Allelic Variation at the Vernalization Genes Vrn‐A1, Vrn‐B1, Vrn‐D1, and Vrn‐B3 in Chinese Wheat Cultivars and Their Association with Growth Habit

Abstract

Information on the distribution of vernalization genes and their association with growth habit is crucial to understanding the adaptability of wheat (Triticum aestivum L.) cultivars to different environments. In this study, 278 Chinese wheat cultivars were characterized with molecular markers for the vernalization genes Vrn‐A1, ‐B1, ‐D1, and ‐B3 Heading time was evaluated in a greenhouse under long days without vernalizaton. The dominant Vrn‐D1 allele showed the highest frequency in the Chinese wheat cultivars (37.8%), followed by the dominant Vrn‐A1, ‐B1, and ‐B3 alleles. Ninety‐two winter cultivars carried recessive alleles of all four vernalization loci, whereas 172 spring genotypes contained at least one dominant Vrn allele. All cultivars released in the North China Plain Winter Wheat Zone were winter type. Winter (53.0%), spring (36.1%), and early‐heading (10.9%) cultivars were grown in the Yellow and Huai River Valley Winter Zone. Most of the spring genotypes from this zone carried only the dominant Vrn‐D1 allele, which was also predominant (64.1%) in the Middle and Lower Yangtze Valley Winter Zone and Southwestern Winter Wheat Zone. In three spring‐sown wheat zones, all cultivars were early‐heading spring types that frequently possessed the strongest dominant Vrn‐A1a allele and combinations with other dominant Vrn gene(s). The Vrn‐D1 allele is associated with the latest heading time, Vrn‐A1 the earliest, and Vrn‐B1 intermediate values. The information is important for breeding programs in countries interested in using Chinese wheats.

Identification of the VERNALIZATION 4 gene reveals the origin of spring growth habit in ancient wheats from South Asia

“…Among modern wheat varieties, the strong Vrn-A1a allele for early flowering is predominant in regions of very cold winters, where spring wheats are planted in the spring. By contrast, the weaker Vrn-B1a and VrnD1a alleles are present at higher frequencies in the Mediterranean climates where spring wheats are planted during the fall (45,59,60). These results provide an example of the selective forces that could have also operated on VRN-D4.…”

“…These two lines also differed from the other T. aestivum ssp. sphaerococcum accessions by the presence of the Vrn-D1a allele (SI Appendix, Table S5), which carries a large intron deletion that is associated with a spring growth habit and that is present at high frequency in China (45).…”

Association of functional nucleotide polymorphisms at DTH2 with the northward expansion of rice cultivation in Asia

“…Flowering time is one of the best-studied ecologically significant traits under natural or artificial selection for adaptation of plants to specific natural environments (1,2). However, only a few floweringtime genes that function in adaptation have been identified, and their underlying molecular mechanisms have been elucidated (4)(5)(6)(7)(8)(9)(10)(11)(12)(13). Among the flowering genes identified in Arabidopsis, only FRIGIDA and FLOWERING LOCUS C, two pivotal regulators of the vernalization pathway, show molecular hallmarks of natural selection, and the polymorphisms in these genes appear to underlie the extensive natural variation of flowering time for local adaptation (4,5).…”

“…Deciphering the molecular mechanisms underlying local adaptation of plants is of great interest not only to plant biologists and evolutionary biologists, but also to crop breeders because it could provide useful guidelines for identifying target genes for selection. In recent decades, several flowering genes involved in local adaptation have been identified, including FRIGIDA and FLOWERING LOCUS C in Arabidopsis; Dwarf8 in maize; Ppd-D1 in wheat (Triticum aestivum); EARLY MATURITY 8 in barley (Hordeum vulgare); vernalization genes VRN1-3 in wheat and barley; and FLOWERING LOCUS T (FT) in sunflower (Helianthus annuus) (4)(5)(6)(7)(8)(9)(10)(11)(12)(13). However, elucidating the adaptive genetic variation in flowering-time control and the underlying molecular mechanisms has remained a challenging task.…”

The expression patterns of threeVRNgenes in common wheat (Triticum aestivumL.) in response to vernalization

“…Common wheat, an allohexaploid, contains three homoeologous copies of VRN1, which are located on the long arms of chromosomes 5A, 5B and 5D, respectively (Yan et al 2003). Allelic variations in the three homoeologous genes (Vrn-A1, Vrn-B1 and Vrn-D1) are the main factors that determine vernalization requirements (Fu et al 2005;Loukoianov et al 2005;Zhang et al 2008). Recently, Zhang et al (2012) found that a single nucleotide variation in the promoter region of Vrn-D1 is associated with the vernalization response in common wheat.…”