Biotechnological Methods for Buckwheat Breeding

Abstract

The Fagopyrum genus includes two cultivated species, namely common buckwheat (F. esculentum Moench) and Tartary buckwheat (F. tataricum Gaertn.), and more than 25 wild buckwheat species. The goal of breeders is to improve the properties of cultivated buckwheat with methods of classical breeding, with the support of biotechnological methods or a combination of both. In this paper, we reviewed the possibility to use transcriptomics, genomics, interspecific hybridization, tissue cultures and plant regeneration, molecular markers, genetic transformation, and genome editing to aid in both the breeding of buckwheat and in the identification and production of metabolites important for preserving human health. The key problems in buckwheat breeding are the unknown mode of inheritance of most traits, associated with crop yield and the synthesis of medicinal compounds, low seed yield, shedding of seeds, differential flowering and seed set on branches, and unknown action of genes responsible for the synthesis of buckwheat metabolites of pharmaceutical and medicinal interest.

Keywords: genomics; interspecific hybridization; metabolites; molecular markers; tissue cultures; transcriptomics.

Figure 1

Morphology of flowers and cross-pollination between pin and thrum plants of Fagopyrum esculentum: left—thrum (Ss), short-styled and long anther and right—pin (ss), long-styled and short anther. The arrows show compatible cross-pollination.

Figure 2

Integrative genomics and breeding approaches for accelerated genetic improvement of buckwheat: GM—genetically modified, AB-QTL—advanced backcross quantitative trait locus, MAS—marker assisted selection, MARS—marker assisted recurrent selection, GWAS—genome wide association study, OMICS—refers to a field in biological sciences, such as genomics, transcriptomics, proteomics, and metabolomics, GBS—genotyping by sequencing, GS—genomic selection, SNP—single nucleotide polymorphism.

Figure 3

Genetic structure of hemizygous plant T0 and after self-pollination of the resulting progeny T1. Transformed plants regenerated from callus, or after in planta transformation of germinating seedlings, are termed T0 plants. T0 plants are always hemizygous, meaning that there is a copy of the transgene at a novel locus in the plant genome; the DNA gets integrated into one chromosome, but not the homolog at the same locus. T0 plants produce T1 seeds, which in turn develop into T1 plants that carry the transgene in either a hemizygous, homozygous positive, or homozygous negative state in an expected 2:1:1 Mendelian ratio if there is a single copy insertion of the transgene.