Epoxysesquithujene, a novel sesquiterpenoid from Valeriana hardwickii var. hardwickii

Epoxysesquithujene, a new sesquiterpene epoxide has been characterized in the essential oil of Valeriana hardwickii var. hardwickii on the basis of chemical reactions and extensive NMR data. Fourteen other terpenoids have also been identified on the basis of GC-MS.     

Genetic diversity and population structure analysis of isolates of the rice false smut pathogen Ustilaginoidea virens in India

Genetic diversity assessment and population structure analysis are essential for characterization of pathogens and their isolates. Markers are essential tools for exploring genetic variation among the isolates. False smut of rice caused by Ustilaginoidea virens, formerly Villosiclava virens, is a major emerging disease of rice in India. A high level of variability is observed at the field level, but no information is available from India on genetic diversity and population structure. This is the first report of genetic diversity and population structure of U. virens from India that included 63 isolates distributed across the vast geographical area of eastern and north-eastern India (18.9 to 26.7°N and 82.6 to 94.2°E). Seventeen RAPDs and 14 SSRs were identified as polymorphic and a total of 140 alleles were detected across the populations. The average number of alleles per locus for each primer was 4.5. All the isolates were grouped into two major clusters, with partial geographical segregation that was supported by principal coordinate analysis. Mantel test suggested genetic distance within the isolates increased with increasing geographical distance. Analysis of molecular variation showed more genetic variation within populations and less among populations. This outcome will help in understanding genetic diversity of U. virens from eastern and north-eastern India and in planning effective management strategies.     

Genetic diversity analysis of severely infesting invasive thrips,Thrips parvispinus (Karny) in chilli (Capsicum annuum L.) in India

Phytoparasitica - Thrips are economically important pests of crops and vectors of viral diseases worldwide. Invasion and outbreak of thrips have recently caused havoc in agricultural and...     

Characterization of brown planthopper damage on rice crops through hyperspectral remote sensing under field conditions

Field experiments were conducted to characterize the brown planthopper (BPH) (Nilaparvata lugens (Stål.) damage stress on rice crops through hyperspectral remote sensing. The BPH-damaged rice crop had higher reflectance in visible (VIS) and lower reflectance in near-infrared regions (NIR) of the electromagnetic spectrum compared with uninfested plants. Mean reflectance of the rice crop varied among different BPH damage levels in various wavebands, with the greatest variation in NIR (740–925 nm). Correlations between plant reflectance and BPH damage depicted four sensitive wavelengths, at 764, 961, 1201 and 1664 nm in relation to BPH stress on the rice crop. Three new brown planthopper spectral indices (BPHI) were formulated by combining two or more of these sensitive wavelengths. Some of the hyperspectral indices reported in the literature were also tested for their suitability to detect BPH stress on rice crops. Based on crop reflectance corresponding to the sensitive wavelengths, a multiple-linear regression model was developed (R²=0.71, RMSE=1.74, P<0.0001) and validated (R²=0.73, RMSE?=?0.71, P<0.0001) that would help to monitor BPH stress on a rice crop and to issue forewarnings to growers.     

Removal of Cu and Cd from water by Bacopa monnieri L.

Copper and Cd accumulation was determined in Bacopa monnieri, a common aquatic plant. Plants showed a capability to accumulate both metals in single and mixed metal treatments. Copper accumulation was stimulated by the presence of Cd whereas uptake of Cd was inhibited by Cu. The plants showed high concentration factors for both metals. The results suggest the possibility of using this plant for mitigating Cu and Cd pollution in the aquatic environment.     

美国减少棉产区土壤侵蚀的农业措施

土壤侵蚀已经导致了美国棉花生产地区棉花产量的下降。为控制土壤侵蚀 ,于 1 996～ 1 998年间在美国阿拉巴马 (Ａｌａｂａ ｍａ)州ＢｅｌｌｅＭｉｎａ阿拉巴马农业试验站开展了一项研究。研究包括三种处理方法 :传统耕作方法、覆盖耕作和免耕 ;两种作物配置系统 :一种是冬棉花     

Enzymatic treatment and use of starters for the nutrient enhancement in fermented flour of red and white varieties of finger millet (Eleusine coracana).

Two varieties of finger millet (Eleusine coracana)-a tannin-containing red variety, CO13, and nontannin white variety, CO9-processed by treatment with enzymes (cellulase and hemicellulase) and fermentation with starters (from previously fermented finger millet batter), achieved the desirable goals of reduced fermentation time (12 h), increased acidity (2.2 to 2.4%), enhanced in vitro protein digestibility (IVPD) (14 to 26%), and mineral availability compared to 48 h uncontrolled natural fermentation (Usha Antony and Chandra, 1998). Fermentation with starters alone increased titratable acidity (1.02 to 1.88%), IVPD (5. 5 to 22%) and mineral availability, and decreased phytate (23 to 26%) and tannin (10.8 to 40.5%) in the millets. Enzymatic treatment (3 h, 50 degrees C) did not significantly alter the pH, phytate, tannins, IVPD, or HCl-mineral extractability but enhanced fermentative changes. Overall, the changes were marked when the 48 h starter was used and the improvements in nutrient availability was greater in the CO13 variety.