Soil Temperature Effects on Free Carbohydrate Concentrations in Peanut (<i>Arachis hypogaea</i> L.) Seed1

Abstract

Abstract Research has indicated that variation in the mean soil temperature of only a few degrees results in quality differences of peanut seed. The importance of the carbohydrate-amino acid interaction in the development of roasted peanut flavor and color is well documented. The objective of this study was to determine the influence of controlled field soil temperatures on free carbohydrates in commercially sized peanut seed. Florunner peanuts were grown in 5.48 × 12.19 m plots. Soil temperatures were modified from 28 days after planting to produce mean temperatures warmer (28.8 C) and cooler (21.7 C) than ambient (24.5 C) at the 5.0 cm depth in 1982 and 28.2, 22.5, and 25.8 C, respectively, in 1983. Carbohydrates were determined by gas chromatography. Sucrose concentrations decreased significantly as accumulated heat units and seed size increased. In general, fructose, glucose, and raffinose concentrations followed the same trends. The carbohydrate differences found in sized seed were similar to those found among maturity stages from each soil temperature treatment. The data indicate that seed carbohydrate concentrations decrease with higher soil temperature.