Two outcrossing mechanisms in cowpeas,Vigna unguiculata (L.) Walp

Summary Several types of outcrossing mechanisms in cowpeas are observed in breeding plots at IITA. Two of these have been studied. One is genetic male sterility controlled by the simple recessive conditions of a gene designated as ms ₂ ms ₂. The other is mechanical male sterility involving petals constricted in such a way as to provide an opening for stigma and style to emerge at an early, pre-receptive stage of development; while simultaneously restricting stamen development. It is also inherited as a recessive character with the gene symbol designation of Cp-as normal and cp cp as constricted petal. The flower structure is unique and is easily recognized in large populations. Because fruit set is extremely poor it appears less promising than the genetic male sterility at present.     

Marker assisted accelerated introgression of null allele of kunitz trypsin inhibitor in soybean

Development of kunitz trypsin inhibitor (KTI)-free soybean is crucial for soy-food industry as the heat inactivation employed to inactivate the anti-nutritional factor in regular soybean incurs extra cost and affects protein solubility. In the presented work, a null allele of KTI from PI542044 was introgressed into cultivar ‘JS97-52’ (recurrent parent) through marker assisted backcrossing. Foreground selection in BC₁F₂, BC₂F₂ and BC₃F₂ was carried out using the null allele-specific marker in tandem with SSR marker Satt228, tightly linked with a trypsin inhibitor Ti locus. Background selection in null allele-carrying plants through 106 polymorphic SSR markers across the genome led to the identification of 9 KTI-free lines exhibiting 98.6% average recurrent parent genome content (RPGC) after three backcrosses, which otherwise had required 5–6 backcrosses through conventional method. Introgressed lines (ILs) were free from KTI and yielded at par with recurrent parent. Reduction of 68.8–83.5% in trypsin inhibitor content (TIC) in ILs compared to the recurrent parent (‘JS97-52’) was attributed to the elimination of KTI.     

Induction and assessment of morpho-biochemical mutants in Artemisia pallens Bess.

Artemisia pallens Bess. is a low volume and high value essential oil plant used in perfumery, cosmetic and flavouring industries. On account of the failure of conventional procedures to induce variability in species, mutation techniques have been tried in our experiments. Dry and viable seeds (moisture content 8%) of homozygous pure breeding lines were subjected to 150–500 Gy doses of gamma rays and 0.01–0.1% ethyl methane sulphonate (EMS) for 8 h. Desirable qualitative mutants were recovered from segregating M₂ generation (4,283 plants scored) raised as single plant progenies. The spectrum of morphological mutants included late and early flowering types; bushy and high yielding types; tall and more capitula-producing types and high oil and high davanone yielding types. These were raised through M₃ families to evaluate stability and transmission of mutant characters. As such out of 15 different types selected in M₂, only 11 types bred true to their characteristic variability. Based on their performance, the mutants were characterised depending upon their distinguishing features. Davanone, the main component of oil showed the maximum increase (64.22% against 54.64% in control) in mutant ‘S–5’ recovered from exposure with 250 Gy γ-rays. Mutant ‘E-6’ was economically most viable having increased oil biosynthesis (0.36% against 0.22% in control) and hence yields higher oil per unit area than the parental control (isolated from 0.05% EMS treatment).     

Assessment of Atmospheric Arsenic Level in Airborne Dust Particulates of an Urban City of Central India

An assessment of arsenic contamination in Raipur city (21°14′N, 18°38′E) of Chhattisgarh in the central part of India is reported here, for a monitoring period between November 1996 to June 1997, in airborne dust particulates. The concentration level of As were higher in the industrial site, followed by heavy traffic as compared to other sites. The monthly atmospheric arsenic deposition, in μg As per g of dust fall, of 6 sites are in the range of 0.100(μ0.020)–4.00(μ0.020); site no. 1 industrial area, 0.100(μ0.020)–0.320(μ0.020); site no. 2 residential area, 0.044(μ0.070)–0.337(μ0.030); site no. 3 commercial area, 0.093(μ0.068)–1.870(μ0.020); site no. 4 residential area, 0.111(μ0.020)–1.912(μ0.010); site no. 5 residential area and 0.068(μ0.040)–3.037(μ0.060); site no. 6 heavy traffic area. The total annual flux of As in the fall-out at different zones is in the range 0.033–1.12 kg km^-2 yr^-1. The month wise collection and analysis of dust fall out rate between 3.0(μ0.10)–91.3(μ1.4) mt (metric tonnes) km^-2 month^-1 were observed at all 6 sampling sites. Anthropogenic and environmental factors play important roles in the contribution of arsenic in airborne particulate matters.     

Genetics and molecular mapping of gynoecious (F) locus in cucumber (Cucumis sativus L.)

Gynoecious is an important economic trait of cucumber for determinant of earliness and yield, yet genetic mechanism is not well understood for this trait. The experiment was conducted using F₂ mapping population by crossing of PPC-2, a gynoecious and parthenocarpic line with Pusa Uday (monoecious and non-parthenocarpic cultivar). Out of 179 SSR markers screened, 39 markers differentiated the gynoecious and monoecious parents. However, only 17 markers were segregating with F₂ mapping population, those were used for genotyping and linkage map analysis and these markers were placed along with F locus on chromosome 6 covering a total distance of 100.4cM. The SSR markers, SSR13251 and UW020605 were found to be closely linked to gynoecious (F) locus at 1.0 and 4.5 cM, respectively. The segregation of F₂ population of PPC-2 × Pusa Uday and GPC-1 × Punjab Naveen and test crosses for sex type herein suggested that single dominant gene controlled the gynoecious sex expression in cucumber particularly in gynoecious genotypes PPC-2 and GPC-1. Therefore, the monogenic dominant nature of gynoecious sex identified in the present experiment and SSR markers closely linked to the F locus will be useful in marker-assisted backcross breeding for transfering gynoecious trait into horticulturally desirable varieties.     

Synthesis and Characterisation of Novel-Activated Carbon from Waste Biomass Pine Cone and Its Application in the Removal of Congo Red Dye from Aqueous Solution by Adsorption

The present study deals with the synthesis and subsequent application of Fe₃O₄@n-SiO₂ nanoparticles for the removal of Cr(VI) from aqueous solutions. Rice husk, an agrowaste material, was used as a precursor for the synthesis of nanoparticles of silica. Synthesized nanoparticles were characterized by XRD and SEM to investigate their specific characteristics. Fe₃O₄@n-SiO₂ nanoparticles were used as adsorbent for the removal of Cr(VI) from their aqueous solutions. The effects of various important parameters, such as initial Cr(VI) concentration, adsorbent dose, temperature, and pH, on the removal of Cr(VI) were analyzed and studied. A pH of 2.0 was found to be optimum for the higher removal of Cr(VI) ions. It was observed that removal (%) decreased by increasing initial Cr(VI) concentration from 1.36?×?10^-2 to 2.4?×?10^-2 M. The process of removal was found to be endothermic, and the removal increased with the rise in temperature from 25 to 45 °C. The kinetic data was better fitted in pseudo-second-order model in comparison to pseudo-first-order model. Langmuir and Freundlich adsorption capacities were determined and found to be 3.78 and 1.89 mg/g, respectively, at optimum conditions. The values of ΔG ⁰ were found to be negative at all temperatures, which confirm the feasibility of the process, while a positive value of ΔH ⁰ indicates the endothermic nature of the adsorption process. The present study revealed that Fe₃O₄@n-SiO₂ nanoparticles can be used as an alternate for the costly adsorbents, and the outcome of this study may be helpful in designing treatment plants for treatment of Cr(VI)-rich effluents.     

Assessment of genetic diversity,population structure and phytochemical variations in Polygonatum cirrhifolium (Wall.) Royle: an endangered medicinal herb

Genetic Resources and Crop Evolution - Polygonatum cirrhifolium (Wall.) Royle is an important medicinal herb of the family Asparagaceae used to cure several ailments. The rhizome of the species...     

Association mapping,trait variation,interaction and population structure analysis in cucumber (Cucumis sativus L.)

Genetic Resources and Crop Evolution - In several regions of the world, low productivity in this crop is attributed to several factors including poor understanding of the genomic complexity of...