Polymorphisms in the ALS gene of weedy rice (Oryza sativa L.) accessions with differential tolerance to imazethapyr

Land degradation and soil fertility deterioration are two of the main causes of agricultural production stagnation and decline in many parts of the world. The model of crop production based on mechanical soil tillage and exposed soils is typically accompanied by negative effects on the natural resource base of the farming environment, which can be so serious that they jeopardize agricultural productive potential in the future. This form of agriculture is destructive to soil health and accelerates the loss of soil by increasing its mineralization and erosion rates. Conservation agriculture, a system avoiding or minimizing soil mechanical disturbance (no-tillage) combined with soil cover and crop diversification, is considered a sustainable agro-ecological approach to resource-conserving agricultural production. A major objective of tillage is supposed to be weed control, and it does not require very specific knowledge because soil inversion controls (at least temporarily) most weeds mechanically (i.e., by way of burying them). However, repeated ploughing only changes the weed population, but does not control weeds in the long term. The same applies to the mechanical uprooting of weeds. While in the short term some tillage operations can control weeds on farms, tillage systems can increase and propagate weeds off-farm. The absence of tillage, under conservation agriculture, requires other measures of weed control. One of the ways in which this is realized is through herbicide application. However, environmental concerns, herbicide resistance and access to appropriate agro-chemicals on the part of resource-poor farmers, highlight the need for alternative weed control strategies that are effective and accessible for smallholders adopting conservation agriculture. Farmers in semi-arid regions contend with the additional challenge of low biomass production and, often, competition with livestock enterprises, which limit the potential weed-suppressing benefits of mulch and living cover crops. This paper reviews the applicability and efficacy of various mechanical, biological and integrated weed management strategies for the effective and sustainable management of weeds in smallholder conservation agriculture systems, including the role of appropriate equipment and prerequisites for smallholders within a sustainable intensification scenario.Keywords: smallholder farming; conservation agriculture; sustainable and ecological weed management; preventive; cultural and direct control methods of weed management

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“…), a close relative of cultivated rice (Oryza sativa L. or Oryza glaberrima Steud. ), can cause up to 70% yield loss to cultivated rice [63,64].…”

Section: Preventive Weed Managementmentioning

confidence: 99%

Sustainable Weed Management for Conservation Agriculture: Options for Smallholder Farmers

Sims¹,

Corsi²,

Gbèhounou³

et al. 2018

Agriculture

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“…Natural hybridization between the Clearfield ® and weedy rice is well documented. In North America this could range from 0.003 to 0.46% depending on the cultivar, weedy rice type, and planting date (Zhang et al, 2006;Shivrain et al, 2007;Shivrain et al, 2009a). These numbers 3 may be low, but this equates to hundreds of herbicide-resistant outcrosses per hectare.…”

Section: Introductionmentioning

confidence: 99%

Cross-Resistance to Imazapic and Imazapyr in a Weedy Rice (Oryza sativa) Biotype Found in Malaysia

et al. 2018

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Planta Daninha 2018; v36:e018182239 DILIPKUMAR, M. et al. Cross-resistance to imazapic and imazapyr in a weedy rice (Oryza sativa) biotype found in Malaysia 1 151103-PD-2016 (9 páginas) PROVA GRÁFICA ABSTRACT -The Clearfield ® rice production system is an effective management tool for weedy rice and other weeds in the direct-seeded rice culture. However, if farmers cultivating the Clearfield ® rice disregard stewardship recommendations, the industry could face a problem of herbicide-resistant weedy rice which would occur through the selection of outcrosses. This study aimed to confirm imidazolinoneresistant weedy rice in Malaysia. The resistant weedy rice (R-WR) was found to be 67 fold more resistant to OnDuty ® (premix of imazapic and imazapyr) than the susceptible weedy rice (S-WR) based on the GR 50 values (rate that causes 50% inhibition of shoot growth). The Clearfield ® rice cultivar was 32-fold more tolerant to OnDuty ® than the S-WR. Furthermore, the R-WR was 54 and 89 fold more resistant to imazapic and imazapyr applied separately than the S-WR, respectively. The Clearfield ® rice was 140-and 40-fold more tolerant to imazapic and imazapyr, respectively than the S-WR. The R-WR biotype was susceptible to non-selective herbicides glyphosate and glufosinate, as well as the selective graminicide quizalofop. Oxadiazon controlled the R-WR biotype, but pretilachlor was ineffective. The present study documented the first case of weedy rice that was cross-resistant to imazapic and imazapyr in Malaysian Clearfield ® rice field. Keywords:Clearfield ® system, imidazolinone-resistance, direct-seeded rice, ALS-inhibitor herbicide, ACCase-inhibitor herbicide. RESUMO -O sistema de produção de arroz

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“…With gene flow from CL cultivars being the primary cause of IMI resistance in WR [10], the vast majority of RWR can be identified by these validated assays. New assays can be readily developed and validated for the detection of other point mutations like V 669 M (G 1927 A), associated with a decreased susceptibility to IMI in WR collected from Arkansas, United States [9], or new IMI resistance mutations being developed for CL.…”

Section: Approach Iii: Agreement Between As-pcr and Kaspmentioning

confidence: 99%

“…IMI resistance reported to date in WR is due to point mutations in the ALS gene [9]. Hence, the methods of choice for RWR detection are those which enable the identification of SNP in the ALS gene determining IMI resistance [21].…”

mentioning

confidence: 99%

“…Once assimilated, IMI resistance alleles severely limit the efficacy of the Clearfield system in rice. Gene flow events have been reported as the main source of RWR in the US [9,15], Brazil [10], Italy [16], Greece [17] and Uruguay [4]. Therefore, it is recommended that the Clearfield rice production system should not be used for more than two consecutive seasons, and should be complemented by exclusive use of certified seed, prevention of WR seed set by rouging, and rotation with non-ALS herbicide applications [18].…”

mentioning

confidence: 99%

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One-step, codominant detection of imidazolinone resistance mutations in weedy rice (Oryza sativa L.)

Rosas

Bonnecarrère

Vida

2014

Electronic Journal of Biotechnology

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Background: Weedy rice (Oryza sativa L.) is a noxious form of cultivated rice (O. sativa L.) associated with intensive rice production and dry seeding. A cost-efficient strategy to control this weed is the Clearfield rice production system, which combines imidazolinone herbicides with mutant imidazolinone-resistant rice varieties. However, imidazolinone resistance mutations can be introgressed in weedy rice populations by natural outcrossing, reducing the life span of the Clearfield technology. Timely and accurate detection of imidazolinone resistance mutations in weedy rice may contribute to avoiding the multiplication and dispersion of resistant weeds and to protect the Clearfield system. Thus, highly sensitive and specific methods with high throughput and low cost are needed. KBioscience's Allele Specific PCR (KASP) is a codominant, competitive allele-specific PCR-based genotyping method. KASP enables both alleles to be detected in a single reaction in a closed-tube format. The aim of this work is to assess the suitability and validity of the KASP method for detection in weedy rice of the three imidazolinone resistance mutations reported to date in rice. Results: Validation was carried out by determining the analytical performance of the new method and comparing it with conventional allele-specific PCR, when genotyping sets of cultivated and weedy rice samples. The conventional technique had a specificity of 0.97 and a sensibility of 0.95, whereas for the KASP method, both parameters were 1.00. Conclusions:The new method has equal accuracy while being more informative and saving time and resources compared with conventional methods, which make it suitable for monitoring imidazolinone-resistant weedy rice in Clearfield rice fields.

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Polymorphisms in the ALS gene of weedy rice (Oryza sativa L.) accessions with differential tolerance to imazethapyr

Cited by 20 publications

References 32 publications

Sustainable Weed Management for Conservation Agriculture: Options for Smallholder Farmers

Sustainable Weed Management for Conservation Agriculture: Options for Smallholder Farmers

Cross-Resistance to Imazapic and Imazapyr in a Weedy Rice (Oryza sativa) Biotype Found in Malaysia

One-step, codominant detection of imidazolinone resistance mutations in weedy rice (Oryza sativa L.)

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