INFLUENCE OF AIR TEMPERATURE, LIGHT INTENSITY AND SOIL MOISTURE ON THE GROWTH, YIELD AND SOME GROWTH ANALYSIS CHARACTERISTICS OF CHINOOK WHEAT GROWN IN THE GROWTH CHAMBER

Abstract

The response of Chinook wheat to light intensity, air temperature and soil moisture stress was studied under controlled environmental conditions in a 3 × 3 × 2 factorial experiment.Increasing day temperature from 21 to 27 °C or night temperature from 13 to 21 °C did not affect tillering, but the plants had shorter, slimmer culms with smaller individual leaves, less total leaf area, and less vegetative and grain dry matter. Temperature changes had little effect on leaf area ratios and their influence on net assimilation rate and relative growth rate was inconsistent. Percent grain protein was increased by temperature.A reduction of light intensity from 17 to 6 cals cm−2hr−1 did not change individual leaf size, but did produce shorter plants with fewer tillers and weak culms. Vegetative, root and grain dry matter were reduced. Shading reduced the translocation of leaf assimilates and lowered the cellulose content of the straw, but increased percent grain protein.Plants developed more tillers at the lower moisture stress, but this difference disappeared by heading time. The lower stress resulted in taller, thicker-stemmed culms with a greater total leaf area, and greater yields of straw and root. The effect of moisture on leaf area ratio was small and its influence on net assimilation rate and relative growth rate was small and inconsistent. Its influence on grain yield varied with temperature; the latter interaction was traced specifically to the influence of moisture stress on seed set. The effect of moisture on percent protein and carbohydrates in grain and on percent cellulose in the straw was inconsistent.