Haploidy in asparagus by anther culture

Abstract

Asparagus (Asparagus officinalis L., 2n = 2x = 20) is a seed-propagated herbaceous perennial vegetable grown for its tender spears that are harvested primarily in the spring in temperate climates. Due to dioecy, it is obligately cross-pollinating except for occasional self-pollination of perfect flowers that occur on andromonoecious plants (Ellison, 1986). Hybrid cultivars have been developed through double cross breeding schemes or by single crosses after tissue culture methods became available for rapid multiplication of parental clones. Propagation of hybrid asparagus by seed results in almost equal numbers of male and female plants and individual plants vary in yield ability (Ito & Currence, 1965; Tsay et al., 1980). Sex expression is under simple genetic control with maleness dominant to femaleness. Because male plants tend to be more productive than female plants, the potential of all-male hybrid cultivars has attracted the attention of many asparagus breeders. Haploids and doubled haploids can be efficiently utilized to realize such breeding schemes. Anther culture allows the rapid production of haploids and subsequent chromosome doubling can lead to completely homozygous diploid male (YY) or female (XX) plants. Homogeneous all male F1 hybrids can then be obtained by crossing homozygous female and supermale parents (Cateland & Lambert, 1973; Corriols, 1979, 1985; Corriols et al., 1990; Doré, 1974, 1979a,b; Falavigna, 1979; Falavigna et al., 1990; Hondelmann & Wilberg, 1973; Pelletier et al., 1972; Rameau, 1990; Raquin, 1973; Reuther, 1984; Price & Baughan, 1990; Sink & Padmanabhan, 1977; Tsay et al., 1980, 1982a,b; Tsay & Hsu, 1985; Wricke, 1979; Yakuwa et al., 1972). The first hybrid cultivar resulting from a single cross between two selected doubled haploids, one derived by anther culture and the other derived parthenogenically, was released recently (Corriols et al., 1990).KeywordsCallus InductionCallus FormationAnther CultureChromosome DoublingHaploid PlantThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.