Evaluating Grain Yield in Spring Wheat with Canopy Spectral Reflectance

Worldwide, improving grain yield is the most important target for wheat (Triticum aestivum L.) breeders. Fast, cost-effective, and nondestructive phenotyping methods for important traits are needed to increase the efficiency of cultivar development. The present study tested canopy spectral reflectance (CSR) as a potential high-throughput method for assessing wheat grain yield in a diverse set of 540 spring-habit accessions from the USDA-ARS National Small Grains Collection. Plots were grown under irrigated (IR) and terminal drought (DR) treatments over two growing seasons, and CSR was measured at several growth stages in each year. The CSR indices related to canopy water and N status, biomass, and photosynthetic area were evaluated for their relation to grain yield. The CSR indices were significantly correlated with yield at every growth stage, with anthesis and grain filling being the most useful for predicting grain yield in IR and DR environments. Single CSR indices selected up to 57% of the highest 25% yielding lines in DR conditions and the grain yield of accessions selected using CSR was 20% greater than randomly selected genotypes. Canopy spectral reflectance also identified up to 86% of the highest 10% yielding accessions. Canopy spectral reflectance may be valuable as a high-throughput means of selecting for yield in large trials of genetically diverse wheat genotypes.