Alloplasmic lines of beets with new cytoplasm from the wild genus Beta patula

Abstract

The purpose of the study was to obtain new breeding genotypes containing a nuclear genome of a sugar beet sterility maintainer and sterile cytoplasm of wild beet ( Beta patula L.). The donors of a new sterile cytoplasm of B. patula plants were selected by the indirect cytological traits of cytoplasmic male sterility (CMS), especially pollen sterility, abnormal development of the anthers, mosaic patterns of anthers and flowers. The anthers were examined for morphological traits of pollen and microspore degeneration in CMS. During reciprocal crosses, (i) the expression of recessive alleles of the nuclear genes of the CMS sterility maintainers was analysed, (ii) the peculiarities of hybridisation of the experimental genotypes with sterile B. patula cytoplasm were studied, and (iii) the selection of linked genes for hypocotyl colour Rr and one-or two-year growth cycle Bb was carried out. The obtained backcross offspring of BC 3 S B. patula had 95% fertility, 100% CMS-0 type sterility, and sugar content between 19.5% and 21.5%. Recombination in the locus of linked genes of the one-and two-year growth cycles and hypocotyl colour RB rb in hybrids F 1 , B. patula and backcross offspring was detected. At the same time, the one-and two-year growth cycle in seed plants was restored only in the 4th cycle of backcross. Recombinant genotypes with a red hypocotyl and two-year growth cycle BC 3 S B. patula had multi-seed fruits, single or branched stems of seed plants and were chimerical by sterility (CMS-1 and CMS-0 types). The obtained alloplasmic introduced lines containing the cytoplasm of B. patula have economically valuable properties as parent components for the development of new triploid hybrids. The experimental triploid hybrids had root sugar content from 19.5% to 20.5% and dry matter content from 25% to 29%. Alloplasmic lines with the new CMS of B. patula are recommended for sugar beet breeding.