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Copyright of Revista Latinoamericana de la Papa is the property of Asociacion Latinoamericana de la Papa (ALAP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background The Hessian fly response genes, Hfr-1 and Hfr-2, have been reported to be significantly induced in a Hessian fly attack. Nothing is known about the allelic variants of these two genes in susceptible (S) and resistant (R) wheat cultivars. Results Basic local alignment search tool (BLAST) analysis of Hessian fly response genes have identified three alleles of Hessian fly response gene 1 (Hfr-1) on chromosome 4AL and 7DS, and 10 alleles of Hessian fly response gene 2 (Hfr-2) on chromosome 2BS, 2DL, 4BS, 4BL, 5AL and 5BL. Resequencing exons of Hfr-1 and Hfr-2 have identified a single nucleotide polymorphism (SNP) in the lectin domain of each gene that segregates some R sources from S cultivars. Two SNP assays have been developed. The SNP883_Hfr-1 assay characterizes a ‘G/A’ SNP in Hfr-1, which differentiates 14 Hessian fly R cultivars from S ones. The SNP1294_Hfr-2 assay differentiates 12 R cultivars from S ones. Each of the two SNPs identified in Hfr-1 and Hfr-2 is ‘G/A’ and resulted in an amino acid change from isoleucine to valine in the lectin domain of the proteins of the alleles in the R cultivars. In addition to the genotype profiles of Hfr-1 and Hfr-2, generated for a set of 249 wheat cultivars which included a set of 39 R cultivars, this study has genotyped the Hessian fly response gene, HfrDrd, and the H32 gene for the wheat germplasm. Resistant cultivars from different origins with one, two, three or four resistance (R) genes in various combinations/permutations have been identified. Conclusion This study has identified allelic differences in two Hessian fly response genes, Hfr-1 and Hfr-2, between S and R cultivars and developed one SNP assay for each of the genes. These two SNP assays for Hfr-1 and Hfr-2, together with the published assays for HfrDrd and the H32 gene, can be used for the selection and incorporation of one or more of these 4 R genes identified in the different R sources in wheat breeding programs.

The relationship between Epichloë endophytes found in a wide range of temperate grasses spans the continuum from antagonistic to mutualistic. The diversity of asexual mutualistic types can be characterised by the types of alkaloids they produce in planta. Some of these are responsible for detrimental health and welfare issues of ruminants when consumed, while others protect the host plant from insect pests and pathogens. In many temperate regions they are an essential component of high producing resilient tall fescue and ryegrass swards. This obligate mutualism between fungus and host is a seed-borne technology that has resulted in several commercial products being used with high uptake rates by end-user farmers, particularly in New Zealand and to a lesser extent Australia and USA. However, this has not happened by chance. It has been reliant on multi-disciplinary research teams undertaking excellent science to understand the taxonomic relationships of these endophytes, their life cycle, symbiosis regulation at both the cellular and molecular level, and the impact of secondary metabolites, including an understanding of their mammalian toxicity and bioactivity against insects and pathogens. Additionally, agronomic trials and seed biology studies of these microbes have all contributed to the delivery of robust and efficacious products. The supply chain from science, through seed companies and retailers to the end-user farmer needs to be well resourced providing convincing information on the efficacy and ensuring effective quality control to result in a strong uptake of these Epichloë endophyte technologies in pastoral agriculture. [ABSTRACT FROM AUTHOR]

In this paper, epidemic diseases among pests are assumed to occur, so pests are divided into susceptible pests and infected pests, and only susceptible pests are harmful to crops. Considering spraying pesticides and releasing of natural enemies and infected pests to control pests, as well as the long-term application of the same pesticide to induce resistance, an integrated pest management with pesticide resistance is established. The pollution emission model is introduced to model the action process of pesticides, which well reflects its residual and delay effects. By using comparison theorem of impulsive differential equation and analysis method, the threshold condition for eradication of susceptible pests is obtained. Then we analyze the frequency of spraying pesticide on the success of pests control. It shows that it is not that the more frequently pesticides are applied, the better the result of the susceptible pests control is. From the sensitivity analysis, the key factors on the threshold are obtained. Finally, the strategies to control susceptible pests are given, including switching pesticides and releasing infected pests and natural enemies elastically. [ABSTRACT FROM AUTHOR]

Background: Muscadine (Muscadinia rotundifolia) is known as a resistance source to many pests and diseases in grapevine. The genetics of its resistance to two major grapevine pests, the phylloxera D. vitifoliae and the dagger nematode X. index, vector of the Grapevine fanleaf virus (GFLV), was investigated in a backcross progeny between the F1 resistant hybrid material VRH8771 (Vitis-Muscadinia) derived from the muscadine R source 'NC184–4' and V. vinifera cv. 'Cabernet-Sauvignon' (CS). Results: In this pseudo-testcross, parental maps were constructed using simple-sequence repeats markers and single nucleotide polymorphism markers from a GBS approach. For the VRH8771 map, 2271 SNP and 135 SSR markers were assembled, resulting in 19 linkage groups (LG) and an average distance between markers of 0.98 cM. Phylloxera resistance was assessed by monitoring root nodosity number in an in planta experiment and larval development in a root in vitro assay. Nematode resistance was studied using 10–12 month long tests for the selection of durable resistance and rating criteria based on nematode reproduction factor and gall index. A major QTL for phylloxera larval development, explaining more than 70% of the total variance and co-localizing with a QTL for nodosity number, was identified on LG 7 and designated RDV6. Additional QTLs were detected on LG 3 (RDV7) and LG 10 (RDV8), depending on the in planta or in vitro experiments, suggesting that various loci may influence or modulate nodosity formation and larval development. Using a Bulked Segregant Analysis approach and a proportion test, markers clustered in three regions on LG 9, LG 10 and LG 18 were shown to be associated to the nematode resistant phenotype. QTL analysis confirmed the results and QTLs were thus designated respectively XiR2, XiR3 and XiR4, although a LOD-score below the significant threshold value was obtained for the QTL on LG 18. Conclusions: Based on a high-resolution linkage map and a segregating grapevine backcross progeny, the first QTLs for resistance to D. vitifoliae and to X. index were identified from a muscadine source. All together these results open the way to the development of marker-assisted selection in grapevine rootstock breeding programs based on muscadine derived resistance to phylloxera and to X. index in order to delay GFLV transmission. [ABSTRACT FROM AUTHOR]

Thenkaali, a Musa cultivar with genetic constitution AAB shows no infestation by Odoiporus longicollis Olivier, the pseudostem borer (PSB) under field conditions. The whole life cycle of this highly destructive pest is completed within the host plants. Thenkaali possesses high content of secondary metabolites such as total phenols, total flavonoids and elevated activity of related enzymes such as phenylalanine ammonia lyase, polyphenol oxidase and peroxidase. Rearing of larvae of PSB in the live pseudostem of Thenkaali has resulted in 100% mortality within one week. The pseudostem possesses a larvicidal compound stigmasterol- 3-O-glucoside, a steroid present at very low concentration (less than 0.0001%). The compound induces strong allelopathy on PSB, resulting in haemocytopenia and numerical changes in haemocytes. Other allelopathic changes are hyperprotenemia of haemolymph with changes in protein profile and sharp decrease in total free amino acids. The allelopathic compound induces antagonistic response on two proteolytic enzymes, evidenced by elevation of cathepsin D and inhibition of leucine amino peptidase activity. Imbalance in the activity of aspartate amino transferase and alanine amino transferase results in increased catabolism of amino acids, which leads to sharp increase in the haemolymph uric acid. Toxicity by stigmasterol-3-O-glucoside results in sharp elevation of 20 hydroxy ecdysone in the haemolymph and subsequent disruption of the endocrine system of the larvae might have contributed to cessation of feeding activity and its death. [ABSTRACT FROM AUTHOR]

In agriculture, plant transformation is a versatile platform for crop improvement with the aim of increased pest resistance and an improved nutrient profile. Nanotechnology can overcome several challenges that face conventional methods of gene delivery. Specifically, nanomaterials offer an optimal platform for biomolecule delivery with unique physiochemical properties as well as the ability to traverse the challenging barrier of the plant cell wall. We review the potential of diverse nanovehicles for biomolecule delivery in plant systems to obtain desired genetic traits. The efficacy of nanoparticles against pests or pathogens is also explored, as well as the interaction of nanovehicles with plant organelles, with due consideration of the effects and toxic profile of nanoparticles. To enhance crop productivity, genetic engineering is an important technique for introducing traits of interest into plant species. The desired trait can provide increased pest resistance and an improved nutrient profile, ultimately ensuring food security. Compared with conventional methods of biomolecule delivery, modern nanotechnology offers high efficiency and diverse cargo delivery options. The unique properties of nanomaterials, such as tunable physicochemical properties and the ability to traverse the plant cell wall, can be exploited to deliver species-dependent biomolecules. Nanoparticles are also effective as micronutrients and as agents against pests or bacterial infections. [ABSTRACT FROM AUTHOR]

Okra leaf cotton has great potential to confer resistance to insect pests; however, very few okra leaf cotton cultivars have been developed in the world. Generally, cotton breeders have perception that okra leaf trait has linkage with relatively inferior agronomic traits thus avoid introducing okra leaf trait in cotton cultivars containing broad leaves. The present research was conducted to find the genetics of okra leaf trait, its correlation with agronomic traits as well as genetics of agronomic traits in okra leaf genetic background. The genetics of okra leaf and agronomic traits were studied by using six generations (P1, P2, BC1, BC2, F1, F2) developed by crosses involving okra leaf and normal leaf genotypes/cultivars. The okra leaf trait showed monogenic control with partial dominance of normal leaf shape. The results of generation mean analysis mainly revealed additive, dominance and additive×additive gene action for the traits. Number of sympodial branches, number of monopodial branches, number of bolls per plant, boll weight, number of seeds per boll, 100 seed weight, ginning out-turn, fiber length, fiber strength and seed cotton yield had additive, dominance and additive×additive gene action while plant height and fiber fineness had additive, dominance, additive×additive as well as additive×dominance gene action. Generally higher order interactions were not found in the genetics of agronomic trait in okra leaf genetic background. Correlation results revealed that okra leaf had not negative correlation with agronomic traits. Present study recommends tailoring of okra leaf cotton cultivars for a good control of insect pests. [ABSTRACT FROM AUTHOR]

Copyright of Cientifica is the property of Fundacao de Apoio a Pesquisa e Extensao and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Aleppo pine responded to herbivory with quantitative and qualitative changes in chemical defences. • Moderate drought stress decreased the resistance of Aleppo pine against the pine weevil Hylobius abietis L. • The chemical profile of induced responses to herbivory was altered by drought. • The resistance to pine weevil under drought stress was fairly consistent across pine populations. During their long lifespan, pines must cope with simultaneous abiotic and biotic stresses such as drought and herbivory. Mediterranean pines are isohydric species that rapidly close their stomata in response to drought reducing carbon fixation. In such situations, the synthesis of chemical defences could be impaired. Here, we tested the hypothesis that drought stress may constrain the capability of Mediterranean pines to defend against herbivory and to induce chemical defences. For this purpose, we subjected three contrasting populations of Aleppo pine (Pinus halepensis Mill.) to three levels of drought stress, thereafter exposing the seedlings to the herbivore Hylobius abietis L. A suite of ecophysiological and defensive traits was measured to explore the interaction between both stresses. Drought significantly affected the 13C signature and reduced starch and fatty acids concentration. Damage caused by the insect was affected by drought stress, being 75% higher at the moderate stress level but returning under severe stress to similar values as control seedlings. Seedlings responded to herbivory by decreasing the concentration of total polyphenolics and condensed tannins, increasing the concentration of total diterpenes, and modifying the profile of major terpenes. Induced responses to herbivory were, as expected, altered by drought. Inducibility of polyphenolics decreased as drought stress increased while for diterpenes it was higher at moderate stress. Moreover, a significant drought × herbivory interaction was found on the multivariate terpene profile. These results should be considered for predicting responses of pine forests to the forecasted increase of abiotic and biotic risks associated with global change. [ABSTRACT FROM AUTHOR]

A field investigation was executed in sugarcane producing area of Zhanjiang, Guangdong Province with YT03-373 as the test variety to understand the possible impacts of seaweed extracts on phenology, yield and quality attributes of sugarcane. Foliar application of seaweed extracts were carried out on sugarcane at seedling and tillering stages. Agronomic traits, yield, sugar content, leaf drought resistance and pest resistance of sugarcane were analyzed for optimization of application time at proper phenological stages. The results that compared to the control, the application of seaweed extracts at different stages of sugarcane enhanced production of sugarcane with increase rate of 10.83%-12.87%, and improved theoretical sugar yield of sugarcane up to 1.9 t/ha while enhancing water retention capacity and water content of sugarcane leaves that consequently led to wilting risk reduction by escaping drought and improved resilience to drought impact on sugarcane. Seaweed extracts also performed excellent in pest management of sugarcane, and they exerted different control effects on sugarcane borers, aphids and thrips. An increase in output of sugarcane was observed to be 15. 09% compared to control, while the net income was improved by up to 32.64% in the seaweed extracts application treatment. Foliar application of seaweed extracts not only enhanced growth, cold resistance, pest resistance, output value but also improved economic returns, giving a positive affirmation for the recommendation of seaweed extract application. [ABSTRACT FROM AUTHOR]

Abstract: Special attention should be given to forest plantings in order to minimize the probability of exotic pest introduction and, consequently, of production losses. The objective of this review was to present, under a historic perspective, the main exotic insects that harm the Brazilian forest sector. Therefore, to better describe the phytosanitary context of introduced forest pests in Brazil, the main information regarding these insects was gathered here. Introduced species and species with a risk of introduction were listed. The following species were registered: 12 exotic introduced species related to eucalyptus, non-quarantine; 9 species related to pine, one quarantine; and 1 species related to teak, quarantine. Overall, the core problems for 57 pest species were addressed, followed by projections on current risks and priorities. Biological control programs and their respective agents were also mentioned. For eucalyptus plantations, the species belonging to the genera Ophelimus and Leptocybe are priorities and should be emphasized. Regarding pine species, the main current concerns are Bursaphelenchus xylophilus (transmitted by species of Monochamus), Rhyacionia frustrana, and Dendroctonus frontalis. Better risk management requires reinforcement of phytosanitary inspections and constant refinement of contingency plans, whose actions include monitoring by visual sampling, employment of sentinel plants, and preventive breeding programs aiming at pest resistance.

The results of comprehensive assessment of the collection samples of carrot are presented. Such traits as a resistance to carrot psylla and carrot fly, high yield, earlyripeness, high content of carotene were evaluated. The carrot varieties total resistant to psylla were not found. The genotypes with combination of such traits as a mild tolerance to pests, stable productivity and fruits quality are recommended as the initial breeding material for development of new varieties and hybrids of carrot.

Safflower (Carthamus tinctorius L.) is an important oilseed crop in Iran and many other countries around the world. Safflower fly, Acanthiophilus helianthi Rossi is one of the main limiting agents to expand the production area of the crop in different countries and the most major pests of safflower in Iran. In this research, the influence of 10 safflower genotypes on biology and population parameters of A. helianthi was evaluated under the laboratory conditions at 25±1°C, 65±5% relative humidity, and a photoperiod of 16:8 (L: D) hours. The shortest and longest total developmental time were recorded in Mexico 37 (16.85±0.31) and Goldasht (21.76±0.59), respectively. The intrinsic rate of natural increase (r) ranged from 0.129 to 0.186 (day-1), which was lowest on Goldasht and highest in Mexico 37. The net reproductive rate (R0) ranged from 50.809 to 125.846 offspring on different genotypes. The values of finite rate of increase (λ) and mean generation time (T) on different safflower genotypes ranged from 1.138 to 1.205 day-1 and 25.778 to 30.421 days, respectively. The results demonstrated that Goldasht, Line 411, and KW2 genotypes were less suitable host plants, suggesting that they are more resistant to A. helianthi than the other genotypes, have high yield, and could have the potential for using in Integrated Pest Management program (IPM) of A. helianthi in safflower fields. [ABSTRACT FROM AUTHOR]

Copyright of Fruits is the property of International Society for Horticultural Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fruits is the property of International Society for Horticultural Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pilot experiments on molecular marker application in breeding of winter wheat at the Krasnodar Lukyanenko Research Institute of Agriculture (KNIISH) are described. The most efficient ways of marker application in creating new cultivars are outlined. A variety of genes responsible for valuable agronomic traits in KNIISH varieties have been detected.

Pest resistance of 8 transgenic Bt rice events with a synthetic cry1Ac gene linked to rice rbcS - tp sequence were assessed under laboratory conditions. Bioassays were conducted with neonates and third instar larvae of Cnaphalocrocis medinalis , which is a significant pest of rice in Asia. C. medinalis larvae were shown to be susceptible to all eight events, even though there were differences between the causes of death. The results differed between developmental stages of the larvae, despite the fact that all 8 events led to high mortalities. Neonates displayed feeding avoidance and death by starvation on six Bt rice events. In the case of third instar larvae however, only two events resulted in feeding avoidance. Nevertheless, all Bt rice events were shown to be highly effective against C. medinalis larvae in laboratory conditions. These results may be a significant foundation for the evaluation of improved transgenic Bt rice. [ABSTRACT FROM AUTHOR]

Limitations of Bt rice in the entomological rice cropping context in sub-Saharan Africa and Madagascar. A review. In sub-Saharan African countries and Madagascar, rice crops host many insect species, which have been inventoried and studied for almost 40 years. Management of these rice pests using synthetic chemical pesticides is not common practice. In Asia, genetically modified rice varieties (Bt rice) resistant to some insects were engineered in the 1990s. In 2009, two Bt rice varieties were authorized to be marketed in China. Bt rice is not grown in African countries. We therefore decided to analyze the published literature on Bt rice and to compare the findings with the current insect pest situation in African rice fields. The activity spectrum and the efficacy of Bt toxins represent the first limitation encountered in the use of currently available Bt rice varieties. For instance, the effect of Bt toxins against Diptera (Diopsidae) species is unknown, since these species only occur in Africa. On the African continent and in Madagascar, it would be essential to enhance or promote taxonomic, biological and ecological knowledge concerning rice pests and to more accurately measure the impact of various insect species on crop yields. The broad range of rice insect pests, including insect vectors of disease, the risk of target insects developing resistance to Bt toxins and the lack of economic assessments suggest that, with the current state of knowledge in Africa, it would be inappropriate to introduce currently available Bt rice varieties there.

Soybean is a major source of vegetable protein and oil in the world. Worldwide demand continues to be high and production has more than doubled in the past 20 years to a total of 264.2 million metric tons in 2011 (National Agricultural Statistics Service 2012). Much of this increase has been due to increased planting in Argentina and Brazil. But, there have been genetic gains as well. We now have powerful genetic tools and these will be useful in gene discovery and in developing selectable markers for those genes. But for traits that are quantitative and multigenic, marker assisted selection may not be practical. We are facing unprecedented changes in our climate which will require resourceful use of the new genetic tools along with standard plant breeding methodology to maintain soybean productivity and quality.

Chickpea (Cicer arietinum L.), is an important pulse food. During storage this commodity is severely attacked bybean beetle Callosobruchus maculatus (Fabricius) resulting losses in quantity and nutritional quality. Research studies onrelative resistance of 12 chickpea genotypes to the attack of C. maculatus during storage were carried out. The genotypesmost tolerant to bruchids comprised CH-52/02 and B-8/03, whereas, the most susceptible reactions were apparent inCH-86/02 and CC-117/00. The moderate pest incidence was observed in CH-28/02, CH-4/02, CH-32/02, CH-31/02, CH-9/02,CM-772/03, B-8/02 and CM-628/03 genotypes. The tolerant genotypes exhibited hard and wrinkled seed coat, dark browncolour and small size grain. These characteristics demonstrated a significant harmful effect to pest appearance and graindamage. The vulnerable genotypes had soft and smooth seed coat, white seed colour and bigger grain size that causedvulnerability to C. maculatus. Based on the present investigation, chickpea genotypes CH-52/02 and B-8/03 deserve specialconsideration and may be recommended for relatively longer storage to achieve the goal of long term and sustainable pestmanagement strategies.

The objective of this work was to study the density of trichomes and hydrocarbons associated with the resistance by antixenosis of 42 subsamples of tomato plants from the Horticultural Germplasm Bank of the Universidade Federal de Viçosa (HGB-UFV) to Liriomyza trifolii. These subsamples were studied in addition to 'Santa Clara' cultivar, which was used as a standard of susceptibility to leafminers. The evaluated characteristics were the number of mined leaflets per plant, mines per plant, trichome density and chemical compounds in the leaves. Differences were detected among the subsamples in the variables studied. We identified 20 peaks in the chromatograms of leaf hexane extract the subsamples tested. The subsamples HGBs - 216, 813, 985, 987, 991, 992, 993, 1532, 1989, 1991, 2048, 2055, 2064, 2068, 2073, 2075, 2089, 2096 and 2097 were selected as sources of resistance to L. trifolii. The resistance mechanism associated to these subsamples was antixenosis. In addition, the low density of trichomes and the chemical compounds in the subsamples can be possible causes of pest resistance.O objetivo desse trabalho foi estudar a densidade de tricomas e os hidrocarbonetos associados à resistência por antixenose de 42 subamostras de tomateiro do Banco de Germoplasma de Hortaliças da Universidade Federal de Viçosa (BGH-UFV) a Liriomyza trifolii. Essas subamostras foram estudadas e a cultivar 'Santa Clara' que foi utilizada como padrão de suscetibilidade a insetos minadores. As características avaliadas foram os números de folíolos minados/planta, minas/planta, densidade de tricomas e compostos químicos presentes nas folhas. Detectaram-se diferenças entre as subamostras nas variáveis avaliadas. Foram identificados 20 picos nos cromatogramas dos extratos hexânicos das folhas das subamostras testadas. As subamostras HGBs - 216, 813, 985, 987, 991, 992, 993, 1532, 1989, 1991, 2048, 2055, 2064, 2068, 2073, 2075, 2089, 2096 e 2097 foram selecionadas como fontes de resistência a L. trifolii. O mecanismo de resistência associado dessas subamostras foi a antixenose. Além disso, a baixa densidade de tricomas e compostos químicos presentes nas subamostras avaliadas podem ser as possíveis causas da resistência à praga.

Plants possess a broad array of defenses that could be actively expressed in response of pathogenic organisms or parasites but also following beneficial saprophytic microorganisms recognition. Specifically, there are compounds derived from these organisms and called elicitors that are perceived by the plant to induce a locally or systemically expressed resistance. The understanding of the physiological and biological basis of these induced immunity mechanisms have greatly advanced over the past years but a deeper investigation of the mechanisms underlying the perception of elicitors is essential to develop novel strategies for pest control. The application of chemical and biological stimulators of plant immune defenses in conventional agriculture is expected to increase within the next years. Because of their organic origin and as they provide means for conferring plant protection in a non-transgenic manner, elicitors of plant immunity have a huge potential as biocontrol products. Through this review, we want to illustrate the diversity of compounds identified as stimulators of the plant immune system and describe the mechanisms by which they could be recognized at the plasma membrane level.

Potato crops are susceptible to various insect pests including the aphid Myzus persicae (Hemiptera, Aphididae) and the beetle Diabrotica speciosa (Coleoptera, Chrysomelidae). Induced resistance through silicon treatment of plants represents a potential strategy in pest management. The objective of the present study was to evaluate the effects of silicic acid on the development, productivity and level of infestation by beetles and aphids following foliar application to potato plants cultivated in the presence of organic compost or chemical fertiliser. Four experimental groups were studied, namely, plants cultivated in soil supplied with organic compost (30 t/ha) and either treated or non-treated with 0.5% silicic acid, and plants cultivated in soil supplied with NPK fertiliser (4:14:8; 4 t/ha) and either treated or non-treated with 0.5% silicic acid. The number of aphids and beetles detected on the leaves and the number of lesions caused by the beetles were evaluated. The height and the stem diameter of the plants were determined 60 days after the emergence and the productivity was determined 95 days after the planting of the seed potatoes. The results demonstrated that there were no interactions between silicic acid treatment and way of cultivation. Moreover, the incidence of beetles and aphids was not influenced by weekly application of silicon, and neither were the development and the productivity of plants. Although the development and productivity of organically cultivated plants were inferior to those grown in the presence of chemical fertiliser, plants cultivated on organic compost were less susceptible to attack by beetles.A cultura da batata é suscetível a diversos insetos-praga, incluindo os pulgões (Hemiptera: Aphididae) e a vaquinha Diabrotica speciosa (Coleoptera: Chrysomelidae). A indução de resistência, por meio do tratamento com silício, é uma das táticas usadas no manejo integrado de pragas. Objetivou-se, no presente trabalho avaliar o efeito da aplicação foliar de ácido silícico sobre o desenvolvimento, produtividade e grau de infestação por pulgões e vaquinhas, em batateiras cultivadas em composto orgânico ou fertilizante químico. Foram testados quatro tratamentos: plantas cultivadas em solo suplementado com composto orgânico (30 t/ha) (tratadas e não tratadas com 0,5% de ácido silícico) e plantas cultivadas em solo suplementado com fertilizante NPK (4:14:8; 4 t/ha; tratadas e não tratadas com 0,5% de ácido silícico). O número de pulgões e vaquinhas observados nas folhas, assim como o número de lesões causadas pelas vaquinhas, foi determinado durante o desenvolvimento das plantas. A altura e o diâmetro da haste foram determinados 60 dias após a emergência das hastes, enquanto a produtividade foi determinada 95 dias após o plantio da batata-semente. Pelos resultados demonstrou-se que não houve interação entre a aplicação de silício e o tipo de cultivo. Além disso, a incidência de vaquinhas e pulgões não foi influenciada pela aplicação foliar semanal de silício, bem como o desenvolvimento e produtividade da cultura. Embora o desenvolvimento e produtividade das plantas cultivadas na presença de composto orgânico tenha sido inferior àquelas cultivadas em presença de fertilizante químico, as primeiras mostraram-se menos suscetíveis ao ataque das vaquinhas.

O objetivo deste trabalho foi avaliar a flutuação populacional de cigarrinhas-das-pastagens em Brachiaria brizantha, Brachiaria decumbens e Pennisetum purpureum. As avaliações foram realizadas em campo, entre setembro de 2005 e março de 2007. Ninfas e adultos de cigarrinhas-das-pastagens foram contabilizados em: B. brizantha cultivares Marandu, Xaraés e Arapoti, submetidas a rodízios de carga animal; em B. decumbens, em sistema silvipastoril; e em 78 genótipos de P. purpureum. A densidade populacional de Deois schach, na cultivar Arapoti, foi superior à de Xaraés e de Marandu. Em B. decumbens, o número de cigarrinhas-das-pastagens foi quatro vezes maior que em B. brizantha. Não foram observadas diferenças significativas no número de cigarrinhas-das-pastagens nos diferentes genótipos de P. purpureum.The objective of this work was to evaluate the fluctuation of spittlebug population in Brachiaria brizantha, Brachiaria decumbens and Pennisetum purpureum. The evaluations were conducted in field conditions, between September 2005 and March 2007. Spittlebug nymphs and adults were counted on B. brizantha cultivars Marandu, Xaraés and Arapoti, subjected to alternating grazing; on B. decumbens in a silvipastoral system and on 78 genotypes of P. purpureum. The Deois schach population density was greater on the Arapoti cultivar than on the Xaraés and Marandu cultivars. On B. decumbens, the number of spittlebugs was four times greater than on B. brizantha. No significant differences were observed in the number of spittlebugs infesting the different genotypes of P. purpureum.

O objetivo deste trabalho foi avaliar genótipos de capim-elefante (Pennisetum purpureum Schum.) quanto à resistência à cigarrinha-das-pastagens (Mahanarva spectabilis). Para avaliação da antibiose, aos trinta dias após o plantio, cada planta foi infestada com seis ovos próximos à eclosão, em delineamento inteiramente casualizado, com 30 genótipos e dez repetições. Quarenta e cinco dias após a eclosão das ninfas, avaliou-se a porcentagem de sobrevivência do inseto-praga nos diferentes genótipos. Para avaliação da não-preferência, foram quantificados, quinzenalmente, o número e tamanho de ninfas por vaso, em plantas mantidas em casa de vegetação, onde adultos de M. spectabilis eram periodicamente liberados, em delineamento inteiramente casualizado, com três repetições por genótipo, em dois períodos de amostragem. Os genótipos Cameroon de Piracicaba, Pioneiro, Cuba 169, Santa Rita, Mineiro Ipeaco, Mercker Comum de Pinda e CNPGL 96-27-3 foram selecionados quanto à resistência, pelo mecanismo de antibiose. O número e o tamanho médio das ninfas variaram significativamente em razão do genótipo de capim-elefante, no estudo da não-preferência. Os genótipos Roxo de Botucatu e Pioneiro são candidatos à testemunha suscetível e resistente, respectivamente, pelo mecanismo de antibiose, e os genótipos Cameroon e Cameroon Piracicaba são promissores pelo mecanismo de não-preferência.The objective of this work was to evaluate genotypes of elephant grass (Pennisetum purpureum Schum.) regarding resistance to the spittlebug Mahanarva spectabilis. For antibiosis evaluation, each plant was infested with six eggs near hatching, thirty days after planting, in a completely randomized design with 30 genotypes and ten repetitions. Forty-five days after the nymphs hatched, the insect survival rate was evaluated on the different genotypes. For nonpreference mechanism evaluation, the size and number of the nymphs per pot were assessed every 15 days, in plants kept at greenhouse, where adults of M. spectabilis were periodically released, in a completely randomized design, with three repetitions per genotype in two sampling periods. Cameroon de Piracicaba, Pioneiro, Cuba 169, Santa Rita, Mineiro Ipeaco, Mercker Comum de Pinda and CNPGL 96-27-3 genotypes were selected for resistance, by antibiosis mechanism. In the study of the nonpreference mechanism, the number and average size of the nymphs varied significantly as a function of the elephant grass genotype. Roxo de Botucatu and Pioneiro genotypes are, respectively, susceptible and resistant check candidates by the antibiosis mechanism, and Cameroon and Cameroon Piracicaba genotypes are promising by the nonpreference mechanism.

O objetivo deste trabalho foi determinar a herança da produção de acilaçúcares em genótipos de tomateiro, em uma população segregante (F2) do terceiro retrocruzamento, para Lycopersicon esculentum Mill. 'TOM-584', a partir da espécie L. pennellii 'LA-716'. A determinação do teor de acilaçúcares foi realizada com metodologia para determinação de açúcares redutores. Os dados foram utilizados para verificação da herança monogênica, sob diferentes graus de dominância (GD) presumidos, por meio do teste qui-quadrado. Para verificar a existência de efeitos aditivos e não aditivos de um gene maior e de possíveis poligenes, utilizou-se o método da máxima verossimilhança. Para os diferentes GD testados, na faixa compreendida entre -0,7 e -0,4, a hipótese de herança monogênica não pôde ser descartada, o que indica a ação de alelo recessivo, com dominância incompleta na expressão de alto teor de acilaçúcares. Por meio de modelos genéticos pela função de verossimilhança, a hipótese de herança monogênica foi confirmada. Plantas de tomateiro, com boa resistência a artrópodos-praga, mediada pelo aleloquímico acilaçúcar, podem ser obtidas com eficiência em populações de retrocruzamentos, a partir do cruzamento interespecífico L. esculentum x L. pennellii.The objective of this work was to determine the inheritance of acylsugar contents in tomato genotypes, from the F2 generation of the third backcross of L. esculentum Mill. 'TOM-584', after the original cross with the wild accession L. pennellii 'LA-716'. Acylsugar contents in tomato leaflets were measured according to a methodology for reducing sugars determination. The data obtained were evaluated with chi-square tests of monogenic hypotheses of inheritance, under different presumed degrees of dominance, and also under genetic models with the maximum likelihood function, in which presence of a major gene and possible polygenes with additive and non additive effects were tested. For the different presumed degrees of dominance (DD) tested in an array between -0.7 and -0.4, the hypotheses of monogenic inheritance could not be rejected, indicating that high acylsugar contents are controlled by a recessive allele in a locus with incomplete dominance. Genetic models tested under the maximum likelihood function also confirmed the hypothesis of monogenic inheritance. Tomato plants with adequate levels of acylsugar-mediated resistance to arthropod pests can be efficiently obtained in backcross populations, derived from the interspecific cross L. esculentum x L. pennellii.

Analysis of antibiosis resistance to common cutworm (Spodoptera litura Fabricius) in soybean (Glycine max (L.) Merr.) has progressed significantly, but the immediate cause remains unknown. We performed quantitative trait loci (QTL) analysis of pubescence density and plant development stage because these factors are assumed to be the immediate cause of resistance to cutworm. The QTLs for pubescence appeared to be identical to the previously detected the Pd1 and Ps loci controlling pubescence density. We found no candidate loci for flowering time QTLs, although one could be identical to the gene governing the long-juvenile trait or to the E6 loci controlling maturity. None of the QTLs overlapped with the QTLs for antibiosis resistance.