In vitro gynogenesis in Beta vulgaris L.: Effects of plant growth regulators,temperature, genotypes and season

In order to increase the yield of haploid sugarbeet plants obtained from in vitro culture of unfertilized ovules, we have studied several factors: (1) the nature and concentration of various growth hormones, (2) the temperature for the cultured ovules, (3) genotypes and (4) seasonal effects. We found N6 medium [7] supplemented with 2.85 M of indoleacetic acid (IAA) and 0.88 M of 6-benzylaminopurine (BAP) or N6 medium containing 2.3 M of kinetin (KIN) to give the best qualitative and quantitative results for the culture of ovules. A two-step process for the induction and the development of gynogenic embryos was used. For the initiation of the embryos from the cultured ovules, the temperature of 27°C was favoured to that of 24°C. A pronounced and very significant seasonal effect was observed; the month of June was favoured to that of the other summer months tested. The effect of genotype was significant only for certain media. Using the above concentrations and combinations, a yield of viable gynogenic plants (plants/100 cultured ovules) between 6 and 10% (depending on the genotype) was obtained. In each case, 81% of these were haploids.