Peanut Arachis Hypogaea Research Articles

Genotypic Differences in Spectral and Photosynthetic Response of Peanut to Iron Deficiency

To assess the genetic variability of peanut (Arachis hypogaea L.) in tolerance to iron (Fe) deficiency, spectral and photosynthetic parameters of 12 peanut cultivars were determined. The results showed that peanut exhibit significant variations in spectral and photosynthetic parameters within cultivars in response to Fe deficiency. The 12 peanut cultivars were separated into three groups, which include (i) a Fe-deficient tolerant cultivar (‘Zhenghong 3’), (ii) a Fe-deficient sensitive cultivar (‘Huayu 22’), and (iii) ten intermediate cultivars. Iron deficiency caused an increase in root biomass, root/shoot ratio, structure independent pigment index and intercellular carbon dioxide (CO2) concentration, but resulted in a decrease in net photosynthetic rate (Pn), quantum yield of PS II photochemistry (Fv/Fm), effective quantum yield of PS II (ΦPS II), photochemical reflectance index, red edge point, and chlorophyll normalized difference index. Iron deficiency-induced decline in net photosynthetic rate may be resulted from the reduction of photosynthetic pigment contents and inhibition of PSII photochemistry.

Effects of Exogenous Salicylic Acid on Physiological Characteristics of Peanut Seedlings under Iron-Deficiency Stress

The effects of salicylic acid (SA) on iron (Fe) deficiency in peanut (Arachis hypogaea L.) were studied by adopting the hydroponic experiment. Iron deficiency caused serious chlorosis, inhibited plant growth and dramatically decreased the concentration of Fe in the roots. Furthermore, it decreased the active Fe content and chlorophyll content, and disturbed ionic homeostasis. In addition, Fe deficiency significantly increased the content of malondialdehyde (MDA) and the superoxide anion (O2•−) generation rate. Addition of SA increased Fe concentration in the shoots and roots, active Fe content, chlorophyll content, the net photosynthetic rate, and transpiration rate. Moreover, SA supplementation alleviated the excess absorption of manganese (Mn), copper (Cu) and zinc (Zn) induced by Fe deficiency. In addition, the chlorosis symptom was alleviated and the plant growth was improved. Meanwhile, addition of SA increased the activities of catalase (CAT) and peroxidase (POD), and decreased the content of MDA and the O2•− generation rate. These results suggest that exogenous SA can alleviate Fe-deficiency induced chlorosis by promoting the plant growth, improving the efficiency of Fe uptake, translocation and utilization, protecting antioxidant enzymes system, and stimulating mineral element maintenance.

Mining tissue-specific contigs from peanut (Arachis hypogaea L.) for promoter cloning by deep transcriptome sequencing.

Peanut (Arachis hypogaea L.), one of the most important oil legumes in the world, is heavily damaged by white grubs. Tissue-specific promoters are needed to incorporate insect resistance genes into peanut by genetic transformation to control the subterranean pests. Transcriptome sequencing is the most effective way to analyze differential gene expression in this non-model species and contribute to promoter cloning. The transcriptomes of the roots, seeds and leaves of peanut were sequenced using Illumina technology. A simple digital expression profile was established based on number of transcripts per million clean tags (TPM) from different tissues. Subsequently, 584 root-specific candidate transcript assembly contigs (TACs) and 316 seed-specific candidate TACs were identified. Among these candidate TACs, 55.3% were root-specific and 64.6% were seed-specific by semi-quantitative RT-PCR analysis. Moreover, the consistency of semi-quantitative RT-PCR with the simple digital expression profile was correlated with the length and TPM value of TACs. The results of gene ontology showed that some root-specific TACs are involved in stress resistance and respond to auxin stimulus, whereas, seed-specific candidate TACs are involved in embryo development, lipid storage and long-chain fatty acid biosynthesis. One root-specific promoter was cloned and characterized. We developed a high-yield screening system in peanut by establishing a simple digital expression profile based on Illumina sequencing. The feasible and rapid method presented by this study can be used for other non-model crops to explore tissue-specific or spatially specific promoters.

Annotation of stress responsive candidate genes in peanut ESTs.

Peanut (Arachis hypogaea L.) is an internationally important crop for human consumption as a good source of protein and vegetable oil. Peanut is widely cultivated around the world in tropical, sub-tropical and warm temperate climate. Because of its huge genome size (2.8 Gb) and unsequenced genome, studies on genomics and genetic modification of peanut are less as compared to other model crops. As peanut can be cultivated in arid and semi-arid regions, and its growth is drastically affected by various stresses that reduces the yield. Therefore, study on stress responsive genes and its regulation are very much important. Here we report about the identification and annotation of some stress responsive candidate genes using peanut Expressed Sequences Tags (ESTs). The selection of genes was based on the publically available expression data. Due to good expression data and lack of available literature in peanut some of the stress responsive genes were screened. Individual EST of the said group were further searched in peanut ESTs (1, 78,490 whole EST sequences) using computational approach. Various tools like Vec-Screen, Repeat Masker, EST Trimmer, DNA Baser and WISE2 were being used for stress responsive gene identification and annotation. Research progress made towards contigs assembly, determination of biological function of genes, and prediction of domain as well as 3D structure for related protein are included.

Effects of Nitric Oxide on Iron-Deficiency Stress Alleviation of Peanut

The aim of this research was to study the role of nitric oxide (NO) in alleviating iron deficiency induced chlorosis of peanut (Arachis hypogaea L.). For this study, sodium nitroprusside (SNP) was used to supply NO for hydroponic peanut plants. After 18 days, the peanut seedlings growing without iron exhibited significant leaf interveinal chlorosis, and this iron-deficiency induced symptom was completely prevented by NO. An increased content of chlorophyll and active iron was observed in NO-treated young leaves, suggesting an improvement of iron availability in plants. In addition, the improved rhizosphere acidification and increased secretion of organic acids by root in NO-treated plants suggesting that NO is effective in modulating iron uptake and transport inside the peanut plants. Furthermore, NO treatment alleviated the increased accumulation of superoxide anion (O2•−) and malondialdehyde (MDA), and modulated the antioxidant enzymes. However, the SNP with a prior sunlight treatment that does not release NO had no significant effect on the chlorophyll levels in iron-deficient plants. Therefore, these results support a physiological action of NO on the availability, uptake and transport of iron in the plant.

Effects of low light stress on rubisco activity and the ultrastructure of chloroplast in functional leaves of peanut

Aims In recent years, intercropping system has become one of the major practice of peanut(Arachis hypogaea) cultivation in northern China because of the high land and energy utilization efficiency, to some extent compensating for the production loss caused by decreasing area of cultivation land. Intercropped peanut plants often have a lower pod yield compared with monoculture due to constraint on light availability. This study was conducted to explore the shade-tolerance mechanism in two peanut cultivars, ‘Huayu 22' and ‘Baisha 1016', that grew in an intercropping system, by studying chloroplast ultrastructure and rubisco activity under different levels of shading. Methods A field experiment was conducted with three levels of light treatments, including full natural light(CK), 50% natural light indensity(NLI), and 15% NLI. The ‘Huayu 22' was used as a shade-tolerant cultivar and the ‘Baisha 1016' as a shade-susceptible cultivar based on previous studies. Experimental plants of both cultivars were shaded for 40 days from emergency in 2006. Rubisco activity, the number and shapes of chloroplasts and starch grains, and number of grana and granum lamella were investigated in functional leaves of plants in all treatments. Important findings The functional leaves of peanut plants in the 50% and 15% NLI treatments had a lower rubisco activity than those in the CK treatment. In the ‘Baisha 1016', the reduction in rubisco activity was 40.1% in the 50% NLI treatment and 59.4% in the 15% NLI treatment, respectively, compared to the CK treatment;whereas no significant differences were found among treatments in the ‘Huayu 22' in the rubisco activity. Compared with the CK, the number of chloroplasts remained unchanged, the number of grana and lamella in grana increased, and the individual chloroplast was longer and in perfect development in the functional leaves of plants of the ‘Huayu 22' grown in the 50% NLI treatment. In contrast, the number of chloroplasts, grana and starch grains of the ‘Huayu 22' plants decreased significantly, the chloroplast membrane and grana lamella were damaged, the number of granum lamella increased, and the individual chloroplast became longer in the 15% NLI treatment. The number and ultrastructure of chloroplasts in the ‘Baisha 1016' plants followed similar patterns of changes as those of the ‘Huayu 22' in the 50% NLI treatment. For plants of the ‘Baisha 1016' in the 15% NLI treatment, their chloroplasts became more roundly shaped, with decreasing number of grana lamella and increasing number of starch grains, compared with the CK. There were a greater decrease in the grana number and more damage in the grana lamella in plants of the ‘Baisha 1016' than those of the ‘Huayu 22'. In conclusion, the shade tolerance of the ‘Huayu 22' resulted from lack of changes in rubisco activity and less damage in the ultrastructure of chloroplasts when under low light stress compared with the ‘Baisha 1016'.

An evaluation of amino acid, fatty acid and isoflavone composition in Korean peanut (Arachis hypogaea l.) seeds to improve the nutritional quality of breeding lines

Peanut is grown primarily for human consumption due to their favorable nutrient profile and functional compound such as isoflavone in seeds. The aim of this study was to evaluate the amino acid, fatty acid, and isoflavone profile in seeds of seven peanut cultivars (Suwon 88, Daewon, Daekwang, Seonan, Saedeul, Satonoka, and Pungan) grown in Korea. The protein and oil contents in peanut seeds varied at the range of 21.4 to 32.0% and 41.7 to 47.2%, respectively. The quantity of protein was relatively similar in all peanut cultivars except Pungan seeds. The result of amino acid analysis showed that Suwon 88, Daewon, and Seonan seeds had higher concentration of amino acid (Asp, Thr, Ser, Glu, Pro, Gly, Ala, Cys, Val, Met, Ile, Leu, Tyr, Phe, His, Lys, and Arg) than other peanut cultivars. However, the quantity of oil was higher in Suwon 88, Daekwang, Seonan, and Satonoka seeds, whereas the fatty acid profile analysis revealed that higher levels of oleic acid, arachidic acid, gondoic acid, behenic acids, and lower levels of palmitic, stearic, and linoleic acids were found in Saedeul seeds. In addition, the isoflavones, daidzin, genistin, and daidzein were higher in Satonoka (97.96, 63.19, and 33.8 μg/g, respectively) followed by Daewon. The results of the present study suggest that the cross among identified peanut cultivars, Satonoka (high yielding isoflavones), Seadeul (high yielding oleic acid), Suwon 88, Daewon, and Seonan (high yielding amino acid) would improve the nutritional and functional compounds of breeding lines.

Accumulation Of Biomass And Mineral Elements By Peanut: Application Of The Expanded Growth Model

A number of factors influence crop production including crop species, time of planting and sampling, level of fertilizer application, water availability (rainfall or irrigation), plant population, frequency of harvests (for perennials), soil characteristics, insect control, and weed control. A conceptual model is required within which measurements and observations can be interpreted. For this analysis the expanded growth model is used to described biomass accumulation with calendar time. Field data for peanut (Arachis hypogaea L.) grown in North Carolina on a sandy loam soil are used for this application. Measurements of biomass and mineral elements (nitrogen, phosphorus, potassium, and magnesium) were reported for whole plant and nuts (kernels + shells). The theory provided reasonable description of the results. It was concluded that the rate limiting process in the system was biomass accumulation by photosynthesis, and that accumulation of mineral elements proceeded in virtual equilibrium.

Exogenous Nitric Oxide Effects on Physiological Characteristics of a Peanut Cultivar Growing on Calcareous Soil

This study examined the effects of exogenous nitric oxide (NO) on physiological characteristics of peanut (Arachis hypogaea L.) growing on calcareous soil. Sodium nitroprusside (SNP) was added into slow-release fertilizer (SRF) or sprayed on leaves to supply NO for iron-deficient peanut. The results showed that root application of SNP at 5.63 mg/g and foliar spray of SNP at 1.0 mmol L−1 significantly enhanced the peanut growth, pod yield, and quality. The soil pH was reduced, and available iron content and iron (Fe3+) reductase activity in root were increased, indicating NO application improved the availability of iron in the soil. Additionally, NO increased the chlorophyll and active iron content in young leaves, implying NO enhanced the availability of iron within the plant. Nitric oxide also inhibited the malondialdehyde (MDA) accumulation in leaves and increased the activity of antioxidant enzymes, which protected peanut against iron-deficiency-induced oxidative stress. It was concluded that NO might be employed for ameliorating iron-deficient chlorosis of peanut on calcareous soil when added into SRF or sprayed on leaves.

NATURAL ANTIOXIDANT INGREDIENT FROM BY-PRODUCTS OF FRUITS

The contents of total phenolics compounds and their phenolic constituents were quantified in organic and aqueous of four varieties (Zebdia, Sukkari, taimor and Hindi) of mango (Mangifera indica L.), seeds pulp and kernel, one varieties of pomegranate (Punica ranatum L., peel) and peanut (Arachis hypogaea L., Giza 6, shell) by-products. The antioxidant activities of all by products extracts were assessed by five antioxidant methods as well as by rancimate test. The total Phenolic content of aqueous and organic extracts of among all mango varieties, pomegranate and peanut shell showed the content values ranging from 71.06 to 124.18 mg/100g, 95.07 to 124.18 mg/100g and 41.64 to 71.06, respectively. Nineteen phenolic compounds were identified by High Performance Liquid Chromatography (HPLC) among all mango varieties, of which vanillic acid, benzoic acid and mangiferin were occurred in high amounts. The major phenolic compounds were detected in pomegranate and peanut shell were chlorogenic and gallic and caffeic (24.42%), respectively. All fruits by products were exhibited remarkable antioxidant activity, with various degrees in all tested methods. However, among all by-products extracts, organic extract had higher antioxidant than that aqueous extracts toward all antioxidant tested. Mango kernel peel and pomegranates showed high radical scavenging activity, which could be compared with the synthetic antioxidants Butylated Hydroxyanisol (BHA). However, all by-products extracts exhibited high inhibit effect against the lipid peroxidation of sunflower oil (at 100°C) as assessed by rancimat methods. However, this antioxidant activity was found to be strong significant correlation with phenolic contents (p

Effect of Peanut (Arachis hypogaea) on Kidney in Rats

Background: Kidney is the main excretory organ which can be damaged by various disease conditions, foods, exposure to some chemicals, toxins, or infectious agents. Peanuts (Arachis hypogaea) may have antioxidant activity thereby can be used for the improvement of kidney functions though its exact role is yet to be explored. Objective: To observe the effect of peanut kernel powder on kidney by observing the histology and some biochemical parameters (serum creatinine and blood urea) in Wistar albino rats. Materials and method: This experimental study was conducted between October 2012 to December 2012 in the Institute of Food and Nutrition, University of Dhaka, Bangladesh. A total number of 20 apparently healthy Wistar albino male rats, weighing between 120 to 150 grams, age range 90 to 120 days were used. Prior to conducting the study, the animals were acclimatized for 14 days. Then, they were divided into two groups; control group (Group A) consisted of 10 rats and experimental group (Group B- Peanut treated group) consisted of 10 rats. All groups of animals received basal diet for 21 consecutive days and in addition, experimental group received peanut kernel powder (500mg/kg body weight/day; orally) in the morning along with food for 21 consecutive days. All the animals were sacrificed on 22nd day. The blood and kidney samples were collected. Blood urea, serum creatinine levels were measured and histopathology of kidney was done by using standard laboratory procedure. Results: The mean body weight of peanut treated group was significantly lower than that of control group. The mean blood urea and creatinine levels were higher in peanut treated group in comparison to those of control group but the differences were not statistically significant. On histology, kidney revealed normal findings both in control and peanut treated group. Conclusion: Role of peanut kernel powder in normalizing the biochemical parameters is controversial. DOI: http://dx.doi.org/10.3329/dmcj.v2i1.17792 Delta Med Col J. Jan 2014; 2(1): 17-21

BORON NUTRITION OF PEANUT GROWN IN BORON-DEFICIENT CALCAREOUS SOILS: GENOTYPIC VARIATION AND PROPOSED DIAGNOSTIC CRITERIA

Field studies were conducted to assess boron (B) requirement, critical concentrations in diagnostic parts based on yield response curves and genotypic variation by growing three peanut (Arachis hypogaea L.) cultivars (‘Golden’, ‘BARD-479’, ‘BARI-2000’) on two B-deficient calcareous soils. Boron application significantly increased pod yield of all the cultivars over control. Maximum pod yield increases were: ‘Golden’, 16−23%; ‘BARD-479’, 21−27%; and ‘BARI-2000’, 25−31%. The cultivars varied in B efficiency and cv. ‘Golden’ was the most B efficient (81−86%) while cv. ‘BARI-2000’ was the least efficient (76−80%). Boron requirements for near-maximum (95%) dry pod yield were 0.65 kg ha−1 for ‘Golden’, 0.75 kg ha−1 for BARD-479 and 0.80 kg ha−1 for BARI-2000. Critical B concentrations in shoots and seeds were: ‘Golden’, 33 mg kg−1 and 26 mg kg−1; ‘BARD-479’, 38 mg kg−1 and 31 mg kg−1; and ‘BARI-2000’, 42 mg kg−1 and 33 mg kg−1.

Mycological and aflatoxin contamination of peanuts sold at markets in Kinshasa, Democratic Republic of Congo, and Pretoria, South Africa

Peanut (Arachis hypogaea L.) is an important food crop in sub-Saharan Africa. In this survey, the mycological and aflatoxin contamination of peanuts collected from Kinshasa, Democratic Republic of Congo, and Pretoria, South Africa, was assessed. Twenty peanut samples were purchased randomly at informal markets in the two cities and analysed for mycoflora and aflatoxins (AFB1, AFB2, AFG1 and AFG2) using standard methods. The results indicated that 95% of the Kinshasa samples and 100% of the Pretoria samples were contaminated with aflatoxigenic fungi in the ranges 20–49,000 and 40–21,000 CFU/g, respectively. Seventy-five per cent of the Kinshasa samples and 35% of the Pretoria samples exceeded the maximum limits of AFB1 as set by The Joint FAO/WHO Expert Committee on Food Additives. Residents of both cities are at a high risk of aflatoxin exposure despite their apparent cultural, socio-economic, geographic and climatic differences. Further work needs to be done to understand the supply chains of peanut trade in informal markets of the two countries so that interventions are well targeted on a regional rather than a national level.

Expression and characterization ofLysophosphatidyl acyltransferasegenes from peanut (Arachis hypogaeaL.)

Lysophosphatidyl acyltransferase (LPAAT) is a pivotal enzyme controlling the metabolic flow of lysophosphatidic acid into different phosphatidic acids in diverse tissues. The functions of LPAAT genes have been intensively studied in Arabidopsis, but not in peanut (Arachis hypogaea L.). In this study, conventional RT-PCR or RACE (rapid amplification of cDNA ends)-PCR were used to clone four AhLPAAT genes from peanut. Quantitative real-time RT-PCR analysis indicated that AhLPAAT2 transcript was more abundant in seeds, whereas the transcript abundances of other three genes were higher in flowers than in other tissues examined. During seed development, levels of AhLPAAT6 transcripts decreased, whereas levels of other three transcripts remained relatively high at the initial stages of seed development but dramatically decreased in abundance during later stages. Expression analysis of four genes under conditions of cold, salt, drought and ABA stresses indicated that AhLPAAT transcripts were differentially regulated during abiotic stresses. Transcripts of the four genes increased substantially in leaves exposed to drought stress. Levels of AhLPAAT2 transcript were distinctly enhanced after exposure to cold, salt and drought stresses, whereas AhLPAAT4 was obviously up-regulated after salt, drought and ABA treatments. The expressions of AhLPAAT6 increased in all materials after stress treatments except for salt-stressed leaves, whereas transcript levels of AhLPAAT5 only increased in cold- and drought-stressed leaves and ABA-treated roots. These insights into peanut LPAATs may facilitate modification of oil deposition and improvement of abiotic stress resistance in this important crop.

The Use of Sugar Baits for the Integrated Management of Soil Arthropod Pests in Peanut (Arachis hypogaeaL.) in Ghana, West Africa

Soil arthropods cause kernel and pod damage and can lower yields of peanut (Arachis hypogaea L.) in Ghana, West Africa. On-station and on-farm experiments were conducted during 2007 and 2008 at Kwadaso and Hiawoannwu, respectively, using an improved peanut cultivar/line RRR-ICGU 88709 in a soil arthropod pests management trial. The trial included four treatments, i.e. chlorpyrifos (Dursban™) insecticide as a standard, three levels of granulated sugar as baits, and an untreated control. Soil arthropod pests observed in peanut plots during both years from the two locations were white grubs, millipedes, symphilids, termites, earwigs, and red ants while predators included centipedes and black ants. Termites and red ants were the predominant arthropod pests and predatory black ants (Hymenoptera: Formicidae) exceeded that of centipedes (Myriapoda: Chilopoda) in the two trial locations. The proportion of unfilled pods was high in the two locations during both years. Generally, the population of centipedes was lo...

Prevention of pre-harvest aflatoxin production and the effect of different harvest times on peanut (Arachis hypogaea L.) fatty acids

The aim of this study was to investigate the relationship between aflatoxin and fatty acids and to determine the optimum harvest time to avoid pre-harvest aflatoxin formation. It was established that harvest time had statistically significant effects on the levels of saturated fatty acids: myristic acid (C14:0), palmitic acid (C16:0), heptadecanoic acid (C17:0), stearic acid (C18:0), arachidic acid (C20:0), behenic acid (C22:0), lignoceric acid (C24:0), monounsaturated fatty acids; palmitoleic acid (C16:1), heptadecenoic acid (C17:1), oleic acid (C18:1) and gadoleic acid (C20:1); and on polyunsaturated fatty acids: linoleic acid (C18:2) and linolenic acid (C18:3). By delaying the harvest time, the ratio of saturated fatty acids decreased and unsaturated fatty acids increased. It was shown that the longer harvesting was delayed, the greater the quantity of oleic acid that was produced. Before harvest time, if the soil moisture was 5% or higher, aflatoxin was produced by fungi. It was found that the weather conditions of the region were suitable for aflatoxin production. Soil moisture appears to be more important than soil temperature for aflatoxin formation. The production of aflatoxin was not observed in the first and second harvests, both of which are at early harvest times. It was found that aflatoxin B1 during harvest time was the most significant of the four toxins. The third harvest time, which is the most widely used, was observed to have significant problems due to aflatoxin formation. Therefore, it is suggested as a result of this study that the harvest of peanuts must be done considering seed yield before the middle of September to avoid aflatoxin formation at harvest time.

Generation Means Analysis of Fatty Acid Composition in Peanut

Optimizing the chemical composition of peanut (Arachis hypogaea L.) oil is essential for the production of biodiesel. Specifically, increasing the ratio of oleic to linoleic acid (O/L) in peanut oil and reducing the long chain saturated fatty acid concentration (which includes arachidic, behenic, and lignoceric acids) produces high-quality, stable methyl esters for biodiesel. Therefore, elucidating the inheritance of these factors and their relationships in peanut populations segregating for high oil is critical. The F1, F2, and backcross generations derived from two crosses, both involving a high oil concentration, low O/L runner breeding line (31-08-05-02) and two high O/L, normal oil concentration, adapted runner genotypes (Tamrun OL01 and Tamrun OL07), were evaluated in College Station, Texas, in 2010. The results from generation means analysis confirm that the high-oleic trait is under simple genetic control and can be manipulated through breeding and selection. Most fatty acids were controlled primarily by additive gene action, which is highly selectable. Dominance effects also played an important part in the inheritance of most fatty acids. Additive × dominance interaction was significant in the inheritance of stearic and arachidic acids in the cross involving Tamrun OL07. Oil concentration was also negatively correlated with oleic acid concentration in the F2 generations of both crosses and positively correlated with arachidic acid in most of the segregating generations evaluated. Therefore, developing a peanut genotype high in oil and oleic acid concentration that has reduced long chain saturates will require the evaluation of large numbers of segregating progeny.

Likelihood of Stink Bugs Colonizing Crops: A Case Study in Southeastern Farmscapes

Stink bugs, including Nezara viridula (L.), Euschistus servus (Say), and Chinavia hilaris (Say), are economic pests across agricultural farmscapes where they can colonize closely associated crops. This 4-yr on-farm study was conducted to examine the likelihood of these three stink bug species colonizing crops in corn-cotton, corn-peanut-cotton, and peanut-cotton farmscapes by using odds ratios. Corn (Zea mays L.), peanut (Arachis hypogaea L.), and cotton (Gossypium hirsutum L.) served as host plants for E. servus and N. viridula. Corn did not serve as a host plant for C. hilaris. Although peanut was a relatively poor host plant, cotton was a relatively good host plant for this stink bug. For N. viridula and E. servus adults, the risk of crop colonization was higher for peanut in peanut-cotton farmscapes with corn than without corn and was highest for cotton in corn-peanut-cotton, followed by peanut-cotton, and lastly corn-cotton farmscapes. The likelihood of oviposition by E. servus, though, was higher in cotton in corn-cotton than peanut-cotton farmscapes. For C. hilaris adults, the risk of crop colonization was highest for cotton in peanut-cotton, followed by corn-peanut-cotton, and lastly corn-cotton farmscapes. Corn was more likely than peanut or cotton to harbor adults and immatures, i.e., egg masses and young nymphs, of N. viridula and E. servus. Adults of all three stink bug species colonized cotton more often than peanut in peanut-cotton farmscapes. However, oviposition by N. viridula and E. servus occurred more often in peanut than in cotton. These assessments of the likelihood of stink bug colonization are essential for modeling predictions of stink bug colonization and designing more comprehensive landscape management approaches for control of stink bugs in these farmscapes.

Characterization of Resistance of Peanut to Puccinia arachidis

Peanut rust, caused by Puccinia arachidis Speg, is an important foliar disease of peanut (Arachis hypogaea L.) in tropical countries. The best option for disease management is host resistance. The objectives of this project included characterizing peanut genotypes for resistance to P. arachidis, assessing the genetic variation of newly developed Collaborative Research and Support Program (CRSP) peanut breeding lines, and assessing genetic variability among P. arachidis populations. In field studies conducted over 2010-2011, several CRSP breeding lines demonstrated varying levels of rust resistance. Detached leaf assays were used to examine the components of resistance to P. arachidis. Few significant differences were observed in these studies. We used SSR markers to characterize newly developed CRSP breeding lines, plant introductions, and commonly grown cultivars. The SSR markers used detected polymorphisms but were not able to distinguish resistant from susceptible peanut genotypes. Sequences of the 5.8S-ITS2-28S region of P. arachidis isolates collected from different regions in the United States and other countries do not indicate high genetic variability among the populations. Accepted for publication 23 September 2013. Published 25 November 2013.

Erratum to: 56 SINGLE LAYER CENTRIFUGATION THROUGH PURESPERM® 80 IMPROVES QUALITY OF CRYOPRESERVED DOG SPERMATOZOA

Density gradient centrifugation with PureSperm® (PureSperm® 40 + PureSperm® 80; Nidacon International, Mölndal, Sweden) has been satisfactorily used to enhance the quality of dog semen samples; however, no studies have been performed on the effect of single layer centrifugation (SLC) with PureSperm® on frozen–thawed dog semen. The aim of this study was to investigate if SLC with PureSperm® 80 can improve the post-thaw semen quality of dog. Semen from 5 dogs was collected by digital manipulation. Two ejaculates from each dog were centrifuged with Tris-based extender, supernatant was removed, and sperm pellet was suspended to a final concentration of 300–400 × 106 sperm mL–1 with CaniPROTM Freeze A plus 20% egg yolk at 22°C. Extended semen was cooled to 5°C within an hour and then diluted to a final concentration of 150–200 × 106 sperm mL–1 in CaniPROTM Freeze B plus 20% egg yolk at 5°C, loaded in 0.5-mL plastic straws and frozen horizontally in ranks placed 4 cm above the surface of liquid nitrogen vapors for 10 min, after which they were directly placed in liquid nitrogen. After 24 to 48 h of storage, straws were thawed in a water bath at 37°C for 30 s. After thawing, semen samples were divided in 2 aliquots: one of them was used as control and the other one was processed by SLC PureSperm® 80. Assessment of sperm motility (assessed by computerized-assisted semen analysis), morphology (Diff-Quick staining), and viability [triple fluorescent stain of propidium iodine/isothiocyanate-labeled peanut (Arachis hypogaea) agglutinin/Rhodamine 123] were evaluated in control and treated semen samples. Data were studied by ANOVA. Results are expressed as mean ± SEM. Significant (P < 0.001) differences were found between SLC-treated and control semen for sperm motility (percentage of total motile spermatozoa: 93.65 ± 0.05 v. 83.79 ± 0.13; percentage of progressive motile spermatozoa: 79.38 ± 6.66 v. 54.61 ± 16.11), morphology (86.45 ± 0.01 v. 83.51 ± 0.01), and viability (percentage of viable sperm with an intact acrosome: 58.32 ± 0.04 v. 36.50 ± 0.17; percentage of viable sperm with an acrosome reaction: 2.81 ± 0.01 v. 9.74 ± 0.21). Based on our results, we can conclude that SLC with PureSperm® 80 is an alternative and successful method for improving the quality of frozen–thawed dog spermatozoa, selecting good-quality spermatozoa (motile, morphologically normal, viable, and acrosome intact spermatozoa) from the rest of the semen sample.