Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2007
Publication Date: 5/1/2008
Citation: Turuspekov, Y., Beecher, B.S., Darlington, Y., Bowman, J., Blake, T., Giroux, M. 2008. Hardness locus sequence variation and endosperm texture in spring barley. Crop Science 48:1007-1019. Interpretive Summary: The texture, or hardness of cereal grains has a tremendous impact upon their suitablity for various end-uses. The importance of endosperm texture differences is well established and best characterized in wheat, where wheat is marketed according to whether the grain is 'hard' or 'soft'. Barley is a cereal grain related to wheat that also varies somewhat in endosperm texture. However the degree of textural variation in barley is much less than that of wheat. Further modification of barley endosperm texture is believed to be advantageous to improving barley for end uses, such as improved feed quality. The genes controlling endosperm texture in wheat and barley have been identified. This study found that these genes vary greatly in barley varieties from diverse locations.
Technical Abstract: Grain texture is an important quality parameter in both wheat and barley. Cultivars with good malting quality tend to be softer than their poor malting counterparts. Harder textured barley seeds with lower dry matter digestibility may potentially be better in feed quality for beef cattle. Most grain textural variation in wheat is controlled by small, basic proteins called puroindolines (PINA and PINB). Small differences in puroindoline sequence can have large effects upon wheat hardness. The barley puroindoline homologs, the hordoindolines have been implicated in barley textural control. The hardness (Ha) locus in barley consists of Hina, Hinb-1, Hinb-2, and GSP tightly linked on short arm of chromosome 5H. In this study, eighty one barley accessions from diverse backgrounds were analyzed for hardness, ruminant digestibility, and haplotypes of hina, hinb-1, hinb-2, and GSP. When individual samples were grouped in alleles and haplotypes, ANOVA indicated that allele GSP-3 was significantly associated with grain hardness, and most common alleles of HINA, HINB-1, and HINB-2 were significantly associated with dry matter digestibility. When alleles of four genes grouped with accordance to a number of non-conservative changes that compared to wheat sequences, one-tail t-test suggested that Hina was significantly related to grain hardness, and Hina and Hinb-2 were significantly associated with dry matter digestibility. A negative correlation exists between barley grain hardness and ruminant dry matter digestibility. The results of this study indicate that a greater degree of genetic control of barley grain texture may be available than was previously thought. Variation in genes of Ha locus can be exploited as a useful tool for improving the food and feed value for this important grain species.