INFLUENCE OF SOIL MOISTURE STRESS APPLIED AT VARIOUS STAGES OF GROWTH ON THE YIELD COMPONENTS OF CHINOOK WHEAT

Abstract

Two series of moisture treatments were used to determine if there was a specific growth stage at which low soil moisture stress caused poor seed set in Chinook wheat, and also to determine whether grain yield could be maximized by manipulating time of increasing or decreasing moisture stress.Maintaining soil moisture at 25 to 10% (dry) until the shot-blade stage produced 80% seed set, compared with only 30% seed set when moisture was maintained at 25% to 16% (wet) during the same period. Increasing or decreasing the soil moisture stress at different growth stages had little effect on the number of florets per head or the mean kernel weight. Under the conditions of this experiment, the number of heads and percent seed set were the main components influencing grain yield. The highest grain yields were obtained when plants were grown under dry conditions until late shot-blade and under wet conditions thereafter. Conversely, minimum grain yields were realized where plants were grown under wet conditions until late shot-blade and under dry conditions thereafter. Straw yield was closely related to the total moisture used.