Selling behavior of cytoplasmic male sterile barley in Norway and the United States*

Abstract

This research is needed to determine if adequate sterility can be maintained in cytoplasmic male sterile stocks used for the female parent of hybrid barley. We investigated the effect of environment, number of back-crosses, cultivars and cytoplasmic background on seed set under bags in Norway and the United States, at 61o N and 46o N latitude, respectively. Cultivars studied were all adapted to the northern plains of the U.S. These 12 cultivars as recurrent parents were backcrossed to the msml and msml cytoplasm and the recessive restorers from Hordeum vulgare ssp. spontaneum (C. Koch) Thellung. The maintenance of sterility in the msm rfmrfrn genotype decreases with additional number of backcrosses to the recurrent parent, and with cultivars originating from below 50o N latitude. Apparently, photoperiod influences maintenance of cytoplasmic male sterility since the sterility is more difficult to maintain at Bozeman which has shorter days. Maintenance of sterility was not as good in the greenhouse as in the field at As. It is more difficult to maintain sterility in the msml than the msml cytoplasm. For the production of the female row for hybrid barley it would be better to utilize the msml cytoplasm and backcross to cultivars which originate from above 50o N latitude. Numerous additive genes are probably responsible for the maintenance of sterility in the cytoplasmic male sterile stocks.