The spontaneous diploidization rates in oilseed rape (Brassica napus L.) via in vitro androgenesis are too low for practical applications. In contrast, artificial doubling of chromosomes of the microspore has proven to be more successful and allows homozygous plants to be obtained in a short time. Here, we present the efficiency of diploidization of B. napus haploids using three different chromosome doubling methods.

Using the in vitro approach in microspores, the rate of chromosome doubling in 24 populations of androgenic plants ranged from 15.8% to 94.0%. An alternative in vivo method for the induction of chromosome doubling involves colchicine treatment of young haploid plants, and this yielded doubling rates ranging from 47.5% to 86.4% in 10 different plant populations. Another in vivo method of chromosome doubling is colchicine treatment of the excised young axillary shoots of haploid plants at the early flowering stage. The high efficiency of this method was confirmed in haploid plant populations from 11 genetically distinct donors in which the frequency of occurrence of diploids ranged from 53.3% to 100%. However, in this case, the time required for seed formation from doubled haploids increased by about 3–5 months. The availability of several methods of chromosome doubling at various stages of the androgenic process – from isolated microspores through to young plants and flowering plants – allows seeds to be obtained from nearly every selected individual haploid.

Our study involved the first-ever evaluation of the performance of anther culture and wheat × maize hybridization techniques in producing haploids or doubled haploids as a result of spontaneous doubling of the chromosome number during androgenesis in plants from 30 wheat genotypes including ancient, local and modern types. The results indicated that the best induction rates of androgenic structures and haploid embryos for the hexaploid and tetraploid wheat genotypes were obtained with anther culture and wheat × maize hybridization, respectively. Whereas only one regenerated plant from 15 genotypes of tetraploid wheat was obtained, 13 plants were regenerated from 15 genotypes of hexaploid wheat. Moreover, haploid embryos obtained in wheat × maize hybridization 60 and 100% green plants regenerated in relation to the number of the cultured haploid embryos. Genotypes with high induction capacity to produce androgenic structure or haploid embryos did not have desired haploid plantlets regeneration capacity and vice-versa. However, with both methods, hexaploid wheat genotypes had a considerable ability to produce green plants. Doubled haploid plants were obtained from ancient and local wheat genotypes by both methods, but not from modern wheat. Those genotypes can be used as parents in future wheat breeding programs and new varieties may be obtained by selecting pure lines in wheat populations

Using in vitro androgenesis serves as a unique opportunity to produce doubled haploid (DH) plants in many species. More benefits of this biological phenomenon have kept these methods in the focus of fundamental research and crop breeding for decades. In common wheat (Triticum aestivum L.), in vitro anther culture is one of the most frequently applied DH plant production methods. The efficiency of in vitro wheat anther culture is influenced by many factors, such as the genotype, growing conditions, collection time, pre-treatments, and compositions of media and culture conditions. According to some critical review, the genotype dependency, low efficiency and albinism are mentioned as limitations of application of the anther culture method. However, some research groups have made significant efforts to diminish the effects of these bottlenecks. Due to the improvements, a well-established in vitro anther culture method can be an efficient tool in modern wheat breeding programs.

Rye is an important crop widely cultivated in Europe, but one of the hardest to improve due to its allogamy and self-incompatibility. The market for rye-based products is constantly growing thanks to the popularity of organic farming, feed production and diverse industry applications. To address these demands, new highly productive hybrid rye varieties are needed. Currently, full potential of heterosis in rye breeding is hard to reach due to the limited success in in vitro cultures. This review summarizes the progress in rye in vitro cultures and proposes novel approaches to overcome recalcitrance in this species.

Using doubled haploid technologies inbreeding can significantly reduce the time to obtain homozygous parental lines required for the production of F1-hybrid of vegetable crops. This study aims to investigate the influence of factors on the efficiency of carrot embryogenesis in isolated microspore culture to optimise the elements of protocol for producing doubled haploids. Microspores were isolated from inflorescences of 21 genotypes and incubated in NLN13 medium supplemented with 0.1 mg·dm ^–3 2,4-dichlorophenoxyacetic acids, 0.1 mg·dm ^–3 1-naphthyl acetic acids, 130 g·dm ^–3 sucrose, and 400 mg·dm ^–3 casein hydrolysate and its modifications. Embryoids and their groups were formed after 2–6 months, in some cases after 12 months of cultivation. Depending on the variant, the embryogenesis efficiency averaged from 0 to 4.9 embryoids or groups of embryoids per Petri dish (10 cm ³). Embryoids within the group were formed from different microspores. No significant effects of inflorescence position on the plant (branching order), sucrose, and casein hydrolysate concentration in the medium were observed. Significant advantages (p ≥ 0.05) for some genotypes were shown: 1) microspore suspension density 4·104 cells·cm ^–3 (5.0 embryoids per Petri dish were formed at a microspore suspension density of 4·104 cells·cm ^–3, 0.0 embryoids per Petri dish at a density of 8·104 cells·cm ^–3); 2) cultivating microspores of tetrad and early mononuclear stage (4.9 ±3.1 embryoids per Petri dish were obtained by culturing tetrads and early mononuclear microspores, while 0.6 ±0.7 embryoids per Petri dish were obtained by culturing of later developmental stages); 3) high-temperature treatment duration of five days (4.9 ±2.1 embryoids per Petri dish were obtained after five days of high-temperature treatment, 2.7 ±2.6 embryoids per Petri dish formed after two days of high-temperature treatment; 9.8 ±4.7, 10.1 ±6.1, 0.0 ±0.0 embryoids per Petri dish formed after two, five and eight days of high-temperature treatment respectively); 4) adding colchicine 0.5 mg·dm ^–3 to the nutrient medium for two days of high-temperature treatment, followed by medium replacement (3.3 ±2.6 embryoids per Petri dish were obtained by using a nutrient medium with colchicine, while 1.7 ±1.5 embryoids per Petri dish were obtained by culturing in the reference variant).