Creation of homozygous genetically marked sugar beet lines using haploinductors

Abstract

Goal. To develop a genetic model and search for haploinductor lines among interspecific hybrids of sugar beet and wild species of the genus Beta L. (Beta maritima and Beta patula), as well as apozygotic progeny of substituted dioecious pollen-sterile lines. To isolate haploinductor genotypes for differentiation of haploids in vivo by morphometric parameters and transfer of haploids to the digaploid level in vitro. Methods. The study was carried out using field (obtaining interspecific F1 hybrids between wild species Beta maritima and Beta patula, and sterility fixers of sugar beets; study of germination and uniformity in soil conditions of the breeding greenhouse complex, and selection of homozygous lines according to the marker color of the hypocotyl; hybridization of candidates for haploinductors of dominant homozygotes by grafted genes of the one-year development cycle B+ and hypocotyl color R+ with pollen-sterile lines with cytoplasmic male sterility (CMS) of different genetic origin), laboratory (methods of induction of haploids and digaploids using unripe seed rudiments for their selection in vitro and differentiation by marker color of the hypocotyl, morphometric method of isolation of haploids by the root length on the 2nd-3rd day of seed germination, cytological method using acetoorsein staining of meristem chromosomes, cytophotometric method for studying ploidy by the amount of nuclear DNA using Partec ploidy analyzer (Germany), method of isolation of digaploids in the process of clonal micro-multiplication using a ploidy analyzer), and statistical (determination of the error of representativeness mp by seed germination, germination energy, hypocotyl color to control the accuracy of the experiment) methods in the cytogenetics laboratory of the Institute of Bioenergy Crops and Sugar Beet (IBCSB), the apomixis and polyploidy laboratory of the Yaltushkiv Experimental Selection Station (YaESS) during 2017–2024. Results. For the use of interspecific hybridization, biotechnological methods of induction of haploids from hybrids of the first generation F1 and apomictic progeny of substituted lines, control genotype gaploinductors, dominant homozygotes by genes of the one-year cycle of development B+ and anthocyanin (red) color of hypocotyl R+ are distinguished. Genotypes gaploinductors (F1S maritima (Greece) plant No. 7 type ChS-II R+B+R+B+Y+Y+M+M+ 2n; VC2S maritima (Greece) A1:17 plant No. 2 type ChS-II R+B+R+B+Y+Y+M+M+; VC6S patula plant No. 5 type ChS-II R+B+R+B+Y+Y+M+M+; F1S maritima (France) clones No. Em/1-7 type ChS-II R+B+R+B+Y+Y+M+M+) were bred in vitro and rooted in conditions of vegetation containers of the IBCSB and the breeding greenhouse complex of YaESS. It was established that the frequency of matrocline haploidy in the selection number ChS-0 20-12 Beta vulgaris r-b-r-4YaESS at low germination (45%) of the hybrid seed in the case of crossing with haploinductors had the same value — 45 haploid seedlings, of which 42 — with green recessive color and 3 seedlings — with the presence of the dominant allele R+. The results of the analysis of the ability to matrocline haploidy in pollen-sterile lines of sugar beets were different and depended on the genotype of donor plants. Conclusions. A genetic model was developed, and candidates for haploinductors, interspecific hybrids, dominant homozygotes by genes of the one-year cycle of development, and the color of the hypocotyl R+ based on sterile cytoplasms Beta maritima and Beta patula were obtained. Candidates for haploinductors were evaluated by crossing with divisible pollen-sterile lines of YaESS and substituted lines with high tying of apozygotic seeds, identified by the green color of the hypocotyl. The yield of homozygous lines with recessive green color of the hypocotyl depended on the genotype of donor plants. It was established that stabilization from haploid and myxoploid to diploid levels could occur in vitro in the process of depositing and selection for ploidy without the action of colchicine, which greatly simplified the process of creating homozygous lines.