II. 35 Heterosis for yield and grain size in six-rowed winter x two-rowed spring barley F1 hydbrids.
J. Spunar, Research and Breeding Institute of Cereal Crops, Kromeriz, Havlickova 2787, Czechoslovakia.
In the year 1977, genetic studies dealing with the usage of 6-rowed barleys in breeding programs were started in our institute. Our attempts began by using six-rowed winter barley (H. vulgare) in hybridization with two-rowed spring barley (H. distichum). In the present time both these forms have reached highest yields under our ecological conditions.
In the year 1977, the first results from the manifestation of heterosis in Fl hybrids were obtained. The following material for the study has been used:
six-rowed winter barley - varieties (Mirag, Kiruna), strain/HVW 531/ two-rowed spring barley - varieties (Hassan, Spartain - new Czechoslovak variety released 1977), strain (NE 748). Parental spring forms and hybrid grain were sown to the pots (15 grains of each form and hybrid combination) and cultivated in a glasshouse from August to November. No parental winter forms have been sown since previous experience had shown that artificial vernalization unfavourably influence manifestation of yielding characters. The same fact was published by Fedak and Fejer (1975). At the harvest all plants were submitted to following analysis: Number of ears per plant, thousand grain weight per plant, total grain yield per plant.
In all 12 presented combinations (Table 1) complete dominance of two-rowed ear and spring growth habit has been established. Analysis of F1 generation has sown heterosis in grain yield per plant in 10 combinations and thousand grain weight in 8 combinations. In these hybrid combinations, highly significant differences in both characters in comparison with spring parents were determined. These results are in accordance with those of Tseng and Poehlmann (1974), Elliot and Poehlmann (1976) reached in six- x two-rowed spring barley hybrids.
On the base of these results we conclude, that heterosis in yield and thousand grain weight is due to the genetic divergence of six-rowed winter - and two-rowed spring barleys. Material used in this experiment has differences in genetic background as for three loci: Vv locus on chromosome 2, Ii on chromosome 4 and Sh on chromosome 7.
Heterosis in presented characters can be attributed to genes closely linked with Vv, Ii and Sh loci or direct on them. Gymer (1977) determined heterosis in grain weight in F2 generation and concluded that 6-rowed parents contribute genes for large grain.
Studies of Takahashi et al. (1976) have shown the possibility of obtaining high yielding two-rowed as well as six-rowed derivatives from crosses between two- and six-rowed cultivars. Effect of Sh locus on yield components was studied by Yasuda (1976). Strains with dominant genes (Sh2I, Sh2II ) for spring growth habit significantly outyielded the respective recurrent parents, regardless of genetic background, after their incorporation into two winter cultivars. On the other hand, Fejer and Fedak (1977) found, that in hybrids derived from spring and winter parents, a mean yield advantage of 5.8% over the spring parents was obtained. It is hoped to investigate this subject further in 1978 by studying F2's hybrids.
References:
Elliott, W.A. and J.M. Poehlman. 1975. Inheritance of kernel-weight in six-rowed x two-rowed barley crosses (Hordeum vulgare L. x H. distichum L.). Proceedings of III. Barley Genetics Symposium Garching: 678-685.
Fedak, G and S.O. Fejer. 1975. Yield advantage in F1 hybrids between spring and winter barley. Cand. J. Plant. Sci. 55:547-553.
Fejer, S.O. and G. Fedak. 1977. Genetic Analysis of hybrids between spring and winter barley. Z. Pflanzenzucht. 79:196-202.
Gymer, P.T. 1976. Heterosis for grain size in six-row x two-row F1 hybrids. BGN 6:30-33
Gymer, P.T. 1977. Heterosis for grain size in six-row x two-row F1 hybrids. 7:35-37.
Takahaski, R., J. Hayashi, and I. Moriya. 1975. Basic studies on breeding barley by the use of two-rowed and six-rowed varietal crosses. Proceedings of the III. International Barley Genetics Symposium, Garching, 662-667.
Tseng, Shu-Ten and J.M. Poehlman. 1974. Hybrid performance among six-rowed x two-rowed winter barley (Hordeum vulgare L. and Hordeum distichum L.). Theor. Appl. Genet. 44:294-303.
Yasuda, S. 1975. Effects of four different spring genes on earliness of heading grain yield and some yield components. Proceedings of the III. International Barley Genetics Symposium, Garching, 702.
