Interference of Red Rice (Oryza sativa) Densities in Rice (O. sativa)

Weed Science ◽  
1991 ◽  
Vol 39 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Sam L. Kwon ◽  
Roy J. Smith ◽  
Ronald E. Talbert
Keyword(s):  
Oryza Sativa ◽  
Rice Plant ◽  
Field Experiments ◽  
Dry Weight ◽  
Rice Cultivars ◽  
Red Rice ◽  
Head Rice ◽  
Reduced Height ◽  
Panicle Number ◽  
Rice Yields

Field experiments were conducted at Stuttgart, AR, from 1986 to 1988 to determine effects of season-long interference of red rice densities of 1, 2, 5, 10, 20, and 40 plants m–2on ‘Lemont’ and ‘Newbonnet’ rice cultivars. This interference reduced straw dry weights of Newbonnet and Lemont by 100 and 130 kg ha–1per red rice plant, and grain yields by 178 and 272 kg ha–1per red rice plant, respectively. Grain yield reductions were due to decreases in panicle number and length, and in number of grains per panicle. Ten plants m–2or more reduced height of Lemont, while 40 plants m−2were required to reduce height of Newbonnet. Red rice at 10 plants m−2or more reduced total milled and head rice yields of Lemont, but red rice did not affect these components for Newbonnet. Red rice interfered with rice, even at densities as low as two plants m−2, and interference was greater in Lemont, a semidwarf cultivar with mature plants 92 cm tall, than in Newbonnet, a conventional cultivar with mature plants 115 cm tall. Red rice produced more panicles m−2and 31 to 64% greater straw dry weight when grown with Lemont than when grown with Newbonnet because red rice shaded Lemont more than Newbonnet. Red rice plants grew taller as red rice densities increased and also were taller when grown in Newbonnet than when grown in Lemont.

Interference Durations of Red Rice (Oryza sativa) in Rice (O. sativa)

Weed Science ◽  
1991 ◽  
Vol 39 (3) ◽  
pp. 363-368 ◽  
Author(s):  
Sam L. Kwon ◽  
Roy J. Smith ◽  
Ronald E. Talbert
Keyword(s):  
Grain Yield ◽  
Dry Weight ◽  
Rice Cultivars ◽  
Regression Analyses ◽  
Red Rice ◽  
Panicle Length ◽  
Milled Rice ◽  
Linear Relationships ◽  
Head Rice ◽  
Rice Yields

Red rice at 20 plants m−2was grown with two rice cultivars for 0, 40, 60, 80, 100, or 120 days after emergence. Red rice interference for 120 days after rice emergence reduced straw dry weights of Lemont and Newbonnet 58 and 34%, respectively. Grain yield of Lemont and Newbonnet was reduced 86 and 52%, respectively, by red rice interference for 120 days after emergence. Regression analyses indicated that red rice interference reduced straw dry weights of Newbonnet and Lemont 25 and 50 kg ha−1day−1, respectively, for interference durations of 40 to 120 days after emergence. Grain yield of Newbonnet and Lemont was reduced 60 and 93 kg ha−1day−1, respectively, for interference durations of 60 to 120 days. Negative linear relationships occurred between interference durations of red rice and plant height, panicles m−2, spikelets panicle−1, filled grains panicle−1, or panicle length of both cultivars. However, all parameters were reduced more for Lemont than for Newbonnet as interference duration increased. Head rice (whole kernels) and total milled rice yields of both cultivars were reduced by season-long red rice interference. Red rice straw dry weight and number of culms m−2were greater when red rice was grown with Lemont than when grown with Newbonnet.

Red Rice (Oryza sativa) Control and Suppression in Rice (O. sativa)

1991 ◽  
Vol 5 (4) ◽  
pp. 811-816 ◽  
Author(s):  
Sam L. Kwon ◽  
Roy J. Smith ◽  
Ronald E. Talbert
Keyword(s):  
Oryza Sativa ◽  
Plant Growth ◽  
Grain Quality ◽  
Field Experiments ◽  
Red Rice ◽  
Two Cultures ◽  
The Two Cultures ◽  
Rice Yields ◽  
Sequential Treatments ◽  
High Yields

Two field experiments were conducted from 1986 to 1988 to determine efficacy of herbidices and plant growth regulators for red rice control and suppression in water- and drill-seeded rice. Molinate applied PPI with fenoxaprop applied at panicle initiation (PI) of rice controlled 94 and 86% of red rice in water- and drill-seeded rice, respectively, compared with 79 and 49%, respectively, for molinate PPI alone in the two cultures. Although this treatment injured rice slightly (< 30%), rice so treated produced high yields with improved grain quality. Sequential treatments of molinate PPI followed by sethoxydim applied at PI or amidochlor applied at > 90% heading produced comparable rice yields with improved red rice control or suppression and grain quality in both cultures, compared with PPI molinate. Drill-seeded rice treated with molinate PPI followed by fenoxaprop applied at late boot or MH (maleic hydazide) applied 7 d after heading produced higher yield than rice treated with molinate PPI.

Reciprocal Yield Analysis of Red Rice (Oryza sativa) Competition in Cultivated Rice

Weed Science ◽  
1991 ◽  
Vol 39 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Dan J. Pantone ◽  
John B. Baker
Keyword(s):  
Oryza Sativa ◽  
Grain Yield ◽  
Rice Plant ◽  
Competitive Ability ◽  
Field Experiments ◽  
Yield Losses ◽  
Red Rice ◽  
Cultivated Rice ◽  
Yield Model ◽  
Yield Analysis

Four years of field experiments were used to assess the competitive ability of red rice, a weedy variety of rice, and ‘Mars’, a cultivar of rice. Red rice was the dominant competitor each of the 4 yr, and an average of one red rice plant reduced Mars grain yield per plant equal to the effect of four Mars plants. Intervarietal competition was more important than intravarietal competition for Mars, whereas the reverse was true for red rice. The product of the coefficients for intravarietal competition did not significantly exceed the product of the coefficients for intervarietal competition, indicating that the two varieties were competing for the same resources. Using the reciprocal yield model coefficients from 1989, grain yield losses of Mars, due to red rice densities of 4, 16, 25, and 300 plants m−2, were predicted to approximate 13, 37, 48, and 92%, respectively, at a fixed cultivar density of 100 plants m−2.

Red Rice (Oryza sativa) Control in Drill-Seeded Rice (O. sativa)

Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 703-707 ◽  
Author(s):  
Amadou Diarra ◽  
Roy J. Smith ◽  
Ronald E. Talbert
Keyword(s):  
Oryza Sativa ◽  
Grain Yield ◽  
Field Experiments ◽  
Growing Season ◽  
Rice Cultivar ◽  
Rice Grain ◽  
Rice Seed ◽  
Red Rice ◽  
Culm Density ◽  
High Yields

Field experiments were conducted to investigate methods of controlling red rice (Oryza sativaL. ♯ ORYSA) in drill-seeded rice (O. sativa). Treatments included the rice cultivar ‘Mars', coated with calcium peroxide (CaO2) at 40% (w/w) and a crop protectant, R-33865 (O,O-diethyl-O-phenyl phosphorothioate) at 0.5 and 1% (v/w). Molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate) at 6.7 kg ai/ha was applied preplant incorporated (ppi). The land was flooded (2.5 to 5 cm deep) after seeding with rice (100 kg/ha, 2.5 cm deep), and the water was maintained throughout the growing season. CaO2, with or without molinate, increased rice grain yield 50% and increased rice culm density fivefold above untreated rice. Molinate applied ppi controlled 96% of the red rice. Rice seed coated with only CaO2or with CaO2plus R-33865 at 0.5%, each combined with ppi molinate, produced 5690 and 6030 kg/ha of grain, respectively. These high yields were associated with red rice control by molinate and good stands of rice provided by O2supplied by CaO2. R-33865 applied to rice seed at 1% (v/w) injured rice by reducing rice culm densities 41%, compared with rice without protectant.

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.

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.

Red Rice (Oryza sativa) Biology. II. Ecotype Sensitivity to Herbicides

1999 ◽  
Vol 13 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Jose A. Noldin ◽  
James M. Chandler ◽  
Mary L. Ketchersid ◽  
Garry N. McCauley
Keyword(s):  
Oryza Sativa ◽  
Rice Cultivar ◽  
Rice Cultivars ◽  
Red Rice

Greenhouse studies were conducted to evaluate sensitivity of red rice ecotypes from Arkansas, Louisiana, Mississippi, and Texas to soil- and foliar-applied herbicides. Ecotype response to herbicides was variable. Molinate at 4.48 kg ai/ha controlled red rice ecotypes 92 to 100% and cultivars ‘Lemont,’ ‘Mars,’ and ‘Maybelle’ 39 to 63%. Red rice control with thiobencarb at 4.48 kg ai/ha was at least 89%. The tank mixture of fenoxaprop at 0.08 kg ai/ha plus fluazifop-P at 0.10 kg ai/ha controlled red rice and rice cultivars more than for either herbicide applied alone. Red rice and rice cultivar control with paraquat at 0.70 kg ai/ha was 83 to 100%. Blackhulled red rice TX 4 was less sensitive to paraquat and glufosinate than other ecotypes and cultivars. Glufosinate at 1.12 kg ai/ha was required to provide at least 94% control of ecotype TX 4.

Glufosinate-Resistant, BAR-Transformed Rice (Oryza sativa) and Red Rice (Oryza sativa) Response to Glufosinate Alone and in Mixtures

1997 ◽  
Vol 11 (4) ◽  
pp. 662-666 ◽  
Author(s):  
Sujatha Sankula ◽  
Michael P. Braverman ◽  
Steven D. Linscombe
Keyword(s):  
Oryza Sativa ◽  
Seed Weight ◽  
Rice Plant ◽  
Rice Yield ◽  
Field Studies ◽  
The Other ◽  
First Year ◽  
Red Rice ◽  
Second Year ◽  
100 Seed Weight

Glufosinate applied postemergence alone and in mixture with pendimethalin, thiobencarb, quinclorac, propanil, bensulfuron, bentazon, acifluorfen, or triclopyr was evaluated on bialaphosresistant (BAR) rice and red rice in field studies. Glufosinate at 2.2 kg ai/ha alone was less phytotoxic (6%) to BAR-transformed rice than when it was applied in combination with 0.4 kg ai/ha triclopyr (59%) or 0.6 kg ai/ha acifluorfen (22%). Rice yield with glufosinate alone was similar to the weed-free check the first year, but 13% less than the weed-free check the second year. For the glufosinate plus triclopyr mixture, rice yield was reduced by 39 and 76% compared with glufosinate alone in 1994 and 1995, respectively. Red rice control was 92% with either 3.4 kg ai/ha propanil or 0.6 kg/ha acifluorfen mixed with 0.6 kg/ha glufosinate, which was greater than for glufosinate alone and the other combinations. Propanil or acifluorfen mixed with glufosinate reduced red rice plant height, panicle maturity, and 100-seed weight 16, 31, and 24%, respectively, compared to glufosinate alone and 30, 48, and 43%, respectively, compared to the nontreated weedy check.

Interference Durations of Bearded Sprangletop (Leptochloa fascicularis) in Rice (Oryza sativa)

Weed Science ◽  
1994 ◽  
Vol 42 (2) ◽  
pp. 180-183 ◽  
Author(s):  
V. Frank Carey ◽  
Roy J. Smith ◽  
Ronald E. Talbert
Keyword(s):  
Oryza Sativa ◽  
Plant Height ◽  
Dry Weight ◽  
Rice Cultivars ◽  
Grain Yields

Effects of bearded sprangletop interference durations on Lemont and Newbonnet rice cultivars were studied. Interference durations of 63, 70, and 130 d after rice emergence reduced Lemont grain yields 11, 21, and 50%, respectively, and lowered Newbonnet grain yields 11, 13, and 37%, respectively. Interference durations of 21 to 56 d after emergence did not reduce grain yields of either cultivar. Bearded sprangletop grown in Lemont rice produced more biomass than that in Newbonnet. Season-long interference reduced plant height and straw dry weight of Lemont more than that of Newbonnet.

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.

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