Water stress and phenology in wheat

Abstract

Single wheat plants (cv. Gabo) were sown in tall pots and top-watered so that growth proceeded without stress until the time of floral initiation. Having reached this stage, plants encountered increasing stress as soil water was depleted. At intervals after the dawn leaf water potential, ψ₁, had reached values of –5, –10, –15 bars etc., the stress was relieved with water sufficient for unstressed development until anthesis. The anthesis dates of plants which had encountered mild stress (ψ₁ down to about ndash;15 bars) were ahead of the well-watered control, while those which had encountered more severe stress (ψ₁ from about ndash;25 to ndash;40 bars) flowered after the controls. The results are discussed in relation to the possibilities of including the effects of stress in crop development models.