Effect of organic and inorganic sources of nutrients on soil microbial activity and soil organic carbon build-up under rice in west coast of India

The effect of medium-term (5 years) application of organic and inorganic sources of nutrients (as mineral or inorganic fertilizers) on soil organic carbon (SOC), SOC stock, carbon (C) build-up rate, microbial and enzyme activities in flooded rice soils was tested in west coast of India. Compared to the application of vermicompost, glyricidia (Glyricidia maculate) (fresh) and eupatorium (Chromolaena adenophorum) (fresh) and dhaincha (Sesbania rostrata) (fresh), the application of farmyard manure (FYM) and combined application of paddy straw (dry) and water hyacinth (PsWh) (fresh) improved the SOC content significantly (p < 0.05). The lowest (p < 0.05) SOC content (0.81%) was observed in untreated control. The highest (p < 0.05) SOC stock (23.7 Mg C ha^?1) was observed in FYM-treated plots followed by recommended dose of mineral fertilizer (RDF) (23.2 Mg C ha^?1) and it was lowest (16.5 Mg C ha^?1) in untreated control. Soil microbial biomass carbon (C_mb) (246 µg g^?1 soil) and C_mb/SOC (1.92%) were highest (p < 0.05) in FYM-treated plot. The highest (p < 0.05) value of metabolic quotient (qCO₂) was recorded under RDF (19.7 µg CO₂-C g^?1 C_mb h^?1) and untreated control (19.6 µg CO₂-C g^?1 C_mb h^?1). Application of organic and inorganic sources of nutrients impacted soil enzyme activities significantly (p < 0.05) with FYM causing highest dehydrogenase (20.5 µg TPF g^?1 day^?1), phosphatase (659 µg PNP g^?1 h^?1) and urease (0.29 µg urea g^?1 h^?1) activities. Application of organic source of nutrients especially FYM improved the microbial and enzyme activities in flooded and transplanted rice soils. Although the grain yield was higher with the application of RDF, but the use of FYM as an organic agricultural practice is more useful when efforts are intended to conserve more SOC and improved microbial activity.     

Morpho-physiological and biochemical response of maize (Zea mays L.) plants fertilized with nano-iron (Fe3O4) micronutrient

Nano-sized formulations of micronutrient iron (Fe) were found to substantially alter the growth and metabolism of maize plants. Plants fertilized with the optimal recommended dose of Fe in the nano-form (54 μM) registered an enhancement in morphological features, viz. plant height, biomass (shoot and root), and diminution in antioxidant enzyme activities than the plants fertilized with the sub-optimal dose of Fe in the macroform (salts). However, half of the recommended dosage of Fe (27 μM) in the nano-form positively influenced leaf area and proline content of plants too. This indicated that there is a possibility of reducing the dose of Fe supplement for plants in the nano-form to increase the nutrient use efficiency in a major cereal crop like maize. This may open a new era in plant nutrient management with a scope for improvement in nutrient use efficiency using nano-nutrient formulations.     

A molecular approach for identification of paramphistomes from Africa and Asia

Paramphistomiasis is a disease of domestic and wild ruminants caused by some digenetic trematodes of the superfamily Paramphistomoidea. Human infections with certain species of paramphistomes have been reported. Given their ubiquity and their abundance within hosts, it seems likely that the importance of these worms is underestimated globally. Based on the reported difficulties of morphological identification of paramphistomes, the development of alternative approaches to better delineate species is needed. Paramphistome samples examined during this study were cercariae, rediae from snail hosts and adult flukes obtained from slaughterhouses from Kenya, Tanzania, Egypt and Nepal. The results confirm that ITS2 is a good molecular marker for paramphistome identification and can be used to determine the affiliation of samples among the different taxa of Paramphistomoidea. Our 22 samples include eight species of paramphistomes. Ten samples of paramphistome larvae (cercariae or rediae) yielded seven species and the 12 samples of adult flukes from bovines yielded four, only one of which was not also represented among the larvae. We found three cases in which the sequences for adult worms and larvae matched, thus revealing the hosts involved locally in those particular life cycles. We interpret our specimens to include five species from Kenya, two from Nepal, two from Tanzania and one from Egypt. Bulinus forskalii was found infected with three species of paramphistomes. The results of the present study will help construct a framework to facilitate identification and eventually control of this underestimated cosmopolitan group of digeneans.     

Survival and development of spotted bollworm, <Emphasis Type="Italic">Earias vittella</Emphasis> (Fabricius) (Lepidoptera: Nolidae) on different transgenic <Emphasis Type="Italic">Bt</Emphasis> and isogenic non-<Emphasis Type="Italic">Bt</Emphasis> cotton genotypes

Four Bt cotton hybrids, each with one of four different events, viz., MRC 6301 Bt (cry1Ac gene), JKCH 1947 Bt (modified cry1Ac gene), NCEH 6R Bt (fusion cry1Ac/cry1Ab gene) and MRC 7017 Bollgard II (cry1Ac and cry2Ab genes) were compared for survival and development of Earias vittella (Fabricius) along with their isogenic non-Bt genotypes. None of the neonates were able to complete the larval period and reach pupal stage on squares of 90, 120 and 150 days old crop of all Bt hybrids. Likewise, on bolls also, zero per cent larval survival was observed in all Bt hybrids except JKCH 1947 Bt where 0.67 per cent larvae could manage to reach pre-pupal stage at 120 and 150 days old crop but failed to form cocoon and enter pupal stage. The surviving larva took more development time (3.7 to 5.4 days) as compared to larvae fed on bolls of JKCH 1947 non-Bt. The average survival period (ASP) of larvae was in order of 150 > 120 > 90 days old crop among the crop ages; JKCH 1947 Bt > MRC 6301 Bt > NCEH 6 R Bt > MRC 7017 Bollgard II among Bt hybrids; and bolls > squares between fruiting bodies. However, reverse was true for speed index of toxic effect. The concentration of Cry toxin varied significantly in squares and bolls and also among the crop ages. The amount of Cry toxin in squares and bolls had significant negative correlation with ASP of the E. vittella larvae.     

A PCR-based assessment of genetic diversity,and parentage analysis among commercial mango cultivars and hybrids

Summary

Three different PCR methods [Random Amplified Polymorphic DNA (RAPD), Inter-Simple Sequence Repeats (ISSR), and Directed Amplification of Minisatellite DNA (DAMD)] were used to analyse genetic diversity and parentage among 20 mango cultivars, including 18 landraces and two hybrids (‘Amrapali’ and ‘Mallika’). These hybrids together with a third hybrid (‘Ratna’), and an out-group species (Mangifera sylvatica) were also analysed for parentage. Fifteen, seven and four primers were used to amplify a total of 158, 69 and 59 distinct DNA fragments by RAPD, ISSR and DAMD, respectively. Of these, approx. 85%, 64% and 90% were polymorphic, respectively. Genetic distances between pairs of mango cultivars were measured separately by each method and depicted graphically as a Neighbor Joining (NJ) tree. The three methods revealed different groupings of cultivars and hybrids. A NJ tree based on the cumulative data from all methods correlated well with the parentage of the mango hybrids, and the grouping of cultivars on a regional basis. Genetic markers likely to be associated with important agronomic traits were identified by further analysing the hybrids, with their respective parents, using all three methods. On the basis of the highest number of polymorphic bands observed (90%), DAMD was judged to be the best method with which to analyse mango germplasm.     

Inhibition of estrogen-mediated mammary tumorigenesis by blueberry and black raspberry

We previously demonstrated the protective effects of blueberry (BB) and black raspberry (BRB) supplemented at 2.5% dose in an ACI rat mammary tumor model. Here, we assessed a dose-related alteration in tumor indices with diet supplemented with 5% BB or BRB powder. The diet was well tolerated. Tumor palpation from 12 weeks revealed first tumor appearance by 84 days in the control group, that was delayed by 24 and 39 days with the BB and BRB diets, respectively (p = 0.04). Ellagic acid detected in the plasma of rats fed the BRB diet was in the range of 96.6-294.2 ng/mL. While the BB diet showed better efficacy in reducing mammary tissue proliferation and tumor burden, tumor latency was delayed efficiently by BRB. Furthermore, BB was effective in downregulating CYP1A1 expression, while BRB downregulated ERα expression effectively. Distinct anticarcinogenic effects of the two berries correspond to their distinct phytochemical signatures.     

Genetic variation among highly endangered <Emphasis Type="Italic">Bacopa monnieri</Emphasis> (L.) Pennell from Southern India as detected using RAPD analysis

Randomly amplified polymorphic DNA (RAPD) fingerprinting approach was applied to assess genetic diversity in different accessions of rejuvenating and intellect-promoting ancient ayurvedic medicinal herb Bacopa monnieri (L.) Pennell collected from four Southern Indian states, along with in vitro micropropagated samples maintained in the laboratory for 5 years. With the 10 analyzed primers, 110 distinct bands, in the size range of 250–870 bp were observed, and among which 14 (12.72%) were polymorphic. Among the random primers used, only OPD 02 generated highest percentage of polymorphism with 30.77. Whereas OPD 08 generated a maximum of 18 amplified bands, but with only 1% polymorphism. Cluster analysis done on the basis of similarity co-efficient generated from RAPD profiles indicated all the accessions were divided into two sub-groups based on genetic distances under one major cluster. Major cluster is only the lone loose group of the Bm.2 collected from Kerala (KER) and in vitro micropropagated plant (IVMP) maintained in the lab. The other sub-group consisted of Bm.1 and Bm.3 collected from Tamil Nadu (TN) and Andhra Pradesh (AP) respectively, which are genetically similar and showed similarity with accessions from Karnataka Bm.4 (KK). These two sub-groups were joined together at 0.66 genetic distance level. Overall, the levels of genetic similarity within the accessions varied from 0.24 to 0.80, the matrix ranged from 0.36 to 0.80, with a mean value of 0.68 indicating genetic similarity at low level.     

Prospective use of bacteriocinogenic Pediococcus pentosaceus as direct-fed microbial having methane reducing potential

Direct-fed microbials(DFM), generally regarded as safe status, are successfully used in improving rumen ecology, gastro-intestinal health, feed efficiency, milk production and growth rate in ruminants. On the other hand, methanogenesis in rumen, which accounts for a significant loss of ruminant energy and increased greenhouse gas in environment, is of great concern, therefore, use of DFM for improving productivity without compromising the animal health and ecological sustainability is encouraged. The present study was conducted to investigate the methane reducing potential of bacteriocinogenic strain Pediococcus pentosaceus-34. Since, the culture showed no hemolysis on blood agar and DNase activity, hence, it was considered to be avirulent in nature, a prerequisite for any DFM. The culture also showed tolerance to pH 5.0 for 24 h with 0.5% organic acid mixture, whereas when given a shock for 2 h at different p H and organic acids concentrations, it showed growth at pH 3.0 and 4.0 with 0.1 and 1.0% organic acids, respectively, as having good animal probiotics attributes. The total gas production was significantly(P<0.05) higher in live pedicoccal culture(LPC) and dead pedicoccal culture(DPC) both with wheat straw, when compared to the control. In sugarcane bagasse, gas production was significantly lower(P<0.05) with LPC compared to the control and DPC both. Methane was reduced by the inclusion of LPC in sugarcane bagasse(0.07 mL CH4 mg–1 dry matter digestibility) with no effect on other rumen fermentation parameters. However, with wheat straw and LPC total gas, in vitro dry matter digestibility, total volatile fatty acids increased significantly but no reduction in methane production was observed in comparison to the control. Therefore, further research is warranted in this direction, if the bacteriocinogenic strains can be used as DFM for ruminants to improve the ruminant productivity.     

Effect of planting date on growth, development, aerial biomass partitioning and essential oil productivity of wild marigold (Tagetes minuta) in mid hills of Indian western Himalaya

A field investigation was conducted at the Institute of Himalayan Bioresource Technology, Palampur during the year 2005 to study the effect of planting dates on duration of growth and development in wild marigold (Tagetes minuta). Duration of growth phases (vegetative phase to budding phase and budding phase to 50% flowering phase), aerial biomass partitioning and essential oil production were analysed. Plantings were done in seven consequent meteorological standard weeks (MSWs) starting from the 30th MSW (30 July–5 August). Planting time coincided with distinct changes in weather parameters and consequently significant variation in the performance of the crop. The results indicated that the crop planted in the 30th and 31st MSW had the longest duration of growth and highest aerial biomass. But it partitioned more biomass towards the stem, whereas the crop planted in the 35th MSW produced significantly less biomass than the former and partitioned more towards leaf and flower and had maximum essential oil content and production. The crop planted at the 36th MSW had the minimum field duration of growth of 50 days, but the partitioning towards leaf and flower were higher than the longest field duration of growth (30th MSW). The study clearly indicated that planting dates had profound influence on growth and development of T. minuta as reflected from the significant variation on growth phase duration, aerial biomass partitioning, herb and essential oil yield.