Adoption of rubber-integrated farm-livelihood systems: contrasting empirical evidence from the Indian context

This paper examines the influence of important socio-economic, institutional/policy level factors in determining the adoption/non-adoption of rubber-integrated farming systems in traditional and non-traditional rubber-growing regions in India. The empirical analysis is based on a survey of rubber growers in the traditional rubber regions of Kerala (south India) and the non-traditional rubber regions of Assam, Meghalaya, and Tripura (north east India). In sharp contrast to Kerala, where smallholder responses toward adoption of rubber-integrated farming systems have been lukewarm, the emerging rubber economies (most of which are tribal communities) of north east (NE) India have shown interest in adopting rubber as an integrated farming system along with pre-existing land-use livelihood activities. The study clearly demonstrates contrasting empirical evidence of adoption of rubber-integrated farm-livelihood systems in the rubber-growing regions in Kerala and the NE states in India. The contrasting scenarios of adoption of rubber-integrated farming systems are mostly explained by region-specific factors dominated by socio-economic, institutional variables, and policy-level constraints, as also revealed by multivariate analysis. By and large, the findings of the study have significant bearing on the socio-economic outcomes and the existing institutional development paradigm underlying the rubber-development programmes introduced in India since independence. The study shows that the existing institutional arrangements and policies, which evolved historically to facilitate rubber area expansion in the traditional regions (including Kerala), have been highly instrumental in perpetuating rubber farming as a monoculture system. However, such an institutional mechanism proves to be highly redundant in the context of the NE states which are otherwise diverse in terms of integrated farm-livelihood systems and shifting cultivation.     

Effect of Heat Stress on Grain Growth, Starch Synthesis and Protein Synthesis in Grains of Wheat (Triticum aestivum L.) Varieties Differing in Grain Weight Stability

The effect of heat stress on the components of grain weight was analysed in wheat ( Triticum aestivum L.) varieties differing in grain weight stability. The wheat varieties PBW154, Sonalika and Hindi62 were raised in the field (New Delhi, India; 77°12' E, 28°40' N, 228.6 m a.s.l.) at three dates of sowing: 19 November 1992 (DOS I), 14 December 1992 (DOS II) and 18 January 1993 (DOS III). The late-sown crop (DOS III) experienced 6–8 °C warmer temperatures during grain development than the crop sown at the normal time (DOS I). The heat susceptibility index (S) revealed that grain weight was less susceptible to heat in Sonalika and PBW154 than in Hindi62. Heat stress reduced both the grain growth duration (GGD) and the grain growth rate (GGR). The grain weight reduction in PBW154 and Sonalika was mainly due to a reduction in GGR, while that of Hindi62 was due to a reduction in GGD. In vivo studies on starch and protein synthesis in excised endosperm at 15, 25 and 35 °C revealed that both processes were more thermotolerant in Hindi62 than in PBW154. The grain starch content was stable in Hindi62 while that in PBW154 was significantly reduced under heat stress. The grain nitrogen content at maturity increased in both varieties under heat stress. It was concluded that the heat susceptibility of grain weight in Hindi62 was mainly due to a reduction in GGD, although GGR, starch and protein synthesis were more thermotolerant in developing grains of Hindi62 than in those of PBW154.     

Surface order and stability of langmuir-blodgett films

Angstrom-resolution atomic force microscope images of Langmuir-Blodgett monolayers and multilayers of cadmium arachidate in air and under water show a dramatic change from a disordered arrangement to a crystalline lattice by the addition or removal of a single layer of molecules. The disordered surface is less stable than the ordered one to mechanical stresses such as atomic force microscopy tip forces or at the air-water contact line during contact angle measurements. The difference in the degree of order in the alkyl chains is attributed to the strong attractive interaction between headgroups in the presence of the divalent cation.     

Widespread divergence between incipient Anopheles gambiae species revealed by whole genome sequences

The Afrotropical mosquito Anopheles gambiae sensu stricto, a major vector of malaria, is currently undergoing speciation into the M and S molecular forms. These forms have diverged in larval ecology and reproductive behavior through unknown genetic mechanisms, despite considerable levels of hybridization. Previous genome-wide scans using gene-based microarrays uncovered divergence between M and S that was largely confined to gene-poor pericentromeric regions, prompting a speciation-with-ongoing-gene-flow model that implicated only about 3% of the genome near centromeres in the speciation process. Here, based on the complete M and S genome sequences, we report widespread and heterogeneous genomic divergence inconsistent with appreciable levels of interform gene flow, suggesting a more advanced speciation process and greater challenges to identify genes critical to initiating that process.     

Bright Spots, Structure, and Magmatism in Southern Tibet from INDEPTH Seismic Reflection Profiling

INDEPTH seismic reflection profiling shows that the decollement beneath which Indian lithosphere underthrusts the Himalaya extends at least 225 kilometers north of the Himalayan deformation front to a depth of approximately 50 kilometers. Prominent reflections appear at depths of 15 to 18 kilometers near where the decollement reflector apparently terminates. These reflections extend north of the Zangbo suture to the Damxung graben of the Tibet Plateau. Some of these reflections have locally anomalous amplitudes (bright spots) and coincident negative polarities implying that they are produced by fluids in the crust. The presence of geothermal activity and high heat flow in the regions of these reflections and the tectonic setting suggest that the bright spots mark granitic magmas derived by partial melting of the tectonically thickened crust.     

Terbuthylazine and carbofuran effects on growth and reproduction within three generations of Eisenia andrei (Oligochaeta)

Sublethal effects of terbuthylazine and carbofuran on the growth and reproduction of Eisenia andrei were investigated over a period of three generations. Reproduction was assessed by measuring the coccon production of worms treated chronically with pesticides. Inhibition of cocoon production was found in the parental generation. Hatchlings were raised from cocoons to provide the F₁ generation. During raising a more rapid growth of juveniles treated with terbuthylazine was observed, compared with the growth of untreated worms. The increase in vitality was also found in cocoon production. Groups treated with terbuthylazine produced more cocoons than controls. The F₂ generation was raised from hatchlings of the F₁ generation, and here, also the terbuthylazine treatments increased earthworm growth, but not cocoon production. Exposure to carbofuran decreased cocoon production in all generations. Growth of the F₁ generation was not influenced by low concentrations of carbofuran.     

Anticarcinogenic effects of curry leaves in dimethylhydrazine-treated rats

Curry leaves are one of the spices used in Indian dishes for aroma and preservation. There are no reports on the antioxidant properties of curry leaves. In this study, the antioxidant potential of curry leaves in rats treated with a known chemical carcinogen, dimethylhydrazine hydrochloride (DMH) was investigated. Food intake was reduced in the rats fed curry leaf-supplemented diet but the body and the organ weights were not affected.Vitamin A content in the liver was significantly increased whereas glutathione (GSH) content was not altered. A 50% reduction was seen in the micronuclei induced by DMH and a 30% reduction in the activity of ,-glutamyl transpeptidase when the rats were fed a curry leaf-supplemented diet. These results indicate that curry leaves have highpotential as reducer of the toxicity of DMH.     

DDT and HCH Residues in Basmati Rice (Oryza sativa) Cultivated in Dehradun (India)

Organochlorine pesticides were used earlier for agricultureproduction. Their residues may still be present in soil and mayaccumulate in food crops, posing potential health problems to consumers. DDT, HCH, their isomers and metabolites were analyzedin samples of soil and rice plants collected from ten differentvillages of a well-known Basmati rice growing area in Dehradun.Residues of both pesticides were found in all samples ofsoil and different parts of rice plants except for a few grainsamples. Maximum residue was observed in husk and minimum ingrains. The average concentration of DDT in soil ranged from0.013 to 0.238 ppm. p,p′-DDE was the major metabolite (>63%). Theaverage concentration of DDT in rice grain varied from 0.002 to 0.040 ppm. o,p′-DDT was the main isomer (>93%). Theaverage concentration of HCH in soil ranged from 0.122 to 0.638 ppm. β-HCH was the predominant (43%) isomerfollowed by α-HCH (21%). The average HCH concentrationin rice grain ranged between 0.013 and 0.113 ppm. All four isomers were present in grains. The levels of DDT and CHCin grains were similar in magnitude as those from differentIndian states, but well below the maximum residue limit of 0.1 ppm for DDT and 0.05 ppm for HCH prescribed by the Government ofIndia and WHO/FAO. As such, the pesticide residue levels in thisexport commodity are not of hazardous nature.