Competition of Spreading Dayflower (Commelina diffusa) with Rice(Oryza sativa)

Weed Science ◽  
1984 ◽  
Vol 32 (1) ◽  
pp. 116-119 ◽  
Author(s):  
Roy J. Smith
Keyword(s):  
Oryza Sativa ◽  
Rice Yield ◽  
Paddy Rice ◽  
Rice Seed ◽  
Head Rice ◽  
Rough Rice ◽  
Rice Yields

Rough-rice yield of drill-seeded paddy rice (Oryza sativaL. ‘Lebonnet’ and ‘Starbonnet’) at stands of 215 to 270 plants/m2at Stuttgart, Arkansas were reduced 18% by season-long competition of spreading dayflower (Commelina diffusaBurm. f. ♯3COMDI) at a density of 22 plants/m2. Competition durations of 20, 40, 60, or 80 days did not reduce rice yields. None of the durations of competition affected head-rice yields (percent whole milled kernels) or germination of rice seed.

Competition of Bearded Sprangletop (Leptochloa fascicularis) with Rice (Oryza sativa)

Weed Science ◽  
1983 ◽  
Vol 31 (1) ◽  
pp. 120-123 ◽  
Author(s):  
Roy J. Smith
Keyword(s):  
Oryza Sativa ◽  
Grain Yield ◽  
Paddy Rice ◽  
Rice Grain ◽  
Rice Seed ◽  
Weed Density ◽  
Weed Plant ◽  
Linear Decrease ◽  
Head Rice ◽  
Rice Yields

Yields of drill-seeded paddy rice (Oryza sativaL. ‘Lebonnet’) at optimum stands of 215 to 270 plants/m2at Stuttgart, Arkansas, were reduced 9, 18, 20, and 36% by bearded sprangletop [Leptochloa fascicularis(Lam.) Gray] densities of 11, 22, 54, and 108 plants/m2, respectively. There was a linear decrease in rice grain yield of 21 kg/ha for each bearded sprangletop plant per square meter. Weed densities of 54 and 108 plants/m2reduced head-rice yields (whole milled kernels) and a density of 108 plants/m2reduced germination of rice seed. The number of bearded sprangletop panicles produced per weed plant decreased as the weed density increased.

Broadleaf Signalgrass (Brachiaria platyphylla) Duration of Interference in Rice (Oryza sativa)

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 747-750 ◽  
Author(s):  
John T. McGregor ◽  
Roy J. Smith ◽  
Ronald E. Talbert
Keyword(s):  
Rice Yield ◽  
Dry Weight ◽  
Kernel Weight ◽  
Rough Kernel ◽  
Weed Interference ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield ◽  
Rice Yields ◽  
Brachiaria Platyphylla

Interference from broadleaf signalgrass at a density of 180 plants/m2reduced rough rice yields of ‘Bond’ a maximum of 48% at 95 days after rice emergence and reduced yields of ‘Mars' a maximum of 21% from season-long interference. Interference durations of 40 days or longer reduced the panicles/m2, culms/m2, and plant height of rice. Straw dry weight of Bond and Mars was reduced 41 and 26%, respectively, from season-long interference. Increased durations of weed interference did not affect the number of spikelets/panicle, percent filled spikelets, rough kernel weight, or head rice yield of either cultivar. Broadleaf signalgrass produced less dry weight and fewer panicles/m2when grown with Mars than with Bond.

Estimating Head Rice Yield of Long-Grain Rice using a Bending Force Instrument

2019 ◽  
Vol 35 (3) ◽  
pp. 319-323 ◽  
Author(s):  
Zephania R. Odek ◽  
Terry J. Siebenmorgen
Keyword(s):  
Bending Strength ◽  
Rice Yield ◽  
Polarized Light ◽  
Alternative Methods ◽  
Rice Quality ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield ◽  
Rice Yields ◽  
Rice Milling

Abstract. Head rice yield is an important index of rice quality. The official procedure for determining head rice yield requires a 1000-g sample of rough rice or a lesser sample of rough rice for a modified procedure. In certain situations, such amounts of rough rice may not be available for conducting an actual milling analysis; thus, there is a need to provide alternative methods of estimating head rice yield using a smaller sample. In this study, a PaddyCheck instrument was used to individually measure the three-point bending strength of approximately 250 rough rice kernels per sample. The instrument then classified the kernels as either “hard,” “soft,” or “broken by a force <17 N” (BBF). Additionally, each kernel was individually illuminated using polarized light as a means of estimating chalkiness. The kernel parameters measured using the PaddyCheck were then used to develop an equation for estimating head rice yield, based upon head rice yields determined using a modified milling procedure. The equation developed could be used in conjunction with the PaddyCheck instrument to provide estimates of head rice yield and thus, might allow the instrument to be more useful to practitioners in breeding programs and others involved in harvesting and drying operations to compare head rice yields of various samples/treatments, where the available rough rice sample or time is not sufficient to conduct an actual milling analysis. Keywords: Breaking force, Head rice yield, PaddyCheck, Rice milling, Rice quality, Rough rice.

Utilization of Saflufenacil in a Clearfield® Rice (Oryza sativa) System

2015 ◽  
Vol 29 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Garret B. Montgomery ◽  
Jason A. Bond ◽  
Bobby R. Golden ◽  
Jeffrey Gore ◽  
H. Matthew Edwards ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Weed Control ◽  
Rice Yield ◽  
Palmer Amaranth ◽  
Leaf Stage ◽  
Tiller Stage ◽  
Rough Rice ◽  
Rice Yields ◽  
Clearfield Rice ◽  
The One

Research was conducted in Mississippi in 2012 and 2013 to compare the efficacy of saflufenacil to other broadleaf herbicides applied in mixtures with imazethapyr in a Clearfield rice system. Saflufenacil at 50 g ai ha−1, carfentrazone at 35 g ai ha−1, a prepackaged mixture of halosulfuron plus thifensulfuron at 35 plus 4 g ai ha−1, and a prepackaged mixture of propanil plus thiobencarb at 2,240 plus 2,240 g ai ha−1 were applied in mixture with imazethapyr at 70 g ai ha−1 early-POST (EPOST) to rice in the one- to two-leaf stage or late-POST (LPOST) to rice in the four-leaf to one-tiller stage. No differences in injury among the broadleaf herbicides or between application timings were detected at any evaluation. Imazethapyr combined with propanil plus thiobencarb or saflufenacil provided the greatest control of barnyardgrass 7 and 14 d after treatment (DAT). Hemp sesbania, ivyleaf morningglory, and Palmer amaranth control was greatest and similar for imazethapyr combined with carfentrazone, propanil plus thiobencarb, and saflufenacil; however, rough rice yield was greatest for imazethapyr combined with propanil plus thiobencarb or saflufenacil. Propanil plus thiobencarb or saflufenacil can be used in a Clearfield rice system to achieve optimum weed control and highest rice yields.

Differential Tolerance of Clearfield Rice Cultivars to Imazamox

2011 ◽  
Vol 25 (2) ◽  
pp. 192-197 ◽  
Author(s):  
Jason A. Bond ◽  
Timothy W. Walker
Keyword(s):  
Growth Stage ◽  
Rice Yield ◽  
Field Studies ◽  
First Year ◽  
Growth Stages ◽  
Rice Cultivars ◽  
Rough Rice ◽  
Rice Yields ◽  
Clearfield Rice ◽  
Two Hybrid

Field studies were conducted to compare the response of one inbred (‘CL161’) and two hybrid (‘CLXL729’ and ‘CLXL745’) Clearfield (CL) rice cultivars to imazamox. Imazamox was applied at 44 and 88 g ai ha−1to rice in the panicle initiation (PI) and PI plus 14 d (PI + 14) growth stages and at 44 g ha−1to rice in the midboot growth stage. Maturity of hybrid CL cultivars was delayed following imazamox at 44 g ha−1applied at PI + 14 and midboot. Furthermore, imazamox at 44 g ha−1, applied at midboot, delayed maturity of CLXL745 more than CLXL729. Expressed as a percentage of the weed-free control plots, rough rice yields for CLXL729 were 91% following imazamox at 44 g ha−1applied at PI + 14, 78% following imazamox at 44 g ha−1applied at midboot, and 77% for imazamox at 88 g ha−1applied at PI + 14. Rough rice yield for CLXL745 was 77 to 92% of the control following all imazamox treatments. All imazamox treatments reduced CLXL745 rough rice yield compared with CL161. Rough rice yield, pooled across CL cultivar, varied with imazamox treatment between years, and these differences may have been a consequence of lower temperatures and solar radiation in the first year. Hybrid CL cultivars CLXL729 and CLXL745 were less tolerant than was CL161 when imazamox was applied at nonlabeled rates (88 g ha−1) and/or timings (PI + 14 or midboot). Because of variability in rice growth stages and irregularities in imazamox application in commercial fields, inbred CL cultivars should be planted where an imazamox application will likely be required.

Effects of Rotational Crop Herbicides on Rice (Oryza sativa)

Weed Science ◽  
1995 ◽  
Vol 43 (4) ◽  
pp. 648-654 ◽  
Author(s):  
David H. Johnson ◽  
J. Dwayne Beaty ◽  
Diana K. Horton ◽  
Ronald E. Talbert ◽  
Charles B. Guy ◽  
...  
Keyword(s):  
Dry Matter ◽  
Rice Yield ◽  
Growth And Yield ◽  
Clay Soils ◽  
Silt Loam ◽  
Previous Crop ◽  
Head Rice ◽  
Rough Rice ◽  
Rotational Crop ◽  
One Year

Experiments were conducted from 1989 to 1991 on two silt loam and two clay soils to determine the effect of herbicides applied to the previous crop on growth and yield of rice. All herbicides were applied preplant-incorporated at recommended rates adjusted as needed for soil texture. Rice was planted the following year. Imazaquin, imazethapyr, alachlor, metolachlor, clomazone, trifluralin, and atrazine did not injure rice the year following application. Norflurazon was the only herbicide to injure rice on silt loam soils, with injury at one silt loam location in one of two years. Norflurazon and fluometuron residues caused rice injury on clay soils, and chlorimuron residues caused injury in one year on a day soil. This chlorimuron carryover injury was from August-planted soybean but did not occur from June-planted soybean. Norflurazon, fluometuron, and chlorimuron temporarily reduced rice dry matter early in the season. No herbicide reduced either rough rice or percent head rice yield on any of the soils.

Genetic and Genotype ✕ Environment Effects for Rough Rice and Head Rice Yields

Crop Science ◽  
1991 ◽  
Vol 31 (4) ◽  
pp. 907-911 ◽  
Author(s):  
K. A. Gravois ◽  
K. A. K. Moldenhauer ◽  
P. C. Rohman
Keyword(s):  
Environment Effects ◽  
Head Rice ◽  
Rough Rice ◽  
Rice Yields

X-Ray Detection of Fissures in Rough Rice Kernels

2017 ◽  
Vol 33 (5) ◽  
pp. 721-728 ◽  
Author(s):  
Zephania R. Odek ◽  
Bhagwati Prakash ◽  
Terry J. Siebenmorgen
Keyword(s):  
Rice Yield ◽  
X Rays ◽  
Milled Rice ◽  
Substantial Impact ◽  
X Ray ◽  
X Ray Imaging ◽  
Head Rice ◽  
Rough Rice ◽  
Head Rice Yield ◽  
Rice Drying

Abstract. X-ray imaging is a viable method of fissure detection in rough rice kernels owing to the ability of X-rays to penetrate hulls, thus allowing visualization of internal rice kernel structure. Traditional methods of fissure detection are only applicable for brown and milled rice, and therefore cannot be used to study fissures developed during rough rice drying. In this study, the fissure detection capability of an X-ray system was evaluated and the relationship between head rice yield (HRY), as measured through laboratory milling, and the percentage of fissured rough rice kernels was determined. Long-grain rice lots of various cultivars were dried using heated air at 60°C, 10% relative humidity (RH) for five drying durations to produce different degrees of fissuring, and then milled to determine HRY. A strong linear correlation (R2 = 0.95) between HRY and the percentage of fissured rough rice kernels after drying was determined. This correlation confirms the substantial impact that kernel fissures have on milling yields. Overall, these findings show the effectiveness of X-ray imaging in rough rice fissure detection, which could allow for drying research that may provide a better understanding of kernel fissuring kinetics. Keywords: Fissures, Grainscope, Head rice yield, Rice drying, X-ray imaging.

Interspecific and Intraspecific Interference of Broadleaf Signalgrass (Brachiaria platyphylla) in Rice (Oryza sativa)

Weed Science ◽  
1988 ◽  
Vol 36 (5) ◽  
pp. 589-593 ◽  
Author(s):  
John T. McGregor ◽  
Roy J. Smith ◽  
Ronald E. Talbert
Keyword(s):  
Oryza Sativa ◽  
Field Experiments ◽  
Rice Yield ◽  
Dry Weight ◽  
Quadratic Equation ◽  
Regression Equations ◽  
Area Index ◽  
Rough Rice ◽  
Plant Densities ◽  
Brachiaria Platyphylla

Field experiments were conducted in 1984 and 1985 at Stuttgart, AR, to investigate the interspecific and intraspecific interference of broadleaf signalgrass densities of 0, 10, 50, 100, and 150 plants/m2with rice. In 1984, significant reductions in rice leaf area index (LAI) occurred 6 weeks after emergence with all broadleaf signalgrass densities. The first reduction in LAI occurred 8 weeks after emergence at the density of 150 plants/m2in 1985. Densities of 50 plants/m2or greater reduced rice dry weight 6 weeks after emergence in 1984, and the highest density of 150 plants/m2reduced rice dry weight 12 weeks after emergence in 1985. Height of rice was reduced by densities of 100 and 150 plants/m2. Linear regression equations indicated that each broadleaf signalgrass plant/m2reduced rough rice yield 18 kg/ha both years. Growth of broadleaf signalgrass was reduced by interspecific and intraspecific interference. The dry weight of broadleaf signalgrass increased at a decreasing rate at plant densities of 100 to 150/m2when grown alone in 1984 and 1985, when a quadratic equation best described the response. Regression equations indicated interspecific interference from rice reduced broadleaf signalgrass dry weight an average of 48 and 81% in 1984 and 1985, respectively. The height of broadleaf signalgrass was greater when grown with rice than when grown alone.

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