Effects of different brassicaceous host plants on the fitness of Pieris brassicae (L.)

Pieris brassicae (L.) is a destructive cosmopolitan pest of cruciferous crops. It is present wherever its host plants occur and it is considered to be one of the most widely distributed of all the Lepidoptera. We investigated the affect of various host plants on the fitness of P. brassicae to survive, develop and reproduce. We quantified development time, survival and mortality on cabbage (Brassica oleracea capitata), cauliflower (Brassica oleracea botrytis), radish (Raphanus sativus), broccoli (Brassica oleracea italica), and mustard (Brassica campestris) under laboratory conditions. The developmental time from eggs to adult eclosion was the shortest (30.3 days) on cabbage and the longest (38.0 days) on radish. However, adult longevity was significantly (P < 0.001) greatest on cabbage compared with the other host plants tested. Similarly, the developmental rate of P. brassicae was found to be faster on cabbage than other cole crops. Moreover, the lowest immature mortality was evident on cabbage and highest on mustard and radish. Differences in reproductive parameters of the P. brassicae among host plants were analyzed using pseudo-values, which were produced by jackknife re-sampling. The data showed that the higher intrinsic rate of natural increase (0.116 females/female/day) was found on cabbage. Cabbage was recognized as the most suitable host for P. brassicae because of shorter developmental period, higher percentage survival, lower doubling time (6.00), and higher number of adult emergence (29.7%).     

Repellency of selected biorational insecticides to potato psyllid, Bactericera cockerelli (Hemiptera: Psyllidae)

Bactericera cockerelli has recently become a major concern because of its direct feeding and vectoring of bacterial diseases in many solanaceous crops. The repellency of four biorational insecticides, MOI-201 (a Chinese medicine plant extract), Requiem (a plant extract of Chenopodium ambrosioides), BugOil (a mixture of four plant essential oils), and SunSpray oil (a mineral oil), to B. cockerelli adults was tested on tomato. In a no-choice test, all the insecticides had significant repellency to adults and deterred oviposition as compared with untreated controls. Of the four insecticides, the two oils showed a stronger repellency to adults and deterred oviposition more strongly than Requiem or MOI-201. In a choice test, all insecticides had significant repellency to adults and deterred oviposition compared to untreated controls. Of the four tested insecticides, <1 adults and no eggs were found on the leaves treated with SunSpray Oil, BugOil or Requiem 3 d after treatment. The repellency rates of these three insecticides were 77.2–95.4%. MOI-201 also repelled adults significantly and deterred oviposition compared to untreated controls even though it was the least effective insecticide among the four evaluated. In conclusion, all four insecticides tested showed significant repellency to B. cockerelli adults and deterred oviposition, especially the two oils. The overall repellency to potato psyllid adults can be arranged in a descending order of SunSpray oil > BugOil > Requiem > MOI-201. These insecticides could be used in integrated pest management programs targeted against the potato psyllid on solanaceous crops.     

Repellent effects of five monoterpenoid odours against Tribolium castaneum (Herbst) and Rhyzopertha dominica (F.) in Calabar, Nigeria

Secondary plant compounds are recognised as important components of plant defence system against herbivores and pathogens. Five monoterpenoids, (R)-linalool, 1,8-cineole, (S)-2-heptyl acetate, (S)-2-heptanol and citral, which are natural components of the essential oils of Aframomum melegueta (K. Schum) and Zingiber officinale (Roscoe), were tested at the ratios in which they occur naturally for repellent activity against Tribolium castaneum (Herbst.) and Rhyzopertha dominica (F.) in a 4-way olfactometer. The results showed the repellent properties of the compounds as both beetles spent less time in the olfactometer arm containing the test stimuli. (R)-linalool and (S)-2-heptanol were stronger repellent compounds than the others. Linalool showed good repellent activity against T. castaneum (P = 0.001) as the insect spent 1.22 min in the test arm compared to the control arms (2.78 min), and R. dominica (P = 0.001) with 0.89 min in the test arm compared to 2.87 min in the control arms. With (S)-2-heptanol, T. castaneum spent 1.23 min in the test arm compared to 2.83 min in the control arms. R. dominica spent 1.61 min in the test arm and 2.69 min in the control arms. For the number of entries or visits made, while both insects were significantly repelled (P < 0.05) by the linalool-treated arm than the control, only R. dominica was repelled by the (S)-2-heptanol-treated arm (P = 0.038) compared to the control arms. The results indicate that A. melegueta and Z. officinale essential oils and their components could be suitable as safer repellents or fumigants against T. castaneum and R. dominica.     

A preliminary study on the effects of a transgenic corn event on the non-target pest Dalbulus maidis (Hemiptera: Cicadellidae)

The inclusion of the cry gene in corn may produce direct effects on non-target pests. Our research was focused on the relationship between Bt corn germplasm, expressing the cry1F protein to control the fall armyworm [Spodoptera frugiperda (Noctuidae)], and a non-target pest, the corn leafhopper [Dalbulus maidis (Cicadellidae)]. The aim of this contribution was to elucidate if Bt corn plants have influence on the oviposition preference of the leafhopper and to evaluate the effect of the transgenic plant on the hatching rate of egg. Female corn leafhoppers were released in cages each containing two potted plants in the V2 stage: a Bt germplasm and the corresponding isogenic hybrid. Laid eggs were counted and the number of hatched nymphs recorded. D. maidis females oviposited and laid more eggs in Bt plants. The egg hatching rate was negatively affected by the Bt germplasm. In addition, a field study was conducted in order to determine the abundance of D. maidis adults in Bt corn and the corresponding non-Bt isoline. Two corn plots sown with the same germplasms as used in the laboratory bioassays were sampled weekly. In the field, the population of the corn leafhopper was higher in the Bt corn plot than in the non-Bt isoline. Possible hypotheses for the differences in abundance of the vector in the field are: a) that pleiotropic effects of Bt corn could attract adults; b) the existence of a possible direct competition between the corn leafhopper and the target pest in order to utilize the whorls of corn plants as refuge and feeding sites, so the high populations of the vector could be due to the large supply of healthy whorls in the transgenic plot; and/or c) a differential attack of natural enemies occurring in non-Bt plots.     

Insecticidal effects of Ungernia severtzovii bulb extracts against the grain aphid Schizaphis graminum (Rondani)

Insecticidal effect of Ungernia severtzovii bulbs extract has been investigated against the grain aphid Schizaphis graminum. LC₅₀ value of the ethanolic extract of U. severtzovii against the female aphids was 0.235% (2.35 g/l). There was 100% mortality of the subsequent nymphs of the treated females at 0.25-1.0%. The extract was equally active against the nymphs at the highest concentrations. Hexane and ethanolic extracts were the most active against the aphids of all the extracts. Fractionation of the hexane extract by TLC yielded three fractions. Fraction II was the most active (>90% mortality) against the aphids. Xanthoxylin was identified as the major constituent in fraction II of the hexane extract and may be responsible for the insecticidal effect of U. severtzovii.     

Identification of novel glutelin subunits and a comparison of glutelin composition between japonica and indica rice (Oryza sativa L.)

Glutelin, a major protein in rice grains, is encoded by a multigene family. However, its protein composition is not well characterised. Here, we identified and characterised two novel glutelin subunits, GluBX and GluC. The individual glutelin subunits of japonica cv. Nipponbare and indica cv. 93-11 rice were analysed using 2-dimensional gel electrophoresis, LC–MS/MS, and Western blotting. Comparison of the glutelin profiles between three japonica and three indica cultivars indicated two distinct subunits (GluA-1 and GluA-3 isomers) and a distinction in the subunit composition (notably GluA-3 and Lys-rich GluB-1 components) of these two subspecies. Sequence alignment revealed different nutritional (Lys residues) and functional (Cys residues) characteristics between the type-A and type-B glutelin subfamilies. We also analysed amino acid and total protein contents of the grains in thirty-five cultivars, and we demonstrated that the Lys-rich glutelin composition of indica cultivars is superior to that of japonica cultivars. The Lys-rich and Cys-poor GluBX subunit is a native protein and is a high nutritional protein in grains. Our combined approaches for the identification of glutelin subunits have revealed the nutritional characteristics of individual subunits in rice, and this knowledge will provide new insights for improving grain quality during rice breeding.     

Variability in essential oil content and composition of Origanum hirtum L., Origanum onites L., Coridothymus capitatus (L.) and Satureja thymbra L. populations from the Greek island Ikaria

Plants belonging to four “oregano” plant species (Origanum hirtum L., Origanum onites L., Coridothymus capitatus L., and Satureja thymbra L.) were collected during flowering from 33 sites located in the eastern part of the Greek island of Ikaria in the Eastern Aegean during April, May and July 2008. C. capitatus and O. hirtum were mostly observed in higher altitudes, whereas O. onites and S. thymbra in lower ones. The spatial distribution of all species was depicted on a GIS map. All four species exhibited essential oil concentrations higher than those reported in earlier literature, namely O. onites 3-4.3%, S. thymbra 4-6.5%, C. capitatus 3.7-5.6% and O. hirtum 5.5-10.0% (v/w). Carvacrol was the main constituent of the essential oils of all species, followed by γ-terpinene, p-cymene and caryophyllene, while thymol was not detected. All constituents varied remarkably among the four species, with carvacrol exhibiting the lowest variation. Carvacrol content varied between 72.3 and 89.2% in O. onites; 46.5 and 58.0% in S. thymbra; 82.9 and 90.9% in C. capitatus; and 84.4 and 93.8% in O. hirtum. By applying hierarchical cluster analysis on the basis of the essential oil constituents two main groups, divided into four subgroups of the taxa were evident. The first group consisted of O. onites and S. thymbra, while the second one of C. capitatus and O. hirtum. The results are discussed in terms of topography and climatic variation.     

Mosquitocidal activity of two Bacillus bacterial endotoxins combined with plant oils and conventional insecticides

The full whole culture (FWC), containing parasporal protein toxins of Bacillus thuringiensis israelinsis (Bti) and Bacillus sphaericus 2362 (Bs), either singly or in combination with plant oils and commercial insecticides, was tested against larval and adult stages of Culex pipiens mosquitoes under controlled laboratory conditions. In terms of LC₅₀ values recorded after 24, 48, 72 and 96 h, the bacterial toxins showed high potency towards both larvae and adults of mosquitoes in a dose-dependent manner. Generally, the Bti toxin seemed to be more potent than the Bs toxin. For example, the Bti toxin showed a 24 h LC₅₀ of 8.2 ppm against mosquito larvae compared to 13.6 ppm for the Bs toxin. In the adult bioassay, the obtained 24 h LC₅₀ values were 0.064 and 0.085 mg/cm², respectively for the two bacterial toxins. The bacterial toxins mixed with plant oils or insecticides at equitoxic doses (e.g., LC₂₅ values) mostly showed potentiation effects, either against larvae or adults of the tested insect. Among a total of 14 paired mixtures, only the joint action estimated for the mixture of malathion + Bti or Bs was accounted as additively. Combining Bti or Bs endotoxins at LC₀ with different plant oils and insecticides at LC₅₀ concentration levels each, has resulted in considerable synergism against either larvae or adults. In the case of larval bioassays, the maximum synergistic factor (SF) obtained (ca. 2.0) was entitled to the mixture of Bti + spinosad. In the adult bioassays, the mixtures containing Curcuma longa or Melia azedarach oil extracts with Bti or Bs toxins achieved a SF accounted to 2.0. The results of the present study may be considered as an additional contribution to the area of joint toxicity of biocidal agents combining bacterial toxins, plant oils and traditional insecticides. The reached findings may encourage future research to elucidate its performance under practical field conditions.     

Population development of Phorodon humuli and predators (Orius spp.) within hop cones: Influence of aphid density on hop quality

The price of hops in Spain is given per kilogram of dry product and according to their content of alpha-acids. If any aphids are noted inside cones there is a penalty of up to 10% of the dry weight. Experiments were performed in a hop garden in 2002, 2003 and 2004 to investigate population development of the damson-hop aphid, Phorodon humuli, and its natural enemies in hop (Humulus lupulus) cones. Furthermore, we investigated if the alpha-acid content was affected by aphid populations. Aphids were first observed within hop cones at the beginning of August and numbers rose sharply from mid- to late August onwards. Aphid infestation of cones reflected the numbers observed on foliage in July, with a greater population halfway up the bines (3 m height) than at the top (6 m height). The alpha-acid content of dried hops was unaffected by the aphid population on leaves, but aphid contamination reduced the economic value of the crop because of arbitrary commercial criteria related to the presence of aphids in cones. The hop aphid’s main natural enemies within cones were anthocorids, all belonging to the genus Orius. The anthocorid population in cones grew in tandem with the aphid population, suggesting that these predators are worthy of consideration in an integrated management approach.     

Study on antagonistic effects of Talaromyces flavus on Verticillium albo-atrum, the causal agent of potato wilt disease

Talaromyces flavus a fungal antagonist, was isolated from soil samples collected from potato fields in Varamin and Karaj districts, Tehran province, Iran. Antagonistic effects of T. flavus isolates against Verticillium albo-atrum, the causal agent of potato wilt disease were investigated in the laboratory and greenhouse conditions. T. flavus colonies were recovered after three weeks from soil samples cultured on selective medium. Antagonistic effects of volatile and non-volatile extracts of T. flavus isolates on V. albo-atrum growth were investigated in the laboratory and five that caused higher growth inhibition of V. albo-atrum, were selected for greenhouse experiments. Infection index was compared in the greenhouse in a split plot trial with five isolates applied to soil, seed, or both arranged in a randomized complete block design with four replications. The minimum infection index was observed when seed were treated with T. flavus with the most effective isolate being Tf-Po-V-52. On seed, the minimum infection index was observed with Tf-Po-V-50. The most effective T. flavus isolate was also evaluated in a field experiment. Results indicated that infection index in seed treatment contained this isolate was 0.15 whereas that of control was 3.5. The overall results of this study showed that it may be possible to manage potato Verticillium wilt disease effectively by using T. flavus, a biocontrol fungus.     

Comparative susceptibility of Ostrinia furnacalis, Ostrinia nubilalis and Diatraea saccharalis (Lepidoptera: Crambidae) to Bacillus thuringiensis Cry1 toxins

Transgenic corn hybrids that express toxins from Bacillus thuringiensis (Bt) are highly effective against the European corn borer, Ostrinia nubilalis (Hübner), and the closely related Asian corn borer, Ostrinia furnacalis (Guenée). Since the registration of Bt corn hybrids in the U.S. in 1996, there has been a great deal of information generated on O. nubilalis. However, relatively little information exists for O. furnacalis. To help determine whether the information generated for O. nubilalis can be leveraged for decisions regarding the use of transgenic Bt corn against O. furnacalis, experiments were designed to determine whether the pattern of sensitivity to various Bt Cry1 toxins is similar between the two species. Test insects included laboratory-reared O. furnacalis originating from Malaysia, a Bt-susceptible laboratory colony of O. nubilalis maintained at the University of Nebraska-Lincoln (UNL) and an out-group consisting of the sugarcane borer, Diatraea saccharalis (F.), from Louisiana which represents a different genus from the same family. O. furnacalis and O. nubilalis exhibited a similar pattern of susceptibility to all the Cry1 toxins and were highly susceptible to the range of Bt toxins tested including Cry1Aa, Cry1Ab, Cry1Ac and Cry1F. Both of the Ostrinia species were more tolerant to Cry1Ba compared with D. saccharalis, although sensitivity of O. furnacalis was intermediate and did not differ significantly from that of O. nubilalis and D. saccharalis. D. saccharalis was also susceptible to the range of toxins tested but unlike the two Ostrinia species, was more tolerant to Cry1F and more susceptible to Cry1Ba. These results indicate that both of the Ostrinia corn borer species are similar in sensitivity to the Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba and Cry1F toxins, thus suggesting shared toxin receptors and mechanisms of toxicity for the two species.     

Effect of herbicide and cover crop on weed control in no-tillage jack-o-lantern pumpkin (Cucurbita pepo L.) production

Field experiments were conducted to evaluate cover crop (none, winter wheat, or winter rye) and pre-emergence (PRE) applications of clomazone plus ethalfluralin alone or with halosulfuron [PRE or post-emergence (POST)] for smooth crabgrass [Digitaria ischaemum (Schreb. ex Schweig) Schreb. ex Muhl.] and redroot pigweed (Amaranthus retroflexus L.) control in no-tillage ‘Aspen’ jack-o-lantern pumpkin (Cucurbita pepo L.). At pumpkin harvest, cover crops had reduced smooth crabgrass density, but not redroot pigweed. Although PRE or POST applications of halosulfuron alone were more effective at reducing redroot pigweed density than clomazone plus ethalfluralin PRE, the combination of halosulfuron plus clomazone and ethalfluralin PRE reduced redroot pigweed density to the greatest extent. Pumpkin yields were not affected by cover crop, although average pumpkin sizes were greater with the inclusion of cover crop residues. Pumpkin fruit sizes and yields were the greatest with clomazone and ethalfluralin PRE in combination with halosulfuron applied PRE or POST. Overall, cover crop had relatively little influence on pumpkin yields compared with herbicide treatments. The addition of halosulfuron to clomazone and ethalfluralin provided greater broadleaf weed control resulting in greater jack-o-lantern pumpkin yields.     

Development of simple and co-dominant PCR markers to genotype puroindoline a and b alleles for grain hardness in bread wheat (Triticum aestivum L.)

Grain hardness is one of the most important quality characteristics of cultivated bread wheat (Triticum aestivum L.). A large deletion in the puroindoline a (Pina) gene or single nucleotide polymorphisms (SNPs) in the puroindoline b (Pinb) gene results in hard grain texture. So far, nine Pina alleles (Pina-D1a–Pina-D1b, Pina-D1k–Pina-D1q) and seventeen Pinb alleles (Pinb-D1a–Pinb-D1g, Pinb-D1p–Pinb-D1ab) have been identified in bread wheat. The major Pina and Pinb alleles identified in hard wheat cultivars are Pina-D1b, Pinb-D1b, Pinb-D1c and Pinb-D1d. In this study, a three-primer PCR system was employed to develop nine co-dominant STS markers for genotyping Pina-D1a and Pina-D1b, whereas temperature-switch (TS) PCR was used to develop six co-dominant SNP markers for genotyping the Pinb-D1a, Pinb-D1b, Pinb-D1c and Pinb-D1d alleles. These STS and TS-PCR markers were used to verify the grain hardness genotype of 100 wheat cultivars. The reliability and genotyping accuracy of TS-PCR markers were confirmed through sequencing of PCR products and a comparison with previously published results. Therefore, STS and TS-PCR markers offer a simple, cost-effective and reliable method for high-throughput genotyping Pina and Pinb alleles to select grain hardness in wheat quality breeding programs and for wheat market classification.     

Differences in leaf yield and indigo precursors production in woad (Isatis tinctoria L.) and Chinese woad (Isatis indigotica Fort.) genotypes

Isatis tinctoria L. (woad) is one of the earliest known sources of indigo in Europe where it was cultivated since the Middle Ages. Isatisindigotica Fort. (Chinese woad), widely distributed in China, had been used from ancient times as indigo-producing plant and medicinal plant. Both species produce indigo precursors indican (indoxyl β-d glucoside) and isatan B (indoxyl ketogluconate) in their leaves. In order to identify new suitable crops for indigo production in Italy, 17 woad lines were studied under field conditions in Central Italy (Pisa, 43°40′N, 10°19′E) from 2001 to 2003. We analyzed the effects of year, genotype, and harvest times together with their reciprocal interactions on leaf yield and indigo precursors production. Woad lines were then compared with seven I. indigotica lines in a field crop experiment set up in 2003. Extraction and quantification of indigo precursors were accomplished by HPLC-ELSD. Isatan B and indican content, as well as equivalent indigo and fresh/dry leaf yield, were compared between species and among genotypes.     

Differential expression of defence-related proteins in Vigna unguiculata (L. Walp.) seedlings after infection with Fusarium oxysporum

This work aimed to study the induction of defence proteins in cowpea seedlings during the first days after infection with the fungi Fusarium oxysporum f. sp. cubenses and F. oxysporum f. sp. phaseoli. Cowpea seeds, after disinfection, were transferred to Petri dishes containing 0.5% agar and, after germination, were infected with a drop of a suspension containing 0.5 × 10⁴ spores ml⁻¹. Seedlings were collected at 24, 48, 72 and 96 h after infection and were dissected into leaves, hypocotyls, roots, cotyledons and teguments, which were measured and weighed for morphometric analysis. The agar medium was also analyzed. Enzymatic assays of proteic extracts yielded antimicrobial peptides detected by Western blotting. The cowpea seedlings showed a complex pattern of induction and repression of defence proteins in response to infection by both pathogens. Furthermore, morphometric analysis showed differences between infected and control seedlings. Infected samples did not at any time exhibit chitinase activity, but did exhibit different β-1,3-glucanase and peroxidase activities. Western blotting for lipid transfer protein (LTP) demonstrated its presence in all parts of the infected seedlings. Exuded proteins, also obtained from cowpea seeds in the germination medium, were separated by SDS-PAGE and tricine gel electrophoresis. The analysis showed that some proteins were exuded from moistened cowpea seeds, particularly after F. oxysporum infection.     

Compatibility of entomopathogenic nematodes (Nematoda: Rhabditida) with registered insecticides for Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae) under laboratory conditions

The fall armyworm, Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae) is considered the main key pest of corn crops in Brazil. Entomopathogenic nematodes (EPNs) may be used to control this pest, applied together with other different entomopathogen agents or phytosanity products in the spraying mixture. Thus, the objective of work was to evaluate the compatibility of EPNs with different insecticides used of S. frugiperda control in laboratory conditions. Three species of EPNs (Heterorhabditis indica, Steinernema carpocapsae and Steinernema glaseri) and 18 insecticides registered to control of S. frugiperda in corn crops were tested. Compatibility of the insecticides with EPNs was evaluated by observing mortality and infectivity of infecting juveniles (IJs) 48 h after immersion in solution of the insecticide formulations. Among all insecticides tested, Lorsban™ (chlorpyrifos), Decis™ (deltamethrin), Match™ (lufenuron), Deltaphos™ (deltramethrin + triazophos), Dimilin™ (diflubenzuron), Stallion™ (gamacyhalothrin), Karate Zeon™ (lambdacyhalothrin) Tracer™ (spinosad), Vexter™ (chlorpyrifos), Galgotrin™ (cypermethrin), Certero™ (triflumuron), and Talcord™ (permethrin) were compatible (class 1) with the three nematode species tested under laboratory conditions.     

Partial purification and characterization of polyphenoloxidase from durum wheat (Triticum durum L.)

A bright yellow color of pasta is an important qualitative trait for the durum wheat industry. Final color is the result of the balance between yellow and brown components in semolina. Polyphenoloxidase (PPO) is implicated as playing a significant role in darkening. This study aimed to characterize PPO activity of durum wheats. PPO was extracted and partially purified by ion-exchange chromatography on a column packed with diethyaminoethyl cellulose (DEAE). This procedure led to 26.33-fold purification with 24.7% recovery. The optimum temperature and pH of PPO were found to be 40 °C and 6.5, respectively. Heat stability of durum wheat PPO decreased as the temperatures increased from 30 to 80 °C. The z-value was calculated as 23.4 °C. It increased to 26.3 and 48.4 °C in the presence of 40% sucrose and 1 M NaCl, respectively. Durum wheat PPO was shown to use several phenolic compounds as substrate. Among the substrates used, the greatest substrate specificity was observed with catechol. Durum wheat PPO was sensitive to inhibitors such as ascorbic acid, cysteine, oxalic acid and citric acid. Ascorbic acid was the most effective inhibitor.     

Impact of intercropping of medicinal and aromatic plants with organic farming approach on resource use efficiency in arecanut (Areca catechu L.) plantation in India

The present investigation was conducted at Vittal, Karnataka, India during 2004-2007 to study the feasibility of intercropping of medicinal and aromatic plants (MAPs) in arecanut plantation. The results revealed that MAPs can be successfully grown as intercrops in arecanut plantation with increased productivity and net income per unit area. Kernel equivalent yield of MAPs varied between 272 kg ha⁻¹ in case of Piper longum to 1218 kg ha⁻¹ in Cymbopogon flexuosus. Pooled data indicated that Asparagus racemosus produced fresh root yield of 10,666 kg ha⁻¹ of arecanut plantation and contributed to maximum kernel equivalent yield of 1524 kg ha⁻¹ among all medicinal and aromatic plants. Intercropping of MAPs in arecanut was found economical. The net return per rupee investment was highest in C. flexuosus (4.25) followed by Bacopa monnieri (3.64), Ocimum basilicum (3.46) and Artemisia pallens (3.12). The total system productivity of arecanut + MAPs intercropping system varied from 2990 to 4144 kg ha⁻¹. Arecanut + O. basilicum intercropping system registered significantly higher production efficiency 8.2 kg ha⁻¹ day⁻¹ than other systems. Intercropping of MAPs had more positive effect on soil pH in arecanut based cropping system. The soil pH was 5.6 in 2004 and it was 0.3-0.9 units higher in 2007. Soil organic carbon (SOC) content varied significantly due to intercropping of MAPs at the end of experiment. The SOC content increased in Aloe vera, A. pallens, P. longum and B. monnieri, while it depleted in grasses and rhizomatic MAPs. Based on demand and marketing opportunities for MAPs, farmers are advised to grow aromatic plants in large areas on a community basis to meet huge industrial demand and variety of medicinal crops in small areas to meet the requirement of traditional systems of medicine.     

Characterization of Solanum chomatophilum resistance to 2 aphid potato pests, Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer)

The aphids Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer) (Hemiptera: Aphididae) are responsible for yield reduction in potato (Solanum tuberosum) production by direct phloem feeding and by spreading viruses. Breeding resistant traits from Solanum chomatophilum into the potato germplasm provides alternative means to control aphid infestations. Integrated pest management strategy, using plant resistance, benefits from the characterization of the resistance and of its impact on aphid biology. Our objective was to characterize the resistance of S. chomatophilum by assessing the effects of accessions, plant parts on aphid performance, and by assessing the impact of the resistance factors on different aphid developmental stages and on alate morph production. Detailed aphid performance was obtained by measuring fecundity, survival, percentage of nymphs that reached adult moult, and population growth using whole plant and clip cage experimental designs. Accession and plant physiological age, but not aphid developmental stage, influenced all life-history parameters, except for alate morph production which was not induced on the resistant accessions. Plant part influence was independent of plant species and accession. Both experimental designs resulted in congruent resistance levels at the accession level for each of the two aphid species, supporting the use of any of them in S. chomatophilum resistance screening. PI243340 was resistant to both aphid species, while PI365324 and PI310990 were also resistant to M. euphorbiae and M. persicae, respectively.     

Isolation and characterization of EMS-induced Dy10 and Ax1 high molecular weight glutenin subunit deficient mutant lines of elite hexaploid wheat (Triticum aestivum L.) cv. Summit

The mixing properties of the dough are critical in the production of bread and other food products derived from wheat. The high molecular weight glutenin subunits (HMW-GS) are major determinants of wheat dough processing qualities. The different alleles of the HMW-GS genes in hexaploid wheat vary in their effect on dough quality. To determine the contribution of the individual HMW-GS alleles, lines deficient in HMW-GS proteins were generated by chemical mutagenesis in the elite bread wheat Triticum aestivum cv. Summit. In this report we describe the identification and characterization of Dy10 and Ax1 deficient lines. Examination of the effect of Dy10 and Ax1 deficiency on dough rheological properties by mixography showed shorter mixing time to reach peak resistance, and weaker and less extensible doughs relative to the wild type control. This is the first time that the role of Dy10 in vivo has been examined apart from the Dx5 + Dy10 allelic pair combination.