Changes in Frost Resistance of Wheat Young Ears with Development During Jointing Stage

Abstract

During the jointing stage, the frost resistance of young ears (FRYE) was tested each day for the main stem, and also for the first, second and third tillers of the wheat cultivars Jinmai 47 and Jing 411. At the same time, the developmental progression of young ears (DPYE) of the same four shoots was also recorded each day. In the shoots of both cultivars, FRYE decreased as development advanced through the jointing stage. FRYE dropped off particularly sharply at the point when the anther connective tissue formation phase (ACFP) started. Shoots developing later, though with lower levels of soluble sugar, tended to suffer less from frost injury than those developing earlier. Frost resistance of 12 cultivars (six early‐ and six late‐maturing) was evaluated at ACFP. The results indicate that only one cultivar (Xin 11) is frost resistant, with no significant differences appearing among the other 11 cultivars. The results suggest that DPYE is an important factor affecting FRYE. Evaluation of frost resistance of wheat cultivars should thus be performed at the same phase to obtain a true measure of frost resistance. The early ACFP phase is suggested as being the most appropriate one for frost resistance evaluation.

Frost affects grain yield components in winter wheat

“…Hence, a field movable climate chamber (FMCC) was used to simulate temperature decreases in situ and similar to those occurring naturally in the field. The FMCC employed was able to simulate radiation frosts and has been used previously in related studies (Zhong et al 2007(Zhong et al , 2008. A single frost treatment was imposed on each plot on 30 or 31 March 2012 when all three Frost affects grain yield components 195 cultivars had entered the jointing stage corresponding to Zadoks 32 (Zadoks et al 1974).…”

“…This is for two reasons: first, because the growing point is pushed above the insulating soil surface, also losing the protection of its enclosing leaf sheath (Single 1984); and second, because the growing point switches to the more frost-vulnerable reproductive phase. As development advances, susceptibility to subfreezing temperature continues to increase (Whaley et al 2004;Zhong et al 2008). After ear emergence, it becomes most frost sensitive because ice may form directly on the reproductive tissue when the ear is no longer protected by the stem and leaf sheath (Single & Marcellos 1974;Marcellos & Single 1984;Cromey et al 1998).…”

“…Unlike these regions, China typically has a continentalmonsoon climate with a very wide annual temperature range. Earlier in spring, from mid March through to early April, cold air flows from the north are not uncommon and frosts often occur 3 or 4 weeks before head emergence when plants are at the jointing stage (Feng et al 1999;Zhong et al 2008).…”

“…A large number of winter wheat cultivars have been bred and these are planted over extensive areas throughout the world. However, most of these areas are susceptible to spring frosts and significant yield losses occur in many countries (Paulsen & Heyne 1983;Single 1984;Boer et al 1993;Cromey et al 1998;Zhong et al 2008).…”

Frost Hardiness Expression and Characterisation in Wheat at Ear Emergence

“…Whilst crop damage at this time can be caused by decreased photosynthesis, leaf death or stem damage, it is apparent that ear or spikelet death is responsible for most of the recorded losses (Zhong et al. ).…”