Analysis of the physiological and reproductive responses of five wheat varieties under rainfed and irrigated conditions in southern Italy

Five wheat varieties (Creso, Latino, Manital, Appio, Iapigia) were grown in a field plot experiment from November 1985 to June 1986 in Apulia (Bari area). The winter rainfall was well distributed and sufficient to meet the crop water requirements until the anthesis, occurring early in April. No more rains fell after that period so that, after anthesis, a severe drought occurred in the dry treatment. Physiological, morphological and reproductive responses of the varieties under the above-mentioned conditions and in a well irrigated treatment were analyzed. A high correlation between post-anthesis LAU and yield was found. A short duration of the pre-anthesis crop cycle and the reduced canopy size was related to yield; such result occurred far LATINO, APPIO and MANITAL, the highest productive varieties under dry condition. High sink strength showed to be always desirable because under both dry and well watered post-anthesis conditions it resulted to increase maximum yield; such result occurred for LATINO and APPIO, the highest productive varieties under both dry (5.1 tons/ha) and wet conditions (8.h tons/ha). The analysis based on source-sink relations, linked to the dynamics of the environmental water availability, showed to give a much clearer picture of the wheat responses under post-anthesis drought than the one based on short-term physiological relations at plant scale, such as stomatal resistance and photosynthesis. The canopy temperature measurements did not allow to draw coherent inferences.