Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Plants, Soils, and Insects

Major Professor

V.H. Reich

Committee Members

John H. Reynolds, F.F. Bell, J.W. Hilty


Exploitation of induced male sterility has now become a potential tool in plant breeding. Ethephon (2-chloroethyl-phosphonic acid) has induced male sterility in winter cultivars of wheat and barley.

The purpose of this research was to further elucidate the response of winter wheat (Triticum aestivum L. em Thell), and winter barley (Hordeum vulgate L.) to foliar application of ethephon.

Ethephon was foliarly sprayed on winter cultivars of wheat and barley which were Arthur and Blueboy, and Barsoy and Volbar respectively, at 0.05, 0.10, and 0.20 and 0.40 percent active ingredient, when plants were in mid-boot and late boot stages in the field study at Knoxville, Tennessee. In the growth room wheat winter cultivars Arthur and Blueboy, and barley winter cultivars Keowee and Harrison were sprayed at 0.02 and 0.05 percent active ingredient at the late boot stage of development.

The most effective level was 0.40 percent ethephon in mid-boot and late boot stages for both cultivars of wheat and barley in the field study.

Concentration, replication, date, cultivar, date X concentration, date X cultivar, concentration X cultivar, date X concentration X cultivar effects were significant for all variables except seed weight, date headed, and date mature. No overall replication, date X concentration, date X cultivar, and concentration X cultivar effects occurred for seed weight. No overall date X concentration X cultivar effect occurred for date mature. Concentration and cultivar effects per plant were strongly and positively associated with induction of male sterility.

Clearly female fertility was not impaired to any great extent from ethephon treatments from data obtained from open-pollinated spikes.

Certain beneficial effects, such as reduced height and lodging, were accompanied by reduced yields.

The successful utilization of this technique using ethephon in enhancing production of hybrid plants, however, depends on the economics of hybrid seed production. The results of this research project indicate the induction of male sterility with ethephon in wheat and barley appears feasible.

Files over 3MB may be slow to open. For best results, right-click and select "save as..."