Associations between Vrs1 alleles and grain quality traits in spring barley Hordeum vulgare L.

摘要

Barley head row type is a major trait affecting end-use quality. 6-rowed forms emerged due to mutations in the Vrs1 gene in 2-rowed barleys. Whether barley is 2 (Vrs1) or 6 rowed (vrs1) directly affects a wide range of morphological traits related to seed yield and grain quality. Vrs1 has been cloned and encodes a homeodomain transcription factor with a linked leucine zipper motif. To test the association between Vrs1 alleles and grain quality, the Vrs1 alleles among a well-described collection of 81 spring barley accessions selected for divergence in head type and dry matter digestibility (DMD) were characterized. Results indicated that the majority of 2-rowed barleys have the Vrs1.b3-1 allele and the majority of 6-rowed barleys carry the vrs1.a1-8 allele. In comparison with 2-rowed barleys, 6-rowed barleys were more variable in grain hardness. This divergence in hardness values was associated with specific vrs1 alleles, with barley accessions carrying the less severe amino acid missense mutation VRS1.a3-1 isoform being softer and having higher DMD than those accessions carrying the more common VRS1.a1-1 amino acid frameshift isoform. It is suggested that the assignment of 6-rowed barley cultivars to different vrs1 allele groups may prove beneficial for the selection of specific grain-quality parameters.