Analysis of Water Soluble Carbohydrates Accumulation in Wheat Stem Using NIR Spectroscopy.

The capacity for storage and utilization of water soluble carbohydrates (WSC) in the stem is an important trait to support grain filling, particularly under limited water availability. WSC have been found to be an important contributor to yield, biomass, and harvest index under drought. The main objectives of this study were to develop a near-infrared (NIR) spectroscopy model to dissect genotypic differences in water soluble carbohydrates in diverse wheat genotypes. A set of 400 diverse breeding lines, 30 varieties and 3 check varieties, were planted in western Kansas, to evaluate their performance under two treatments: irrigated and limited irrigation. The breeding lines were planted in a type II modified augmented design and the 30 varieties were replicated 6 times and arranged in a randomized complete block design (RCBD) with three blocks in each treatment. The NIR reflectance was measured in finely ground wheat stems fifteen days after mid-flowering. The NIR data were calibrated and cross-validated to WSC using multivariate calibration technique Partial Least Square Regression with 105 diverse set of samples at R² of 0.83 and SECV (Standard Error of Cross Validation) of 40.8 mg/g. There were significant differences between the varieties with a mean value ranging from 132 mg/g to 340mg/g. Accumulation was significantly higher below top node compared to the stem part above top node. NIR spectroscopic techniques have been shown to be effective in monitoring plant physiological process rapidly and nondestructively. These results suggest that breeding for high WSC will be possible in wheat.