Submitted to: Journal of Plant Registrations
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/11/2007
Publication Date: 1/15/2008
Citation: Bregitzer, P.P., Raboy, V., Obert, D.E., Windes, J., Whitmore, J. 2008. Registration of 'Clearwater' Low-Phytate Hulless Spring Barley. Journal of Plant Registrations. 2: 1-4. Interpretive Summary: A new barley variety, Clearwater, developed by the U. S. Dept. of Agriculture's Agricultural Research Service, has been developed that is the first of a new class of barley that produces grain which is hulless and low in phytate. Hulless barley grain, which looks more similar to wheat than to normal, hulled barley, is desirable for certain types of animal rations. The phytate content--which is the where the majority of grain phosphorus is stored in barley grain--is reduced to about half of that in other cultivars, but total phosphorus levels remain the same. This is desirable because phytate cannot be digested by non-ruminant animals such as swine and fish, and the undigested phosphorus ultimately ends up as water pollution. In Clearwater, the extra phosphorus can be digested by the animal, reducing phosphorus pollution and also eliminating or reducing the need for expensive phosphorus supplements. This is the first cultivar to be released that is both hulless and low-phytate, and it is suitable for growth throughout the Intermountain West and the Pacific Northwest. The yield and other agronomic characteristics of Clearwater are competitive with other hulless barley cultivars.
Technical Abstract: 'Clearwater' is a spring two-rowed barley (Hordeum vulgare L.) developed by the Agricultural Research Service, U.S. Department of Agriculture, and the Idaho Agricultural Experiment Station. Clearwater was selected and released based on competitive agronomic performance in combination with low-phytate (LP), hulless grain. Clearwater derives from an BC2F3:4 selection from the cross 'Baronesse'*2/Pmut640//HB317. It was tested under the experimental designation 01ID435H. The parent Pmut640 is a sodium-azide generated mutant induced in the two-rowed malting cultivar Harrington. The mutation conferring reduced phytate in Pmut882 is believed to be allelic to lpa2-1, which results in a reduction of phytate (myo-inositol 1,2,3,4,5,6-hexakisphosphate) of approximately 40-50% and an increase in inorganic P of greater than 400%. Studies have shown that these changes are associated with increased feed quality and reduced environmental impacts when fed to non-ruminant animals, based on increased P digestibility and reduced fecal P content.