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Elimination of chromosomes is a phenomenon widespread in distant hybrids. It ranges from the loss of one or two chromosomes to elimination of whole chromosome complement of one of the parents. Such elimination leads to the production of haploid plants, which then are treated with colchicine to double the chromosome number and to develop DH‑lines. Homozygosity of doubled haploids serves as a basis for their wide use in plant genetics and breeding. The use of this approach reduces the time required for obtaining homozygous lines by 5 years on the average. It leads to savings in human resources, energy and acreage. The development of the “bulbosum” method for haploid barley production had a strong influence on the chromosome engineering in cereals and its implementation in plant breeding. However, the method developed on that basis could not be used effectively for producing haploids of wheat, triticale, etc. because of Hordeum bulbosum L. pollen sensitivity to genes inhibiting wheat crossability (Kr genes). The crosses with Imperata cylindrica (L.) Raeusch. is an efficient alternative to the widely used wheat × maize and triticale × maize crosses due to abundant pollen supply within a longer time period, significantly higher frequency of embryos formation and haploid plants regeneration.

Gametic embryogenesis is one form of totipotency of plant cells, in which either male or female gametes are induced to form embryoids (sporophytes). Regeneration of haploid plants from embryoids and subsequent chromosome duplication result in doubled haploids and DH-lines. The production of haploids and doubled haploids (DHs) through gametic embryogenesis allows a single-stage development of complete homozygous lines from heterozygous plants. The development of effective haploid protocols to produce homozygous plants has a significant impact on plant breeding, shorting the time and costs required to establish new cultivars. There are several available methods to obtain haploids and DHs-lines, of which anther or isolated microspore culture in vitro are the most effective. Microspore embryogenesis is more commonly applied. This is in part because more male gametophytes are contained in a single anther compared to the single female gametophyte per embryo sac. Microspore embryogenesis is regarded as one of the most striking examples of plant cell totipotency. The switch of cultured microspores from gametophytic to sporophytic mode of development has been induced by stress treatments of various kinds applied to donor plants, inflorescences, buds, anthers or isolated microspores both in vivo and in vitro. Physical or chemical pretreatments (cold and heat shock, sugar starvation, colchicine, n-butanol, gametocydes) act as a trigger for inducing the sporophytic pathway, preventing the gametophytic pathway development of microspore. The recent investigations have revealed that cold pretreatment during microspore reprogramming acts rather as an anti-stress factor alleviating the real stress caused by nutrient starvation of anthers or microspores isolated from donor plants. Under stress pretreatment a vacuolated and polarized microspore transformed into a depolarized and dedifferentiated cell, which is an obligatory condition for reprogramming their development. We summarize data concerning the role of various stresses in the induction of microspore embryogenesis and possible mechanisms of their action at cellular and molecular levels. Identification of new stresses allows creating efficient protocols of doubled haploid production for end-user application in the breeding of many important crops.