bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Analytical Methods for Optimizing Peanut Roasting for Snack Foods
Authors: Smyth D. A. , Macku C. , Holloway O. E. , Deming D. M. , Slade L. , Levine H.
Published: April 2010

Roasting Arachis hypogaea L. seeds for snack foods requires control of roasting temperature and time to optimize eating quality. Extra large virginia and jumbo runner peanut seeds were oil roasted at different thermal input levels to examine relationships between roast color and other analytical measurements related to roast quality. A laboratory roaster and commercial lots of peanut seeds were used to simulate the commercial process. The concentration of volatiles such as pyrazines increased in roasted seeds with increased thermal energy. Descriptive sensory analyses on these same roasted seed samples showed that optimal balance of important flavor characteristics such as roasted peanut, dark roast, and sweet had distinct roast temperature and time requirements. Excessive heat increased negative flavor components such as bitter. Conventional tests for roaster control such as roast color (CIELAB L*) or seed moisture content changed only slightly during the period when optimal roast quality was achieved. For a given seed lot, optimal roast required both appropriate roast color and tests of roasted peanut flavor. Roasted peanut products dependent on the enhanced stability of the high oleic acid trait required measurements of either oxidative stability, or the fatty acid profile, to ensure the desired product shelf life. Analytical methods such as those discussed here allow the commercial roaster to reach an optimal roast quality while using a diverse raw material supply.
Stem Rot of Peanut: Relationship Between in Vitro Fungicide Sensitivity and Field Efficacy of Fungicides
Authors: Franke M. D. , Brenneman T. B. , Stevenson K. L.
Published: April 2010

Isolates of Sclerotium rolfsii exhibiting varying degrees of in vitro fungicide sensitivity were exposed to fungicides in field microplots in 1995 and 1996. Individual peanut (Arachis hypogaea L.) plants in 0.9-m microplots were inoculated with isolates of S. rolfsii collected from peanut fields throughout Georgia. The 60 isolates used in the study represented the full range of sensitivity to the fungicides tebuconazole, flutolanil, and PCNB. After inoculation, microplots were treated with recommended rates of tebuconazole (0.227 kg ai/ha), flutolanil (0.337 kg ai/ha), PCNB (5.6 kg ai/ha), or were left untreated. Disease ratings were made at harvest, and pod yield from each plant was recorded. In both years, disease severity was significantly lower in treated microplots for all three fungicides. Isolates with lower in vitro fungicide sensitivity responded as well to labeled rates of all three fungicides as those with high in vitro sensitivity. In vitro sensitivity and percent control in treated microplots were not correlated for all three fungicides. Fungicide sensitivity and the level of infection in nontreated microplots also were not correlated for flutolanil and tebuconazole indicating that virulence was not affected by fungicide sensitivity. However, there was a negative correlation between in vitro sensitivity to PCNB and the level of infection in nontreated microplots in 1995, indicating that isolates with lower in vitro sensitivity were more virulent. However, this trend was not observed when the same isolates were evaluated in 1996. In 1995, plants in PCNB-treated microplots had a significantly higher yield than those in the nontreated microplots. In 1996, all fungicide treatments significantly enhanced yield. Because in vitro sensitivity and field efficacy were not correlated for all three fungicides, labeled rates should control stem rot in the field.
Effect of Sowing Spacing on Vegetative Growth, Dry Matter Production, and Peanut Pod Yield
Authors: Giayetto O. , Cerioni G. A. , Asnal W. E.
Published: April 2010

Peanut growth and pod yield are influenced by sowing spacing and plant density. Production and distribution of dry matter on peanut cultivars sown in different spacings and densities and their relationships with pod and kernel yields were assessed. The factors evaluated were two cultivars (Florman INTA, virginia-type “runner” and Colorado Irradiado, valencia-type erect), three interrow spacings (IRS) (0.70, 0.50, and 0.30 m) and two interplant spacings (IS) (0.06 and 0.12 m). The 12 treatments were disposed in a factorial arrangement of 2×3×2 and a randomized block design with three replications. Weeds were controlled with Imazetapir (100 g ai/ha) and also hand weeded while leaf spot control was done with Fluzilasole (60 g ai/ha). Sowing spacings did not affect phenologic stage duration, but the differences observed were due to the cultivar. Vegetative growth was sensitive to spacings effect. At an individual plant level, dry matter and leaf area decreased significantly because of the greater intraspecific competition produced by the shortening of distances between rows (from 0.70 to 0.30 m) and between plants (from 0.12 to 0.06 m) and the corresponding density increase from 12 to 56 plants/m2. However, at a population level, most compact spacings produced more dry matter per surface and leaf area index. This also is related to the lesser time required for plants at these spacings to achieve a radiation interception higher than 90%. Dry matter distribution did not vary with sowing spacings. The number of branches per plant was reduced with the increase of density. The effect was greater in the late maturing cultivar. The most compact sowing spacings (0.30×0.06, 0.50×0.06 and 0.30×0.12 m) produced higher pod and kernel yield/ha than those less dense. This response is based upon the significant correlations between the dry matter and number of branches per surface area, and leaf area index and pod yield.
Visual Estimation of Aflatoxin Production in Peanut with Aspergillus Norsolorinic Acid Mutants1
Authors: López Y. , Keller N. P. , Sarr B. , Phillips T. D. , Cuero R. G. , Smith O. D.
Published: April 2010

Peanut seed and pods are susceptible to contamination by aflatoxin (AF), a carcinogenic mycotoxin produced by Aspergillus flavus Links Fr. and A. parasiticus Speare. Efforts to evaluate peanut lines for resistance to AF contamination have been impeded by limitations to the methodologies available for AF detection. AF cannot be seen by visible light and its detection involves grinding seed tissue in organic solvents, separation of phases, and detection by ELISA, high performance liquid chromatography (HPLC) or thin layer chromatography. These methodologies are time-consuming, expensive, labor-intensive, and are uninformative in defining the tissues of the peanut seed and pod that are most frequently contaminated with AF. Aspergillus AF mutants which accumulate norsolorinic acid (NOR), an orange-pigmented AF pathway intermediate, provide an easy and convenient mean to detect AF contamination. A visual rating scheme for NOR contamination of peanut seed was developed that correlated favorably to HPLC detection of both NOR and AF (r = 0.96 and 0.95, respectively). When screening the 38 plant progenies that comprise Tamspan 90 (a spanish cultivar), NOR was first seen in the intercotyledonary cavity and the interfacial surface of cotyledons and testae in seeds examined from infected pods. Immature pods were often heavily contaminated with NOR. Six of the 38 lines accumulated low levels of NOR in two laboratory tests. Additional studies are needed to determine if these results are predictive of aflatoxin contamination under field conditions.
Effect of Continuous Seed Size Selection Among Two Runner-Type Peanut Cultivars1
Authors: Branch W. D. , Culbreath A. K.
Published: April 2010

The major peanut (Arachis hypogaea L.) producing regions in the U.S. are currently faced with an increasing tomato spotted wilt tospovirus (TSWV) problem, and the most effective control is the use of resistant cultivars. This study was conducted to compare the field performance and TSWV disease intensity among different seed sizes of two runner-type cultivars. For three consecutive years, 1995–97, the effect of continuous seed size selection on yield, grade, and TSWV intensity among the two runner cultivars Georgia Green and Florunner was evaluated at the Univ. of Georgia Coastal Plain Exp. Sta. Sound mature kernels from both cultivars were divided into four seed sizes (jumbo, medium, No. 1, and the combined mill run check). Seed size selection pressure was applied to both cultivars each year. Seed stock for planting each year was obtained from the corresponding seed size produced the previous year. The results showed that the Georgia Green cultivar significantly out-performed the Florunner cultivar in yield, grade, dollar value, and had significantly less TSWV. Georgia Green had a similar percentage of jumbo seed, more medium seed, and fewer No. 1 seed than Florunner. Both runner-type cultivars responded similarly to continuous selection pressure with small but significant changes in seed size distribution over a relatively short 3-yr period.
Inhibition of Fungal Colonization of Stored Peanut Kernels with Products from Some Medicinal/Culinary Plants
Authors: Awuah R. T.
Published: April 2010

Products from five medicinal/culinary plants—Citrus aurantifolia fruit peel oil, Cymbopogon nardus leaf oil, Ocimum gratissimum leaf powder, Xylopia aethiopica fruit powder, and Syzigium aromaticum clove powder—were tested for activity against fungal colonization of stored peanut. The natural microflora of kernels were supplemented with a norsolorinic acid (NOR) mutant of Aspergillus parasiticus before treatment with the various plant products. Treated kernels were stored at 5.7% moisture content in mini-polyethylene bags for 11 mo. Of the five plant products, the Syzigium clove powder proved to be most efficacious. After 4 mo storage, a low colony-forming unit (CFU) value of 0.601 log units of NOR A. parasiticus was recorded per gram of kernels treated with the powder. Significantly higher CFU values (P ≤ 0.05) were associated with kernels that received no plant product (3.099 log units) and kernels treated with the other plant products(1.459–2.930 log units). CFU of total fungi, superficial fungal growth, internal kernel discoloration, and fungal growth/sporulation on the internal surfaces of the cotyledons also were suppressed by the Syzigium powder after 11 mo. The Citrus oil and the Ocimum leaf powder were moderately effective, being similar to each other in several storage parameters. The Cymbopogon leaf oil was the least effective of the plant materials tested. In a test tube experiment, the Syzigium and Ocimum powders were more efficacious when mixed with stored peanut kernels than when separated from kernels with a piece of mosquito-proof screen. The optimum rates of the two powders for preventing superficial fungal growth on kernels at 8% moisture in mini-polyethylene bags at 28 C were 150 and 100 g/kg of kernels, respectively, for Syzigium and Ocimum. At these rates, 93 and 56% of kernels treated with the Syzigium and Ocimum powders, respectively, were free from superficial fungal growth after 4 mo. These results point to the potential of the two powders, especially Syzigium, for preventing mold growth and possibly aflatoxin production in stored peanut.
Diclosulam for Weed Control in Texas Peanut1
Authors: Grichar W. J. , Dotray P. A. , Sestak D. C.
Published: April 2010

Field experiments were conducted in 1995 through 1997 in south and west Texas to evaluate diclosulam [N-(2,6-dichlorophenyl)-5-ethoxy-7-fluoro(1,2,4)-triazolo(1,5c)-pyrimidine-2-sulfonamide] for weed control in peanut. Diclosulam applied preplant incorporated at 0.01 kg ai/ha in combination with ethalfluralin at 0.84 kg ai/ha controlled Texas panicum, Palmer amaranth, morningglory species, and golden crownbeard at least 95% and devil's-claw 91%. When diclosulam rates were increased to 0.02 kg/ha, yellow and purple nutsedge were controlled at least 89 and 72%, respectively. Diclosulam applied postemergence (POST) provided erratic yellow nutsedge control.
Peanut Seedling Response to Dinitroaniline Herbicides Applied Preplant Incorporated and Preemergence1
Authors: Johnson W. C. , Mullinix B. G.
Published: April 2010

Greenhouse studies were conducted in 1995, 1996, and 1998 to measure the effect of preplant incorporated (PPI) and preemergence (PRE) applications of ethalfluralin and pendimethalin on growth of individual peanut seedlings in pots. Herbicide rates evaluated were 0, 0.6, 1.1, and 2.2 kg ai/ha for each herbicide. Parameters measured were time of emergence, seedling height, canopy width, foliage biomass, root length, and root biomass of individual plants. PPI applications were more injurious than PRE applications for all parameters regardless of herbicide. Ethalfluralin PPI inhibited peanut seedling growth more than equivalent rates of pendimethalin PPI. However, peanut seedling responses to PRE applications of ethalfluralin and pendimethalin were generally the same.
Managing Nematodes, Fungal Diseases, and Thrips on Peanut with Pesticides and Crop Rotations of Bahiagrass, Corn, and Cotton1
Authors: Johnson A. W. , Minton N. A. , Brenneman T. B. , Burton G. W. , Culbreath A. K. , Gascho G. J. , Baker S. H. , Johnson W. C.
Published: April 2010

The influences of bahiagrass, corn, and cotton in rotation with peanut and treatments with aldicarb, flutolanil, and aldicarb plus flutolanil on nematodes, thrips, diseases caused by soilborne fungal pathogens, and yield of peanut were studied for 3 yr. Peanut yields following either 1 or 2 yr of bahiagrass, corn, or cotton were higher than those of continuous peanut. Peanut yield was greatest in the aldicarb plus flutolanil treated plots (5270 kg/ha), intermediate where aldicarb (4060 kg/ha), or flutolanil (4597 kg/ha) was used without aldicarb, and least in untreated (3690 kg/ha) plots. Yield increases in response to cropping sequences and pesticide treatments resulted primarily from suppression of crop damage by Meloidogyne arenaria, Sclerotium rolfsii, Rhizoctonia solani, and Frankliniella spp. The data document the pest management benefits and yield response associated with using two widely grown agronomic crops (corn and cotton), an improved bahiagrass cultivar, and pesticide treatments in peanut production.
Influence of Harvest and Post-Harvest Conditions on the Physiology and Germination of Peanut Kernels
Authors: Dey G. , Mukherjee R. K. , Bal S.
Published: April 2010

Harvesting, storage, and shelling procedures can greatly affect seed vigor. In regions where mechanical harvesting and drying procedures are not standard, seeds are often damaged and germination is poor. The objective of this research was to study the effects of different drying procedures on seed quality. Germination of peanut kernel (Arachis hypogaea L., cv. J-11) was significantly affected by harvesting and post-harvest handling and operations. Harvesting at or around 110 d after. emergence showed higher numbers of matured kernels, with high quality and better storability. Pods after harvest were dried in the field following different methods. Field drying of pods with haulms, in heaps to avoid direct exposure to sunlight following the DOR method, was found to be highly suitable in reducing mechanical injury during shelling and also in maintaining higher germinability of seeds in storage. Effects of shelling were assessed in terms of physical damage. Only sound mature kernels (SMK) were used for drying and storage tests, which involved temperatures ranging from 20–50 C (in an air velocity 0.61 to 1.0 m/sec) and ambient to 50% RH conditions. Effects of drying on occurrence of physical damage like % split kernel, bold kernel, and skin slip then were assessed. Both shelling and drying had shown significant effects on germinability, seedling vigor, membrane integrity, dehydrogenase activity, and lipid peroxidation when tested under ambient or accelerated aging conditions. Slow drying or low temperature/low humidity drying reduced physical damage and maintained high vigor and viability during storage.
Feasibility Tests for a Two-Stage Batch Dryer for Curing Farmer Stock Peanuts1
Authors: Butts C. L. , Omary M. S.
Published: April 2010

A two-stage batch dryer for farmer stock peanut was developed by a commercial grain dryer manufacturer and tested at a commercial peanut buying point during the 1996 and 1997 harvests. A 7.3-m diameter grain bin provided the superstructure for two peanut curing chambers. Each chamber had an approximate capacity of 18,000 kg of in-shell peanuts. Comparisons between conventional peanut curing wagons and the bin dryer were conducted. Recorded data included temperature and relative humidity in both type dryers, drying time, moisture content throughout curing, farmers stock grades, milling quality, and seed germination. A total of 451,717 kg were cured in the two-stage dryer and 215,460 kg in conventional dryers. The initial moisture content of peanuts averaged 19% wet basis and dried at an average moisture removal rate of 0.45%/hr. The moisture removal rates for the two dryers were not significantly different. The final moisture content averaged 11%. Moisture content at the time of grading averaged 9%. Farmers stock grades and milling quality were not significantly different. The average quota support price, including LSK for peanuts cured in conventional dryers, was $630.47/1000 kg compared to $636.08/1000-kg peanuts cured in the two-stage dryer. Seed germination averaged 75.8 and 76.1% for conventional and bin-dried peanuts, respectively. The twostage batch dryer was comparable to the current wagon-drying system. A single batch in the two-stage dryer was equivalent to three peanut wagons.
Comparison of North Carolina, Georgia, and Florida Isolates of Cylindrocladium parasiticum
Authors: Hollowell J. E. , Shew B. B. , Beute M. K.
Published: April 2010

Thirteen isolates of Cylindrocladium parasiticum Crous, Wingfield & Alfenas from North Carolina and 11 from Georgia were grown on plates of PDA at 20,25, and 30 C on a temperature-gradient plate. Culture diameters were measured daily for 6 d. Significant differences were not observed among isolates grown at 20 C and cultures was smaller as compared with those grown at 25 and 30 C. At 25 and 30 C, isolates varied consistently in growth. On average, Georgia isolates grew slightly less than North Carolina isolates, and all isolates grew better at the warmer temperature. Growth of three North Carolina isolates was compared to four Florida isolates in a second experiment. Florida isolates grew significantly faster than North Carolina isolates at all temperatures. Isolates from the three states were compared for their ability to cause root rotting on peanut at 25 and 30 C. Plants were grown in soil infested at a standardized inoculum density in temperature-controlled water bath tanks for 7 wk at which time roots were rated for Cylindrocladium black rot development. Georgia isolates caused more root rot than either North Carolina or Florida isolates at both temperatures and also caused more seedling disease. State effects were significant; Florida isolates caused less root rot than Georgia isolates. Temperature by state interactions were not significant which means that high temperature-tolerant isolates of C. parasiticum have not evolved from regional differences in soil temperature. Further, North Carolina field isolates do not appear to have changed in temperature optima since the 1970s.
Localization of Tomato Spotted Wilt Virus (Genus Tospovirus, Family Bunyaviridae) in Peanut Pods
Authors: Pappu S. S. , Pappu H. R. , Culbreath A. K. , Todd J. W.
Published: April 2010

The localization of tomato spotted wilt virus (TSWV, genus Tospovirus, family Bunyaviridae) in peanut pods was determined by enzyme-linked immunosorbent assay (ELISA) using TSWV specific antibodies. Pods were collected from symptomatic and asymptomatic fieldgrown plants. All the plants were tested by ELISA for presence or absence of TSWV infection. Normal and abnormal looking pods from symptomatic plants were assayed by ELISA. Each pod was divided into shell, testa, and cotyledons. All of the shell and testa samples of both normal and abnormal pods from symptomatic plants were positive for TSWV, whereas TSWV could not be detected in the cotyledons. Similar results were observed by polymerase chain reaction, except that the cotyledons occasionally had a TSWV-specific sequence. No virus could be detected in any part of the pod collected from asymptomatic, virus-free plants. In growout tests of seed from both symptomatic and asymptomatic plants, none of the plants showed TSWV infection when assayed by ELISA. Results demonstrated the preferential accumulation of the virus in the shell and testa.
Response of Early, Medium, and Late Maturing Peanut Breeding Lines to Field Epidemics of Tomato Spotted Wilt
Authors: Culbreath A. K. , Todd J. W. , Gorbet D. W. , Brown S. L. , Baldwin J. A. , Pappu H. R. , Holbrook C. C. , Shokes F. M.
Published: April 2010

Epidemics of tomato spotted wilt, caused by tomato spotted wilt Tospovirus (TSWV), were monitored in field plots of runner-type peanut (Arachis hypogaea L.) cultivars Georgia Green and Georgia Runner and numerous breeding lines from four different breeding programs as part of efforts toward characterizing breeding lines with potential for release as cultivars. Breeding lines were divided into early, medium and late maturity groups. The tests were conducted near Attapulgus, GA and Marianna, FL in 1997 and in Tifton, GA and Marianna, FL in 1998. Epidemics in some early and medium maturing breeding lines, including some genotypes with high oleic acid oil chemistry, were comparable to those in Georgia Green, the cultivar most frequently used in the southeastern U.S. for suppression of spotted wilt epidemics. No early maturing breeding lines had lower spotted wilt final intensity ratings or higher yields than Georgia Green. However, spotted wilt intensity ratings in some late maturing lines and a smaller number of medium maturing lines were significantly lower than those of Georgia Green. Several of those lines also produced greater pod yields than Georgia Green. Results from these experiments indicated that there is potential for improving management of spotted wilt though development of cultivars that suppress spotted wilt epidemics more than currently available cultivars. There was no indication that differences in spotted wilt ratings corresponded to differences in numbers of thrips adults or larvae.
Aspergillus Species Colonization of Termite-Damaged Peanuts in Parts of West Africa and Its Control Prospects
Authors: Umeh V. C. , Waliyar F. , Traoré A.
Published: April 2010

A survey of farmers' peanut fields in Benin showed that Aspergillus flavus Link ex Fries infection was influenced by Microtermes (Isoptera: Termitidae) damage. Field trials conducted at the ICRISAT station and a farmer's plot in Mali on termite damage and Aspergillus spp. infection showed that peanut plots treated with carbofuran at planting and supplemented with chlorpyrifos at 40 days after planting (dap), or treated with only chlorpyrifos at 40 dap, significantly reduced pod damage by the termite M. lepidus Sjöstedt. and colonization by A. flavus. The cultivar ICG 10946 which had significantly more A. flavus (P < 0.05) also had a higher percentage of damaged pods compared with the other cultivars at the on-station trials. The least infected cultivar in all the trials was 47–16 which also had a comparatively lower percentage of termite-damaged pods, although this was not significant. However, termite damage was correlated with A. flavus percentage colonization.
Performance and Economic Benefit of Herbicides Used for Broadleaf Weed Control in Peanut
Authors: Wehtje G. , Brecke B. J. , Martin N. R.
Published: April 2010

Field experiments were conducted over two growing seasons (1995 and 1996) and at two locations (Jay, FL, and Headland, AL) to identify the most effective herbicide program for Florida beggarweed [Desmodium tortuosum (SW) D.C.] control in peanut (Arachis hypogaea L.). The most common herbicides used for Florida beggarweed control—including preemergence (PRE), early-postemergence (EPOST), mid-postemergence (MPOST) and late-postemergence (LPOST) applied treatments—were evaluated in a factorial treatment arrangement. All treatments had merit and could be assembled into programs that resulted in maximum weed control, crop yield, and net returns. However, at least two of the four treatment timings were required to reach this level. Four systems were consistently associated with the maximum statistical grouping for both yield and net returns, as well as acceptable Florida beggarweed control (> 81%). These systems were (a) paraquat + bentazon applied EPOST, followed by pyridate + 2,4-DB MPOST; (b) same as (a) only preceded by norflurazon applied PRE; (c) imazapic applied EPOST followed by pyridate + 2,4-DB MPOST; and (d) norflurazon applied PRE, followed by imazapic EPOST.
Herbicide Systems for Golden Crownbeard (Verbesina encelioides) Control in Peanut1
Authors: Grichar W. J. , Sestak D. C.
Published: April 2010

Field studies were conducted in south Texas in 1994 and 1995 to evaluate various soil-applied herbicides alone and in combination with postemergence herbicides for golden crownbeard control. Ethalfluralin preplant incorporated (PPI) followed by imazapic or lactofen postemergence (POST) provided 100% golden crownbeard control. Ethalfluralin PPI followed by oxyfluorfen applied preemergence (PRE) or metolachlor + imazethapyr provided 90% control. Dimethenamid, ethalfluralin, and metolachlor alone failed to adequately control golden crownbeard. Golden crownbeard control was most effective when combination treatments were used (PPI or PRE followed by POST). Effective golden crownbeard control increased peanut yields up to 53% over that of the untreated check.
Comparison of Metolachlor and Dimethenamid for Yellow Nutsedge (Cyperus esculentus L.) Control and Peanut (Arachis hypogaea L.) Injury1
Authors: Grichar W. J. , Lemon R. G. , Sestak D. C. , Brewer K. D.
Published: April 2010

Field experiments were conducted during 1996 and 1997 at four locations in Texas to evaluate metolachlor and dimethenamid for yellow nutsedge (Cyperus esculentus L.) control and peanut (Arachis hypogaea L.) injury. Dimethenamid and metolachlor were applied PPI or PRE at 0.6X to 2x the suggested label rates. Yellow nutsedge failed to develop at one location; however, early season yellow nutsedge control with dimethenamid and metolachlor were similar at one location, and at two other locations metolachlor provided greater nutsedge control than dimethenamid. Furthermore, late season yellow nutsedge control at the three locations was better with metolachlor than dimethenamid. Peanut stunting was 20% higher with metolachlor PRE at the 1x rate than dimethenamid PRE at the 1x rate at two locations when rated 4 or 12 wk after treatment (WAT). Peanut yields were variable but, at one location under weed-free conditions, plots receiving pendimethalin only had the highest yield. With excessive moisture and herbicide rates greater than recommended for field use, both dimethenamid and metolachlor caused peanut stunting. However, metolachlor provided better season-long yellow nutsedge control than dimethenamid.
Influence of Adjuvants on Peanut (Arachis hypogaea L.) Response to Prohexadione Calcium
Authors: Jordan D. L. , Swann C. W. , Culpepper A. S. , York A. C.
Published: April 2010

Research has demonstrated that prohexadione calcium (calcium salt of 3,5-dioxo-4-propionylcyclohexanecarboxylic acid) retards vegetative growth of peanut (Arachis hypogaea L.) and in some cases increases pod yield, the percentage of extra large kernels, market value ($/kg), and gross value ($/ha). Spray adjuvants such as crop oil concentrate and nitrogen solution most likely will be recommended for application with prohexadione calcium. However, efficacy of prohexadione calcium applied with adjuvants has not been conclusively determined. Twelve experiments were conducted in North Carolina and Virginia during 1997 and 1998 to determine peanut response to prohexadione calcium applied with crop oil concentrate, urea ammonium nitrate, or a mixture of these adjuvants. Applying prohexadione calcium with urea ammonium nitrate, either alone or with crop oil concentrate, increased row visibility and shorter main stems compared with nontreated peanut or prohexadione calcium applied with crop oil concentrate. Prohexadione calcium increased pod yield, the percentage of extra large kernels, and gross value of peanut in seven of 12 experiments regardless of adjuvant when compared with nontreated peanut. Pod yield, the percentage of extra large kernels, and gross value of peanut were not affected in the other experiments. Prohexadione calcium did not affect the percentage of total sound mature kernels, the percentage of other kernels, or market value in any of the experiments regardless of adjuvant.
Reaction of Peanut Cultivars to Spotted Wilt
Authors: Culbreath A. K. , Todd J. W. , Gorbet D. W. , Brown S. L. , Baldwin J. , Pappu H. R. , Shokes F. M.
Published: April 2010

Field tests were conducted in 1997 and 1998 in Georgia and Florida to compare the effects of 10 and 12 peanut (Arachis hypogaea L.) cultivars, respectively, on epidemics of spotted wilt caused by tomato spotted wilt Tospovirus. Epidemics of spotted wilt were suppressed for the moderately resistant standard Georgia Green, and in Southern Runner, Florida MDR 98, ViruGard, and NC-V11. The reponse of these five cultivars to spotted wilt were similar and resulted in lower final disease intensity and areas under the disease progress curves than in the susceptible standard Georgia Runner, and in SunOleic 97R and Tamrun 96. Southern Runner and Florida MDR-98 consistently had higher yields than the TSWV-susceptible Georgia Runner. Georgia Green and NC-V11 had higher yields than Georgia Runner in three of the four tests. No consistent differences were found among the cultivars for numbers of adult tobacco thrips (Frankliniella fusca) or western flower thrips (F. occidentalis). Differences among cultivars for numbers of larvae of Frankliniella spp. also were few and inconsistent. There was no indication that differences in thrips populations were responsible for differences in severity of spotted wilt in the field.
Economic Assessment and Fungicide Use on Peanut Seed in the Southwestern United States1
Authors: Smith D. T. , Black M. C. , Grichar W. J. , Jaks A. J.
Published: April 2010

Seed protectant fungicides are an important part of a total pest management program of peanut and may reduce the use of other pesticides later in the growing season. A survey of peanut shellers was conducted to determine the amount of fungicide use and the important factors used in selecting particular fungicides for treating seed in the Southwestern United States. All peanut seed planted in Texas, Oklahoma, and New Mexico was treated with one or more fungicides and totaled 19,000 kg of five active ingredients applied on 12 million kg of seed. Captan was the leading active ingredient and made up 49% of all fungicide use. Shellers were the sole decision makers in selecting seed treatment fungicides and cited fungicide effectiveness and assurance of a good crop stand as the major factors in selecting a commercial product. Fungicide treatments made up 4% of the total cost of planting seed, for an average cost of $6.75/ha. A case study on the impact of seed treatments was conducted using 12 yr of field performance data in an economic assessment. Peanut yields were 36% higher when captan-treated compared with using untreated seed. In an economic assessment, net returns above variable costs were $331/ha higher when fungicide-treated seed was planted, compared to untreated seed. The case study showed that seed treatments provided positive economic returns in 10 out of the 12 yr and losses would result in 7 out of 12 yr if untreated seed were planted. Many of the present seed treatment fungicides will be reviewed by the U.S. Environmental Protection Agency and require re-registration under the Food Quality Protection Act of 1996.
Genotypic Variation in Roasted Peanut Flavor Quality Across 60 Years of Breeding1
Authors: Isleib T. G. , Pattee H. E. , Gorbet D. W. , Giesbrecht F. G.
Published: April 2010

In developing new peanut (Arachis hypogaea L.) breeding lines and cultivars, the breeder's primary focus is upon those heritable characteristics with direct, measurable effects. Flavor quality characteristics are heritable but do not have a directly measurable economic value, so they are often overlooked. Failure to monitor and evaluate flavor quality may lead to serious defects in new breeding lines and cultivars. Flavor quality data on lines developed since 1930 were examined to identify trends in flavor quality of the cultivars and breeding populations in the virginia, runner, and fastigiate market types. Virginia-type cultivars have trended toward poorer roasted peanut flavor (reduced intensity of the roasted peanut and sweet attributes and increased intensity of the bitter attribute). Use of the commercially successful cultivars Florigiant and NC 7 in the ancestry of new breeding lines appears to have reduced the flavor quality. Runner-type cultivars increased slightly in average sweetness over time, but there has been an increase in the variance of roasted peanut intensity in the breeding population since 1980. Introgression of disease-resistant germplasm into the breeding populations appears to have had a detrimental effect on the flavor of lines in the runner and virginia market types. Use of Florunner, a multiline cultivar with a superior flavor profile, as a parent of breeding lines has contributed to generally superior flavor in the runner market type. The gains possibly could have been greater had one of Florunner's better-tasting components been used consistently in crossing programs. The limited sample of fastigiate lines and cultivars in this study showed consistent improvement in the intensities of roasted peanut and bitter attributes. Spanish-type cultivars showed improvement in the sweet attribute.
Survival and Reproductive Success of Tobacco Thrips on Three Tomato Spotted Wilt Virus Infected and Noninfected Peanut Cultivars
Authors: Garcia L. E. , Kennedy G. G. , Brandenburg R. L.
Published: April 2010

A comparison of the survival and reproductive success of Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) on tomato spotted wilt virus (Bunyviridae: Tospovirus) (TSWV) infected and uninfected peanut plants was conducted under greenhouse conditions in North Carolina. Three cultivars—NC 9, NC-V11, and NC 12C—adapted to North Carolina production practices were evaluated. A total of 180 individually caged plants, in three replicates, were infested with 20 female F. fusca each. Adult and larval thrips were collected after 30 d on the plants. Final counts were square root transformed and a mixed model analysis of variance conducted. Effects of cultivar and the virus-by-cultivar interaction were not statistically significant. TSWV-infected plants had significantly fewer adult and larval F. fusca than did uninfected plants for adults (P = 0.04) and for larvae (P = 0.01). This study reports on an alternative method of assessing TSWV resistance among peanut cultivars and the trend appears to support the conclusions of a previous field study, which found NC 9 more susceptible to TSWV than either NC-V11 or NC 12C.
Use of Azoxystrobin for Disease Control in Texas Peanut
Authors: Grichar W. J. , Besler B. A. , Jaks A. J.
Published: April 2010

Field studies were conducted at 11 locations across south Texas from 1994 to 1997 to determine the activity of azoxystrobin against southern stem rot (Sclerotium rolfsii Sacc.), Rhizoctonia pod rot (Rhizoctonia solani Kuhn), early leaf spot (Cercospora arachidicola Hori) and late leaf spot [Cercosporidium personatum (Berk. & Curt.) Deighton]. Azoxystrobin at 0.22 to 0.45 kg/ha applied twice provided control of stem rot, Rhizoctonia pod rot, and leaf spot comparable to tebuconazole at 0.2 kg/ha applied four times. Peanut yield increases were evident with all fungicide treatments over the untreated check.
Seeding Rate, Irrigation, and Cultivar Effects on Tomato Spotted Wilt, Rust, and Southern Blight Diseases of Peanut1
Authors: Black M. C. , Tewolde H. , Fernandez C. J. , Schubert A. M.
Published: April 2010

Tomato spotted wilt virus has been the cause of an important peanut disease in southwestern Texas since the mid-1980s. Following observations of elevated disease incidence associated with poor stands, high seeding rates were recommended to reduce risks of spotted wilt. The primary objective of this study was to determine the relationship of spotted wilt incidence to seeding rate and irrigation. Whether the management of rust (Puccinia arachidis Speg.) and southern blight (Sclerotium rolfsii Sacc.) would be affected by seeding rate and irrigation was a secondary objective. Two runner peanut cultivars, GK-7 and Southern Runner, were planted in 1992 and 1993 in single rows with a precision planter at 8, 12, and 22 seeds m−2 and irrigated with amounts ranging from a season total of 0 to 760 mm. Spotted wilt (30.5-cm-loci with symptoms) at digging differed significantly for GK-7 and Southern Runner in 1992 (29 vs. 20%) and 1993 (23 vs. 16%). The seeding rate of either cultivar did not significantly affect spotted wilt in either year. Spotted wilt increased as irrigation increased to a peak of 535 mm total water in 1992 and 587 mm in 1993, and decreased slightly at higher irrigation levels. Rust was significantly affected by seeding rate only in 1992, with lowest rust ratings at 8 seeds m−2. GK-7 had significantly higher rust ratings than Southern Runner in 1992 and 1993. Southern blight in 1993 was lowest with below-optimum irrigation. Reduced seeding rate in irrigated peanut production did not increase risk of spotted wilt under conditions of this study and may have potential to enhance management efforts for rust and southern blight.
Grading High Moisture Farmer Stock Peanut Lots1
Authors: Blankenship P. D. , Lamb M. C. , Butts C. L. , Whitaker T. B. , Williams E. J.
Published: April 2010

Farmers in the U.S. are required to market peanuts as identity preserved lots with less than or equal to 10.49% moisture content (MC) wet basis. A comparison of peanut grades, weights, and values at moisture contents above (Hmc) and below (Lmc) 10.49% was conducted at 16 buying points during crop year 1998 and at 22 points in 1999. Buying points were located in all three U.S. peanut-producing areas both years. Randomly selected Hmc lots of runner-, spanish-, and virgina-type peanuts were weighed and unofficially graded by Federal State Inspection Serv. personnel with standard procedures. Lots were cured to MC ≤ 10.49% and graded officially for farmer marketing. Data from both years were combined for analysis. Both Hmc and Lmc grades were conducted on 543, 62, and 81 runner-, spanish-, and virginia-type lots, respectively. Moisture contents for runner type averaged 16.3% at Hmc grading and 8.7% at Lmc grading; for spanish type, 15.8 and 8.7%; and for virginia type, 17.0 and 9.1%. Only 3.8% of all lots evaluated had Hmc moisture contents greater than 25%. Equations were derived that predicted Lmc grade factors, lot weights (LW) and lot values (LV) from measured Hmc factors by peanut type. Equations to estimate Lmc LW and LV for runner-type peanuts had correlation coefficients of 0.998 and 0.997, respectively. Correlation coefficients for spanish type Lmc LW and LV were 0.998 and 0.995 and for virginia type 0.996 and 0.993, respectively. Derived equations for Lmc grade factors, LW, and LV may offer an alternative modification in U.S. peanut grading and farmer marketing allowing an increase in the maximum MC at grading.
Response of Peanut Cultivars to Full and Reduced Spray Programs of Tebuconazole for Control of Southern Stem Rot1
Authors: Besler B. A. , Grichar W. J. , Smith O. D. , Jaks A. J.
Published: April 2010

Eleven commercially grown peanut cultivars were evaluated for disease and yield response to two and four applications of tebuconazole under moderate disease pressure (< 12 hits/12.2 m) by southern stem rot (Sclerotium rolfsii). The incidence of southern stem rot was reduced in all cultivars when treated with two and four sprays of tebuconazole. Tamrun 96 and Southwest Runner had the lowest disease incidence. Cultivars responded with higher yields when sprayed with two and four applications of tebuconazole compared to the unsprayed plots. Peanut grade (SMK + SS) was not affected by tebuconazole. Georgia Runner and Tamrun 96 produced the highest grade while Southwest Runner was the lowest.
Effects of Overweight Samples and Rounding of Grade Percentages on Peanut Grades and Prices
Authors: Pebe Diaz E. F. , Brorsen B. W. , Anderson K. B. , Kenkel P.
Published: April 2010

Two possible sources of error in measuring grade factors and prices with the current peanut (Arachis hypogaea L.) grading procedure are rounding of grade factors and taking overweight samples. Rounding did not affect average grade factors or prices. Instead, rounding introduced noise, increased the probability of regrading, and provided an incentive for taking overweight samples. Taking overweight samples resulted in higher producer prices. A 1% increase in the sample weight resulted in a 1% increase in the producer price. A policy implication is that USDA should round to tenths rather than whole percentages.
Consumer Acceptance of American Peanut Products by Bulgarian Consumers
Authors: Paraskova P. , Jordanov J. , Resurreccion A. V. A. , Moon W. , Florkowski W. J. , Chinnan M. S. , Beuchat L. R.
Published: April 2010

A 1997 nationwide survey in Bulgaria revealed a high demand for roasted peanuts (Arachis hypogaea L.) and peanut products. The study reported here was conducted to determine the level of acceptance by Bulgarian consumers of three American cultivars of roasted peanuts and to identify the type of commercial peanut butter preferred using sensory affective tests. Consumers (N = 601) participated in central location tests at an international fair in Plovdiv, Bulgaria in May 1999 to evaluate roasted peanuts (spanish type, cv. Georgia Green, and cv. Flavorunner) and three types of commercial American peanut butter [very low sodium (creamy), regular creamy, and extra crunchy]. Each consumer was interviewed and asked to evaluate these products by pointing at a printed 9-point hedonic scale (1 = dislike extremely, 9 = like extremely). Most (98.7%) of the participants were Bulgarian. Ages ranged from 18 to 50 yr (79.9%) or older (20.1%); 53.7% were females. The mean overall acceptance rating for roasted Flavorunner peanuts (6.9, like slightly) was significantly higher (P ≤ 0.05) than that for Georgia Green (6.1, like slightly), which was significantly higher than for Spanish type (5.6, neither like nor dislike). Mean overall acceptance of extra crunchy peanut butter was higher (6.7, like slightly; P ≤ 0.05) than acceptance of regular creamy (6.4, like slightly) and very low sodium (5.4, neither like nor dislike) types. Consumers rated the overall acceptance of regular creamy peanut butter higher (P ≤ 0.05) than that of very low sodium creamy peanut butter. Results of the survey indicate good potential for sale of Georgia Green and Flavorunner roasted peanuts and extra crunchy and regular creamy peanut butter in Bulgaria.
Use of Plant Introductions in Peanut Cultivar Development
Authors: Isleib T. G.. , Holbrook C. C. , Gorbet D. W.
Published: April 2010

The genetic base of peanut (Arachis hypogaea L.) in the U.S.A. has at times been extremely narrow, particularly in specific production areas where a single cultivar may be grown in near-monoculture. Because peanut is not a native North American species, all U.S. cultivars necessarily trace their ancestry to plant introductions (PIs), but most of the genetic base of current cultivars rests on selections from farmer-stock peanuts of obscure origin. The objectives of this study were to (a) summarize and document the use of introduced genetic resources in cultivar development and (b) estimate the resulting economic impact. Different PIs were used as parents in early breeding programs. B.B. Higgins used Gambian line Basse as a parent of the GA 207 cross that gave rise to selections used in Georgia, Florida, and North Carolina as the basis for further improvement. PI 121067 was one of seven parents used by W.C. Gregory to initiate the program in North Carolina. A different set of PIs including PI 121070, PI 161317, PI 168661, and A. monticola Krapov. & Rigoni were used in the Texas and Oklahoma programs. Recycling of lines as parents and exchange of germplasm among breeding programs proliferated these PIs in the pedigrees of cultivars released since 1960. Over the past 20 yr, there have been concerted efforts to incorporate additional germplasm into U.S. breeding populations, usually with the purpose of improving resistance to diseases or pests, but also with the objective of broadening the genetic base. These efforts have had a significant economic impact on U.S. peanut farmers, the largest from the development of cultivars with resistance to Sclerotinia blight (Sclerotinia minor Jagger), root-knot nematodes (Meloidogyne spp.), and tomato spotted wilt virus. Use of these resistant cultivars has an economic impact of more than $200 million annually for U.S. peanut producers. In the runner and virginia market types, the average PI ancestry of all cultivars was 17.9%. There are several examples of successful cultivars with up to 25% ancestry from a single PI, including Georgia Green and NC-V11. In the spanish market type, most successful cultivars have derived 50% or more of their ancestry from PIs. Several recent or impending releases incorporate PI germplasm but have not yet been proven in the U.S. seed market.
Use of Wild Arachis Species/Introgression of Genes into A. hypogaea L.
Authors: Simpson C. E.
Published: April 2010

The use of wild Arachis L. in cultivar improvement programs has been considered an option for more than 50 yr. Both A. Krapovickas and W.C. Gregory, independently, made interspecific hybridizations in the 1940s. However, only three cultivars have been released as a result of interspecific hybridizations, and only one of those has a clearly identifiable genetic component from the wild species. Several breeding lines have been reported and several germplasm releases are documented from Texas, North Carolina, and ICRISAT. At least four potential options exist for transferring genes from wild Arachis to the cultigen: a) The hexaploid pathway consists of crossing a diploid wild species directly with A. hypogaea, doubling the chromosome number to the hexaploid level, then backcrossing for several generations to restore the tetraploid condition. Several options are possible in this pathway involving various crossing schemes prior to crossing a diploid hybrid with A. hypogaea. North Carolina and ICRISAT have had success with this pathway. b) The diploid/tetraploid pathway has been the most successful in Texas to date. This pathway involves crossing diploid species (two to several), doubling the chromosome number of the hybrid, then crossing to A. hypogaea and backcrossing with selection for the desired character. This pathway is most successful when both A-and B-genome species are involved. Germplasm lines and a cultivar have been released in Texas using this pathway. c) Another diploid/tetraploid pathway could be to double chromosome numbers of diploid species and cross the amphiploids directly with A. hypogaea. Several attempts have been made with this technique, but no germplasm releases have been reported, in large part because sterility is too great when both A and B genomes are not included in the hybrid. Many of the sections/species of wild Arachis are so greatly isolated from A. hypogaea that plant transformation will be the likely method to introduce genes into the cultigen. d) Molecular methods of “inserting” genes into peanut that have been modestly successful and include use of Agrobacterium spp., electroporation, and direct DNA delivery techniques such as the gene gun, whiskers, and sonication. No releases have resulted.