Subcrown Internode Length of Spring Wheat and Barley as Influenced by Light and Soil Temperature

Abstract

AbstractBiological theory and some field observations during a dry spring suggest that small grains have an adaptive advantage in an environment with dry surface soil if the crown sets near the seed, because crown roots would have a better chance of forming in moist soil. Our objective was to measure how subcrown internode length in spring wheat (Triticum aestivum L.) and spring barley (Hordeum vulgure L.) responds to soil temperature and light regimes. Eight cultivars of both wheat and barley were evaluated at each of two light intensities and four soil temperature regimes. Both wheat and barley had shorter subcrown internodes when subjected to light as opposed to shade. Decreasing soil temperatures produced shorter subcrown internodes in both species. When averaged over the light and soil temperature regimes, there was a wide range of subcrown internode lengths among the cultivars, with values ranging from 28.1 to 8.3 mm for wheat and from 34.7 to 0.2 mm for barley. Wheat cultivars responded similarly to light and soil temperature treatments, but a differential response to light and temperature was observed with barley. One barley entry initiated its crown at or near the seed across all light and soil temperature regimes. These data suggest that under semiarid conditions, plant breeders should consider subcrown internode length as a selection criterion for spring cereals.