Monday, 7 November 2005
7

Rice Yield Components as Affected by Cultivar and Seeding Rate.

Brian V. Ottis, University of Missouri - Columbia, Delta Research Center, P.O. Box 160, Portageville, MO 63873 and Ronald E. Talbert, University of Arkansas, 1366 W. Altheimer Drive, Fayetteville, AR 72704.

New rice cultivars have been released that have yield potential greater than 10,000 kg ha-1. Some of these new cultivars have increased costs associated with them due to patented traits and hybrid technology. It is not well understood how these new, high-yielding cultivars respond to various rice plant densities and if currently recommended seeding rates are required to obtain maximum yield. Therefore, the objectives of this research were to determine the effects of rice seeding rates and on yield components of three popular long-grain rice cultivars near Stuttgart, AR, in 2002 through 2004. The main effect of seeding rate was not significant for rice biomass, panicle density, harvest index (HI), or rice yield, regardless of cultivar. ‘Wells' produced higher panicle weights and had a higher harvest index than ‘CL161' at seeding rates of 52, 104, 208, and 416 seeds m-2. ‘XL8' and Wells produced similar yields, and were higher than CL161 across the four seeding rates. Cultivar, rice density, and thermal time were significant factors affecting rice canopy closure. XL8 achieved canopy closure sooner than CL161 or Wells. As rice density increased, canopy closure increased by 3% for every additional 100 plants m-2. As thermal time increased, canopy closure increased 0.4% oCd-1. Results from this study indicated that recommended seeding rates for CL161, Wells, and XL8 can be reduced while still maintaining maximum yield potential.

Back to Agricultural Systems: Weeds, Seeding Rates, and Planting Date
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Back to The ASA-CSSA-SSSA International Annual Meetings (November 6-10, 2005)