Molecular characterization and variability analysis of <Emphasis Type="Italic">Apple scar skin viroid</Emphasis> in India

Apple scar skin viroid (ASSVd) infection is a major limitation to apple fruit quality and causes huge economic losses. In surveys of apple orchards in the northern Indian state of Himachal Pradesh, fruits with dappling symptoms were noticed. ASSVd was detected from these fruits and molecularly characterized. Ten clones from three isolates were sequenced, of which seven were new sequence variants of ASSVd. The clones had significant sequence variability (94–100%) with each other. Variability was more common in the pathogenic domain of the viroid genome. Four of the clones were 330 nucleotides (nt) long, and the other six had an additional nucleotide. Phylogenetic analysis showed close affinity of the present isolates with some Chinese and Korean isolates. The study reports seven new variants of ASSVd and also provides the first molecular evidence of viroid infection (ASSVd) in apple in India.     

Atmospheric Deposition in a Rural Area in India - Net and Potential Acidity

Atmospheric deposition in India is generally described as alkaline and well buffered against an increase of acidifying components. Such conclusion has been based on measurements usually performed in urban or suburban areas. Our data on deposition in NE India (in the countryside N of Bhubaneswar) obtained with wet-only and bulk collectors show that: 1) the weighted mean concentrations (and wet deposition) of H⁺ and HCO₃ ^? are almost equal, with dustfall contributing a negligible amount of HCO₃ ^?, 2) the deposition of potential acidity, defined as the acidity that would give the same acidity contribution to the receiving surface as the actual deposition provided that all ammonium was converted to nitrate in the soil, could be as high as 40 mmol H⁺ m^?2 a^?1 corresponding to a pH of 4.3 in precipitation. The low buffer capacity against acidification and high potential acidity were discovered from long- term measurements in a vegetation covered rural area. Similar measurements in a nearby suburban area gave a much higher input of HCO₃ ^? both in wet deposition and dustfall. Further increase of the emission of acidifying components in the region will increase the acid deposition.     

Leaf yield component combining abilities in mulberry (Morus spp.)

A line × tester analysis was carried out in mulberry (Morus spp.) to determine the genetic interaction in the expression of various quantitative characters including leaf yield. Eight clonal varieties were selected, 3 of them were designated as lines (♀) viz. Berhampore-1, China white and MS-5 and 5 of them were called as testers (♂) viz. Mandalaya, Kosen, Assamjati, MS-1 and Kajli. Combining ability studies were conducted on these parents along with their F₁ hybrids for the variables laminar index, growth rate, weight of 100 dry leaves, number of primary branches per plant, plant height, nodal distance, leaf-twig ratio, aerial biomass, moisture content, moisture retention capacity and leaf yield. Broad genetic variability was observed among the genotypes. The ratio of General Combining Ability (GCA) and Specific Combining Ability (SCA) indicated the predominance of non-additive genes in mulberry. While China white (female) and MS-1 (male) were the best general combiners among the parents, Berhampore-1 × Kajli was the best cross for leaf yield. Results suggest that selective crossing followed by proper screening may be the best approach for breeding of high yielding varieties in mulberry. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of Ocimum sanctum Linn. (Tulsi) extract on the immunity and survival of Labeo rohita (Hamilton) infected with Aeromonas hydrophila

A 60 days study was conducted to evaluate the efficacy of water extract of Ocimum sanctum Linn. leaf on the immune response and disease resistance of Labeo rohita fingerlings against the Aeromonas hydrophila infection. Ocimum sanctum extract was incorporated in the diets (at 0.0%, 0.05%, 0.1%, 0.2%, 0.5% and 1%) of Labeo rohita, rohu fingerlings (6.6 ± 0.013 g). After 42 days blood, plasma and serum were sampled to determine super oxide anion production, lysozyme activity, total immunoglobulin in plasma, blood glucose, serum total protein, albumin, globulin, albumin:globulin ratio, WBC, RBC, haemoglobin content. Fish were challenged with A. hydrophila after 42 days and mortalities were recorded over 18 days post infection. The results demonstrate enhanced super oxide anion production, lysozyme activity, total immunoglobulin in plasma, serum total protein, globulin, total RBC counts, total WBC counts and haemoglobin content (P < 0.05) in treatments group compared with control group. Dietary O. sanctum extracts of 0.2% showed significantly (P < 0.05) higher protection relative percentage survival (RPS 40.00 ± 5.773%) against A. hydrophila infection than control. These results indicate that O. sanctum leaf extract stimulates the immunity and makes L. rohita more resistant to bacterial infection (A. hydrophila).     

Screening new <Emphasis Type="Italic">Arachis</Emphasis> amphidiploids,and autotetraploids for resistance to late leaf spot by detached leaf technique

Cultivated groundnut is susceptible to late leaf spot (LLS) caused by Phaeoisariopsis personata [(Berk. & M.A. Curtis) Aex] and resistance is low to moderate in the primary gene pool of groundnut. Closely related wild species in the secondary gene pool are highly resistant to the disease. All the closely related Arachis species are diploid and cultivated groundnut is a tetraploid. Utilization of diploid Arachis species to transfer LLS resistance is time consuming and cumbersome. New sources of Arachis hypogaea (also called synthetic groundnut) were developed at ICRISAT. These are tetraploids and the present investigation has shown that they are resistant to LLS.     

Effect of conservation agriculture on soil organic and inorganic carbon sequestration and lability: A study from a rice–wheat cropping system on a calcareous soil of the eastern Indo-Gangetic Plains

Increasing soil carbon (C) in arable soils is an important strategy to achieve sustainable yields and mitigate climate change. We investigated changes in soil organic and inorganic carbon (SOC and SIC) under conservation agriculture (CA) in a calcareous soil of the eastern Indo-Gangetic Plains of India. The treatments were as follows: conventional-till rice and wheat (CT-CT), CT rice and zero-till wheat (CT-ZT), ZT direct seeded rice (DSR) and CT wheat (ZT-CT), ZTDSR and ZT wheat without crop residue retention (ZT-ZT), ZT-ZT with residue (ZT-ZT+R), and DSR and wheat both on permanent beds with residue (PB-PB+R). The ZT-ZT+R had the highest total SOC in both 0–15 and 15–30 cm soil layers (20% and 40% higher (p < .05) than CT-CT, respectively), whereas total SIC decreased by 11% and 15% in the respective layers under ZT-ZT+R compared with CT-CT. Non-labile SOC was the largest pool, followed by very labile, labile and less labile SOC. The benefits of ZT and residue retention were greatest for very labile SOC, which showed a significant (p < .05) increase (~50%) under ZT-ZT+R compared with CT-CT. The ZT-ZT+R sequestered ~2 Mg ha⁻¹ total SOC in the 0–15 cm soil layer in 6 years, where CT registered significant losses. Thus, the adoption of CA should be recommended in calcareous soils, for C sequestration, and also as a reclamation technique.     

Extension of shelf life of tuberose flowers using a combination of gamma irradiation and generally regarded as safe (GRAS) preservatives and assessment of antimicrobial potency of senesced flowers

Tuberose cut flowers, available as loose flowers, were treated with gamma (γ) irradiation and generally regarded as safe (GRAS) preservative solutions for extension of shelf life. The flowers were packaged in low-density polyethylene bags, heat sealed and stored at 23 ± 2°C, 80% relative humidity (RH) and 4 ± 1°C, 40% RH, respectively. The flowers stored at these two temperature regimes were subjected to sensory evaluation and biochemical analyses. From these assessments, the longest shelf life of tuberose flowers was found to be 8 days at 23 ± 2°C, 80% RH (compared to 4 days for control) and 24 days at 4 ± 1°C, 40% RH (compared to 8 days for control) using combination treatment of low dose γ-irradiation (0.02 kGy) and preservative solutions (4% sucrose and 0.02% CaCl₂). Ethanolic extract of tuberose flowers of the most shelf stable set (stored at 4 ± 1°C), i.e. at the end of 24 days, showed antimicrobial potency against the common skin pathogen Staphylococcus aureus (ATCC 25923 and MDR strains), suggesting utility of the senesced tuberose flowers for therapeutic applications. This preservation technique would promote export of tuberose flowers by extension of their shelf lives and allow utilization of these flowers, post senescence.