Intra-callus variability for rice blast resistance genes in Oryza sativa L. indicated by genetic analysis of androgenic doubled haploids

In vitro culture of cells and tissues of agricultural crops can be conditionally divided into two groups, those to generate a genetically modified initial breeding material and those for mass cloning of existing forms and varieties. Androgenesis in vitro makes it possible to redirect the microspore development from the gametophytic to the sporophytic pathway with the formation of doubled haploids (DHs) in diploid species or the fixation of dihaploids (polyhaploids) in tetraploid species for their wide use in plant breeding. The variability of plants derived from anther or microspore cultures of one donor plant has been studied to a greater extent at the genomic and chromosomal level, since researchers and breeders are primarily interested in spontaneous chromosome duplication and, as a result, completely homozygous fertile offspring. In this work, for the first time, the frequency of intra-callus genetic variability for Pi family blast resistance genes (two and three genes) was estimated using rice ( Oryza sativa L.) doubled haploids (DHs) obtained via androgenesis in vitro of hybrid plants. No significant increase in intra-callus genetic variability was shown with an increase in the number of detected genes. The intra-callus variability frequency in androgenesis in vitro in rice was studied in order to determine the genetic homogeneity degree of doubled haploids (DHs) from one anther. Studies were carried out on doubled haploids obtained in androgenesis in vitro of thirteen F1 hybrids and one F2 hybrid of rice O. sativa . Molecular genetic analysis of 1271 plants (83 callus lines) was performed to reveal resistance/susceptibility alleles of the genes Pi-z , Pi-b , Pi-1 , Pi-2 , Pi-ta for rice blast-resistance to Pyricularia oryzae Cav. [ Magnaporthe grisea (Hebert Barr.)]. In doubled haploids, one to four blast-resistance genes were identified depending on the presence of heterozygotes in the original hybrids. When determining one gene in DHs, the frequency of variable callus lines accounted for 24.0 %. For two genes, polymorphism occurs among 47.7 % of calli. For three genes, 62.5 % of callus lines were polymorphic. No more than four combinations of rice blast resistance gene alleles are present in one callus line. There are no differences in the monomorphic callus lines frequency detected for one, two and three genes (χ2 = 0.21-0.95, p = 0.33-0.65). With the same combination of two resistance gene alleles, up to 66 plants were formed, and with the same combination of three genes alleles, up to 18 plants were produced per callus line. There was no dependence of polymorphism on the number of doubled haploids in the callus line. The correlation coefficients between the number of DHs and the number of alleles for one, two and three genes in the combination accounted for r = -0.14, r = 0.25, and r = -0.35 (р function show_eabstract() { $('#eabstract1').hide(); $('#eabstract2').show(); $('#eabstract_expand').hide(); }