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.

Implications of cytoplasmic male-sterility systems for development and deployment of pest resistant hybrids in cereals.

“…Hordeum vulgare acts as a perfect maintainer for this system, but fertility restorers have not been identified [97]. The two CMS, msm 1 and msm 2 have restorer genes [98][99][100][101], and Rfm1a gene restores the fertility of msm 1 CMS lines, but none of these are complete restorers. Locus msg50, with alleles [80]…”

New insights into genotypic thermodependency of cytoplasmic male sterility for hybrid barley breeding

“…Adoption of hybrid breeding in barley is hampered mainly by instability of the CMS system, which leads to spontaneous fertility restoration in CMS barley (in the absence of Rfm1). The exact reasons for this instability are still unknown, but it has been observed that environmental conditions can affect pollen development (Ahokas 1979, Hockett et al 1989, Abdel-Ghani et al 2013. While some authors reported a negative effect of high temperature on pollen development or pollen viability in barley (Sharma andReinbergs 1976, Sakata et al 2000), others mentioned an opposite effect in different crop species like sorghum (Downes and Marshall 1971) and pearl millet (Reddy and Reddi 1972).…”

“…B€ uckmann et al (2014, 2016) found a strong effect of low temperature on spontaneous fertility restoration in CMS maize. Besides temperature, the reaction to photoperiod can also influence spontaneous male fertility restoration in CMS barley (Hockett et al 1989). Moreover, drought stress was recognized as an influential factor on fertility restoration in sorghum (Gupta et al 2010).…”

“…The exact reasons for this instability are still unknown, but it has been observed that environmental conditions can affect pollen development (Ahokas , Hockett et al. , Abdel‐Ghani et al. ).…”

“…Besides temperature, the reaction to photoperiod can also influence spontaneous male fertility restoration in CMS barley (Hockett et al. ). Moreover, drought stress was recognized as an influential factor on fertility restoration in sorghum (Gupta et al.…”