Performance Tests of Cytoplasmic Male‐Sterile Barley at Two Different Latitudes1

Abstract

Unrestored and restored derivatives of msm1, a cytoplasmic male‐sterile barley (Hordeum vulgare L.), were investigated at 46 (Bozeman, Mont.) and 61° (Elimaki, Finland) N Lat. The isoline derivatives of ‘Adorra,’ HA 6‐33‐02, ‘Hankkija's Aapo,’ ‘Hankkija's Eero,’ Kindred’ (uc2), ‘Kuoreton,’ ‘Mari,’ ‘Olli,’ and ‘Tammi’ were maintainers of sterility in both the environments. The isoline derivative of ‘Pirkka’ permitted 0.3% selfing at Elimaki, but was a maintainer of sterility at Bozeman, where it had some anthers of normal appearance. The female fertility in msm1‐Addora was normal in both the environments. Adorra‐like derivatives, heterozygous for the restorer gene Rfmla, had normal seed set under bags (similar to those in normal Adorra) in both environments. Some of the restored derivatives with approximately 50% of their genotype wild barley (ssp. spontaneum) and heterozygous for either Rfm1a, Rfm1b, Rfm1c, or Rfm1d had a slightly lower fertility than the control at Elimaki. This decrease in fertility was attributed to the fast vegetative development of these plants at Elimaki, where they headed 27 to 33 days after emergence. The rapid development in these crosses with spontaneum barleys was probably caused by the long light periods of the season that are up to 24 hours at 61° N Lat. Our results indicated that the msm1‐Rfm1 system can be used in hybrid seed production under both environmental conditions.