Submitted to: Arkansas Experiment Station Research Series
Publication Type: Experiment Station
Publication Acceptance Date: 8/1/2001
Publication Date: N/A
Citation: Interpretive Summary: Interpretive summary not required.
Technical Abstract: The 1999 test for the evaluation of straighthead in U.S. cultivars and foreign germplasm accessions, the relationship of straighthead, grain yield, plant height and heading with arsenic and nitrogen fertilization was repeated in 2000. As in 1999, Cocodrie, Kaybonnet, Bengal and Mars were the most susceptible to straighthead. Priscilla and Jefferson were the most tolerant to straighthead, followed by Cypress, Drew, Wells, LaGrue an Japan 92.09.31. Zhe 733, a Chinese germplasm accession, was almost immune to straighthead. Arsenic applied as MSMA was essentially responsiblle for straighthead as suggested by significant correlation coefficients with straighthead rating (r=0.50) and grain yield (r=-0.55). Arsenic reduced plant height (r=-0.32) more than it delayed heading (r=0.16). As straighthead rating increased, grain yield was reduced (r=-0.90), plant height was reduced (r=-0.34), and heading was delayed (r=0.62). Within the erange of nitrogen fertilization in the test, increasing nitrogen rate intended to reduce the severity of straighthead. In the 2000 Straighthead Uniform Rice Nursery Test the average straighthead ratings of the advanced breeding lines from Arkansas, Louisiana, Mississippi and Texas were 7.3, 7.5, 7.1,and 6.7, respectively. Seven elite lines from the Arkansas breeding program had straighthead ratings of 6.0 or less.