Shortening vernalization in winter wheat (Triticum aestivum L.) using plant growth regulators and cold stratification

Facing and controlling the adverse effects of global warming on crop production, especially under arid and semi arid conditions is an important question, which must be addressed by research work. This may be achieved by alternating crop phonological properties including the vernalization stage, essential for the vegetative/reproductive transition of winter wheat (Triticum aestivum L.). Shortening vernalization, during spring, can be a suitable method for the earlier production of crop plants, especially under stress conditions. Accordingly, it was hypothesized that it is possible to shorten vernalization, using priming (seeds) and spraying (plants) treatments while achieving optimum yield, in winter wheat, under the arid and semi arid conditions of Isfahan, Iran. The objective was to investigate the effects of plant growth regulators including gibberellic acid (GA, 100 mg/l), kinetin (100 and 200 mg/l), 6-benzyl adenine (BA6, 50 mg/l) and cold stratification on shortening vernalization in winter wheat. The research was a split plot experiment on the basis of a completely randomized block design, with four replicates, conducted in 2016. Different traits including number of fertile tillers (NFT), number of grains per spike (NGS), weight of 1000 grains (W1000), number of spikelet per spike (NST), grain yield (GY), protein percentage (PRO), and moist gluten percentage (MGP) were determined. The results indicated that priming and spraying winter wheat with the single or combined use of GA, kinetin and BA6 is the most suitable replacement for vernalization and increasing grain yield, under arid and semi arid conditions. However, priming winter wheat with cold stratification was not as effective, compared with the use of plant growth regulators. The highest grain yield (15.13 t/ha) was resulted by autumn planting + B8 (GA + BA6), followed by spring planting + GA and B9 (14.82 t/ha). Spraying wheat planted in spring (without priming and vernalization) with kinetin + GA3+GA7 (100 mg/l), increased PRO and MGP. The important results of this research work are: 1) planting winter wheat as spring wheat (vernalization not required) resulted in optimum yield amounts by priming and spraying techniques using gibberellins, kinetin and 6-benzyl adenine. This is of significance, with respect to the issue of global warming. 2) Shortening vernalization in winter wheat, which is especially important under arid and semi arid conditions, as the plant is subjected to different stresses including drought. 3) Improving wheat grain quality by the increased rate of protein and gluten. It is possible to plant winter wheat under arid and semi arid conditions using gibberellins, kinetin and benzyl adenine. Such a method results in alleviating the adverse effects of global warming on wheat production. It is also possible to plant winter wheat under different stresses including drought and cold by controlling the vernalization process.