Impact of Multiple Insect-Pest Incidence on Yield in Basmati Rice

The experiments for determining the multiple insect-pest incidence on yield loss in basmati rice was conducted for two crop seasons. Five treatments were, viz. application of imidacloprid in vegetative stage; application of granular insecticide in vegetative stage; application of higher dose of Urea; augmentive releases of yellow stem borer egg mass at vegetative and booting stage; untreated control. During both the years, the correlation between grain yield and dead heart, leaf folder damage and planthopper population at 50 and 65 DAT and white ear at maturity was negative. The analysis of variance of regression analysis of yield Vs damage levels at different crop growth stages during both the years revealed a significant linear relationship. The yield loss was highly related to incidence of stem borer and leaf folder damage at 50 and 65 DAT during both the years. For integrated pest management, effective monitoring of stem borer and leaf folder from 50 to 65 DAT is required, which appeared as a critical crop growth stage. The farmers should remain cautious during this period to prevent yield loss

Geographic and research center origins of rice resistance to asian planthoppers and leafhoppers: Implications for rice breeding and gene deployment

2017 by the authors. This study examines aspects of virulence to resistant rice varieties among planthoppers and leafhoppers. Using a series of resistant varieties, brown planthopper, Nilaparvata lugens, virulence was assessed in seedlings and early-tillering plants at seven research centers in South and East Asia. Virulence of the whitebacked planthopper, Sogatella furcifera, in Taiwan and the Philippines was also assessed. Phylogenetic analysis of the varieties using single-nucleotide polymorphisms (SNPs) indicated a clade of highly resistant varieties from South Asia with two further South Asian clades of moderate resistance. Greenhouse bioassays indicated that planthoppers can develop virulence against multiple resistance genes including genes introgressed from wild rice species. Nilaparvata lugens populations from Punjab (India) and the Mekong Delta (Vietnam) were highly virulent to a range of key resistance donors irrespective of variety origin. Sogatella furcifera populations were less virulent to donors than N. lugens; however, several genes for resistance to S. furcifera are now ineffective in East Asia. A clade of International Rice Research Institute (IRRI)-bred varieties and breeding lines, without identified leafhopper-resistance genes, were highly resistant to the green leafhopper, Nephotettix virescens. Routine phenotyping during breeding programs likely maintains high levels of quantitative resistance to leafhoppers. We discuss these results in the light of breeding and deploying resistant rice in Asia

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Not AvailableLoss in yield and quality of crop produce due to pest infestation could be reduced considerably if the pest occurrence is known in advance and timely remedial measures are taken. Weather plays an important role in pest development. Therefore, weather based models can be an effective scientific tool for forewarning pests in advance. In this study, weather based forewarning models have been developed for yellow stem borer [Scirpophaga incertulas(Walker)] and leaf folder [Cnaphalocrocis medinalis(Guenee)] of rice for different locations, viz., Aduthurai (Tamil Nadu), Chinsurah (West Bengal), Karjat (Maharashtra), Mandya (Karnataka), Ludhiana (Punjab) and Raipur (Chhattisgarh). The pest data comprised of population of yellow stem borer and leaf folder moths caught in light trap per week for different locations. Weather data relating to maximum and minimum temperature (°C), morning and evening relative humidity (%) and rainfall (mm) in respect of the locations were obtained from the meteorological observatories of the locations per se. Data of pest and weather on weekly basis in respect of Kharif and Rabi seasons of 11 years (2000-2010) for all locations, and of 16 years (1995-2010) for Mandya (KA) were used for developing the forewarning models. Weather of six lag weeks from week of forecast were used for development of weather indices. These weather indices were used as independent variables in model building against the pest population as dependent variables. Stepwise regression models for predicting the yellow stem borer population for peak periods of occurrence during Kharif [Aduthurai (TN), Karjat (MH) & Raipur (CG)] and Rabi [Chinsurah (WB) & Mandya (KA)] were developed with R2 ≥ 0.9. Prediction of leaf folder for different weeks of Kharif for Aduthurai (TN) (32-35 SMW) and Ludhiana (PB) (32-36 SMW) and of Rabi for Aduthurai (TN) (44-47 SMW) gave R2 between 0.6 and 0.8, respectively indicating better leaf folder prediction for Rabi over Kharif season at Aduthurai (TN). Validation of the models for subsequent years (2011) has been done for all cases. These developed models were converted into web-based forewarning system using 3-tier architecture. Net Beans 8.0.1 IDE (Integrated Development Environment), MS SQL Server, Java Server Pages (JSP) technologies have been used for the development of the web enabled forecasting of the two rice pests.Not Availabl

Virulence of brown planthopper (Nilaparvata lugens) populations from South and South East Asia against resistant rice varieties

This study examines the utility of resistant varieties and their associated resistance genes against brown planthopper, Nilaparvata lugens (Stal), populations from South and South East Asia. A collection of 39 rice accessions that included resistant, tolerant and susceptible varieties and breeding lines were examined for performance against populations of N. lugens from India (4), Bangladesh (1), Myanmar (1), Vietnam (1), Indonesia (1), China (1), Taiwan (1), and the Philippines (2). Planthopper virulence varied between regions; however only 6 varieties were generally less damaged than the susceptible check Taichung Native 1 (TN1) among >= 50% of the test populations. Each of these 6 varieties contained multiple resistance genes. One further variety, also with multiple resistance genes, and a modern cultivar (possibly with the Bph3 gene) were moderately effective against the South Asian populations, whereas a traditional variety with the Bph6 gene was effective against South East Asian populations. Bph1, bph2, bph5, bph7, bph8, Bph9, Bph10 and Bph18 were ineffective against most planthopper populations. Bph20, Bph21, and Bph17 have potential to be used in resistance breeding in both South and South East Asia, whereas BPH25 and BPH26 have potential for use in South Asia. The results indicate that only a few of the currently available resistance genes will be effective in monogenic rice lines; but that pyramiding of two or more genes with strong to weak resistance could improve resistance strength and durability as apparent with the most resistant, traditional varieties. Strategies to avoid planthopper adaptation to resistant rice varieties are discussed. (C) 2015 Elsevier Ltd. All rights reserved