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Title: Registration of "Rex" Southern Long-Grain Rice

item SOLOMON, WALTER - Mississippi State Extension Service
item KANTER, DWIGHT - Mississippi State Extension Service
item WALKER, TIMOTHY - Mississippi State Extension Service
item BAIRD, III, GEORGE - Mississippi State Extension Service
item Scheffler, Brian
item LANFORD, LELAND - Mississippi State Extension Service
item SHAIFER, SANFRID - Mississippi State Extension Service

Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2011
Publication Date: 1/8/2012
Citation: Solomon, W.L., Kanter, D.G., Walker, T.W., Baird, III, G.E., Scheffler, B.E., Lanford, L.S., Shaifer, S. 2012. Registration of "Rex" Southern Long-Grain Rice. Journal of Plant Registrations. 6(1).

Interpretive Summary: This paper deals with the registration of the rice cultivar “Rex.” In the past 10 years the cultivar “Cocodrie” has been the industry standard for a popular conventional rice cultivar. In comparison to Cocodrie, Rex has stronger yield performance, enhanced lodging resistance and similar milling performance and disease resistance. In replicated trials the average percentage of lodging in Rex fields was less than 1% and was often below 0.5% which is vastly superior to Cocodrie which had averages in the range of 5-~7%. Furthermore, Rex produces a longer, wider and thicker milled whole grain which is generally preferred by the milling industry. While Rex is susceptible to the two diseases “rotten neck blast” and “sheath blight” it does carry levels of field tolerance that gives it advantage over similar susceptible cultivars. Rex should be a desirable cultivar for the southern U.S.A. rice production areas.

Technical Abstract: ‘Rex’ (Oryza sativa L.) (Reg. No. CV-136, PI 661111) is a conventional, southern, long-grain rice cultivar developed at the Mississippi Agricultural and Forestry Experiment Station, Delta Research and Extension Center, Stoneville, MS, and officially released in February 2010. Rex is a semidwarf cultivar with good straw strength, good standability, and good milling, and it exhibits exceptional and stable yield performance. Rex was tested in Arkansas, Louisiana, Mississippi, Missouri, and Texas in a total of 35 environments from 2006 to 2010. Averaged over the 35 replicated trials, Rex had an average grain yield of 10.16 t ha-1. Its consistency in grain yields across production sites and years can be contributed, in part, to its excellent straw strength as shown by a lodging incidence of less than 1% over the same number of environments. Furthermore, Rex averaged a whole milling yield of 579 g kg-1 and a total milling yield of 692 g kg-1. While Rex is susceptible to rotten neck blast [caused by Pyricularia grisea (Cooke) Sacc.] and sheath blight disease (caused by Rhizoctonia solani J.G. Kühn), its level of field tolerance has permitted its overall field performance to match or numerically exceed the performance of other similar susceptible varieties. Rex should be well adapted to the growing conditions found in the southern USA.