Doubled haploid sugar beet: An integrated view of factors influencing the processes of gynogenesis and chromosome doubling

摘要

Haploid and doubled haploid plant production through unpollinated ovule culture, with diverse benefits and applications, is considered among the effective and advantageous breeding methods for sugar beet (Beta vulgaris L). Sugar beet is not responsive to androgenesis that is widely used for most plant species. It is a recalcitrant plant in vitro due to the very low spontaneous chromosome doubling and low gynogenesis rates. Thus, a steadily increasing gynogenesis efficiency has always been an important target. Given the lack of papers focusing on gynogenesis in sugar beet, this review covers haploid and doubled haploid production through ovule culture of unfertilized flowers as a practical method. Besides haploid and doubled haploid methods, factors affecting both gynogenesis and doubling rates are also reviewed. In addition, outlooks and possibilities for doubled haploid production are discussed, trying to capture the elusive concept of the factors applied and taking into account some of them, e.g. genotype, plant growth regulators, plant/explant physiology and growth condition, chemicals, in vitro and in vivo methods, and transgenic method. By providing enough information and new groundwork through novel and wide perspectives on factors affecting gynogenesis, it should be easier to collect knowledge useful for future research.