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Peri-urban lands are often used for production of vegetables for better market accessibility and higher prices. But most of these lands are contaminated with heavy metals through industrial effluents, sewage and sludge, and vehicular emission. Vegetables grown in such lands, therefore, are likely to be contaminated with heavy metals and unsafe for consumption. Samples of vegetables i.e., spinach (Spinacia oleracea L.) and okra (Abelmoschus esculentus L.); soil and irrigation water were collected from 5 peri-urban sites of New Delhi to monitor their heavy metal loads. While heavy metal load of the soils were below the maximum allowable limit prescribed by the World Health Organization (WHO), it was higher in irrigation water and vegetable samples. The spinach and okra samples showed Zn, Pb and Cd levels higher than the WHO limits. The levels of Cu, however, were at their safe limits. Metal contamination was higher in spinach than in okra. Spatial variability of metal contamination was also observed in the study. Bio-availability of metals present in soil showed a positive relationship with their total content and organic matter content of soil but no relationship was observed with soil pH. Washing of vegetables with clean water was a very effective and easy way of decontaminating the metal pollution as it reduced the contamination by 75 to 100%.

The cereal cyst nematode (CCN, Heterodera avenae) is a major pest of wheat (Triticum spp) that reduces crop yields in many countries. Cyst nematodes are obligate sedentary endoparasites that reproduce by amphimixis. Here, we report the first transcriptome analysis of two stages of H. avenae. After sequencing extracted RNA from pre parasitic infective juvenile and adult stages of the life cycle, 131 million Illumina high quality paired end reads were obtained which generated 27,765 contigs with N50 of 1,028 base pairs, of which 10,452 were annotated. Comparative analyses were undertaken to evaluate H. avenae sequences with those of other plant, animal and free living nematodes to identify differences in expressed genes. There were 4,431 transcripts common to H. avenae and the free living nematode Caenorhabditis elegans, and 9,462 in common with more closely related potato cyst nematode, Globodera pallida. Annotation of H. avenae carbohydrate active enzymes (CAZy) revealed fewer glycoside hydrolases (GHs) but more glycosyl transferases (GTs) and carbohydrate esterases (CEs) when compared to M. incognita. 1,280 transcripts were found to have secretory signature, presence of signal peptide and absence of transmembrane. In a comparison of genes expressed in the pre-parasitic juvenile and feeding female stages, expression levels of 30 genes with high RPKM (reads per base per kilo million) value, were analysed by qRT-PCR which confirmed the observed differences in their levels of expression levels. In addition, we have also developed a user-friendly resource, Heterodera transcriptome database (HATdb) for public access of the data generated in this study. The new data provided on the transcriptome of H. avenae adds to the genetic resources available to study plant parasitic nematodes and provides an opportunity to seek new effectors that are specifically involved in the H. avenae-cereal host interaction.

Sequestration of soil organic carbon (SOC) is an important strategy to improve soil quality and to mitigate climate change. To investigate changes in SOC under conservation agriculture (CA), we measured SOC concentrations after seven years of rice (Oryza sativa L.)-wheat (Triticum aestivum L.) rotations in the eastern Indo-Gangetic Plains (IGP) of India under various combinations of tillage and crop establishment methods. The six treatments were as follows: conventional till transplanted rice followed by conventional till wheat (CTR-CTW), CTR followed by zero-till wheat (CTR-ZTW), ZT direct-seeded rice followed by CTW (ZTDSR-CTW), ZTDSR followed by ZT wheat both on permanent raised beds with residue (PBDSR-PBW+R), and ZTDSR followed by ZTW both with (ZTDSR-ZTW+R) and without residues (ZTDSR-ZTW). We hypothesized that CA systems (i.e. ZT with residue retention) would sequester more carbon (C) than CT. After seven years, ZTDSR-ZTW+R and PBDSR-PBW+R increased SOC at 0-0.6 m depth by 4.7 and 3.0 t C/ha, respectively, whereas the CTR-CTW system resulted in a decrease in SOC of 0.9 t C/ha. Over the same soil depth, ZT without residue retention (ZTDSR-ZTW) only increased SOC by 1.1 t C/ha. There was no increase in SOC where ZT in either rice or wheat was followed by CT in the next crop (i.e. CTR-ZTW and ZTDSR-CTW), most likely because the benefit of ZT is lost when followed by tillage. Tillage and crop establishment methods had no significant effect on the SOC stock below the 0.15-m soil layer. Over the seven years, the total carbon input from above-ground residues was ca. 14.5 t/ha in ZTDSR-ZTW+R and PBDSR-PBW+R, almost sixfold greater than in the other systems. Our findings suggest that the increased biomass production achieved through a combination of ZT and partial residue retention offers an opportunity to increase SOC whilst allowing residues to be used for other purposes.

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There is a lack of information on the molecular characterization of Ocimum species and hence, efforts have been made under the present study to characterize 17 Ocimum genotypes belonging to 5 different species (O. basilicum, O. americanum, O. sanctum, O. gratissimum and O. Polystachyon) through random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) markers. PCR amplification using 20 RAPD primers generated a total of 506 loci, of which 490 (96.47 %) loci were found polymorphic. The PIC value for RAPD ranged from 0.907 (OPF 14) to 0.954 (OPC 11) with an average of 0.937. The ISSR primers generated a total of 238 loci, of them 234 (98.17 %) loci were polymorphic. The PIC value ranged from 0.892 (UBC 808) to 0.943 (ISSR A12) with an average of 0.923. The average Jaccard’s similarity coefficient based on RAPD and ISSR analysis was 0.58 and 0.52, respectively. Clustering pattern of dendrogram generated using the pooled RAPD and ISSR data showed all Ocimum genotypes in their respective species groups at a cutoff value of 0.49 and 0.42, respectively. Many unique species-specific alleles were amplified by RAPD and ISSR markers. In both marker systems, a maximum number of unique alleles were observed in O. sanctum. The results of the present investigation provided valid guidelines for collection, conservation and characterization of Ocimum genetic resources.