scholarly journals Genetic Identity Based on Whole-Genome SNP Array Data of Weedy Rice in Nagano, Japan

Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 472 ◽  
Author(s):  
Wenjing Bi ◽  
Jian Sun ◽  
Jun Hosoi ◽  
Masaharu Aoki ◽  
Nagao Sakai ◽  
...  
Keyword(s):  
Weed Management ◽  
Production System ◽  
Large Scale ◽  
Management Practices ◽  
Oryza Sativa L ◽  
Snp Array ◽  
Rice Production ◽  
Weedy Rice ◽  
Whole Genome ◽  
Population Genetic Analysis

The rice production system in Japan is changing due to the aging of rice farmers, shortage of labor, mechanization, and increase of large-scale rice fields and increased application of direct sowing, all of which contribute to the lack of sophisticated weed management practices. Because the changing production system has not improved and likely worsened weed management practices, weedy rice (Oryza sativa L.) has become a serious threat to rice production in Japan. We analyzed weedy rice accessions from Nagano, the central part of Japan, and other rice accessions to elucidate the origin of this weedy rice using a whole-genome single nucleotide polymorphism (SNP) array. For developing sustainable weedy rice management practices, the elucidation of the origin of re-emerging weedy rice is crucial. Population genetic analysis indicated that weedy rice in Nagano was phylogenetically independent from the local red rice cultivar with low genetic diversity. Past and recently re-emerging weedy rice ecotypes in Nagano shared a similar genetic background which implies the evolution of weedy rice by severe natural selection. Window-based FST and selection sweep analysis revealed the divergence of some of the known key domestication-related genes, such as shattering gene sh4 and qsh1, of weedy rice from domesticated rice cultivars.

scholarly journals Interactive Effect of Weeding Regimes, Rice Cultivars, and Seeding Rates Influence the Rice-Weed Competition under Dry Direct-Seeded Condition

2020 ◽  
Vol 13 (1) ◽  
pp. 317
Author(s):  
Sharif Ahmed ◽  
M. Jahangir Alam ◽  
Akbar Hossain ◽  
A. K. M. Mominul Islam ◽  
Tahir H. Awan ◽  
...  
Keyword(s):  
Weed Management ◽  
Oryza Sativa L ◽  
Interactive Effect ◽  
Rice Production ◽  
Weedy Rice ◽  
Rice Grain ◽  
Rice Cultivars ◽  
Seeding Rate ◽  
Direct Seeded ◽  
Hybrid Cultivar

Dry direct-seeded rice (Oryza sativa L.), a climate-smart and resource-efficient (labor and water) rice production technology is gaining popularity in many parts of Asian countries; however, weeds are the major constraints for its early establishment and optimum productivity. Chemical weed management is effective, rapid, and also decreases weed management costs in dry direct-seeded rice (DSR) system; however, chemical use for weed management have a negative effect on the environment and also have human health hazards. Therefore, integrated weed management (IWM) is the best option for the sustainability of rice production under the DSR system. Improving competitiveness against weeds, weed-competitive rice cultivars, and high seeding rates were found to be the most promising IWM strategies in DSR. In this context, a field study was conducted to evaluate the weed competitiveness of rice cultivars and seeding rates on the performance of aus rice in dry direct-seeded systems in Bangladesh. Three inbred rice cultivars (CV), namely “BRRI dhan26”, “BRRI dhan48”, and “BRRI dhan55”, and one hybrid cultivar, “Arize” were tested in a seeding rate (SR) of 20, 40, and 80 kg ha−1 under two weeding regimes (WR) of weed-free and partially-weedy. Rice grain yield was strongly affected (p < 0.01) by the interactions of WR, CV, and SR. In weed-free conditions, the yield of all three inbred cultivars was increased up to SR of 40 kg ha−1 and for the hybrid cultivar, up to SR of 20 kg ha−1, and with further increment of SR, there was no yield advantage. Conversely, under partially weedy conditions, the yield of three inbred cultivars increased up to SR of 80 kg ha−1; however, for the hybrid cultivar, this increment was up to SR of 40 kg ha−1 and thereafter, no yield gain. In weedy conditions, the higher SR compensates for the yield losses by increasing the competitiveness of rice with weeds. Across SR, the hybrid cultivar had a significantly (p < 0.01) higher weed competitive index (WCI) than all the inbred cultivars and the highest SR always had a higher WCI.

Stakeholder and field surveys on weed issues and research needs in rice production in Texas

2020 ◽  
pp. 1-9
Author(s):  
Rui Liu ◽  
Vijay Singh ◽  
Xin-Gen Zhou ◽  
Muthukumar Bagavathiannan
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Rice Production ◽  
Rice Fields ◽  
Weedy Rice ◽  
Research Needs ◽  
Field Surveys ◽  
Herbicide Resistant ◽  
Late Season ◽  
Hemp Sesbania

Abstract A paper-based survey was conducted from 2015 to 2017 among stakeholders of the Texas rice industry on current weed management challenges and factors influencing management decisions. A total of 108 survey questionnaires were completed by stakeholders at the rice Cooperative Extension meetings conducted in the rice-growing counties of Texas. In addition, late-season field surveys were conducted prior to harvest in 2015 and 2016 across the rice-growing counties to understand dominant weed escapes occurring in rice fields. Results from the questionnaire survey revealed that rice–fallow–rice was the most common rotation practiced in Texas rice production. Echinochloa spp., Leptochloa spp., and Cyperus spp. were the top three problematic weed issues faced by the respondents. Among the Leptochloa species, Nealley’s sprangletop, a relatively new species in rice fields, was indicated as an emerging concern. Clomazone was the most frequently used PRE herbicide, whereas quinclorac, propanil, imazethapyr, and cyhalofop were the popular POST herbicides. Most respondents (72%) made weed-control decisions on the basis of economic thresholds, whereas 63% made decisions on the basis of weed problems from previous years. Most respondents (88%) expressed moderate to high concern for herbicide-resistant weeds in their operations. Strategies to manage herbicide-resistant weeds and economical weed management practices were among the top suggested research needs. The field survey revealed that jungle rice, Nealley’s sprangletop, and hemp sesbania were the top three late-season weed escapes in rice production in Texas, with frequencies of occurrence of 28%, 19%, and 13%, respectively. Furthermore, average field area infested by a species was the greatest for jungle rice (13%), followed by hemp sesbania (11%) and weedy rice (11%). Findings from the stakeholder and field surveys help direct future research and outreach efforts for sustainable weed management in Texas rice.

Padi Aerob Untuk Mengatasi Masalah Kekurangan Air

2014 ◽  
Vol 70 (6) ◽  
Author(s):  
Sariam Othman ◽  
Zainudin P. M. D. Hussain ◽  
Chan Chee Sheng ◽  
Azmi Man ◽  
Rosniyana Ahmad ◽  
...  
Keyword(s):  
Weed Management ◽  
Production System ◽  
Management Practices ◽  
Aerobic Condition ◽  
Rice Production ◽  
Lowland Rice ◽  
High Yield ◽  
Integrated Weed Management ◽  
Aerobic Rice ◽  
Rice Varieties

Irrigated lowland rice is the most important rice ecosystem in Malaysia. The present and future food security in rice for the country depends largely on the irrigated lowland rice production system which consumes a large amount of water. Signs of declining water availability due to increased demand of water for domestic and industrial uses besides irregularity of rainfall and climate change threatens the sustainability of irrigated rice production. This scenario may change the way rice is produced in the future. Aerobic rice is a potential water saving rice production system and will be the best option of producing rice in water scarce environment. The availability of aerobic rice varieties that can withstand aerobic condition, responds to irrigation and fertilizers, competitive against weeds and deliver a high yield is crucial to make aerobic rice cultivation successful. Since weeds are major constraints to aerobic rice, it must be effectively controlled through integrated weed management. Appropriate nutrient and other crop management practices will ensure successful aerobic rice production system.

scholarly journals Sensitivity of imidazolinone-resistant red rice (Oryza sativa L.) to glyphosate and glufosinate

2015 ◽  
Vol 45 (9) ◽  
pp. 1557-1563 ◽  
Author(s):  
Guilherme Vestena Cassol ◽  
Luis Antonio de Avila ◽  
Carla Rejane Zemolin ◽  
Andrey Piveta ◽  
Dirceu Agostinetto ◽  
...  
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Oryza Sativa L ◽  
Dry Weight ◽  
Integrated Weed Management ◽  
Rio Grande Do Sul ◽  
Red Rice ◽  
Resistance Evolution ◽  
Logistic Analysis ◽  
Imidazolinone Herbicides

<p>Dose-response experiments were carried out to evaluate the sensitivity of imidazolinone-resistant red rice to nonselective herbicides currently used in rice-soybean rotation in Rio Grande do Sul. Two red rice biotypes previously identified as resistant and susceptible to the imidazolinone herbicides were treated with imazapic plus imazapic, glyphosate and glufosinate under nine herbicide rates. A non-linear log-logistic analysis was used to estimate the herbicide rate that provided 50% red rice control and dry weight reduction (GR<sub>50</sub>). Imidazolinone-resistant red rice exhibited greater GR<sub>50</sub> values than imidazolinone-susceptible biotype for imazapyr plus imazapic. In contrast, both imidazolinone-resistant and susceptible red rice showed similar GR<sub>50</sub>values for glyphosate and glufosinate. These results indicate that glyphosate and glufosinate effectively control imidazolinone-resistant red rice at similar herbicide rates used to control imidazolinone-susceptible; however, integrated weed management practices must be adopted in rice-soybean rotation to delay resistance evolution of red rice populations to glyphosate and glufosinate</p>

scholarly journals Effect of Crop Establishment Methods and Weed Management Practices on Weed Density and Productivity of Basmati Rice (Oryza sativa L.)

2021 ◽  
pp. 235-243
Author(s):  
Shipra Yadav ◽  
R. B. Yadav ◽  
R. K. Naresh ◽  
. Vivek ◽  
B. P. Dhyani
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Oryza Sativa L ◽  
Basmati Rice ◽  
Management Options ◽  
Yield Attributes ◽  
Weed Density ◽  
Crop Establishment ◽  
Weed Dynamics ◽  
And Performance

Aim: Present experiment was conducted to study the effect of crop establishment methods and weed management options on weed dynamics and performance of Basmati rice. Study Design: Split plot design. Place and Duration of Study: Iinvestigation was conducted during the kharif-season of 2019 and 2020 at Crop Research Center, S.V.P.University of Agriculture &Technology, Meerut (U.P.), India. Methodology: Mainfactors consist of the crop establishment methodsviz.(1) Conventional Puddled Transplanting, (2) Unpuddled Flat and (3) Furrow Irrigated Raised Beds, the sub factors consist of five weed management options viz., (1) Pretilachlor @ 0.75 Kg ha-1 PE fb Bispyribac sodium @ 20 g a.i.  ha-1 POE at 20 DAT, (2) Almix 4 g a.i. ha-1 + Bispyribac sodium @ 20 g a.i. ha-1 POE at 20 DAT, (3) Bispyribac sodium @ 25 g a.i. ha-1 POE at 20 DAT, (4) Two hand weedings and (5) Weedy check. Results: Minimum total weed density was recorded under CPT (E1) followed by FIRB(E3) while itwas maximum under UPF(E2). Two hand-weedings effectively reduced total weed density. In herbicides, application of pretilachlor @ 0.75 Kg ha-1fb Bispyribac sodium @ 20 g a.i. ha-1 (W1) was found most effective in reducingtotal weed density.Higher yield and yield attributes were found under CPT which was significantly higher than the UPF and at par with FIRB. Amongweed management practices highest yield and yield attributes were obtained with pretilachlor @ 0.75 Kg ha-1fb Bispyribac sodium @ 20 g a.i. ha-1.Lowest yield and yield attributes were obtained in weedy check. Conclusion: Puddled transplantation in rice might be the best option to get higher yield and for weed control, application of Pretilachlor @ 0.75 Kg ha-1 PE fb Bispyribac sodium @ 20 g a.i.  ha-1 POE at 20 DAT may be done to get higher yield.

scholarly journals Effective weed management practices to control complex weed flora in different cultivars of hybrid and high yielding varieties of rice (Oryza sativa L.)

2016 ◽  
Vol 2 ◽  
pp. 14-19
Author(s):  
Paramita Biswas ◽  
◽  
Ratikanta Ghosh ◽  
Keyword(s):  
Grain Yield ◽  
Weed Management ◽  
Management Practices ◽  
Hybrid Rice ◽  
Oryza Sativa L ◽  
Weed Flora ◽  
High Yielding Varieties ◽  
Hand Weeding ◽  
Control Complex ◽  
Plot Design

A field experiment was conducted during Summer and Kharif seasons of 2007-08 and 2008-09 at Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal, India to study the effect of hand weeding and Pretilachlor 50 EC @ 500 g a.i. ha-1 as pre-emergence on weed management of different varieties of hybrid and high yielding rice. The experiment was laid out in a split-plot design with three replications for both the years. It has been observed that Pretilachlor 50 EC @ 500 g a.i. ha-1 has a significant effect to control complex weed flora both in hybrid and high yielding varieties of rice but hand weeding twice gave the better result as expected. Among the varieties, the hybrid varieties recorded 36% and 32% more grain yield in Summer and Kharif seasons respectively than high yielding varieties (HYV). The high yielding variety 6444 (V2) showed more grain yield during Summer and Kharif seasons than that of the hybrid 6129 (V1), 97158 (V6), and 96110 (V3), respectively. Regarding weed management, hand weeding twice recorded (13% & 36%) higher grain yield during Summer than that of the chemical treatment and unweeded check, and (20% & 42%) during Kharif seasons respectively. Among the interaction, hand weeding combined with all varieties of hybrid rice recorded higher yield in comparison to other treatment combinations.

scholarly journals Weed control efficiency and weed index as influenced by weed management practices in machine transplanted rice (Oryza sativa L.)

2016 ◽  
Vol 8 (4) ◽  
pp. 1947-1952
Author(s):  
R. B. Negalur ◽  
A. S. Halepyati
Keyword(s):  
Oryza Sativa ◽  
Weed Control ◽  
Weed Management ◽  
Management Practices ◽  
Oryza Sativa L ◽  
Dry Weight ◽  
Weed Population ◽  
Transplanted Rice ◽  
Hand Weeding ◽  
Row Space

Field experiment on effect of different weed management practices in machine transplanted rice (Oryza sativa L.) was conducted at ARS, Gangavathi, University of Agricultural Sciences, Raichur, Karnataka during kharif, 2012 and 2013 under irrigated condition in clay soil. Pooled mean indicated that, application of butachlor 50 EC fb passing of power operated low land rice weeder twice at 20 and 30 DAT with hand weeding in intra row space recorded significantly lower grassy weed population and dry weight at 40, 60 DAT and at harvest (1.98, 2.47, 2.97/0.25 m2 and 1.00, 1.20, 1.47 g /0.25 m2, respectively), sedge weed population and dry weight (2.61, 3.21, 3.52 /0.25 m2 and 1.19, 1.48, 1.71 g /0.25 m2, respectively) and broad leaved weed population and dry weight (1.68, 2.10, 2.52 / 0.25 m2 and 0.91, 1.06, 1.28 g /0.25 m2, respectively). Significantly higher WCE (87.53%), lower weed index (3.11 %), grain and straw yield (5160 and 6482 kg ha-1, respectively), gross and net returns (Rs. 92,212 and 50,410 ha-1, respectively), and B:C of 2.22 over unweeded check. Hence, application of butachlor 50 EC fb passing of power operated low land rice weeder at 20 and 30 DAT with hand weeding in intra row space was found to be the best weed control method as it recorded higher B:C. Present conventional manual weeding is which is not advantageous as it is costlier, time consuming and labour may trample and damage rice seedlings. Mechanical weeder and sequential application can overcome the same.

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