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Pea (Pisum sativum L.) is a species for which there is no efficient method for the recovery of haploid plants yet. This research investigated the influence of various genotypes, nutrient media, and stress treatments on callus formation, embryogenesis and plant regeneration in anther cultures of pea. A wide range of pea genotypes and nutrient media was studied. Morphogenic calli were initiated on media supplemented with α-naphthaleneacetic acid (NAA), 6-benzyladenine (BA), and 2,4-dichlorophenoxyacetic acid (2,4-D) without application of stress treatments. Embryogenic calli and embryos were regenerated on media with low sucrose content in the presence of 2,4-D or indole-3-butyric acid (IBA) after cold stress (4°C) of isolated buds, alone or in combination with in vitro treatment of isolated anthers at higher temperatures (35-38°C). The efficiency of regeneration via shoot morphogenesis on different nutrient media and the peculiarities of regeneration from embryogenic calli were investigated. Green embryogenic calli initiated on 2,4-D were able to develop through shoot morphogenesis on a medium supplemented with BA and NAA. This process led to regeneration of hypertrophic embryos at various developmental stages. The origin of regenerated plants (i.e. from microspores or somatic anther cells) was estimated using marker alleles determining morphological traits. Almost all R 0 regenerants derived from morphogenic calli originated from anther somatic cells.

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Wildlife pea specimen P. fulvum i-609881 of the UIP collection (Saint Petersburg, Russia) in a greenhouse box has demonstrated full resistance to powdery mildew. As a result of crossing with cultivated peas, interspecific hybrids of Stabil × i-6098881 were obtained. In populations of interspecific hybrids, the BC2F3 Stabil × i-609881 line of the leafless morphotype (af), resistant to the powdery mildew pathogen, was isolated as a result of backcrossing. As a result of crossing plants of this line with susceptible plants of the leafy (Af) variety Temp, the following series of pea hybrids was obtained. Analysis of F1 hybrids showed that all plants were characterized by resistance to the pathogen powdery mildew. In the population of F2 hybrids, a splitting analysis was performed on the basis of resistance to powdery mildew. The analysis revealed that the hybrid population consisted of 66 resistant and 20 affected plants. The actual splitting corresponded to the expected one for monogenic inheritance with a phenotype ratio of 3: 1 phenotype ratio (η05 2 test, p=0.7087438). Based on the analysis of populations of F1 and F2 hybrids, it is concluded that resistance to powdery mildew is the result of introgression of the genetic resistance factor from the genome of the P. fulvum i-609881 sample and is encoded by the dominant allele of a single gene.

Electrophoretic spectra of storage proteins in parental plants and interspecific F 1 and F 2 hybrids Pisum sativum × Pisum fulvum have been studied. Correspondence between the polymorphism levels of pro tein components among the species and within the species P. sativum was established. Accessions of P. fulvum I609881 and I609885 manifested low polymorphism. Storage proteins of both parents were observed in spec tra of F 1 hybrids. F 2 hybrids segregated at a limited set of bands. Accession I609881 of P. fulvum is character ized by unique band 7, which was inherited in F 1 .