Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 29, 2004
Publication Date: February 1, 2005
Citation: Gealy, D.R., Black, H.L., Moldenhauer, K.A. 2005. Challenges in developing commercially acceptable weed suppressive rice cultivars for the southern U.S. [abstract]. Rice Technical Working Group Meeting Proceedings. Abstract p. 196 Technical Abstract: Weed control remains a key challenge to profitable rice production systems in the U.S. In previous screening efforts, rice cultivars (e.g. PI 312777 and PI 338046) with good to excellent weed suppressive characteristics were identified from world rice collections as potential components of reduced herbicide systems. Although grain yields and weed suppression levels for these lines have sometimes been promising, other agronomic characteristics and grain quality characteristics generally have not been commercially acceptable. Thus, a rice-breeding program was initiated to combine the desirable grain quality and agronomic characteristics of 'Katy' commercial rice with the weed suppression potential of PI 338046 and PI 312777. In drill-seeded field plots, F5 (??) or later generations of PI 338046/Katy crosses and PI 312777/(PI 338046/Katy) crosses were evaluated along with the original parental lines as well as additional commercial and weed suppressive rice standards. Plots were sprayed post emergence with 1 kg ha-1 propanil, one fourth of the standard use rate. Plant height, days to heading, tiller production, grain yield, milling quality, lodging potential, and visual control of barnyardgrass were among the characteristics evaluated. Certain selections from these original crosses produced commercially acceptable yields and moderately elevated levels of weed suppression. However, these selections generally yielded less and suppressed barnyardgrass less than did their respective commercial, and suppressive cultivar parents.