Studies on pesticides based on coumarin. II. Synthesis and antifungal activity of ten 2-alkyl-7, 8-dihydro-3-hydroxynaphtho[1,2-c]chromen-6-ones

A series of 2-alkyl-7, 8-dihydro-3-hydroxynaphtho[1,2-c]chromen-6-ones was synthesised by the condensation of ethyl 3, 4-dihydro-1-oxonaphthalene-2-carboxylate with substituted phenols in the presence of POCl₃. The compounds were characterised and tested for their toxicity towards the mycelial growth of seven phytopathogenic fungi in culture. Drechslera oryzae, Rhizoctonia solani and Colletotrichum falcatum exhibited maximum sensitivity to these compounds whereas Macro-phomina phaseolina, Fusarium solani, Alternaria alternata and Pythium aphanidermatum were less sensitive. 2-Ethyl-7, 8-dihydro-3-hydroxy-naphtho[1,2-c]chromen-6-ones possessed greatest toxicity with EC₅₀ values ranging from 0.2 to 2.5 μg ml^?1 against all fungi except A. alternata and P. aphanidermatum.     

Association mapping for pre-harvest sprouting tolerance in common wheat (Triticum aestivum L.)

Association mapping was undertaken in common wheat to identify markers associated with pre-harvest sprouting tolerance (PHST). For this purpose, a population of 242 wheat genotypes and 250 SSR markers were used. The population used consisted of diverse germplasm, which carried sufficient phenotypic variation for PHS for conducting association mapping. The population was found to be structured and stratified into 15 sub-populations; the tolerant and moderately tolerant wheat genotypes were distributed in all the sub-populations. This feature of the population along with other information on population structure was used in association mapping using both the available models, the general linear model (GLM) and the mixed linear model (MLM); hopefully, this minimized the rate of false positives. As many as 30 markers were found to be associated with PHST, 26 markers with GLM and 17 markers with MLM; 13 markers were detected using both the approaches. Only eight SSR markers associated with QTL for PHST were such, which were located within the marker intervals that were earlier reported to carry QTLs for PHST. The remaining 22 markers that were found to be associated with PHST could not be associated with any of the genomic regions known to carry QTLs for PHST, which are known to occur on all the 42 chromosome arms of wheat genome.     

Preparation nutritional value and acceptability of barleyrabadi — an indigenous fermented food of India

Rabadi fermentation of barley flour-buttermilk mixture (fresh and autoclaved) at 30, 35 and 40°C for 6, 12, 18, 24 and 48 h lowered pH, enhanced titratable acidity and did not change fat and total mineral (Ca, Fe, Cu, Zn, Mn and P) content. Protein content of fermented fresh as well as autoclaved barley flour-buttermilk mixture either decreased or remained unchanged.Rabadi prepared from both types of barley flour at different temperatures and time periods was acceptable; but that which was fermented at 40°C for 48 h was less acceptable in terms of taste.     

Studies on pesticides based on coumarin. III. Synthesis and antifungal activity of substituted 4-methyl-coumarins and related compounds

A series of substituted 4-methylcoumarins was synthesised and the members tested for their toxicity towards mycelial growth of seven phytopathogenic fungi in culture. Rhizoctonia solani, Alternaria alternata and Fusarium solani exhibited maximum sensitivity to these compounds whereas Pythium aphanidermatum, Colletotrichum falcatum, Drechslera oryzae and Macrophomina phaseolina were relatively less sensitive. 6-Ethyl-3-n- propyl-7-hydroxy4-methylcoumarin ( I ) was relatively toxic towards all fungi except C. falcatum, P. aphanidermatum and M. phaseolina. The 6-n-butyl ( III ) and 6-(1, 1, 3, 3-tetramethylbutyl) ( VI ) derivatives were highly toxic to R. solani with EC₅₀, values of lμg ml^?1.     

Genotypic variation for cellular thermotolerance in <Emphasis Type="Italic">Aegilops tauschii</Emphasis> Coss., the D genome progenitor of wheat

Corn leaf aphids (Rhopalosiphum maidis Fitch) are found throughout the year on maize in Hawaii and occasionally cause yield loss. Sweet corn inbred Hi38-71 was observed to have high field resistance to aphids and was chosen for this genetic study. An artificial infestation technique was developed using hair-pin clip cages (2.2 cm diameter) which we devised and built. The cages were applied to field-grown plants into which three wingless viviparous adults were placed. Aphid populations were classified on a 1–10 rating scale after about 2 weeks based on digital images of the cages. Mean aphid coverage ratings were 2.97 for the resistant parent and 7.28 for the susceptible parent (representing >200 insects per cage). The F₁ hybrids showed similar susceptibility (6.72), showing resistance to be recessive in nature. Six generations of the cross between Hi38-71 and susceptible inbred Hi27 were artificially infested to provide a generation mean analysis of 360 treated plants over two growing seasons. A joint scaling test showed that the fit to a 3-parameter additive-dominance model satisfactorily explained the observed variability with no assumed linkage or epistasis. We conclude that resistance to corn leaf aphid in Hi38-71 is conferred by a single recessive gene labeled aph. These results concur with a previous study under uncontrolled natural infestation in a single environment. The hair-pin clip cage method was most effective in distinguishing resistant and susceptible genotypes under diverse natural growing conditions in Hawaii.     

Genetic Analysis of Some Chemotypes in Ocimum basilicum var. glabratum

Screening of a population of Ocimum basilicum var. glabratum Benth., raised from seeds collected from France, West Africa and Kerala (India) was carried out for chemical composition of its essential oils. In all three collections, plants were found to be comprised of 3 chemotypes which were morphologically indistinguishable, but each chemotype was found to be capable of intercrossing freely with the other two. Selfing was carried out during 4 consecutive generations, after which three pure lines were established. Study of the selfed progeny of each collection exhibited an interesting segregation in S₂ and S₃ generations. Along with segregation in F₂ and F₃ generations of various hybrids the results can be explained by assuming a gene ‘M’ existing in 3 (or more) allelic forms: The allele M₀ for biosynthesis of estragole (methyl chavicol) is dominant to allelcs M₁ , for eugenol and M₂ for camphor. Also, allele M₁ is dominant to allele M₂ . The assumption was further confirmed by testcrosses of F₁ hybrids of each cross with their recessive parent.     

Genome-wide association study for spot blotch resistance in Afghan wheat germplasm

Spot blotch (SB), caused by Bipolaris sorokiniana, is a devastating disease of wheat globally, especially in South Asia and South America. Understanding the genetics of resistance to SB is important for developing breeding strategies to improve resistance. A panel of 301 genotypes from Afghanistan was phenotyped over two crop seasons using a mixture of virulent B. sorokiniana isolates and genotyped using DArTSeq to obtain genome-wide markers. Fifty genotypes (16.6%) showed disease scores less than the resistant control. Principal component analysis using the genotypic data clustered the genotypes into five different groups. Among models used for genome-wide association mapping, the multilocus mixed model, and fixed and random model circulating probability unification algorithms were most effective in identifying significant marker-trait associations (MTA). Twenty-five MTAs at p ≤ .001 were identified on chromosomes 1A, 1B, 1D, 2B, 2D, 3A, 3B, 4A, 5A, 5B, 6A, 7A, and 7D, indicating the quantitative nature of resistance to SB. Phenotypic variation explained by these markers ranged from 2.0% to 17.7%, and genomic regions on the chromosomes 1D, 2D, 3A, 3B, 4A, 5A, and 5B coincided with loci identified in previous studies. Three single nucleotide polymorphism (SNP) markers on chromosomes 1B (SNP 1113207) and 5A (SNPs 5411867 and 998276) were significant in both crop seasons as well as in the combined analysis across seasons. Marker 5411867 is close to Vrn-A1, shown to be associated with SB in previous studies. Furthermore, among known SB resistance genes, Sb2 on chromosome 5B was predicted to be significant in this panel.     

Integrated effect of transplanting date, cultivar and irrigation on yield, water saving and water productivity of rice (Oryza sativa L.) in Indian Punjab: Field and simulation study

Individual effect of different field scale management interventions for water saving in rice viz. changing date of transplanting, cultivar and irrigation schedule on yield, water saving and water productivity is well documented in the literature. However, little is known about their integrated effect. To study that, field experimentation and modeling approach was used. Field experiments were conducted for 2 years (2006 and 2007) at Punjab Agricultural University Farm, Ludhiana on a deep alluvial loamy sand Typic Ustipsamment soils developed under hyper-thermic regime. Treatments included three dates of transplanting (25 May, 10 June and 25 June), two cultivars (PR 118 inbred and RH 257 hybrid) and two irrigation schedules (2-days drainage period and at soil water suction of 16 kPa). The model used was CropSyst, which has already been calibrated for growth (periodic biomass and LAI) of rice and soil water content in two independent experiments. The main findings of the field and simulation studies conducted are compared to any individual, integrated management of transplanting date, cultivar and irrigation, sustained yield (6.3-7.5 t ha⁻¹) and saved substantial amount of water in rice. For example, with two management interventions, i.e. shifting of transplanting date to lower evaporative demand (from 5 May to 25 June) concomitant with growing of short duration hybrid variety (90 days from transplanting to harvest), the total real water saving (wet saving) through reduction in evapotranspiration (ET) was 140 mm, which was almost double than managing the single, i.e. 66 mm by shifting transplanting or 71 mm by growing short duration hybrid variety. Shifting the transplanting date saved water through reduction in soil water evaporation component while growing of short duration variety through reduction in both evaporation and transpiration components of water balance. Managing irrigation water schedule based on soil water suction of 16 kPa at 15-20 cm soil depth, compared to 2-day drainage, did not save water in real (wet saving), however, it resulted into apparent water saving (dry saving). The real crop water productivity (marketable yield/ET) was more by 17% in 25th June transplanted rice than 25th May, 23% in short duration variety than long and 2% in irrigation treatment of 16 kPa soil water suction than 2-days drainage. The corresponding values for the apparent crop water productivity (marketable yield/irrigation water applied) were 16, 20 and 50%, respectively. Pooled experimental data of 2 years showed that with managing irrigation scheduling based on soil water suction of 16 kPa at 15-20 cm soil depth, though 700 mm irrigation water was saved but the associated yield was reduced by 277 kg ha⁻¹.     

Comparative analysis of mechanical properties of size film. I. Performance of individual size materials

Starch has been the most popular and economic size material. Synthetic binders have also been developed to be used as size material to improve weaving loom efficiency. Some synthetic size materials have got restrictions in use mainly because of ecological reasons. In the recent years, many modifications have come up in the starch as a sizing agent. Different modification can give different properties, which can be suited for a particular application. In the present study, for comparative analysis of different varieties of natural starch, modified starch and synthetic size material have been evaluated and mechanical properties like cohesion power, adhesion power, abrasion resistance, bending rigidity etc. were studied. PVA shows best properties among all size material. Among modified starch, starch ester shows better properties.     

Characterization of oil palm empty fruit bunch and glass fibre reinforced recycled polypropylene hybrid composites

The effects of hybridization of glass fibre on oil palm empty fruit bunch (EFB) and recycled polypropylene-based composites are described in this paper. The compounding process involved extrusion followed by injection moulding technique to prepare the samples for characterizations. Fibre loading were considered as 40 % of the total weight of the blends and EFB:glass fibre ratio was maintained as 30:70, 50:50, 70:30 and 90:10. Two types of coupling agents of maleic anhydride-grafted polypropylene such as polybond-3200 and fusabond P-613 of different molecular weight and maleic anhydride level were used to improve the interfacial adhesion between the fibres and the matrix. Composites were characterized by density, melt flow index, tensile, Izod impact and flexural testing. Morphological images of the fractured surfaces of the composites were examined by field-emission scanning electron microscopy. Samples were also characterized by thermal tests such as thermogravimetric analysis and differential scanning calorimetry to evaluate the thermal and crystalline properties, respectively. Optimization of hybridization of the fibres and effect of coupling agents were evaluated in terms of various properties of the samples. The composite prepared with EFB:glass fibre ratio of 70:30 showed better reinforcing properties than that of others.