II. 13. Fertility restoration of cytoplasmic male sterile barley.
E. A. Hockett, AR-SEA-USDA, Plant and Soil Science Department, Montana State University, Bozeman, Montana 59717, U.S.A. "R"
Crosses were made at Bozeman in 1978 of adapted barley cultivars and cytoplasmic male sterile stocks supplied by H. Ahokas. Fertility restoration occurred only in the Steptoe and Washonupana (waxy-short awned-nude-Compana) F1 plants (Table 1). The seed set on Steptoe was much higher at Bozeman in 1979 than at Finland in 1978. Ahokas (1979b) reported 0% seed set on Steptoe although some yellow anthers indicated a partial restoration of fertility. F1 plants of msml/3*Tammi//Steptoe grown in the greenhouse at Bozeman in 1978-79 had only 17.8%-seed set which is the opposite of the results in Finland (Ahokas, 1979b), where he found increased seed set in greenhouse grown material. The Washonupana (Compana) seed set of 10.6% in the field (Table 1) is higher than Ahokas (1979b) found with Washonupana (0% seed set), but similar to two other Compana types (9.2 and 12.2 seed set) he studied in 1978. The Bozeman seed set with Washonupana is lower than Ahokas (1979a) found with two Compana types in 1977 (18.2 and 22.1% seed set). With this variation in restoration by the Compana stocks, possibly better Hordeum vulgare restorers might be found in Composite Cross I from which Compana was selected.
Environment plays a strong role in these crosses where partial fertility is restored by the cultivars studied here. However, with those cultivars which restore full fertility or maintain full sterility, environment does not play a significant role (Ahokas and Hockett, 1980). These results on the partially restored cytoplasmic male steriles agree with the studies on genetic male sterile stocks where seed set varied with environment and was higher at the lower latitude (Hockett and Ahokas, 1979).
The seed set at Bozeman on the Steptoe and Compana restored material was largely at the base of the spike, which agrees with the results in Finland (Ahokas, 1979b).
The other cultivars shown in Table 1 did not restore fertility to the msml type which is in agreement with the results of Ahokas (1979a and 1979b). However, F1 plants in four of the crosses had pale yellow anthers indicating a tendency for restoration. Possibly these four crosses grown at a lower latitude than Bozeman, would produce some selfed seed - in a manner similar to the genetic male steriles.
Ahokas, H. 1979a. Cytoplasmic male sterility in barley. Acta Agric. Scandinavica 29:219-224.
Ahokas, H. 1979b. Cytoplasmic male sterility in barley. III. Maintenance of sterility and restoration of fertility in the msml cytoplasm. Euphytica 28:409-419.
Ahokas, H. and E. A.Hockett. 1980. Cytoplasmic male sterility in barley. VI. Tests on performance at two different latitudes. Crop Science (in preparation).
Hockett, E. A. and H. Ahokas. 1979. Male and female fertility levels of genetic male sterile barley grown at two different latitudes. Heriditas 91:65-71.