Field evaluation and simulation of frost tolerance in Syrian durum wheat landraces

Abstract

Forty-nine Syrian durum wheat landraces were sown in late Nov. 1989 at Tel Hadya, Syria (a low-yielding site) and 38 were sown in mid-Dec. at Homs (a high-yielding site) with or without N + P fertilizer. Jan. frosts caused less than 5% apparent foliar damage in any of the landraces. However, foliar damage by Mar. frosts averaged 23% (range 3-65%). Late frost tolerance of foliage appeared to be related to minimum winter temperatures in the regions of origin, with landraces from coastal regions showing the highest sensitivity. Fertilizer did not significantly affect foliar damage. In simulation studies based on observed foliar damage rates at Tel Hadya due to Mar. frosts, foliar damage alone did not decrease grain yield but decreased straw yield. Additional floret damage decreased grain yield and increased straw yield.