Oat haploids from wide hybridization

Abstract

Haploids of cultivated oat (Avena sativa L., 2n=6x=42) have been produced from wide hybridizations with Panicoidae species, particularly maize (Zea mays L.), by procedures similar to ones described for the production of wheat (Triticum sp.) haploids from wheat x maize hybridizations (Laurie and Bennett, 1988; Rines et al., 1997). As in wheat, oat haploid production by the maize wide cross method appears to be much less genotype restricted than haploid production by anther culture. However, in oat the plant recovery frequencies reported to date of 1–2% of florets maize-pollinated is much lower than that attained with wheat and, like for oat haploid production in oat anther culture (Kiviharju et al., 2000), not yet adequate for routine use in breeding. Also, there are important differences in the types and in the reproductive behavior of plants recovered in oat x maize compared to wheat x maize hybridizations. These include on occasion maize chromosome retention in the recovered oat plants and partial self-fertility in oat haploid plants (Riera-Lizarazu et al., 1996). These differences in products can be detrimental in trying to produce doubled haploids routinely for breeding, but on the plus side they have led to the recovery of valuable novel materials for genetic studies. The following protocols described for haploid and doubled haploid oat plant recovery and characterization are ones in our current use, but modifications in factors such as oat and maize genotype effects, post pollination treatment, embryo rescue medium hormone components, and plant growth conditions are being investigated in ours and other laboratories.