Composition and random elimination of paternal chromosomes in a large population of wheat × barley (Triticum aestivum L. × Hordeum vulgare L.) hybrids

Abstract

Key message Statistical analysis of the chromosomal composition in a population of 210 primary plants regenerated from two intergeneric wheat–barley cross combinations revealed the random nature of uniparental elimination for barley chromosomes. Abstract Uniparental chromosome elimination is a common process in interspecific and intergeneric cereal hybrids. To characterize the frequency of paternal chromosomes, a population of 218 independent green plants was generated from two wheat (♀) × barley (♂) cross combinations via embryo rescue. The chromosomal composition of 210 primary plants was analyzed with chromosome-specific DNA markers representing all seven barley chromosomes. The analysis revealed an equal proportion of haploid and full hybrids (20.5% and 19.5%, respectively), while the rest of the population contained hypoploids (partial hybrids) with no preference for any possible numbers (one to six) of barley chromosome additions. Contrary to the previous reports, there was no statistical bias or preferential elimination for any individual barley chromosome (1H–7H) in this population. The reasons for the apparent contradiction and the implications of the above findings for cereal breeding are discussed. Electronic supplementary material The online version of this article (10.1007/s00299-019-02405-1) contains supplementary material, which is available to authorized users.

Molecular characterization of intergeneric hybrids between Malus and Pyrus

“…When Polgári et al 34 where both parents are diploid with the same chromosome number 2n=34, while B. napus (2n=38) is tetraploid and L. fendleri is diploid (2n=12). Similarly, wheat (2n=42) is hexaploid and barley (2n=14) is diploid.…”

Exploration of incompatible crosses in plants for novel and useful variations

“…Xu et al (2019) used SRAP markers to identify the paternal introgressions and novel DNA bands in the intergeneric hybrids of Brassica rapa and Orychophragmus violaceus . Chromosome‐specific STS, SSR, and gene‐specific markers, one for each of all seven barley chromosomes, were used in a population of 210 intergeneric wheat–barley cross derivatives, which revealed random nature of uniparental elimination for barley chromosomes without preferential elimination for any individual barley chromosome (Polgári et al, 2019). Amplified fragment length polymorphism (AFLP) pattern of the parents and hybrids have identified new bands in hybrids (Shan et al, 2005; Zhang et al, 2013).…”

“…The somatic metaphase chromosome karyotype of Brassica × Raphanus lines was assessed by FISH while meiotic pairing behaviour and meiotic abnormalities was assessed by GISH (Belandres et al, 2019; Silva et al, 2018). Polgári et al (2019) used GISH in young roots from tillering wheat × barley hybrid plants including both haploids and hypoploids that showed additional barley chromosomes and no translocations. GISH in the rare F 1 hybrid between Narenga porphyrocoma and Erianthus rockii was studied in mitotic metaphase stage, which showed n + n transmission of equal chromosomes from both parents (Chang et al, 2020).…”

Karyotype Reorganization in Wheat–Rye Hybrids Obtained via Unreduced Gametes: Is There a Limit to the Chromosome Number in Triticale?

“…One reason for the absence of rye chromosomes from F 2 might be their elimination in hybrid embryogenesis [69]. Alien chromosome elimination has been reported in crosses of wheat with Secale cereale, species of genus Hordeum, and species more distantly related to wheat, such as maize (Zea mays), pearl millet (Pennisetum glaucum), sorghum (Sorghum bicolor), and Imperata cylindrica [83][84][85][86][87][88][89][90][91][92][93][94][95][96][97]. The preferred elimination of wheat D-genome chromosomes in the first generations after synthetic wheat (BBAADD) × rye (RR) hybridization was also observed, and an F 2 seedling carrying 48 chromosomes was observed [56].…”