Effectiveness of SC2053 as a chemical hybridizing agent for winter wheat

The use of chemical hybridizing agents (CHA) allows production of hybrid wheat seeds. We evaluated the effectiveness of a new CHA (SC2053) to induce male sterility on winter wheat in controlled growth conditions. CHA effectiveness was measured with the application of 4 doses (0–400–700–1000 g.ha−1) at 7 stages. These stages were defined by the length of the main stem spike (1–4–7–11–15–20–40 mm). At heading, individual ears were isolated with a greaseproof paper bag. The seeds formed were counted on treated and control ears. The spikes' sterility was calculated three weeks after flowering. The sterility of the main stem's spike reached 95% to 100% for application of 700 g.ha−1 and 1000 g.ha−1 for main stem spike length of 7 mm to 20 mm. The effects of ear tillering (5 tillers per plant) on CHA effectiveness were also investigated. We observed a significant delay of ear development between the main stem and tillers so that complete sterilities were not reached for each dose. Since tillering in field conditions rarely exceeds 3 ears per plant, CHA effectiveness was studied on plants bearing 3 ears. The mean sterility of the first 3 ears was close to 100% for applications with 700 g.ha−1 and 1000 g.ha−1 at stages from 11 mm to 20 mm of main stem spike length.