Production of Spontaneously Doubled Haploids for Breeding
The utility of haploids in plant breeding eventually requires production of doubled haploids (DH) as discussed above. For this purpose, often efficient colchicines treatments are applied and colchicines doubled haploids (CDH) are obtained. In a system where haploids are detected through genetic markers, we can also identify the spontaneously doubled haploids (SDH), if doubling of chromosomes does occur spontaneously. This will avoid unnecessary colchicines treatment and the breeder can save time and plant material.

Although there are several reports of SDHs produced during haploid production, but at Svalov in Sweden, hap gene was utilized, not only for the production of haploids, but also for the production of SDHs (Hagberg and Hagberg, 1987). It utilized a marker gene system for mildew resistance due to an allele (ml-o), which is recessive to susceptibility allele (Ml-o).

The marker ml-o is suitable, because it allows screening at the seedling stage, but other gene pairs like K-k (hooded (vs normal awns) or V-v (two row vs six row ears) can also be used in barley. It is expected that more work in this direction will be carried out in future to make SDH production system useful to the breeders and cytogeneticists.