirable. Visual examination of individual kernels provides non-destructive identification of severities of the problem. The germination process must be so advanced before visual detection is possible that severe damage to starch in the kernel has already occurred from release of ά-amylase enzyme. Several tests exist for the viscosity of solutions or for alpha amylase directly that are done in bulk and are destructive to the individual kernel. Near-IR imaging with an InGaAs focal plane array provides early localized chemical evidence of the process occurring in multiple kernels in the field of view. A Go/No-Go decision is made on individual kernels by the instrument using a specimen mounting plate that defines the position of the diffusely reflecting kernel, while rejecting adjacent pixels as specular reflection away from the detector array. The chemical imaging reported detects sprouting considerably earlier than can be found by both visual inspection and alpha amylase (ά-amylase) testing procedures. Images are presented to illustrate the contrast between normal and sprouted specimens.