scholarly journals Azoxystrobin Rate and Timing Effects on Rice Sheath Blight Incidence and Severity and Rice Grain and Milling Yields

Plant Disease ◽  
2005 ◽  
Vol 89 (11) ◽  
pp. 1171-1174 ◽  
Author(s):  
D. E. Groth

Lack of sheath blight resistant varieties requires rice (Oryza sativa) farmers to use fungicides to avoid significant reductions in grain yield and milling yield. Studies were conducted to determine the best rate and rice growth stage for a single application of azoxystrobin, a fungicide recently labeled for this use, to effectively control sheath blight. Azoxystrobin was applied foliarly to inoculated field plots in 2000 to 2002 using rates of 0.22, 0.17, and 0.11 kg a.i. ha -1 at 7 days after panicle differentiation (PD+7), boot (B), and heading (H) growth stages and at 0.17 kg a.i. ha-1 at 5, 10, and 15 days after heading. Sheath blight severity (measured on a 0 to 9 scale) and incidence (percent tillers infected) were assessed 1 to 2 weeks before harvest. A fungicide application made between PD+7 and H significantly reduced sheath blight severity, which resulted in significantly higher yield and head rice milling yield compared with inoculated unsprayed plots. There were no significant effects of fungicide rate at the PD+7, B, and H growth stages. Fungicide-treated plots had yield and milling yield similar to the very lightly diseased, uninoculated check plots included for comparison. With fungicide application made postheading, rice had higher disease severity, resulting in lower yields and milling yield compared with rice receiving earlier applications.

Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1055-1058 ◽  
Author(s):  
D. E. Groth

Growing blast susceptible rice (Oryza sativa) cultivars often requires farmers to use fungicides to prevent significant reductions in rice grain and milling yields. Studies were conducted to determine the optimum rate and rice growth stage for single or multiple applications of azoxystrobin to control blast (Pyricularia grisea). Azoxystrobin was applied foliarly to naturally infected field plots in 2001 to 2005 at rates of 0.11, 0.17, and 0.22 kg a.i. ha-1 at boot (B) and heading (H) or only at H growth stages, and at 0.17 kg a.i. ha-1 at 5 (H+5), 10 (H+10), and 15 (H+15) days after H and B with low or high blast pressure. Head blast incidence (percent heads infected) was assessed 1 to 2 weeks before harvest. A fungicide application made at H, H+5, and B+H significantly reduced blast incidence with high and low disease pressure, resulting in significantly higher grain and head rice milling yields compared with unsprayed plots with high blast pressure. There were no significant effects of fungicide rate on blast development or yield following the H, B+H, and H+5 applications. With fungicide applications made at B, H+10, and H+15 days postheading, rice had higher disease incidence, resulting in lower grain and milling yields compared with rice receiving a heading application.


Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1073-1076 ◽  
Author(s):  
D. E. Groth ◽  
J. A. Bond

The lack of sheath blight-resistant cultivars requires rice (Oryza sativa) farmers to use fungicides to control the disease and avoid significant reductions in grain and milling yield. Sheath blight (Rhizoctonia solani) epidemics can begin over a period of weeks during the growing season, and initiation date can have significant effects on crop damage and fungicide application timing. Studies were conducted to determine how different epidemic initiation and azoxystrobin application timings affect disease development, rice yield, and milling quality. Sheath blight epidemics in field plots were initiated by inoculation at the green ring (GR), panicle differentiation (PD), early boot (EB), and late boot (LB) growth stages in 2002 to 2004. Azoxystrobin was applied to the foliage at 0.17 kg a.i. ha-1 at 7 days after PD (PD+7), midboot (B), and 50% heading (H). Inoculation significantly increased sheath blight severity and incidence and reduced yield and milling quality. There were no significant effects of inoculation timing at the GR, PD, EB, and LB growth stages. Fungicide applications made between PD+7 and H reduced sheath blight severity and incidence, resulting in higher yield and head rice milling yield compared with inoculated but nonsprayed plots.


2015 ◽  
Vol 11 (6) ◽  
pp. 777-787 ◽  
Author(s):  
Shabir Ahmad Mir ◽  
Sowriappan John Don Bosco ◽  
Manzoor Ahmad Shah ◽  
Mohammad Maqbool Mir ◽  
Shaiq Ahmad Ganai

Abstract Parboiling is a hydrothermal processing technique during rice has to pass through many stages which alter the physicochemical properties and nutritional profile of grain. Different parboiling techniques have been developed for preparation and industrialization of rice. During parboiling process, starch granules are gelatinized and retrograded as a result various changes occur in rice kernel, which affects its quality parameters. Parboiling has marked influence on organoleptic properties, improved the strength and nutritional profile of grain. Parboiling treatment principally brings the characteristic change in rice grain such as milling, cooking, storage and eating qualities. Milling is an important unit operation for removing the husk and bran from the rough rice. Milling significantly affects the cooking and nutritional properties of rice. The important parameters focussed during milling are the head rice yield and kernel hardness. Milling technology is therefore geared to obtain maximum outturn of milled rice and to reduce breakage.


Plant Disease ◽  
2007 ◽  
Vol 91 (12) ◽  
pp. 1647-1650 ◽  
Author(s):  
D. E. Groth ◽  
J. A. Bond

The development of sheath blight (Rhizoctonia solani)-resistant rice (Oryza sativa) cultivars will allow producers to use less fungicide and to avoid significant reductions in grain and milling yields. Among cultivars currently in cultivation in the southern United States rice-producing region, sheath blight resistance levels range from very susceptible to moderately susceptible. A study was conducted to determine the response of cultivars with different levels of susceptibility to sheath blight inoculations and fungicide applications and to determine the impact of sheath blight disease development on rice yield and quality. Sheath blight epidemics in field plots were initiated by inoculation at the panicle differentiation growth stage from 2003 through 2005. Azoxystrobin at 0.17 kg a.i. ha–1 and flutolanil at 0.56 kg a.i. ha–1 were applied in sequential applications at midboot and 50 to 70% heading. Inoculation significantly increased sheath blight severity and incidence and caused yield losses of 4% in moderately susceptible cv. Francis to 21% in very susceptible cv. Cocodrie. Milling yield was affected to a lesser extent. Fungicide treatments reduced sheath blight incidence and severity regardless of cultivar. Azoxystrobin was more effective than flutolanil in minimizing yield loss due to sheath blight in all cultivars except Francis.


2021 ◽  
Vol 285 ◽  
pp. 02049
Author(s):  
Sergey Garkusha ◽  
Susanna Tesheva ◽  
Dmitry Pischenko

In modern economic conditions, commodity producers need rice varieties that meet specific production requirements. The highest yields are provided by rice varieties that are most fully adapted to cultivation conditions, primarily to soil and climatic conditions, as well as to the material and technical level of production, the state of the rice irrigation system, and the requirements for environmental protection. The article presents the results of an industrial assessment in the transitional delta agrolandscape area of the rice cultivation zone of Krasnodar region. Analysis of the yield and technological indicators of the rice grain quality made it possible to identify varieties adapted to the conditions of “Kubris” LLC, Krasnoarmeyskiy district: Alliance, Veles, Favorit, Yubileiny 85. The average yield for three years was 84.1 c/ha, 82.7 c / ha, 73.6 c/ a, 85.9 c/ha, respectively. Compliance with the technology of growing, harvesting and post-harvest processing on the farm allows ensuring a high milling yield within the range of 65-69 % with a head rice content of 48-59 %. Growing these rice varieties on the farm will effectively develop production by realizing the potential of the variety and obtain high-quality rice grits.


2021 ◽  
pp. 1-36
Author(s):  
Justin McCoy ◽  
Bobby Golden ◽  
Jason Bond ◽  
Darrin Dodds ◽  
Taghi Bararpour ◽  
...  

In Mississippi, rice reproduction and ripening often overlaps with soybean maturation creating potential for herbicide exposure from desiccants applied to soybeans onto rice. Six independent studies were conducted concurrently at the Delta Research and Extension Center in Stoneville, MS from 2016 to 2018 to determine the response of rice to sub-lethal concentrations of soybean desiccants during rice reproductive and ripening growth stages. Studies included the desiccants paraquat, glyphosate, saflufenacil, sodium chlorate, paraquat+saflufenacil, and paraquat+sodium chlorate applied at a rate equal to 1/10 of Mississippi recommendations. Treatments were applied at five different rice growth stages beginning at 50% heading (defined as 0 d after heading (DAH)), with subsequent applications at one week intervals (0, 7, 14, 21, and 28 DAH) up to harvest. Injury was observed 7 days after application (DAA) with five of six desiccants at all application timings. No injury was observed with glyphosate application across all rating intervals. Rough rice grain yield following all glyphosate applications was reduced by >6%. In the studies evaluating paraquat injury ranged from 5 to 18% at all evaluations, regardless of application timing. Rough rice grain yield was reduced >12% 0 to 21 DAH, following paraquat application. Similar trends were observed with paraquat+saflufenacil and paraquat+sodium chlorate, with rice exhibiting yield decreases >6% following an application 0 to 14 and 0 to 21 DAH, respectively. In studies evaluating saflufenacil and sodium chlorate rough rice grain yield was >95% of the untreated across all application timings Yield component trends closely resembled reductions observed in rough rice grain yield. Reductions in head rice yield were >5% following applications of paraquat or paraquat+saflufenacil 0 to 14 and 0 to 21 DAH respectively. Late-season exposure to sub-lethal concentrations of desiccant from 50% heading (0 DAH) to 28 DAH has an impact on rough rice grain yield, yield components, and head rice yield.


Author(s):  
E.Y. Papulova ◽  
◽  
K.K Olkhovaya

The work shows that application of increased doses of nitrogen does not significantly affect the total milling yield and affects the head rice content. The ambiguous nature of the variability of the grain quality of rice varieties under conditions of different doses of nitrogen fertilizers confirms the need for further studies of the varietal reaction to the level of nitrogen nutrition, based on it - the development of rice cultivation technology modes in order to obtain rice yield with high grain quality.


2020 ◽  
Vol 57 (8) ◽  
pp. 2905-2915
Author(s):  
Barış Burak Albayrak ◽  
Necati Barış Tuncel ◽  
Neşe Yılmaz Tuncel ◽  
Mustafa Tuğrul Masatcıoğlu

Weed Science ◽  
1983 ◽  
Vol 31 (1) ◽  
pp. 120-123 ◽  
Author(s):  
Roy J. Smith

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.


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