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Rajendranagar, India

Shanker C.,Directorate of Rice Research DRR | Uthamasamy S.,Tamil Nadu Agricultural University
Archives of Phytopathology and Plant Protection | Year: 2010

Plant based insecticides are gaining importance for their environmental safety. But their efficacy is greatly reduced in the field due to several factors. This study was undertaken to assess the insecticidal properties of medicinal plants viz., Cassia tora, Clerodendron enermi, Calotropis gigantea, Aloe vera, Vitex negundo and Andrographis paniculata, commonly found on farmlands and their mixtures. The extracts and mixtures were bio-assayed against a lepidopteran larva (Heliothis armigera) by modified leaf dip bioassay, and its effect on larval growth, development and survival; the oviposition deterrent effect against moths of H. armigera, and efficacy against the sucking pest Aphis gossypii and a stored product pest Callosobruchus chinensis were studied. The insecticidal activity in descending order was as follows: NSKE 10% > NSKE 5%, Botanical mixture II > A. paniculata > V. negundo > Botanical mixture I > C. gigantea > C. tora > C. enermi > A. vera. All botanicals showed greater ovipositional deterrence than insecticidal activity exhibiting 40-100% inhibition compared to untreated control. A. paniculata showed the highest activity against the store product pest C. chinensis. The complex of compounds in botanical mixtures could be synergistically used in eco-friendly pest management and botanical mixtures with neem as one of the ingredients, which could have a potential role as insect growth regulator. © 2010 Taylor & Francis. Source

Swamy B. P. M.,International Rice Research Institute | Ahmed H.U.,International Rice Research Institute | Henry A.,International Rice Research Institute | Mauleon R.,International Rice Research Institute | And 21 more authors.
PLoS ONE | Year: 2013

Background:Rice (Oryza sativa L.) is a highly drought sensitive crop, and most semi dwarf rice varieties suffer severe yield losses from reproductive stage drought stress. The genetic complexity of drought tolerance has deterred the identification of agronomically relevant quantitative trait loci (QTL) that can be deployed to improve rice yield under drought in rice. Convergent evidence from physiological characterization, genetic mapping, and multi-location field evaluation was used to address this challenge.Methodology/Principal Findings:Two pairs of backcross inbred lines (BILs) from a cross between drought-tolerant donor Aday Sel and high-yielding but drought-susceptible rice variety IR64 were produced. From six BC4F3 mapping populations produced by crossing the +QTL BILs with the -QTL BILs and IR64, four major-effect QTL - one each on chromosomes 2, 4, 9, and 10 - were identified. Meta-analysis of transcriptome data from the +QTL/-QTL BILs identified differentially expressed genes (DEGs) significantly associated with QTL on chromosomes 2, 4, 9, and 10. Physiological characterization of BILs showed increased water uptake ability under drought. The enrichment of DEGs associated with root traits points to differential regulation of root development and function as contributing to drought tolerance in these BILs. BC4F3-derived lines with the QTL conferred yield advantages of 528 to 1875 kg ha-1 over IR64 under reproductive-stage drought stress in the targeted ecosystems of South Asia.Conclusions/Significance:Given the importance of rice in daily food consumption and the popularity of IR64, the BC4F3 lines with multiple QTL could provide higher livelihood security to farmers in drought-prone environments. Candidate genes were shortlisted for further characterization to confirm their role in drought tolerance. Differential yield advantages of different combinations of the four QTL reported here indicate that future research should include optimizing QTL combinations in different genetic backgrounds to maximize yield advantage under drought. © 2013 Swamy B. Source

Pandey M.K.,Directorate of Rice Research DRR | Pandey M.K.,Applied Genomics | Pandey M.K.,University of Georgia | Shobha Rani N.,Directorate of Rice Research DRR | And 11 more authors.
Molecular Breeding | Year: 2013

Bacterial blight (BB) is a major production threat to Basmati, the aromatic rice prized for its unique quality. In order to improve the BB resistance of two elite, traditional BB-susceptible Basmati varieties (Taraori Basmati and Basmati 386), we utilized the strategy of limited marker-assisted backcrossing for introgression of two major BB resistance genes, Xa21 and xa13, coupled with phenotype-based selection for improvement of their plant type and yield. Improved Samba Mahsuri, an elite high-yielding, fine-grain-type BB-resistant rice variety served as donor for BB resistance. Backcross-derived improved Basmati lines at BC1F5 possessing a single resistance gene (i. e. either Xa21 or xa13) displayed moderate resistance to BB, while lines possessing both Xa21 and xa13 showed significantly higher levels of resistance. Two-gene pyramid lines (Xa21 + xa13) possessing good grain and cooking quality similar to their respective traditional Basmati parents, short plant stature (<110 cm plant height) and higher grain yield than the recurrent parent(s) were identified and advanced. This work demonstrates the successful application of marker-assisted selection in conjunction with phenotype-based selection for targeted introgression of multiple resistance genes into traditional Basmati varieties along with improvement of their plant stature and yield. © 2012 Springer Science+Business Media B.V. Source

Gopalakrishnan S.,Indian International Crops Research Institute for the Semi Arid Tropics | Mahender Kumar R.,Directorate of Rice Research DRR | Humayun P.,Indian International Crops Research Institute for the Semi Arid Tropics | Srinivas V.,Indian International Crops Research Institute for the Semi Arid Tropics | And 15 more authors.
Paddy and Water Environment | Year: 2014

Field experiments were conducted at DRR farm located at ICRISAT, Patancheru, in sandy clay loam soils during four seasons, Kharif 2008, Rabi 2008-2009, Kharif 2009 and Rabi 2009-2010, to investigate growth parameters, water-saving potential, root characteristics, chemical, biological, and microbial properties of rhizosphere soil, and grain yield of rice (Oryza sativa L.) by comparing the plants grown with system of rice intensification (SRI) methods, with organic or organic + inorganic fertilization, against current recommended best management practices (BMP). All the growth parameters including plant height, effective tillers (10-45 %), panicle length, dry matter, root dry weight (24-57 %), and root volume (10-66 %) were found to be significantly higher with in SRI-organic + inorganic over BMP. With SRI-organic fertilization, growth parameters showed inconsistent results; however, root dry weight (3-77 %) and root volume (31-162 %) were found significantly superior compared to BMP. Grain yield was found significantly higher in SRI-organic + inorganic (12-23 and 4-35 % in the Kharif and Rabi seasons, respectively), while with SRI-organic management, yield was found higher (4-34 %) only in the Rabi seasons compared to BMP. An average of 31 and 37 % of irrigation water were saved during Kharif and Rabi seasons, respectively, with both SRI methods of rice cultivation compared to BMP. Further, total nitrogen, organic carbon%, soil dehydrogenase, microbial biomass carbon, total bacteria, fungi, and actinomycetes were found higher in the two SRI plots in comparison to BMP. It is concluded that SRI practices create favorable conditions for beneficial soil microbes to prosper, save irrigation water, and increase grain yield. © 2013 Springer Japan. Source

Pandey M.K.,Directorate of Rice Research DRR | Pandey M.K.,Osmania University | Rani N.S.,Directorate of Rice Research DRR | Madhav M.S.,Directorate of Rice Research DRR | And 6 more authors.
Biotechnology Advances | Year: 2012

Starch, composed of amylose and amylopectin, greatly influences rice cooking and textural quality, which in turn is controlled by various isoforms of several enzymes. Activity of one or more isoforms of starch-synthesizing enzymes results in various forms of starch structure based on the amylopectin chain length and average external, internal and core chain length distribution and hence results in varying physicochemical and cooking quality. Since the synthesis of starch is highly complex, it is crucial but essential to understand its biosynthetic pathway, starch structure and effects on the physicochemical properties that control eating and cooking quality, and alongside conduct research on gene/QTL mapping for use in marker-assisted selection (MAS) with a view to improve and select cultivars with most desirable range and class of rice starch properties. This article presents the updates on current understanding of the coordination among various enzymes/isoforms towards rice starch synthesis in endosperm and their effect on rice grain physicochemical, cooking and eating qualities. The efforts in identifying regions responsible for these enzymes by mapping the gene/QTLs have provided a glimpse on their association with physicochemical and cooking properties of rice and, hence, improvement is possible by modifying the allelic pattern, resulting in down or nil regulation of a particular enzyme. The clear understanding of the tissue specific coordination between enzyme isoforms and their subsequent effect in controlling eating and cooking properties will enhance the chances to manipulate them for getting desired range of amylose content (AC) and gelatinization temperature (GT) in improved cultivars through combining desired alleles through MAS. © 2012 Elsevier Inc. Source

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