Rice Infestation Research Articles

Effect of environmental factors on seed germination and seedling emergence of weedy rice (Oryza sativa f. spontanea) in China

Abstract Weedy rice (Oryza sativa f. spontanea Auct. ex Backer) is a troublesome annual weed from the Gramineae family and infests rice (Oryza sativa L.) fields globally, with a notable presence in China. However, limited information is available regarding the effects of diverse environmental factors on its germination and emergence. A better understanding of the seed biology and ecology of weedy rice is crucial for developing effective weed management strategies. Experiments were conducted to evaluate the effects of temperature, light, soil burial depth, wheat (Triticum aestivum L.) crop residue amount, salt stress, osmotic stress, and radiant heat on the germination and seedling emergence of weedy rice. Weedy rice exhibited robust germination (>98%) when exposed to varying day/night temperatures (20/15 to 35/30 C) and remained unaffected by light conditions. Seedling emergence was not influenced within the top 5-cm soil layer, where 100% of the seedlings emerged. However, emergence decreased as the soil burial depth increased, eventually resulting in no emergence from a burial depth of 11 cm. The soil burial depth required for 50% of the maximum emergence was 8.3 cm. Seedling emergence ranged from 97% to 100% across different amounts of the wheat straw residue cover (0 to 10,000 kg ha−1). The sodium chloride concentration and osmotic potential required for 50% were 230.8 mM and −0.5 MPa, respectively. No germination was observed when weedy rice seeds were exposed to >110 C pretreatment (radiant heat for 5 min), indicating that residue burning could reduce infestation of weedy rice. The insights gained from this study contribute valuable knowledge to enhance the integrated management of weedy rice in China.

Infestation of Rice Striped Stem Borer (Chilo suppressalis) Larvae Induces Emission of Volatile Organic Compounds in Rice and Repels Female Adult Oviposition.

Plants regulate the biosynthesis and emission of metabolic compounds to manage herbivorous stresses. In this study, as a destructive pest, the pre-infestation of rice striped stem borer (SSB, Chilo suppressalis) larvae on rice (Oryza sativa) reduced the subsequent SSB female adult oviposition preference. Widely targeted volatilomics and transcriptome sequencing were used to identify released volatile metabolic profiles and differentially expressed genes in SSB-infested and uninfested rice plants. SSB infestation significantly altered the accumulation of 71 volatile organic compounds (VOCs), including 13 terpenoids. A total of 7897 significantly differentially expressed genes were identified, and genes involved in the terpenoid and phenylpropanoid metabolic pathways were highly enriched. Correlation analysis revealed that DEGs in terpenoid metabolism-related pathways were likely involved in the regulation of VOC biosynthesis in SSB-infested rice plants. Furthermore, two terpenoids, (-)-carvone and cedrol, were selected to analyse the behaviour of SSB and predators. Y-tube olfactometer tests demonstrated that both (-)-carvone and cedrol could repel SSB adults at higher concentrations; (-)-carvone could simultaneously attract the natural enemies of SSB, Cotesia chilonis and Trichogramma japonicum, and cedrol could only attract T. japonicum at lower concentrations. These findings provide a better understanding of the response of rice plants to SSB and contribute to the development of new strategies to control herbivorous pests.

Influence of Sowing Techniques, Timing of Herbicide Application and on Weed Infestation and Yield of Rice in Southern Guinea Savannah of Nigeria

Field trial was conducted at the research field of National Cereals Research Institutes Badeggi experimental field, Niger state located at (latitude 9o041 02.05’’N and longitude 0.6o011 3.31’’E) and Bacita located at (latitude 9o1 16’N and longitude 5o59’E) both in the Southern Guinea Savannah Agro Ecological Zone of Nigeria during the wet season of 2021 and 2022. To determine the best combination of sowing techniques and time of herbicide application for optimizing rice yield while minimizing weed infestation and crop injury in the Southern Guinea Savannah of Nigeria. The experiment consists of five sowing methods (broadcasting dry, broadcasting wet, dibbling wet, dibbling dry, and transplanting) and two herbicide application timings (2 and 3 weeks after sowing) were tested in a factorial experiment. Data were collected on weed count before herbicide application, weed count at harvest and grain yield per hectare. The result indicated that the Transplanting technique of sowing significantly improved rice productivity in the study area at both seasons, less weed infestation at harvest was recorded with transplanted methods compared to other panting techniques, herbicide application at early growth stage of 2 weeks after sowing (2WAS) promote healthy crop growth and minimize weed competition

Effect of refugia plant (Zinnia sp.) population on the presence of stem borer (Scirpophaga innotata Walker) and natural enemies in rice

Abstract. Olsiviana, Yassi A, Melina. 2024. Effect of refugia plant (Zinnia sp.) population on the presence of stem borer (Scirpophaga innotata Walker) and natural enemies in rice. Biodiversitas 25: 2652-2660. This study supports biological control by preserving natural enemies in rice cultivation through habitat modification. The research aimed to analyze the effects of different population levels of refugia (Zinnia sp.) on pest attack rates, the presence and diversity of natural enemies of rice stem borer (Scirpophaga innotata Walker 1863), and rice (Oryza sativa L.) production. The study was designed using a Randomized Group Design (RGD) with four population treatment levels: control (no Zinnia sp.), sparse population (32 polybags of Zinnia sp.), medium population (96 polybags of Zinnia sp.), and dense population (160 polybags of Zinnia sp.). The results showed that the dense population (160 polybags of Zinnia sp.) produced the lowest stem borer infestation rate in the eighth week of observation (1.67%). Pests in all treatments belonged to four orders: Lepidoptera, Hemiptera, Coleoptera, and Diptera, with Hemiptera being the most prevalent. Natural enemies of rice pests belonged to three orders: Coleoptera, Hymenoptera, and Orthoptera. The dense population treatment (160 polybags of Zinnia sp.) yielded the highest values for diversity index (H') at 2.1785, species richness index (R) at 2.1837, and evenness index (E) at 0.9915. This treatment also achieved the highest average rice production at 8.64 tons/ha. Meanwhile, the highest dominance value (C) of 0.2489 was found in the control treatment. Thus, this study supports the idea that increasing the population of Zinnia sp. as a refugia plant can increase the diversity of natural enemies, reduce rice stem borer infestation, and increase rice plant production.

Influence of weevil on the physicochemical characteristics, functional properties, and nutritional value of rice (Oryza sativa L.) produced at Yagoua (far-north Cameroon)

The infestation of rice by pests during the post-harvest phase is one of the consequences of the deterioration of its technological and nutritional quality. Therefore, the present study was carried out to determine the physico-chemical characteristics, functional properties and nutritional value of uninfested and weevil-infested rice during storage. To this end, rice samples were collected from a rice production unit in the Far North Region of Cameroon. The physico-chemical and functional properties of uninfested and infested rice flours were determined using standard methods. The results showed that among the functional properties, only porosity showed a significant difference (p˂0.05) between infested (13.88 %) and uninfested (17.30 %) rice flours. Concerning the proximate composition, except for the carbohydrate content, where a significant decrease (p˂0.05) was observed between infested (68.15 %) and non-infested (58.43 %) rice flours, no significant difference (p > 0.05) was observed for the other nutrients evaluated. It was also observed that weevil infestation had a significant (p < 0.05) effect on the mineral content of the rice samples. Furthermore, scanning electron microscopy analysis revealed the presence of smaller granules with imprecise shapes in non-infested rice flour. Thus, this study showed that weevil infestation had a significant negative impact on the nutritional quality of rice and that good practices must be adopted by producers to ensure the quality of rice grains during storage.

Endosymbiotic Fungal Diversity and Dynamics of the Brown Planthopper across Developmental Stages, Tissues, and Sexes Revealed Using Circular Consensus Sequencing.

Endosymbiotic fungi play an important role in the growth and development of insects. Understanding the endosymbiont communities hosted by the brown planthopper (BPH; Nilaparvata lugens Stål), the most destructive pest in rice, is a prerequisite for controlling BPH rice infestations. However, the endosymbiont diversity and dynamics of the BPH remain poorly studied. Here, we used circular consensus sequencing (CCS) to obtain 87,131 OTUs (operational taxonomic units), which annotated 730 species of endosymbiotic fungi in the various developmental stages and tissues. We found that three yeast-like symbionts (YLSs), Polycephalomyces prolificus, Ophiocordyceps heteropoda, and Hirsutella proturicola, were dominant in almost all samples, which was especially pronounced in instar nymphs 4-5, female adults, and the fat bodies of female and male adult BPH. Interestingly, honeydew as the only in vitro sample had a unique community structure. Various diversity indices might indicate the different activity of endosymbionts in these stages and tissues. The biomarkers analyzed using LEfSe suggested some special functions of samples at different developmental stages of growth and the active functions of specific tissues in different sexes. Finally, we found that the incidence of occurrence of three species of Malassezia and Fusarium sp. was higher in males than in females in all comparison groups. In summary, our study provides a comprehensive survey of symbiotic fungi in the BPH, which complements the previous research on YLSs. These results offer new theoretical insights and practical implications for novel pest management strategies to understand the BPH-microbe symbiosis and devise effective pest control strategies.

Assessing the risk and morphological characteristics of weedy rice outbreak in Thap Muoi district, Dong Thap province, Vietnam

The Thap Muoi district in Dong Thap province, Vietnam, is renowned as the largest rice producer, cultivating 112,762 hectares and specialising in three rice crops per year, with some areas achieving 3.5 annual crops. However, changing farming practices, low-quality rice seeds, and mechanisation have led to the emergence and spread of weedy rice (Oryza spp.) in Thap Muoi and the broader Mekong delta. This comprehensive assessment of weedy rice outbreak risks in Thap Muoi provides a vital foundation for effective management strategies to prevent its spread in the Mekong delta. Sixty questionnaires were collected from rice-farming households. Approximately 80% of farmers reported the appearance of weedy rice approximately five years ago. Alarmingly, 95% of surveyed farmers (57 individuals) reported weedy rice infestations, with 40% of them encountering infection levels ranging from 11 to 20 plants/m2. To distinguish weedy rice from cultivated varieties, seven distinct types were identified based on various morphological characteristics, including growth time, leaf blade structure, plant height, leaf/stem colour and shape, grain beard/tail, seed/husk colour, grain length, ripening time, and seed dispersal potential. However, all seven weedy rice varieties exhibited short growth cycles and the capacity to produce seeds, posing significant challenges to rice production management in Thap Muoi. This research underscores the critical importance of assessing weedy rice outbreak risks in Thap Muoi and understanding its morphology and prevalence. This understanding is essential for developing effective preventive measures to mitigate the threat of weedy rice outbreaks across the entire Mekong delta in Vietnam.

Egg-associated secretions from the brown planthopper (Nilaparvata lugens) activate rice immune responses.

The brown planthopper (BPH, Nilaparvata lugens) is a notorious sap-sucking insect pest that damages rice (Oryza sativa) plants throughout Asia. During BPH feeding, saliva enters rice plant tissues, whereas during oviposition egg-associated secretions (EAS) are deposited in damaged plant tissue. Dynamic changes in rice to planthopper salivary effectors have been widely reported. However, the effects of EAS from planthopper on rice immunity remains largely unexplored. In this study, we found that both infestation of rice by gravid BPH female adults and treatment with the EAS elicited a strong and rapid accumulation of jasmonic acid (JA), JA-isoleucine, and hydrogen peroxide in rice. EAS enhanced plant defenses not only in rice but also in tobacco, and these impaired the performance of BPH on rice, as well as the performance of aphids and whiteflies on tobacco. High-throughput proteome sequencing of EAS led to 110 proteins being identified and 53 proteins with 2 or more unique peptides being detected. Some proteins from BPH EAS were also found in the salivary proteome from herbivores, suggesting potential evolutionary conservation of effector functions across feeding and oviposition; however, others were only identified in EAS, and these are likely specifically related to oviposition. These findings point to novel proteins affecting interactions between planthoppers and rice during oviposition, providing an additional source of information for effector studies.

Weedy rice (Oryza sativa L.) seed dormancy features and potential usage for management

Weedy rice infestation has been expanding with the increasing proportion of direct-seeded rice (DSR) systems in China. Limited herbicides are effective against weedy rice due to its high similarity with cultivated rice. Hence, it is important to figure out some non-chemical management strategies for weedy rice. One of the methods is to reduce the size of seed bank by inducing weedy rice germination. Petri dish germination experiment found that weedy rice with different seed morphologies showed an absence of primary dormancy. The field phenology study showed that weedy rice differed from cultivated rice in many features including plant height, number of tillers, fresh weight, and days required for earing when sown from 1 June to 1 October, and in the case of late sowings (between 1 August and 1 October), the plants produced no heads despite a high germination rate. Simulated field experiment to induce germination found that when soil moisture content was 22.2% and day/night temperatures were 20/15 °C, respectively, germination was more than 60% up to 10 days after sowing; at higher levels of soil moisture and temperature, germination was faster and germination percentage was higher. These results indicated that weedy rice seed bank size could be reduced by inducing the seed germination with post harvest irrigation as the seedlings would be killed overwinter in lower-middle reaches of the Yangtze River in China.

Phytochemical composition, toxicity, and repellent effects of medicinal plants Peganum harmala, Pterocarya fraxinifolia, and Tanacetum parthenium extracts against Sitophilus oryzae L.

Sitophilus oryzae is an important pest of stored rice and is usually controlled by the use of aluminum phosphide, which is dangerous to humans. Botanical insecticides deemed promising alternatives in controlling this pest. In this study, extracts of Peganum harmala seeds, Pterocarya fraxinifolia leaves, and Tanacetum parthenium flowers were evaluated against S. oryzae adults. Phytochemical analyses showed that steroid, terpenoid, tannin, alkaloid, and flavonoid are present in the extracts. Bioassays revealed repellency effects of all extracts, besides, P. harmala extract exerted significant mortality (93.33 ± 6.6%, LC50: 521.06 mg/ml) hence it may have applications in preventing infestation of stored rice by S. oryzae. Highlights Plant extracts studied in this research efficiently repel rice weevil. These plant extracts show significant toxicity against rice weevil. Alkaloid, steroid, terpenoid, tannin, and flavonoid are present in extracts of these plants.

Ethylicin Inhibition of Xanthomonas oryzae pv. oryzicola In Vitro and In Vivo

Infestation of rice with the bacterium Xanthomonas oryzae pv. oryzicola (Xoc) causes the serious disease bacterial leaf streak (BLS). We studied the effect of ethylicin, a broad-spectrum bactericide, on Xoc both in vivo and in vitro. Ethylicin increases the defensive enzyme activities and defensive genes expression of rice. Ethylicin also significantly inhibited Xoc activity in vitro compared with other commercial bactericides. The half-maximal effective concentration (EC50) of ethylicin was 2.12 μg/mL. It has been shown that ethylicin can inhibit Xoc quorum sensing through the production of extracellular polysaccharides and enzymes, which disrupt the Xoc cell membrane. We used proteomic analysis to identify two oxidative phosphorylation pathway proteins (ACU12_RS13405 and ACU12_RS13355) which affected the virulence of Xoc and validated them using quantitative real-time polymerase chain reaction (qRT-PCR). The results indicate that ethylicin can increase the defense responses of rice and control Xoc proliferation.

Effect of potassium fertilization levels on rice yield, yield attributes and rice stem borer infestation of Giza 178 rice cultivar grown under nitrogen fertilizer levels

Effect of potassium fertilization levels on rice yield, yield attributes and rice stem borer infestation of Giza 178 rice cultivar grown under nitrogen fertilizer levels

Reducing Seed Shattering in Weedy Rice by Editing SH4 and qSH1 Genes: Implications in Environmental Biosafety and Weed Control through Transgene Mitigation.

Mitigating the function of acquired transgenes in crop wild/weedy relatives can provide an ideal strategy to reduce the possible undesired environmental impacts of pollen-mediated transgene flow from genetically engineered (GE) crops. To explore a transgene mitigation system in rice, we edited the seed-shattering genes, SH4 and qSH1, using a weedy rice line ("C9") that originally had strong seed shattering. We also analyzed seed size-related traits, the total genomic transcriptomic data, and RT-qPCR expression of the SH4 or qSH1 gene-edited and SH4/qSH1 gene-edited weedy rice lines. Substantially reduced seed shattering was observed in all gene-edited weedy rice lines. The single gene-edited weedy rice lines, either the SH4 or qSH1 gene, did not show a consistent reduction in their seed size-related traits. In addition, reduced seed shattering was closely linked with the weakness and absence of abscission layers and reduced abscisic acid (ABA). Additionally, the genes closely associated with ABA biosynthesis and signaling transduction, as well as cell-wall hydrolysis, were downregulated in all gene-edited weedy rice lines. These findings facilitate our deep insights into the underlying mechanisms of reduced seed shattering in plants in the rice genus Oryza. In addition, such a mitigating technology also has practical applications for reducing the potential adverse environmental impacts caused by transgene flow and for managing the infestation of weedy rice by acquiring the mitigator from GE rice cultivars through natural gene flow.

Potential volatile markers of brown rice infested by the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae)

The rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) could cause significant grain loss by feeding internally on seeds. In this study, we tried to analyze the volatile compounds in non-infested and S. oryzae-infested brown rice during different storage periods to identify potential markers in S. oryzae-infested brown rice and facilitate pest monitoring during brown rice storage. Headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC–MS) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) were used to identify the volatile compounds. On the basis of GC–MS and GC-IMS data, a reliable method to distinguish between non-infested and S. oryzae-infested brown rice was discovered using partial least squares-discriminant analysis (PLS-DA). 1-Octen-3-ol, 1-hexanol and 3-octanone were co-selected as potential markers because their variable importance in projection (VIP) was greater than 1 in both models. The current study's findings lay a foundation for further research on the brown rice infestation mechanism and safe storage monitoring.

Influence of sowing date on yield and yield attributes of rice genotypes and infestation by rice leafminer and rice stem borer

Influence of sowing date on yield and yield attributes of rice genotypes and infestation by rice leafminer and rice stem borer

Seed germination responses to temperature and water availability in weedy rice.

Weedy rice is one of the main agricultural weeds infesting transplanted and direct-seeded rice cultures across Japan. However, the environmental factors that facilitate its proliferation are largely unknown. This study investigated the effects of temperature and water availability on seed germination of Japanese weedy and cultivated rice strains differing in degree of seed dormancy and after-ripening. This information could help predict weedy rice infestation and design efficacious control measures. The germination responses of weedy rice to temperature and water availability varied among strains and after-ripening duration. The germination rate varied inversely with the degree of dormancy, increased with water availability, and fluctuated between low and high temperatures. The shallow-dormant tropical japonica-derived strawhull weedy rice (TRJ) germinated at 10°C unlike the temperate japonica-derived weedy rice strains, namely, the intermediate-dormant blackhull (BH) and the deep-dormant strawhull (SH). Seeds of all plant strains germinated below the permanent wilting point of clay loam soil, but the germination rates were higher for TRJ and BH than for cultivated rice. SH germination was more synchronous with rice than the other weedy rice strains. This study has confirmed the overall robustness of germination cold tolerance at 10°C in TRJ, high germinability at low-water availability and high temperature in TRJ and BH, and relatively more synchronous germination between SH and cultivated rice in seeds grown in different years. These observed characteristics are considered advantageous to the coexistence of weedy rice with cultivated rice. © 2022 Society of Chemical Industry.

Occurrence pattern and morphological polymorphism of Chinese weedy rice

Rice, the main food crop in China, has been sporadically reported to suffer from weedy rice infestation. However, the overall occurrence and distribution pattern of Chinese weedy rice remains unclear because a systematic survey has not been conducted. In order to reveal the infestation of Chinese weedy rice, a field survey was conducted in 999 sampling sites all over the rice-growing regions in China from 2009 to 2016 using seven-scale visual scoring of the level of weed infestation. Weedy rice was found 39% occurrence incidence in a total of 387 sites. The sampling sites with 50% or higher overall weedy rice infestation index mainly radiated from Jiangsu, Heilongjiang, Ningxia and Guangdong to the whole East China, Northeast China, Northwest China and South China. A total of 45 morphological characters from 287 populations (collected simultaneously with the field survey) out of those occurred sites were observed and analyzed using multivariate analysis in common gardens with the same cultivation conditions in 2017 and 2019. Canonical correlation analysis showed that 45 morphological characters were significantly related to the latitude, mean temperature, minimum temperature, precipitation and mean diurnal range factors. The 287 weedy rice populations were divided into three morphological groups with climate-dependent geographical differentiation: strong tiller type only in Jiangsu, large leaf type in South China and Central China and large grain type mainly in North China. Weedy rice seriously infested rice fields and had a geography, climate and cultivated rice type-dependent morphological and biotype differentiation in China. It is suggested to pay attention to the harmfulness of weedy rice and adopt comprehensive control strategies.

Effect of Row Spacing and Frequency of Weeding on Weed Infestation, Yield Components, and Yield of Rice (Oryza sativa L.) in Bench Maji Zone, Southwestern Ethiopia

A field experiment was conducted in Bench Maji Zone at Guraferda district during the 2020 main cropping season to assess the effect of row spacing and frequency of weeding on weeds, yield components, and yield of rice and to estimate the economic feasibility of weed control practices of rice. Factorial combination of three-row spacing (20, 25, and 30 cm) and six weeding frequencies (one-hand weeding and hoeing at 2, 3, and 4 weeks after emergence, two-hand weeding and hoeing at 2 and 5 weeks after emergence, and weed-free check and weedy check) were laid out in randomized complete block design with three replications. Weed control efficiency, days to 50% heading, days to 90% physiological maturity, plant height, and straw yield were significantly affected by weeding frequencies but not by row spacing. Significantly higher panicle length (24.07 cm), number of productive tillers (209.08 m−2), number of kernels per panicle (252.22), grain yield (4303.0 kg·ha−1), aboveground dry biomass (10295.4 kg·ha−1), and harvest index (40.79%) were observed under 25 cm row spacing, compared with 20 and 30 cm. Significantly higher panicle length (25.81 cm), number of productive tillers (257.71 m−2), number of kernels per panicle (172.33), thousand kernels weight (35.44 g), grain yield (5226.7 kg·ha−1), aboveground dry biomass (11696.3 kg·ha−1), and harvest index (44.92%) were recorded under complete weed-free check plots. However, the highest net return (46,394.87 ETB·ha−1) was obtained from the combination of 25 cm row spacing and two-hand weeding and hoeing at 2 and 5 weeks after emergence, as the cost of maintaining weed-free plots was much higher. Thus, practicing two-hand weeding and hoeing at 2 and 5 WAE and 25 cm row spacing was found to be both agronomically and economically feasible for Rice (NERICA-4) production in the Guraferda area.

​​Weedy Rice (Oryza sativa f. spontanea) Complexes on Direct Seeded Rice (DSR) and its Management Strategy: A Review

Weedy rice (Oryza sativa f. spontanea) is one of the most notorious weeds occurring in rice growing areas especially in direct-seeded rice (DSR) system, worldwide and the problem is pervasive. It is a complex of Oryza morphotypes widely distributed in the commercial rice fields in more than 50 countries of Asia, Africa, Latin America and Southeast Asia. Weedy rice is progenies of crosses between wild rice and cultivated. The major characteristic of weedy rice is easy shattering. Other characteristics observed are taller plants, fewer tillers, grains having awns and high percentage of red rice in milled rice. It is difficult to manage the infestation of weedy rice because of its morphological similarities with cultivated rice. Recently, biotechnology approach using genetically modified herbicide tolerant rice varieties may be an efficient strategy. A non-transgenic rice variety ‘Clearfield’ is tolerant to Imidazolinone herbicides. It aims at determining whether the integration of Imidazolinone herbicides and tolerant trait in the genotypes can be used for controlling weedy rice in rice field. Satisfactory control of weedy rice requires an integrated approach based on the combination of preventive, cultural, mechanical, chemical and biotechnological means rather than using only a single method for its control.

Weedy Rice Classification Using Image Processing and a Machine Learning Approach

Weedy rice infestation has become a major problem in all rice-growing countries, especially in Malaysia. Challenges remain in finding a rapid technique to identify the weedy rice seeds that tend to pose similar taxonomic and physiological features as the cultivated rice seeds. This study presents image processing and machine learning techniques to classify weedy rice seed variants and cultivated rice seeds. A machine vision unit was set up for image acquisition using an area scan camera for the Red, Green and Blue (RGB) and monochrome images of five cultivated rice varieties and a weedy rice seed variant. Sixty-seven features from the RGB and monochrome images of the seed kernels were extracted from three primary parameters, namely morphology, colour and texture, and were used as the input for machine learning. Seven machine learning classifiers were used, and the classification performance was evaluated. Analyses of the best model were based on the overall performance measures, such as the sensitivity, specificity, accuracy and the average correct classification of the classifiers that best described the unbalanced dataset. Results showed that the best optimum model was developed by the RGB image using the logistic regression (LR) model that achieved 85.3% sensitivity, 99.5% specificity, 97.9% accuracy and 92.4% average correct classification utilising all the 67 features. In conclusion, this study has proved that the features extracted from the RGB images have higher sensitivity and accuracy in identifying the weedy rice seeds than the monochrome images by using image processing and a machine learning technique with the selected colour, morphological and textural features.