Arbuscular Mycorrhizal (AM) Diversity in Prosopis cineraria (L.) Druce Under Arid Agroecosystems

Arbuscular mycorrhizal (AM) fungi associated with Prosopis cineraria (Khejri) were assessed for their qualitative and quantitative distribution from eight districts of Rajasthan. A total of three species of Acaulospora, one species of Entrophospora, two species of Gigaspora, twenty-one species of Glomus, seven species of Sclerocystis and three species of Scutellospora were recorded. A high diversity of AM fungi was observed and it varied at different study sites. Among these six genera, Glomus occurred most frequently. Glomus fasciculatum, Glomus aggregatum, and Glomus mosseae were found to be the most predominant AM fungi in infecting Prosopis cineraria. Acaulospora, G. fasciculatum, Sclerocystis was found in all the fields studied, while Scutellospora species were found only in few sites. A maximum of thirty-six AM fungal species were isolated and identified from Jodhpur, whereas only thirteen species were found from Jaisalmer. Spores of Glomus fasciculatum were found to be most abundant under Prosopis cineraria.     

Identification of novel quantitative trait loci associated with brown planthopper resistance in the rice landrace Salkathi

The brown planthopper (BPH) is a potent pest of rice in Asia and Southeast Asia. Host resistance has been found to be the most suitable alternative to manage the insect. But varietal resistance has been found to be short-lived. There has been a constant search for alternate resistance genes. We developed an F₈ recombinant inbred population for the BPH resistance gene in Salkathi, an indica landrace from Odisha, India. Phenotyping of RILs against the BPH population at Cuttack, Odisha showed continuous skewed variation with four peaks at 2.1–3.0, 4.1–5.0, 6.1–7.0 and 8.1–9.0 SES score, suggesting the involvement of quantitative loci for resistance to BPH in Salkathi. Mapping showed the presence of two QTLs on the short arm of chromosome 4. One QTL, with phenotype variance of 37.02% is located between the markers RM551 and RM335. The other QTL, with phenotype variance of 7.1% is located between markers RM335 and RM5633. The two QTLs have been designated as qBph4.3 and qBph4.4. QBph4.3 seems to be a novel QTL associated with BPH resistance. We have successfully transferred qBph4.3 and qBph4.4 into two elite rice cultivars, Pusa 44 and Samba Mahsuri. Fine mapping of the identified QTLs may lead to a successful transfer of QTLs into other elite germplasm backgrounds.     

Lipid Indexes and Quality Evaluation of Omega-3 Rich Oil from the Waste of Japanese Spanish Mackerel Extracted by Supercritical CO2

Japanese Spanish mackerel (JSM) (Scomberomorus niphonius) is a marine fish species containing health-beneficial polyunsaturated fatty acids (PUFAs). In the present study, the quality of JSM by-products oils extracted by supercritical CO₂ (SC-CO₂) and organic solvent extraction was compared in terms of physico-chemical properties of the oils. Eicosapentaenoic acid (EPA) is one of the important polyunsaturated fatty acids present in SC-CO₂-extracted skin and muscle oil 5.81 ± 0.69% and 4.93 ± 0.06%, respectively. The amount of docosahexaenoic acid (DHA) in SC-CO₂-extracted skin and muscle oil was 12.56 ± 0.38% and 15.01 ± 0.28%, respectively. EPA and DHA are considered as important PUFAs for the development of brain function and the prevention of coronary heart diseases. Extracted oils showed considerable antioxidant activity. In the obtained oils, atherogenic index (AI) values varied from 0.72 to 0.93 and thrombogenic index (TI) ranged from 0.75 to 0.92, which is considered an acceptable level. Fatty acid composition, bio potentiality, thermogravimetric, and vitamin D analysis showed that oils extracted from JSM by-products can be a good source of oil for application in food, pharmaceutical and cosmetic industries. Therefore, the present research revealed the potentiality of green valorisation of S. niphonius by-products as a possible sustainable approach for targeting the era of zero waste.     

Genetical assessment of diploid progenitors of <Emphasis Type="Italic">S. scabra</Emphasis> by isozyme,RAPD and STS markers: a possible strategy for improvement of drought tolerant allo-tetraploid <Emphasis Type="Italic">S. scabra</Emphasis> species

Assessment of genetic variations of two progenitors of S. scabra was investigated employing isozyme, RAPD and STS markers. Earlier reports have conclusively indicated S. seabrana and S. viscosa as two diploid progenitors of allo-tetraploid S. scabra. A total of 476 RAPD bands generated from 32 primers, 104 STS fragments from 17 primer pairs and 73 isoforms from 14 enzyme systems indicated significant sharing of these bands to S. scabra with that of S. seabrana in comparison to its other progenitor i.e., S. viscosa. High frequencies of isozyme band sharing between S. seabrana and S. scabra (0.125–0.30) as well as high genetic similarities (59%) of it with S. seabrana as reveled from dendrogram analysis indicated impact of close proximity of the occurrence of S. seabrana in the development of S. scabra. The proportion of bands shared by RAPD (40%) and STS (40%) markers were also observed high between S. seabrana and S. scabra. However, the numbers of unique bands were less in all these species. More correspondence and sharing of bands by S. seabrana towards S. scabra suggested using selected lines of S. seabrana the genetic base of allo-tetraploid, drought tolerant S. scabra lines can be broaden.     

Screening global <Emphasis Type="Italic">Medicago</Emphasis> germplasm for weevil (<Emphasis Type="Italic">Hypera postica</Emphasis> Gyll.) tolerance and estimation of genetic variability using molecular markers

The genus Medicago encompasses many important forage species for both temperate and tropical regions. M. sativa L., commonly known as lucerne, is one of the most important forage species grown worldwide, but its production suffers seriously from weevil (Hypera postica Gyll.) infestation. The aim of this work was to identify species/accessions with tolerance to weevil and their molecular analysis using simple sequence repeat (SSR) markers. After screening 197 global germplasm encompassing 50 Medicago species for weevil tolerance, 22 lines representing 13 species were identified where leaf damage was ≤15% (P ≤ 0.05). In total, 37 accessions of the 22 lines, five Indian lucerne cultivars with leaf damage ≥75% and 10 accessions of the 13 Medicago species with low to high infestation (>25%) were molecularly assessed using 11 SSR markers (5 newly developed) to delineate closest to lucerne lines for breeding. In total, 33 bands were scored. The SAHN clustering using UPGM algorithm resulted into two main clusters supported with high boot strap values and with genetic similarity ranging from 0.33 to 0.96. Two accessions of M. tenoreana were observed closest to Indian lucerne cultivars. The rich variability revealed can be used as potential resource for transferring genes across species. Although the inter-specific hybridization is difficult preposition in genus Medicago largely due to post fertilization barrier, the identified species/accessions can be utilized on priority in breeding programs especially employing biotechnological tools like culturing of fertilized pods, ovule-embryo culture and electroporation.     

Development of DRAIN-WARMF model to simulate flow and nitrogen transport in a tile-drained agricultural watershed in Eastern Canada

A new watershed model, DRAIN-WARMF, was developed to simulate the hydrologic processes and the nitrogen fate and transport that occur in small, predominantly subsurface-drained, agricultural watersheds that experience periodic freezing and thawing conditions. In this modeling approach, surface flow is simulated using a watershed scale model, WARMF, and subsurface flow is estimated using a field-scale model for subsurface-drained shallow water table fields, DRAINMOD 5.1. For subsurface flow calculations, the watershed is subdivided into uniform cells, and DRAINMOD is run on each cell with inputs based on the individual hydrologic characteristics of the cell. The coupling results in a distributed parameter model that calculates the total flow at the outlet of a watershed as well as the nitrogen losses. The model was evaluated for the St. Esprit watershed, located approximately 50 km northeast of Montreal. Simulations were carried out from 1994 to 1996; data from 1994 and 1995 was used for model calibration and data from 1996 was used for model validation. The new model was able to adequately simulate the hydrologic response and nitrate losses at the outlet of the watershed. Comparing the observed daily flow/monthly nitrogen with the model's outputs over the validation period returned an R² value of 0.74/0.86 and modeling efficiency of 0.72/0.83. This clearly demonstrates the model's ability to simulate hydrology and nitrogen losses occurring in small agricultural watersheds in cold climates.     

Cadmium Regulated Nitrate Reductase Activity in Hydrilla Verticillata (1.f.) Royle

The study was conducted to evaluate the suitability of nitrate reductase activity and the level of some metabolites as an in vivo test system for cadmium toxicity in submerged macrophyte Hydrilla verticillata. Cadmium (Cd) concentrations ranging from 0.01-80 μM affected nitrate reductase activity in a differential way. It had stimulatory effect up to 1.0 μM Cd, while higher concentrations inhibited the enzyme activity significantly. The protein synthesis inhibitor cycloheximide inhibited Cd-stimulated nitrate reductase activity during in vivo and in vitro assays. However, the effect of Cd on NR activity under in vitro assay was more pronounced. Although low Cd exposures had no effect, higher metal exposures augmented nitrate uptake. This Cd-induced NO₃ ^- uptake did not result in recovery of inhibited enzyme activity in vivo. It appears that nitrate reductase activity is more sensitive to Cd toxicity than the eventual products of nitrate assimilation such as total organic nitrogen and soluble proteins. There was a differential response of chlorophyll levels to Cd; lower concentrations enhanced the pigment level while higher ones reduced it. Cadmium exposure always enhanced the levels of carotenoids. Results showed that nitrate reductase activity could serve as an useful bioassay for Cd contamination using H. verticillata.     

Productivity status of traditional agrisilviculture system on northern and southern aspects in mid-hill situation of Garhwal Himalaya, India

The productivity of traditional agrisilviculture system (agricultural crops + trees) was investigated in the northern and southern aspects of mid-hill situation in Garhwal Himalaya, Uttarakhand, India during the 2004-2006. A total of 19 tree species were studied in both northern and southern aspects, out of which 17 tree species were selected in northern aspect and 12 tree species in southern aspect for phytosociological characteristic analysis of trees in agrisilvicultural system. The most dominant tree species are Grewia optiva, Celtis australis and Melia azedarach and successively grown under traditional agrisilviculture system. The results show that the annual productivity of all tree species was 3775 kg·ha-1·a-1 in northern aspect (site-N) and 3101 kg·ha-1·a-1 in southern aspect (site-S). G. Optiva had the highest productivity in both site-N and site-S among the tree species, followed by M. Azedarach, Quercus leucotrichophora and C. Australis. The dominant agricultural crops were Eleusine coracana in summer cereals, Phaseolus vulgaris in summer pulses-oilseeds and Triticum aestivum in the winter season in the area. The average biological productivity of agricultural crops in northern aspect was about 16% higher than that in southern aspect under traditional agrisilviculture system. The sole agricultural crop productivity (without trees) in northern aspect was also higher than that in southern aspect. An obvious difference in annual productivity of trees and agriculture crops was observed between northern aspect and southern aspect. The overall productivity in traditional agrisilviculture system (crop + tree) was 24% (in northern aspect) and 21% (in southern aspect) higher than that in sole cropping system.     

Larvicidal activity of Solanum villosum Mill (Solanaceae: Solanales) leaves to Anopheles subpictus Grassi (Diptera: Culicidae) with effect on non-target Chironomus circumdatus Kieffer (Diptera: Chironomidae)

Chloroform-methanol extract of mature leaves from Solanum villosum Mill (Solanaceae: Solanales) was investigated to establish its biocontrol potentiality under laboratory condition against larval forms of Anopheles subpictus Grassi (Diptera: Culicidae), the vector of human malaria. All the graded concentrations (30, 50, 100 and 200 ppm) showed significant (P < 0.05) larval mortality and results of regression equations revealed that the mortality rates were positively correlated with the concentrations of the extract (R ² close to 1). LC₅₀ values for all instars were between 24.20 and 33.73 ppm after 24 h and between 23.47 and 30.63 ppm after 48 h of exposure period. Significant changes in the larval mortality (F < 0.05) was also recorded between instars during single “ANOVA” analysis. This extract also demonstrated no toxicity to larvae of Chironomus circumdatus Kieffer (Diptera: Chironomidae) which were found to be present as most common non-target dipteran insect in the habitats of A. subpictus. Qualitative and chromatographic analysis of the solvent extract revealed the presence of carbohydrates, saponins, terpenoids, volatile oil, steroids, phenols and flavonoids as major bioactive phytochemicals.     

Genetic divergence and selection indices among the micromutant lines in blackgram [Vigna mungo (L.) Hepper]

Forty five micromutant lines of blackgram variety PU-30, developed by single and combination treatments with Gamma-rays, ethyl methane sulphonate (EMS), N-methyl-N-nitroso guanidine (NG) and maleic hydrazide (MH) were evaluated for yield and component traits. The mutant lines showed significant differences in all 9 traits indicating that the different mutagenic treatments were effective in inducing changes in all the quantitative characters, though magnitude, direction and frequency of changes varied with treatments. Genetic divergence among the mutants and the parent was estimated by D² analysis.100-seed weight, plant height and pod length had high contribution to genetic divergence indicating induction of more micromutations in these traits. The genetic diversity D² estimates among the 45 mutant lines and the parent were significant indicating the effectiveness of mutagenic treatments in isolation of mutant lines with diverse changes in multivariate traits from the parent. Using Tocher’s method the mutants grouped in to 11 diverse genetic clusters. 31 of the 45 mutant lines grouped into 10 different clusters away from the parent. These lines not only exhibited genetic diversity from the parent but also among themselves. The mutant lines derived from the same mutagenic treatment often grouped into different clusters indicating that there was no mutagen specific trend in clustering. On the basis of D² values and character complementation, hybridization of mutant line PM 3-3 with PN 3-2 or PGN 2-2 is expected to produce promising and desirable segregants in subsequent generations. The use of index selection on multiple traits including yield proved to be an effective and efficient method for selection of high yielding productive mutant lines such as PE2-3, PGN 2-3, PGN 2-2, PGM 2-2, PG2-1 and PG 3-2. These productive mutants showed changes in some growth and productivity traits from the parent variety and had 38.5 to 28.7 % yield superiority over parent. Three of these six mutants were derived from combined treatments and other three from single treatment with Gamma-rays or EMS.