Effectiveness of SC2053 as a chemical hybridizing agent for winter wheat

Abstract

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-') at 7 stages. These stages were defined by the length of the main stem spike (1-4-7-1 l-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-' and 1000 g.ha-' 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-' and 1000 g.ha-1 at stages from 11 mm to 20 mm of main stem spike length.

Estimation of heterosis and combining abilities of U.S. winter wheat germplasm for hybrid development in Texas

“…Because of these advantages, CHAs were extensively used in the past and are currently being used in hybrid wheat research (Basnet et al 2018). Some of the CHAs that were developed in the past had negative impact on grain yield when they were used for hybrid seed production (Adugna, Nanda, Singh, & Bains, 2004;Whitford et al, 2013;Wong, Blouet, & Guckert, 1995).…”

Male sterility induced by the chemical hybridizing agent clofencet on wheat, Triticum aestivum and T. turgidum var. durum

“…Pía which had 96% MS. According to Wong et al (1995) 95% MS is high enough for commercial hybrid seed production. Among other factors, the variable rate of MS obtained may be attributed to clofencet doses used, application dates, phenological state of the wheat plants, and to the differences in wheat species and cultivars.…”

“…Therefore, a delayed application of clofencet may induce high MS in the main spike and in the neighboring tillers, as these tillers would be in a susceptible stage for CHA application. An adequate sowing density may diminish the number of tillers, improving the crop uniformity and decreasing the risk of forming self-pollinated seeds (Wong et al, 1995). applied CHA at 500 Lּha -1 obtaining good results, and following the recommendation by Uauy et al, (2003) volumes lower than 1000 Lּha -1 should be used.…”

Hybrid seed production in detergent induced male sterile Helianthus annuus L.

“…It does not require any special scheme, either for the development of male sterile and restorer genes, or for maintenance and increase of parental seeds (Gill, 1993). Chemical inhibitors of pollen development is not a familiar topic to the majority of scientists because these substances are found in patent literature and developed entirely within industrial research laboratories for hybrid seed production Devakumar, 2004, 2006;Wong et al, 1995). Therefore, they become highly expensive and enhance the cost of hybrid seed production, hence the emphasis, these days, is on the use of some new unconventional, cheap and widely used chemical hybridizing agents (Yu et al, 2006).…”