bluuebunny/crossref_metadata_2025 huggingface dataset:
Peanut Cultivar Response to Tillage Systems1
Authors: Colvin D. L. , Brecke B. J.
Published: April 2010

Field experiments were conducted during 1984 and 1985 at Williston, Florida on a Zuber loamy sand (fine, mixed hyperthermic Ultic Hapludalfs) and at Jay, Florida in 1985 on a Red Bay sandy loam (fine-loamy, siliceous, thermic Rhodic Paleudults) to investigate the effects of conventional and minimum tillage on the grade and yield of eight peanut (Arachis hypogaea L.) cultivars. Cultivars studied included: 1) three runner-type peanuts - Florunner. Sunrunner, and GK-7, 2) four virginia-type peanuts - Early Bunch, Florigiant, GK-3, and NC-7, and 3) one spanish-type peanut - Valencia C. Conventional plots were established using a moldboard plow with repeated diskings to provide a smooth even seedbed. Minimum-tillage plots were established using a modified Brown-Harden Ro-Till®. Tillage did not affect peanut yield, and cultivars generally did not differ in response to tillage systems. There appears to be no immediate need for peanut cultivar performance testing in different tillage systems. However, in 1984 at Williston Florunner and Sunrunner yielded 20% and 12% better, respectively, in conventional tillage conditions than in minimum-tillage, whereas in 1985 Early Bunch yielded 17% less in tilled systems compared to minimum-tillage systems. This response may be related to slight plant density differences, harvestability problems or genotypic differences. Results indicate that yield and quality of peanuts, based on the data collected from the cultivars utilized in this study would be equal under conventional or minimum-tillage production.
Tillage Variables for Peanut Production
Authors: Colvin D. L. , Brecke B. J. , Whitty E. B.
Published: April 2010

Effects of minimum tillage (MT) production techniques on peanut (Arachis hypogaea L.) root growth and yield were unknown. Field experiments were therefore conducted during 1984 near Williston and Marianna, FL and during 1985 near Williston and Jay, FL to evaluate effects of surface and subsurface tillage on peanut production. Soil types were a Zuber loamy sand (fine, mixed hyperthermic Ultic Hapludalf) at Williston, a Chipola sandy loam (loamy, siliceous, thermic Arenic Hapludult) at Marianna, and a Red Bay sandy loam (fine, loamy, siliceous, thermic Rhodic Paleudult) at Jay. The Sunrunner peanut cultivar was planted using a modified twin 23 cm row spacing and seeded at a rate of 140 kg/ha. Eight tillage systems that included combinations of conventional tillage, strip-tillage, and no-tillage with and without subsoiling or subsurface slitting were evaluated. Peanuts germinated and grew well except in no-tillage plots that received no subsurface tillage. Without surface or subsurface tillage there was not sufficient soil disturbance to insure proper seed-soil contact or seed cover. Generally, plots that received some degree of conventional tillage yielded better than plots with no surface preparation (4090 vs. 3760 kg/ha avg.). Minimum tillage plots yielded numerically less than conventional plots but in only a few cases were significant differences in yield noted. At most locations, minimum tillage plots that received no subsurface tillage developed a “lazy root syndrome” in which the few roots produced were quite shallow and grew near the soil surface. These treatments yielded less (3680 vs. 4010 kg/ha avg.) than those with conventional seedbed preparation or the minimum tillage treatments receiving subsurface tillage. Root strength and penetration measurements roughly reflect the same trends as peanut yields. The slit-tillage system resulted in peanut yields equal to or better than those obtained with chisel point subsoiling. Slitter wear and breakage problems were encountered but overall, the subsurface slit system appears to be a functional alternative to chisel point subsoiling.
Ovule and Embryo Culture of Arachis hypogaea and Interspecific Hybrids1
Authors: Stalker H. T. , Eweda M. A.
Published: April 2010

Interspecific hybridization in Arachis is difficult between species within sectional groups and nearly impossible among more distantly related species. Embryos usually abort early in the reproductive cycle; thus in vitro techniques are necessary to recover many desirable hybrid combinations in the genus. The objectives of this investigation were to develop techniques whereby mature plants could be recovered from otherwise aborting embryos. First, ovule culture was performed using eight genotypes, three levels of kinetin, and the two basal media Murashige and Skoog (MS) and N6. Two-tenths mg/L kinetin in media resulted in 24% of the ovules swelling to a size of 3-4 mm which could be used for excising embryos. Embryo culture was next performed on five genotypes. The transfer series (I) 0.2 mg/L kinetin for 21 days, (2) 0.5 mg/L 6-benzylamino-purine (BAP) for 14 days and, (3) MS without growth regulators resulted in 34.6% of ovules producing plants across genotypes; other transfer series either resulted in a lower percentage of plant recovery and/or tissues of some genotypes which did not survive to maturity. The BAP medium induced shoot growth, while root growth was induced on the MS without growth regulator medium. Approximately 90% of embryos transferred to a mist system after 7-9 weeks in vitro survived transplanting to soil. Two interspecific hybrids were recovered from incompatible hexaploid x diploid crosses, but only after roots were induced using a MS basal medium with 4 mg/L 1-naphthaleneacetic acid:2 mg/L indole-3-butyric acid in a fourth tissue transfer. The experiments illustrated the feasibility of rescuing embryos of A. hypogaea and interspecific peanut hybrids. The process is slow and will be most applicable to wide crosses which cannot be obtained by more conventional methods.
A Rapid Method for Evaluating Genotype Resistance, Fungicide Activity, and Isolate Pathogenicity of Sclerotinia minor in Peanut.1
Authors: Brenneman T. B. , Phipps P. M. , Stipes R. J.
Published: April 2010

Peanut stem segments 8.5-cm long were inoculated at leaf nodes with mycelial plugs of Sclerotinia minor and incubated in moist chambers at 20 C. Water-soaked lesions were often visible after 24 hr. The rate of lesion elongation was used to quantitatively assess the physiological resistance of peanut genotypes to Sclerotinia blight, screen chemicals for fungicidal activity, and evaluate the pathogenicity of S. minor isolates. The age and/or developmental state of lateral limbs of plants had a marked effect on lesion development; 3 days after inoculation, mean lesion lengths were 58.8, 46.8, and 38.9 mm for terminal, median and basal parts of stems, respectively. The speed, simplicity and adaptability of this method make it a valuable tool for research on Sclerotinia blight of peanut.
Relative Tolerance of Peanuts to Alachlor and Metolachlor1
Authors: Wehtje Glenn , Wilcut John W. , Hicks T. Vint , McGuire John
Published: April 2010

Field studies were conducted during 1984, 1985, and 1987 to evaluate weed control and the relative tolerance of peanuts (Arachis hypogaea) to alachlor and metolachlor when applied at rates from 2.2 to 13.4 kg ai/ha. Both single and split preemergence, and postemergence applications were included. In 1984 and 1985, neither herbicide adversely affected yields compared to a hand-weeded control. In 1987, metolachlor at a rate of 9.0 kg/ha and alachlor at 13.4 kg/ha reduced yields. Across all years, at least a two-fold safety factor existed between the maximum registered rate and the rate necessary for peanut injury. Occurrence of injury appears to be related to rainfall. Metolachlor was slightly more mobile than alachlor in soil chromatography trials, which may be a factor in its slightly greater propensity to be injurious under certain conditions of extensive leaching and/or slow peanut emergence.
Comparison of Visual, Enzyme-Linked Immunosorbent Assay Screening, and HPLC Methods in Detecting Aflatoxin in Farmers Stock Peanut Grade Samples
Authors: Cole R. J. , Dorner J. W. , Kirksey J. W. , Dowell F. E.
Published: April 2010

Grade samples from 152 lots of farmers stock peanuts were analyzed for aflatoxin by both an Enzyme-Linked Immunosorbent Assay (ELISA) rapid screening test and high performance liquid chromatography (HPLC). Results from HPLC and ELISA were compared to the results of the visual inspection method used by the Federal State Inspection Service (FSIS). The results showed 41% of the grade samples with visible Aspergillus flavus (Segregation 3) contained less than 20 ppb aflatoxin when analyzed by both ELISA and HPLC methods; 18.7% of Segregation 1 peanuts actually contained aflatoxin with a range of 26-2542 ppb. The results of ELISA and HPLC agreed in 98.6% of the composite lot analyses with the detection of 20 ppb or greater. However, the ELISA rapid screening test failed to give positive tests 12 of 13 times when the aflatoxin content was between 20-43 ppb in the component samples.
Peanut Cultivar Responses to Bradyrhizobium Inoculation in Northeast Thailand
Authors: Kucey R. M. N. , Toomsan B.
Published: April 2010

Effective combinations of peanut (Arachis hypogaea L.) cultivars and Bradyrhizobium strains were determined under field conditions in NE Thailand in experiments conducted in 1985 and 1986. The experiments measured yields and N2 fixation (N-15 dilution) responses of peanut cultivars Tainan 9, Moket and KAC431 to inoculation with inoculants composed of Bradyrhizobium strains TH205, 32HI or NC92 or mixed cultures of bacteria. Midseason parameters of nodule number and weight and acetylene reduction levels were also determined. Peanut yields varied between years and locations. Cultivar Tainan 9 was shown to be the cultivar with the best average yield for the locations tested. Inoculation with bradyrhizobia resulted in increased seed yields and amounts of N in the plants in most cases. Inoculated peanuts received an average of 71 kg N/ha from fixation; uninoculated peanuts received an average of 62 kg N/ha. Of this N, 55 to 77% remained in the stover. Midseason measurements of plant performance were of minimal value for predicting the relative performance of the three cultivars.
Severity, Distribution, and Losses from Taproot Cankers Caused by Rhizoctonia solani in Peanuts1
Authors: Turner John T. , Backman Paul A.
Published: April 2010

Research on the ecology of peanut roots from fields in Georgia, Florida, and Alabama revealed a high frequency of sunken, dark cankers on the taproot which persisted to harvest. Isolations from these cankers resulted in recovery of Rhizoctonia solani anastomosis group 4 (AG-4) from more than 50% of the cankers. A survey of peanut fields being harvested during early September revealed that 28% of the fields had an average of more than 50% of the taproot surface area cankered. In contrast, for fields in the same area harvested one month later, 77% had disease severities of less than 25% and none were greater than 50%. In an experiment conducted in 1984, roots from 64 plots were examined and rated for root rot severity and yield. When taproot disease severity was regressed against yield, a highly significant negative correlation (r2 − 0.60, P<0.01) was found.
Natural Crossing of Peanut in Virginia1
Authors: Coffelt T. A.
Published: April 2010

Pedigreed natural crossing has been suggested as a technique for increasing the number of hybrids in peanut (Arachis hypogaea L.) breeding programs, when used in conjunction with the conventional crossing procedure. Since the success of this technique is dependent upon the natural crossing frequencies, a study was conducted from 1984-1986 to determine the current natural crossing frequency in Virginia peanut breeding plots. The cultivar Florigiant was used as the female parent, and the genetic line Krinkle was used as the male parent in a field plot each year. Krinkle has a dominant leaf characteristic easily identified in the hybrid progeny. Seed harvested from the Florigiant parent were planted in subsequent years, and the percentage of Krinkle plants determined for calculating the frequency of outcrossing. The frequency varied with environment from 2.8% in 1984 to 0.0% in 1986. The rate in 1984 was about four times the amount of natural crossing previously reported in Virginia. These results indicate that isolation distances between cultivars in seed fields may need to be greater than in current regulations, and cultivars need to be closely rogued for off-type plants during seed increase.
Effect of Chilling Injury on Windrowed Peanuts
Authors: Singleton J. A. , Pattee H. E.
Published: April 2010

Quantitative gas chromatographic analysis of peanut volatiles showed ethanol concentrations in chilled seed with diameters 5.95 and 6.75 mm to be higher than in chilled seed with diameters between 6.75 and 7.94 mm. Normal ethanol concentrations were observed for both large and small seed in the control. Specific conductivity of leachates from the small diameter chilled seed was two to three times higher than the control. Only small differences were observed in the specific conductivity of leachates from the large diameter seed for the chilled treatment and the control. Results suggest that, when exposed to chilling temperatures, respiration in the small seed changed from an aerobic to an anaerobic process. The changes may be caused by modifications in the cell membrane structures of relatively immature seed as a result of exposure to chilling temperatures, with less effect in larger, more mature seed.
Field Evaluations of Peanut Cultivar-Bradyrhizobium Specificities1
Authors: Phillips T. D. , Wynne J. C. , Elkan G. H. , Schneeweis T. J.
Published: April 2010

The peanut (Arachis hypogaea L.) generally is considered promiscuous since it forms symbioses with a diverse group of Bradyrhizobium. However, specific cultivar-strain combinations like Robut 33–1 and strain NC92 have resulted in significant yield increases, suggesting that host-strain combinations may be selected for superior nitrogen fixation and yield. The objectives of this study were to measure nitrogen fixation-related traits during the growing season and evaluate the interactions between host peanut genotypes and Bradyrhizobium strains under field conditions in North Carolina. A factorial experiment with four cultivars and five inoculants was conducted in two years at two locations (Clayton and Lewiston) in North Carolina. Traits measured during the growing season were nodule number and weight, root weight (1983 only), shoot weight, pod weight, nitrogenase activity and specific nitrogenase activity. In 1984, fruit yield was measured at harvest. Results indicated that cultivars and strains were different for most traits in 1983 at Clayton but significant host-strain interactions occurred only for nodule weight at 60 days after planting (DAP) and root weight at 132 DAP. In 1984, Clayton results indicated cultivar-strain interactions for all traits at 73 DAP and for several traits at 109 DAP. At Lewiston only cultivar differences were important. The Clayton fields had low populations of native Bradyrhizobium while Lewiston had a high level of the bacteria. Inoculation produced substantial yield increases at Clayton but not at Lewiston. Robut 33–1 inoculated with strain NC92 did not yield more than with other strains. Further study is needed to explain why repeated increases in yield were obtained with Robut 33–1/NC92 in tropical studies but not in North Carolina. The possibility still exists that superior cultivar-strain combinations can be identified.
Storability of Farmers Stock Peanuts at Two Moisture Levels in Mechanically and Naturally Ventilated Miniature Warehouses
Authors: Smith J. S. , Sanders T. H. , Crippen K. L.
Published: April 2010

Farmers stock peanuts from the same field dried to either 8 or 10% seed moisture content were stored for 6 months (October through March) in mechanically and naturally ventilated miniature metal warehouses. The initial temperatures for the 8% moisture content peanuts were 2–3 C higher than those for the 10% moisture content peanuts. This differential was maintained until early February. Relative humidities, 10 percentage points higher in the 10% initial moisture content peanuts began to equilibrate in December and were similar by late January. Final moisture content of the peanuts from the two mechanically ventilated warehouses was about 7% compared to 7.5% in the two naturally ventilated warehouses. Only small changes in total carbonyls and free fatty acids occurred during storage in the warehouses and sensory evaluation after storage indicated no significant differences among treatments within the medium and No. 1 sizes. No aflatoxin was detected in any seed size category before or after storage. Results indicated that quality of farmers stock peanuts, initial moisture content at 10% or less, can be maintained when stored in a properly constructed and operated mechanically or naturally ventilated warehouse.
Comparison of Stability Statistics as Criteria for Cultivar Development in Peanut1
Authors: Anderson W. F. , Mozingo R. W. , Wynne J. C.
Published: April 2010

Means of yield and qualitative traits are assessed in multi-location tests in the final stages of breeding line evaluation. Due to large environmental variation and genotype x environment interactions, it is often desirable to compare stability of lines over a range of environments. The objective of this study was to use various stability parameters to try and determine the stability of experimental breeding lines. Using data from regional advanced peanut (Arachis hypogaea L.) breeding line yield trials conducted over 3 years and four locations in Virginia and North Carolina, the stability of peanut cultivars and breeding lines was compared. Stability variance was found to be highly correlated (0.91–1.00) with covariate adjusted stability variance. In many instances, the stability-variance parameters produced similar results to pairwise regressions and dissimilarity measures when compared with standard cultivars. However, the distance parameters and regressions provided more precise information on relative responses in varying environments of two advanced breeding lines being considered for release. This allowed for direct comparison to cultivars targetted for replacement. NC 18411 had equal mean yields and qualitative traits but better stability than breeding line NC 18423. Regression analysis indicated that NC 18423 performed best in good environments but worse than most other cultivars in poor environments. Means and stability of value per kilogram and value per hectare were highly correlated with percentage of sound mature kernels and yield (0.92–0.99), respectively. A comparison of means and stability parameters was effective in discerning superiority of peanut breeding lines for potential release and use by growers.
Effect of Metalaxyl Plus PCNB or Metalaxyl Plus Tolclofos-methyl on Peanut Pod Rot and Soil Populations of Pythium spp. and Rhizoctonia solani
Authors: Filonow A. B. , Jackson K. E.
Published: April 2010

Metalaxyl plus PCNB or metalaxyl plus tolclofos-methyl were field tested in 1985–1987 in Oklahoma for their effect on pod rot of Florunner and Spanco peanut caused by Pythium spp. and Rhizoctonia solani. Total a.i. (kg/ha) of metalaxyl and PCNB applied in 1985, 1986 and 1987 were 1.12 and 11.2, 1.12 and 11.2 and 0.92 and 7.40. respectively. Total a.i. (kg/ha) of metalaxyl plus tolclofos-methyl applied in 1986 and 1987 were 1.34 and 3.36 and 1.12 and 2.24, respectively. Fungicides reduced pod rot severity on both cultivars at 2–8 wks prior to harvest; at harvest, however, none of the reductions were significant (P≤0.05). Yield increases were measured from 111–579 kg/ha, but few increases were significant (P≤0.05). Fungicides generally reduced the number of Pythium propagules in soil at several sampling dates, but few of the reductions were significant (P≤0.05). In 1986 and 1987 populations of Pythium spp. in soil peaked at 60 and 75 days, respectively, then declined. At these peaks treated soils generally had fewer Pythium propagules than nontreated soils. Populations of Pythium spp. were not significantly reduced at harvest. Populations of R. solani were highly variable over the seasons and control was erratic from year to year. In combination with metalaxyl, tolclofos-methyl was no more effective than PCNB in reducing pod rot or populations of R. solani. Populations of R. solani at harvest were not significantly (P≤0.05) reduced by the fungicide combinations.
Mechanical Texture Measurement of Whole and Chopped Peanuts1
Authors: Hung Y-C. , Chinnan M. S.
Published: April 2010

Different test cells (a Warner-Bratzler type blade, compression cell and a modified Kramer shear-compression cell) were compared to obtain an objective method for texture measurement of whole and chopped peanuts. The modified Kramer shear-compression cell was found to be the most sensitive in measuring textural characteristics of whole peanuts. Objective parameters, force and energy, correlated well with subjective parameters resulting from sensory evaluation, crispness and crunchiness (r2 = 0.77 and 0.79), respectively. The coefficients of determination (r2) between whole and chopped peanuts for force and energy were 0.81 and 0.72, respectively; which suggested that the modified Kramer shear-compression cell can be used to evaluate the textural quality of chopped peanuts.
The Effect of Peanut Stripe Virus Infection on Peanut Composition
Authors: Ross L. F. , Lynch R. E. , Conkerton E. J. , Demski J. W. , Daigle D. J. , McCombs C.
Published: April 2010

Peanuts (Arachis hypogaea L.), cultivar Florunner, from plants inoculated with peanut stripe virus (PStV) were evaluated for chemical composition in comparison with peanuts from uninoculated plants. At harvest, seed were collected from plants which had been mechanically inoculated with PStV at emergence, or 20, 40, or 60 days after emergence and from uninoculated plants. The seed from PStV-infected plants had increases in manganese, selenium, zinc, iron, tartaric acid, raffinose, glucose, fructose, and total carbohydrate contents as compared to seed from uninoculated plants. Sucrose was increased in seed from plants inoculated with PStV at time of emergence. There was a decrease in the concentration of potassium, magnesium, protein, and total soluble phenolics of seed from plants inoculated with PStV. There were no changes in the concentration of stachyose, inositol, phosphorus, sulfur, calcium, copper, and oil.
Use of Monoclonal Antibodies in Detection and Serological Classification of Peanut Stripe Virus1
Authors: Culver J. N. , Sherwood J. L. , Sanborn M. R.
Published: April 2010

Monoclonal antibodies (MABs) to peanut stripe virus (PStV) were obtained by fusing spleen cells from mice immunized with PStV to a mouse myeloma cell line. Two IgG2a subclass MABs, each binding with different antigenic sites, and rabbit polyclonal antibodies (PABs) were compared for their reaction to PStV and other serologically related plant viruses. One MAB reacted to PStV but not to other serologically related viruses. The other MAB reaction of the MABs and PABs to PStV in peanut leaf and seed tissues were compared by enzyme-linked immunosorbent assay (ELISA), dot-immunobinding assay, and Western blotting. MABs were found to be equivalent to or better than PABs in detecting PStV by ELISA and dot-immunobinding assay, but one MAB was not suitable for Western blotting.
Modeling Quality in Bulk Peanut Curing
Authors: Troeger J. M.
Published: April 2010

A bulk peanut curing model was modified to indicate conditions which affect peanut quality. The model simulates changes in moisture content as affected by the temperature and humidity of the drying air. Equations were developed for simulating hourly changes in the ambient temperature. Conditions promoting mold growth and mycotoxin production were indicated when relative humidities in the dryer exceeded an upper limit. Poor milling quality was indicated by relative humidities below a lower limit based on extension recommendations. Cumulative time for each of these conditions was determined with various levels of ambient temperature, initial moisture and dryer control settings. A control scheme is given for setting the plenum thermostat. The results show that better control of the dryer operating conditions will maintain the quality factors at a satisfactory level.
Reaction of Peanut Genotypes under Drought Stress to Aspergillus flavus and A. parasiticus1
Authors: Azaizeh H. A. , Pettit R. E. , Smith O. D. , Tabef R. A.
Published: April 2010

Seven peanut genotypes (Arachis hypogaea L.) were tested in greenhouse and microplot experiments during two consecutive years to determine peanut peg colonization by Aspergillus flavus and to determine the effect of two drought stress treatments on the susceptibility of peanut shells and kernels to Aspergillus colonization and aflatoxin contamination. Moisture tensions within the soil and temperatures of the soil and air were monitored during these experiments. Colonization of peanut pegs was inconsistent among genotypes and between years. In general, low soil moisture tension enhanced colonization of peanut shells and kernels. Shells of most genotypes were highly colonized after harvest from each moisture regime. Kernels of all genotypes were more susceptible to A. flavus and A. parasiticus colonization under both long and short drought stress conditions compared to non-stressed conditions. However, no significant differences were obtained in the degree of Aspergillus infestation of kernels from PI 337409, Starr, and J-11 in the greenhouse experiments. Under microplot conditions, acomparison of several genotypes revealed that kernels from plants of genotypes TX811956 and TX798736 (short stress treatments) contained significantly lower Aspergillus infestation and kernels from the genotypes PI 337409 and TX811956 and TX798736 contained significantly less aflatoxin.
The Incidence and Survival of Sclerotinia Minor in Peanut Seed
Authors: Porter D. M. , Taber R. A. , Smith D. H.
Published: April 2010

The incidence of Sclerotinia minor was assessed in seed of two peanut (Arachis hypogaea L.) varieties (VA 81B and Florigiant) harvested from two fields in Virginia exhibiting disease symptoms typical of Sclerotinia blight. The incidence of S. minor in peanut seed with pink, light brown and dark brown testae riding a 6.4 × 25.4 mm screen averaged 1.5, 3.9 and 6.0%, respectively, from both fields. Similar trends were evident with colonization of seed by other fungi. The incidence of S. minor from pieces of testa removed from seed from both fields averaged 3.4% and 2.6%, respectively. However, the incidence of S. minor from seed cotyledons with testae removed was extremely low (<0.1%). Sclerotia of S. minor were not observed on, in or under the testa of seed or between the cotyledons of seed in prepared seed lots (lots containing only seed with pink and light brown testae). BOTEC, a seed treatment fungicide applied at recommended rate (2.5 g/kg), reduced the incidence of S. minor in peanut seed from 4.5% to 0.1%. Similar decreases were noted in other seedbome fungi commonly associated with peanut seed.
Peanut Breeding for Leafspot Resistance in Wide and Narrow Intrarow Spacings1
Authors: Knauft D. A. , Gorbet D. W.
Published: April 2010

Sixteen peanut (Arachis hypogaea L.) genotypes were grown without the use of fungicides for two years in two planting arrangements, one an intrarow spacing typically used in commercial production (5 cm between plants) and the other typically used in breeding selection plots (30 cm between plants). At 10-day intervals throughout each growing season the proportion of necrotic leaf area caused by leafspots (Cercospora arachidicola Hori and Cercosporidium personatum (Berk. & Curt.) Deighton), leafspot disease rating (0-9), and stage of vegetative growth (v stage) were assessed. Leafspot disease ratings of genotypes spaced 30-cm apart were significantly correlated with the ratings of genotypes in 5-cm spacing. There was no interaction between genotypes and spacing. Percentage necrotic area in 30-cm and 5-cm plantings was significantly correlated. However, large experimental error and complex interactions among spacings, genotypes, and time of observation lessened the value of this method of disease assessment. While the correlation of v stage in the two spacings was highly significant, differences among genotypes were not consistent.
Inheritance of Symbiotic Nitrogen Fixation in Two Peanut Crosses1
Authors: Phillips T. D. , Wynne J. C. , Elkan G. H. , Schneeweis T. J.
Published: April 2010

Symbiotic nitrogen fixation in peanut (Arachis hypogaea L.) may be improved by genetically manipulating the host plant. This requires an understanding of the inheritance of the traits involved in nitrogen fixation. The objectives of this study were to determine the inheritance of several N2 fixation-related traits for two peanut crosses based on Mather and Jink's fixation-related traits for two peanut crosses based on Mather and Jink's additive-dominance model, and to determine if epistasis was important in the inheritance of these traits. A generation means analysis usingparents, reciprocal F1s and F2s, and two back-cross generations was conducted for both crosses. Plants of different generations were grown in modified Leonard jars in the greenhouse for about 60 days at which time nodule number and dry weight, shoot dry weight, nitrogenase activity, and specific activity were measured. Means of the traits for the generations from both crosses (Robut 33-1 x NC 4 and Robut 33-1 x Argentine) showed significant differences. Reciprocal differences were found for most traits measured in the cross of Robut 33-1 x Argentine, a cross of Virginia x Spanish botanical types. Lack of fit of the additive-dominance model indicated significant epistasis for inheritance of nodule number, nodule weight, top dry weight, and nitrogenase activity in both crosses. Three types of digenic interactions (additive x additive, additive x dominance and dominance x dominance) were found. The presence of nonadditive genetic effects suggests that early generation selection would be ineffective.
Accumulation Pattern of Arachin in Maturing Peanut Seed1
Authors: Basha Sheikh M.
Published: April 2010

Accumulation pattern and compositional changes in peanut (Arachis hypogaea L. cv. Florunner) arachin were determined by monitoring arachin from seeds of different maturities by gel filtration, two dimensional gel electrophoresis and amino acid analysis. The results indicated that arachin deposition was maximum between Immature and Intermediate stages, and that the arachin monomer increased more than the polymer during seed maturation. Arachin polypeptides with apparent molecular weights of 70,000: 32,000 and 29,000 increased in abundance with increasing maturity while a 50,000 molecular weight polypeptide decreased during seed maturation. In addition, amino acid composition of arachin differed in seeds of different maturities. These data suggest that arachin polypeptides are not deposited in equal amounts but individual polypeptides accumulate in different proportions during peanut seed maturation.
CSGR-1: A Computer Simulator of Groundnut Rust1
Authors: Wang Zhenzhong , Lin Kung-hsun
Published: April 2010

A computer simulator of groundnut rust (Puccinia arachidis Speg.), CSGR-1, was constructed based on four mathematical submodels describing environmental effects on (1) the increase rate of disease severity and daily multiplication factor of diseased leaflets, (2) the relationship between host growth and the effective accumulated temperatures, and (3) the relationships between infectious tissue and disease severity. The simulator was validated using independent data sets. With CSGR-1, disease development of groundnut rust can be predicted eleven days in advance given appropriate climatic data.
Colorimetric Assessment of Pod Disease in Peanuts: Comparison with Visual Methods and Efficacy of Use in Selection1
Authors: Parker Gregory B. , Smith Olin D. , Grichar W. James
Published: April 2010

Colorimetry was evaluated as a method to assess pod disease in peanuts (Arachis hypogaea L.) caused primarily by Pythium myriotylum Drechs., Sclerotium rolfsii Sacc., and Rhizoctonia solani Kuhn. Data analyzed were from nineteen replicated tests conducted from 1982 to 1987, exclusive of 1985, in three South Texas locations. Each plot was scored for pod disease colorimetrically and visually. A negative linear relationship (R2>96%) was found between Hunter color values (L and b) and percent infection measured visually for samples hand selected to approximate eleven disease levels varying from 0-100%. Variability among readings was less at extremes of infection. Correlation both between visual ratings and between visual and colorimetric ratings was affected by soil differences, pathogens infecting the pods, pod genotype, and level of infection present. Correlation among visual raters was generally higher than that between color value ratings. Two-thirds of the lines in these tests classified visually as being in the best 50% for pod disease were also in the best 50% according to colorimetric scores. Use of colorimetry in conjunction with a single visual rating was estimated to increase efficiency and reduce costs of evaluation compared to multiple visual ratings.
Peanut Weed Control Systems Utilizing RE-408851
Authors: Mueller T. C. , Banks P. A.
Published: April 2010

RE-40885 (5-(methylamino)-2-phenyl-4-3-(trifluoromethyl phenyl)-3(2H)-furanone), a newly developed herbicide with soil and foliar activity, was evaluated for weed control in peanuts (Arachis hypogea L.). RE-40885 applied to the soil or foliage provided excellent Florida beggarweed (Desmodium tortuosum (Sw.) DC.) and prickly sida (Sida spinosa L.) control at rates of 0.56 to 1.12 kg ai/ha. Sequential applications of RE-40885 were needed to achieve > 90% sicklepod (Cassia obtusifolia L.) control. Texas panicum (Panicum texanum Buckl.) was not adequately controlled by any of the RE-40885 treatments evaluated. Peanuts were not injured by RE-40885 at any of the evaluated rates or application times. The combination of RE-40885 and 2,4-DB applied early postemergence improved sicklepod control 8 weeks after planting when compared to either RE-40885 or 2,4-DB applied alone. The combination of R E-40885 and alachlor applied at peanut emergence improved morningglory (Ipomoea spp.) control 8 weeks after planting and increased peanut yield when compared to either applied alone. All treatments containing RE-40885 resulted in peanut yields that were significantly better than nontreated weedy control plots.
Intrarow Seed Spacing Effects on Morphological Characteristics, Yield, Grade and Net Value of Five Peanut Cultivars1
Authors: Mozingo R. W. , Steele J. L.
Published: April 2010

Peanut (Arachis hypogaea L.) producers in the Virginia-Carolina production area have not adopted row spacings closer than the conventional 91.4 cm. Seeding rates at this row width must be adequate, but not excessive, to maximize net value. With the recent development of new cultivars with different growth habits, this study was conducted to determine the effect of intrarow seed spacing on morphological characteristics, yield, grade, gross value, and net value for five cultivars currently available to growers. The cultivars Florigiant, NC 6, NC 7, Virginia 81 Bunch (VA 81B), and NC 9 were seeded at intrarow spacings of 5.1, 7.6, 10.2, and 15.2 cm in a 3-year field study at the Tidewater Agricultural Experiment Station, Suffolk, Virginia, from 1984 to 1986. Plots consisted of two rows 3.0 m long with interrow spacing of 91.4 cm for all treatments. A split plot design with five replications was used. Generally, main stems were taller and cotyledonary lateral branches were longer with closer intrarow seed spacings. The number of pods/plant decreased and number of pods/m of row increased with closer intrarow spacings. Seed spacings had little effect on the grade characteristics of the five cultivars, except that NC 6 had the greatest percentages of sound mature kernels and total meat at the 10.2-cm spacing, while Florigiant had the greatest percentage of total meat at the 15.2-cm spacing. For the spacings studies, pod yield increased with closer intrarow seed spacings. All cultivars had significantly greater yields at the 5.1-cm spacing than the 15.2-cm spacing. Net value (gross value minus seed cost) was not significantly different among intrarow seed spacings for four of the five cultivars studied. The exception was VA 81B which had a significantly greater net value at 5.1- and 7.6-cm seed spacings than at wider spacings. This study showed that yields generally increase with closer intrarow seed spacing; however, net value may not increase.
Soil Temperature Effects on Free Carbohydrate Concentrations in Peanut (Arachis hypogaea L.) Seed1
Authors: McMeans J. L. , Sanders T. H. , Wood B. W. , Blankenship P. D.
Published: April 2010

Research has indicated that variation in the mean soil temperature of only a few degrees results in quality differences of peanut seed. The importance of the carbohydrate-amino acid interaction in the development of roasted peanut flavor and color is well documented. The objective of this study was to determine the influence of controlled field soil temperatures on free carbohydrates in commercially sized peanut seed. Florunner peanuts were grown in 5.48 × 12.19 m plots. Soil temperatures were modified from 28 days after planting to produce mean temperatures warmer (28.8 C) and cooler (21.7 C) than ambient (24.5 C) at the 5.0 cm depth in 1982 and 28.2, 22.5, and 25.8 C, respectively, in 1983. Carbohydrates were determined by gas chromatography. Sucrose concentrations decreased significantly as accumulated heat units and seed size increased. In general, fructose, glucose, and raffinose concentrations followed the same trends. The carbohydrate differences found in sized seed were similar to those found among maturity stages from each soil temperature treatment. The data indicate that seed carbohydrate concentrations decrease with higher soil temperature.
Apparent Sap Velocity in Peanut Genotypes Under Control and Stress Conditions1
Authors: Ketring D. L. , Erickson P. I. , Stone J. F.
Published: April 2010

In order to sustain plant growth and hydration, water must be continuously supplied to the leaf as it is lost by transpiration. This becomes especially difficult under low soil moisture conditions. The objective of this investigation was to compare peanut (Arachis hypogaea L.) genotypes for their ability to maintain water supply to leaves by measuring apparent sap velocity (Va) under water stress conditions. Va was determined by the thermoelectric heat pulse method. Three genotypes (Chico, Florunner, and PI 355993) that differed in rooting traits were studied in the greenhouse. Plants were grown in fritted clay in PVC tubes (10.2 cm inside diameter and 76.2 cm in length). Six genotypes, including Chico and PI 355993, were studied in the field. Soil type was Teller sandy loam (fine, mixed, thermic, Udic Argiustoll). Under control conditions in the greenhouse and irrigated conditions in the field, Va ranged from about 0.8 to 1.1 cm/min for all genotypes. As water was withheld, Va declined with time in the greenhouse and was significantly lower under rainfed (-0.25 MPa soil potential) than irrigated (-0.10MPa soil potential) conditions in the field. Significant genotypic differences were found in both greenhouse and field experiments. Chico maintained the highest Va ratio (stress Va/control Va) in the greenhouse. PI 404021, Chico, and PI 355993 showed the least reduction (20, 26, and 29%, respectively) in Va under rainfed conditions in the field. Thus, the data are indicative of differences among peanut genotypes in maintaining Va under stress conditions. Knowledge of Va could be useful in determining relationships between root activity, soil water content, and water uptake and in selecting genotypes for inclusion in breeding programs to develop cultivars that avoid drought stress.
Utility of Early Generation Diallel Analysis for Predicting Parental Potential for Yield and Yield Components in Peanuts1
Authors: Holbrook C. Corley
Published: April 2010

Accurate identification of promising parents is crucial for peanut (Arachis hypogaea L.) cultivar development. The objectives of this study were to (1) determine the combining ability for yield and yield components of six genetically diverse peanut cultivars, (2) examine the relationship between F1 diallel analysis predictions and performance in subsequent generations, and (3) determine if parental performance per se could be used to identify desirable parents. Six peanut cultivars were selected to represent a wide range of genetic diversity and intermated using a half-diallel mating design. The cultivars included two Spanish market-types, Dixie Spanish and Spancross; two runner market-types, Southeastern Runner 56–15 and Tifrun; and two Virginia market-types, Virginia Runner G26 and Georgia 119–20. Parents and progenies were field evaluated each year at Tifton, GA. The F2 and F3 generations were tested in 1986 and 1987, respectively. Combining ability analysis showed that general combining ability (GCA) and specific combining ability (SCA) effects were significant (P < 0.05) for all variables measured. Although SCA remained a significant source of variation in the F3 generation, it accounted for a relatively small portion of the total variation. Tifrun had the greatest GCA effects for plot yield, pod weight per plant, seed weight per plant and seed number per plant. GCA estimates from F1 progeny were not effective in predicting performance in subsequent generations. Parental performance per se was highly correlated with performance across cross combinations in the F2 and F3 generations. GCA estimates from F2 and F3 progeny provided little information not available from simply examining parental performance.
Ovipositional Preference and Larval Establishment of the Indian Meal Moth and Almond Moth on Selected Peanut Genotypes1
Authors: Kashyap R. K. , Campbell W. V.
Published: April 2010

Thirty-nine selected peanut (Arachis hypogaea L.) genotypes from a diverse germplasm collection with known resistance and susceptibility to preharvest insects were tested in the laboratory for postharvest resistance to the Indian meal moth, Plodia interpunctella (Hubner), and the almond moth Cadra cautella (Walker). After the initial test the number of genotypes was reduced to 20 to reduce duplication of pedigree and omit some of the genotypes with intermediate resistance. Additional data were collected from the 20 genotypes on ovipositional preference and larval establishment on shelled and unshelled (farmers stock) peanuts.

Genotypes with resistance to moth species included NC 6, GP-NC 343 × NC 5, PI 467307, NC 7 × NC 10247, GP-NC 343 × NC 17367 and breeding line 10-P10-B1-B1-B1-B1-B2. Resistance to preharvest and postharvest insect complexes suggest some common chemicals may be present in the green crop and the harvested seed that elicit ovipositional response.
Inheritance of Fatty Acid Content in Peanut Oil1
Authors: Mercer L. C. , Wynne J. C. , Young C. T.
Published: April 2010

The stability or shelf-life of peanut (Arachis hypogaea L.) oil is related to the fatty acid content of the oil, with the major factor being the ratio of oleic (C18:1) to linoleic (C18:2) acid (O/L ratio). To obtain information needed for development of cultivars with improved oil quality, eight parents representing a range in oleic and linoleic content were crossed in diallel. Individual F1 seeds (F1 embryos) from the greenhouse and F2 bulk seed from the 56 crosses grown in the field were analyzed to determine levels of the eight major fatty acids. General combining ability (GCA) was consistently more important than specific combining ability (SCA) in both generations, suggesting that additive effects are important in the inheritance of fatty acid composition. Maternal effects were significant in the F1 but dissipated in the F2; thus the differences in the environment provided by the maternal parent was more critical to oil composition than heritable extranuclear factors. Reciprocal effects were significant in both generations suggesting an interaction between nuclear and extranuclear factors. Correlations between GCA effects and self means for O/L ratio were nonsignificant. Since no significant correlations were found between percent oil and any of the fatty acids or related variables, selection for improved fatty acid composition should not affect the oil content of seed. Of the lines studied, NC 7, NC-Fla 14, and 73–30 should be used as parents in a breeding program for oil quality.
Hand-Tripped Flowers Promote Seed Production in Arachis lignosa, a Wild Peanut1
Authors: Banks Donald J.
Published: April 2010

In trials conducted in the greenhouse, growth chamber, and outdoors, no pegs or pods were produced when A. lignosa (Chod. et Hassl.) Krap. et Greg. nom. nud. plants were allowed to pollinate naturally. However, hand tripping flowers, especially in the greenhouse, resulted in significant increases in pod production. The results suggest that the high degree of reproductive sterility usually noted for A. lignosa in culture is due to pollination failure rather than to physiological self incompatibility. The somewhat truncated shape of the stigma and its elevated position relative to the anthers probably restricts natural self-pollination without the aid of pollinating vectors such as bees.
Relationship of Seed Mass to Oil and Protein Contents in Peanut (Arachis hypogaea L.)1
Authors: Dwivedi S. L. , Jambunathan R. , Nigam S. N. , Raghunath K. , Shankar K. Ravi , Nagabhushanam G. V. S.
Published: April 2010

Seed mass, oil and protein contents are important quality traits in peanut (Arachis hypogaea L.). Sixty-four genotypes were grown for four seasons to study genetic variation and character association between these three traits. Graded seed samples of 33 genotypes were further studied for possible variation within genotype among grades for oil and protein contents. No significant association of seed mass with percent oil or protein contents was observed among the 64 genotypes. However, oil and protein contents were significantly negatively associated. Oil content variation within a genotype showed a significant linear increase as the seed mass increased in the graded samples, but no such relationship was observed with protein content. Genotypes with desirable traits for confectionery and/or oil types were identified and may be used for germplasm enhancement.
Interaction of Curing Temperature and Inherent Maturity Distributions on Descriptive Flavor of Commercial Grade Sizes of Florunner Peanuts1
Authors: Sanders Timothy H. , Blankenship Paul D. , Vercellotti John R. , Crippen Karen L.
Published: April 2010

Windrow-dried Florunner peanuts were harvested and then cured with ambient air (maximum 35 C), ambient +8.4 C increase, and ambient +16.8 C increase in commercial drying operations. Peanuts from the drying wagons were stored inshell as farmers stock or shelled and then cold stored approximately five months before sensory evaluation. A panel trained in peanut flavor descriptive analysis evaluated peanuts from all commercial grade sizes which had been roasted to similar color. Differences between cold- and farmers stock-stored peanuts were not statistically significant and data were thus combined. Curing treatments produced differences in descriptive terms roasted peanutty, fruity fermented and sour. Fruity fermented intensity was noticeably higher in the medium and No. 1 grade sizes from the higher curing temperatures and roasted peanutty decreased in the No. 1 grade with increasing temperature. Significant differences in intensity of seven descriptors were consistently found among the grades within each curing treatment. For each of these descriptors as size decreased, intensity of desirable flavor descriptors decreased and intensity of off-flavor descriptors increased.