Abstract
Research efforts aimed at producing haploid plants by tissue culture of anthers or isolated pollen grains have increased recently. Likewise, the ability of the plant breeder to utilize haploid plants in the breeding program has added a new dimension and possible efficiency to the manner in which horticultural crops can be genetically improved. This review will discuss the recent progress that has been made in the art and science of anther and pollen culture to produce haploid plants and the potential for use by horticultural plant breeders. Previous reviews on this subject have been published by Bottino (12), DeBerg (24), Kimber and Riley (49), Melchers (57, 58), Smith (87), Sunderland (89) and the publication Haploids in Higher Plants – Advances and Potential from the first international symposium held in this area of plant biology, at Guelph, Ontario in 1974.
To produce nonaploid Japanese persimmon (Diospyros kaki L.f.) by artificial hybridization, we surveyed the natural occurrence of unreduced (2n) pollen among hexaploid cultivars and sorted them from normal reduced (n) pollen. The sorted 2n pollen was crossed with a hexaploid female cultivar and the resultant embryos were rescued by in vitro culture techniques to obtain plantlets. Three out of six male-flower-bearing cultivars (2n = 6x = 90) produced 2n pollen at rates of 4.8% to 15.5% varying with the cultivar, which was estimated by both pollen size and flow cytometry. After sorting giant (2n) from normal pollen grains by using nylon mesh, they were crossed with a hexaploid female cultivar. The seeds obtained from pollination with normal pollen were perfect, but those obtained from pollination with giant pollen were mostly imperfect, with embryo growth being suspended at the globular stage. Although the rate of survival was very low, some embryos at the globular stage were rescued successfully and grown in vitro. Both flow cytometric analysis and chromosome counting proved that the plantlets obtained were nonaploid.
pollen culture system to provide a stable environment for pollen grain growth and succeeded in simulating SI-like responses in vitro using stylar crude protein extracts ( Uchida et al., 2012 ). A high inhibition rate was observed after incompatible
merit realization in commercial fruit culture, when feasible. In conclusion, it can be mentioned that ‘Arka Sahan’ growers can expect better economic returns by hand pollinating with A. squamosa pollen because it gives the best fruit set, size, and
-compatible to SI 3 to 5 d before anthesis ( Uchida et al., 2012b ). Moreover, for investigation of Citrus pollen tubes, we have established an in vitro pollen culture system ( Uchida et al., 2012a ) and an in vitro SI-like reaction system using the stylar
the existence of thousands of microspores in an anther, and the possibility to obtain numerous haploid plants from an anther. Several factors affect embryo regeneration in anther culture. These factors include genotype, age of donor plant, pollen
, the first approaches were conducted to produce doubled haploids in apple by in vitro anther culture ( Nakayama et al., 1972 ). Since then, various homozygous genotypes induction methods such as in vitro anther culture and in situ parthenogenesis in
ornamentals mentioned previously. Santonia ‘Golden Light’, an intergeneric hybrid cultivar of S . aurantiaca × L . modesta , has already been developed through ovule culture ( Clark et al., 2005 ; Eason et al., 2001 ; Morgan et al., 2001 , 2003 ). This
barriers exist to conventional breeding methods ( Donini and Sonnino, 1998 ). Although in vitro culture alone has produced many spontaneous mutations or somaclonal variants ( Veilleux and Johnson, 1998 ), the use of chemical mutagens combined with in vitro
problems associated with use of antimitotic drugs. Stöldt (1994) proposed that in vitro tissue culture could be used to induce spontaneous separation of chimeric tissues. Keller and Korzum (1996) speculated that diploid segments are present within