Percentage Of Extra Large Kernels Research Articles

Disease Management in Overhead Sprinkler and Subsurface Drip Irrigation Systems for Peanut

Experiments were conducted during 2001 and 2002 at one location in North Carolina to compare development of early leaf spot (Cercospora arachidicola Hori), pod yield, and market grade characteristics when peanut (Arachis hypogea L.) was grown under overhead sprinkler irrigation (OSI) and subsurface drip irrigation (SDI) and fungicides were not applied or applied biweekly or based on weather advisories. Incidence of early leaf spot was lower when peanut was grown under SDI compared with OSI when fungicides were not applied. Fewer fungicide applications were needed when applications were based on weather advisories rather than when applied biweekly. There was no difference in early leaf spot control or leaf defoliation resulting from disease when fungicides were applied regardless of irrigation system or fungicide application approach. Pod yield was higher in 2001 under SDI compared with OSI when fungicides were not applied; yield was similar in 2002. Disease severity was much higher in 2001 than in 2002 and most likely explains differences in pod yield between years. No difference in yield was noted when fungicides were applied, regardless of irrigation system. The percentage of extra large kernels (%ELK) was lower in 1 of 2 yr under SDI compared with OSI. There were no differences in percentages of fancy pods (%FP), sound splits (%SS), and other kernels (%OK) among irrigation systems and fungicide programs. In a separate experiment where fungicides were applied biweekly, pod yield, %FP, and %ELK were similar under SDI and OSI but greater than nonirrigated peanut. The %OK was lower when peanut was irrigated.

Peanut Response to Prohexadione Calcium in Three Seeding Rate–Row Pattern Planting Systems

Peanut (Arachis hypogaea L.) in the USA is generally grown in single rows spaced 91 to 102 cm apart. Research suggests that pod yield can be increased by growing peanut in twin rows (18–23 cm spacing) on beds spaced 91 to 102 cm apart. Prohexadione Ca (Ca salt of 3,5‐dioxo‐4‐propionylcyclohexanecarboxylic acid) increases row visibility and in some instances increases pod yield and improves market grade factors. Research was conducted to determine response of peanut grown in three seeding rate–row pattern planting systems (single rows at a seeding rate of 120 kg ha−1 or twin rows spaced 18 cm apart on beds spaced 91 cm apart at seeding rates of 145 and 190 kg ha−1) to prohexadione Ca applied at 50% row closure. Row visibility increased and main stem height was shorter at the end of the season when prohexadione Ca was applied in most environments and for most seeding rate–row pattern combinations when compared with nontreated peanut. Pod yield and gross economic value increased 160 kg ha−1 and $96 ha−1, respectively, when prohexadione Ca was applied irrespective of the seeding rate–row pattern combination or environment. Prohexadione Ca also increased the percentage of extra large kernels (% ELK) but did not affect percentages of sound mature kernels (SMK), other kernels (OK), sound splits (SS), or total sound mature kernels (TSMK). Seeding rate–row pattern combination affected pod yield, market grade, and gross economic value although a consistent trend was not apparent.

Comparison of Virginia and Runner Market-Type Peanut (Arachis hypogaea) Grown in the Virginia-Carolina Production Region

Abstract Research was conducted in North Carolina and Virginia from 1997 through 1999 to compare runner and virginia market-type peanuts as influenced by cultivar selection, fertility practices, and pest management strategies. The runner market-type cultivar Georgia Green yielded and provided gross market value equivalent to the virginia market-type cultivar NC-V11 under a wide range of edaphic and environmental conditions. Calcium (as gypsum) applied at initial pegging increased the percentage of extra large kernels, the percentage of total sound mature kernels, and market value (c/kg) of the virginia market-type cultivar Gregory. The runner market-type cultivars Georgia Green and GK-7 were less responsive to calcium. Response of both market types was dependant upon environmental conditions. Pest management strategy affected pod yield, gross value, and economic return of peanut similarly for both virginia and runner market types. Results from these studies suggest that runner market-type peanut can provide pod yield, gross value, and economic returns similar to commonly grown virginia market-type peanut when grown in the Virginia-Carolina region. However, the peanut industry in the Virginia-Carolina region is designed for virginia market-type peanut used for the in-shell market, and popularity of growing runner market-type peanut in this region will most likely depend upon market pressures rather than agronomic potential.

Diclosulam Does Not Influence Yields in Eight Virginia Market-Type Peanut (Arachis hypogaea) Cultivars1

Abstract: Field studies were conducted in 1996 and 1997 to evaluate response of eight peanut cultivars to diclosulam applied preplant incorporated at 36 g ai/ha in a weed-free environment. Peanut cultivars evaluated included ‘NC 12C’, ‘NC 7’, ‘VAC 92R’, ‘NC-V 11’, ‘NC 10C’, ‘AT VC 1’,‘NC 9’, and the experimental breeding line N90010E. Visible injury 3 wk after planting was less than 5% regardless of cultivar. No injury was observed at 21 d after planting. Diclosulam did not influence the incidence of early leaf spot, late leaf spot, southern stem rot, cylindrocladium black rot, or tomato spotted wilt virus. Diclosulam did not affect percentage of extra large kernels, sound mature kernels, other kernels, and yield. Nomenclature: Diclosulam; peanut, Arachis hypogaea L. NC 12C, NC 7, VAC 92R, NC-V 11, NC 10C, AT VC 1, NC 9, N90010E. Additional index words: Disease interaction, cylindrocladium black rot, Cylindrocladium crotalariae (Loos) Bell et Sobers, early leaf spot, Cercospora arachidicola Hori, late lea...

Influence of Adjuvants on Peanut (Arachis hypogaea L.) Response to Prohexadione Calcium

Abstract 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.

Response of Virginia-Type Peanut to Norflurazon

Abstract Four field experiments were conducted in North Carolina from 1994 to 1996 to determine the effect of norflurazon applied preemergence at 1.6 kg ai/ha to virginia-type peanut (Arachis hypogaea L.) cvs. NC 7, NC 9, NC 10C, NC-V 11, VA-C 92R, and AT VC-1. Injury 3 wk after planting was 7% or less in three experiments. Greater injury was noted on VA-C 92R relative to other cultivars in one of these experiments. Injury ranged from 25 to 41% in the fourth experiment, with greater injury noted on NC 9, NC-V 11, and VA-C 92R than on NC 7, NC 10C, or AT VC-1. Norflurazon did not affect peanut maturity, the percentage of extra large kernels, total sound mature kernels, or fancy pods. Norflurazon reduced peanut yield 6% irrespective of cultivars in two of four experiments.

Foliar Fertilization of Virginia-Type Peanut with MnEDTA— Crop Grade, Pod Yield, and Value1

Abstract Manganese is an essential plant micronutrient and has many functions in the plant. Deficient levels of manganese in the plant result in reduced crop yields. This study was conducted to determine the effects of foliar application of manganese salt of ethylenediamine tetra-acetate (MnEDTA) and the timing of application of the MnEDTA to the peanut (Arachis hypogaea L.) plant on crop grade, pod yield, and value. Field trials were conducted in Virginia during 1990 and 1991 to determine the optimum amounts of MnEDTA needed for production of the virginia-type peanut. The predominant soil type was Yemassee fine sandy loam (fine-loamy, siliceous, thermic Aeric Achroquults). Manganese treatments enhanced fancy pod development and increased the percentage of extra large kernels for NC-V 11 and NC7. Other grade factors were not influenced. Average pod yield increases over the control were 25 and 109% for NC-V 11 in two tests during 1990. In 1991 average pod yield increase for NC-V 11 and NC 7 above the control were 65 and 103%, respectively. Crop values paralleled the pod yield data in comparison to the control and standard treatments. MnEDTA treatments were comparable to the standard treatments especially at the higher rates. Amounts of Mn, as MnEDTA, needed for foliar application to peanut were 0.3 to 0.6 kg ha-1 per application. Results show that early initial application was needed (4 to 6 wk after planting) with at least three applications applied at 2-wk intervals.

Peanut Response to Prohexadione Calcium, a New Plant Growth Regulator

Abstract Experiments in 1992, 1993, and 1994 evaluated prohexadione calcium (calcium salt of 3,5-dioxo-4-propionylcyclohexanecarboxylic acid) as a growth regulator for peanut (Arachis hypogaea L.). Two experiments in 1992 compared prohexadione calcium applied at 140 to 560 g ae/ha at the early pegging stage (PG) or at the row closure stage (RC). Greater suppression of main stem (MS) and cotyledonary lateral branch (CLB) length and greater row visibility at harvest were noted when prohexadione calcium was applied at RC. Prohexadione calcium applied at RC decreased MS and CLB length at harvest 16 to 27% and 14 to 29%, respectively, and greatly improved row visibility. Prohexadione calcium applied at PG generally reduced yield and the percentage of extra large kernels (ELK), fancy pods (FP), and total sound mature kernels (TSMK) but had no effect on crop maturity. Prohexadione calcium applied at RC generally had no effect on yield or the proportion of TSMK but increased the percentage of ELK, decreased the percentage of FP, and enhanced crop maturity. Two experiments in 1993 compared prohexadione calcium at rates of 47 to 280 g/ha applied at RC or at RC and again 3 wk later (RC3). Prohexadione calcium at 140 and 280 g/ha applied at RC suppressed MS and CLB length at harvest 11 to 18% and improved row visibility. Single and sequential applications were equally effective. Prohexadione calcium had no effect on yield, maturity, or the percentage of ELK, FP, and TSMK in 1993. One experiment in 1994 compared prohexadione calcium at rates of 186 to 280 g/ha applied at RC and RC3 or at RC and RC3 and 6 wk after RC (RC6). Results were similar with all treatments. MS and CLB length at harvest was reduced 29 to 34% and 28 to 32%, respectively, and row visibility was greatly improved. Prohexadione calcium increased yield 8% and increased the percentage of ELK but had no effect on the percentage of FP and TSMK. Daminozide [butanedioic acid mono (2,2-dimethylhydrazide)] at 950 to 1430 g ae/ha was included in all experiments as a comparison. Row visibility and suppression of MS and CLB length at harvest in prohexadione calcium-treated peanut were at least as great as in daminozide-treated peanut. Results indicate prohexadione calcium could be an effective-replacement for daminozide.

Conservational Tillage and Cultivar Influence on Peanut Production1

Abstract The influence of conservational tillage and cultivar on pod yield, crop value, and market grade factors was evaluated as a means to increase the production efficiency of peanut (Arachis hypogaea L.). Two conservational tillage systems, in-row and band tillage, and one conventional tillage system were compared over a 4-yr period using the cultivars Florigiant, NC 6, and VA 81B. For all three cultivars, pod yields averaged 15% less and crop values averaged 21% less under the conservational tillage systems as compared to the conventional tillage system. The cultivar NC 6 performed slightly better than Florigiant and VA 81B. The percentage of extra large kernels for NC 6 was significantly higher than for the other two cultivars. There were no significant differences in the percentage of sound mature kernels and total meat content between the three cultivars. Tillage systems did not have a consistent effect on grade factors over the 4-yr period.

Growth Regulator Effects on the Composition of Seed of Five Peanut Cultivars1

AbstractSince composition of the seed of peanut (Arachis hypogaea L.) is an important quality factor, the effect of the plant growth regulator, succinic acid 2,2 dimethylhydrazide (SADH, sold under the trade name Kylar), on seed composition needed investigation. Field tests were grown in Martin County, NC, on a Norfolk loamy fine sand (fine‐loamy, siliceous, thermic Typic Paleudult) and in Suffolk, VA, on an Eunola loamy fine sand (fine‐loamy, siliceous, thermic Aquic Hapludult) in 1981 and 1982. Peanut seed from treated and untreated plots of the cultivars ‘Florigiant’, ‘NC 6’, ‘NC 7’, ‘VA 81B’, and ‘NC 8C’ at each location were evaluated for fatty acid distribution, iodine value (IV), oleic/linoleic (O/L) ratio, percentage of extra large kernels (ELK), and arginine maturity index (AMI). Application of SADH in 1981 reduced the linoleic acid percentage and IV and increased the oleic acid percentage and O/L ratio. In 1982, SADH application led to significantly lower linoleic acid percentage and IV in all cultivars except VA 81B, and significantly increased the O/L ratio for Florigiant, NC 7, and NC 8C. Similar O/L changes were not significant for NC 6 and VA 81B. NC 7 had the greatest number of significant changes in composition percentages with decreases in palmitic, linoleic, arachidic, eicosenoic, behenic, and lignoceric acids, and an increase in oleic acid in seed of plants treated with SADH. The AMI values were lower for all cultivars and ELK percentage was higher for Florigiant and NC 6, indicating more mature seed, with SADH treatment. Thus, from the results of this 2‐yr study, the application of SADH to reduce foliage growth also affected the ELK, AMI, and fatty acid distribution of seed from several peanut cultivars.

Genotype ✕ Environment Interactions in Peanut Multiline Populations1

The stabilities of four peanut (Arachis hypogaea L.) multiline populations plus their component lines were determined over a 4‐year period, 1980‐1983, at two locations in Florida. The study was undertaken to provide information concerning the stability of both yield and market quality factors of multiline cultivars vs. the component lines which form them. Each multiline was obtained from a different cross, and was formed by compositing in equal proportions the seed from four early generation, phenotypically similar sib‐lines. The interactions of genotype (population) with environments was highly significant (P = < 0.01) for pod yield and five quality factors (percentage fancy pod, shelling percentage, weight per 100 seeds, percentage of extra large kernels and sound mature kernel yield) studied. Large differences in yield and market quality traits were not found between sib‐lines. However, differences were found in stability estimated from regression coefficients and deviation from regression of multilines compared to their component lines, possibly due to the buffering action resulting from greater genetic variability. Multilines did not have greater stability in all cases, but the difference between the multiline and its least stable component line was generally greater than the difference between the multiline and its most stable component line. This research indicates that the chance of improving the yield stability and market acceptibility of peanut cultivars is increased when the multiline approach is used.

Growth Regulator Effects on the Market Quality of Five Virginia-Type Peanut Cultivars1

Abstract The growth regulator succinic acid 2, 2-dimethylhydrazide (SADH) was applied to the foliage of five virginia-type peanut (Arachis hypogaea L.) cultivars in 1980, 1981, and 1982 in Martin County, North Carolina, and Suffolk, Virginia. Treated and untreated peanuts at each location were harvested on two dates each year. Market grade, yield, and value/ha evaluations were made on the cultivars Florigiant, NC 6, NC 7, VA 81B, and NC 8C. Yield and value/ha within each cultivar were statistically different across years and locations. The growth regulator significantly reduced the percentage of fancy pods for all cultivars except VA 81B while significantly increasing the percentage of extra large kernels for all cultivars except NC 8C. The percentage of total kernels was not affected with Florigiant or NC 7, but significant reductions were observed with growth regulator application to NC 6, VA 81B, and NC 8C. The yield and value/ha of Florigiant and NC 6 increased significantly with growth regulator applications. Yield/ha of NC 7 increased with growth regulator application but was not statistically different; however, the NC 7 value/ha increased significantly. Growth regulator applications on NC 8C and VA 81B affected neither yield nor value/ha. Thus, applications of the growth regulator SADH can be a beneficial peanut production practice for some cultivars; however, the response within cultivars was inconsistent across years and locations.

Skip‐Row Planting and Row Pattern Effects on Virginia‐Type Peanut Cultivars1

AbstractSince increasing peanut (Arachis hypogaea L.) production per area of land is a constant goal of researchers, skip‐row planting was an avenue that needed exploring. A 3‐year study was conducted at the Tidewater Research and Continuing Education Center in Suffolk, Va. to determine the effects of two planting patterns, two row patterns, and two cultivars on the yield, value, and grade characteristics of virginia‐type peanut. Planting patterns of solid (all rows planted) and skip‐row (two 0.91 m rows planted and one 0.91 m wide row fallow) were used in a 2 × 2 × 2 factorial arrangement with row patterns of a single row centered in a 0.91 m wide row and twinrows (0.18 m apart) centered in a 0.91 m wide row for the cvs. Florigiant and NC 7. Plots were 3.66 m wide and 10.67 m long with the two center rows harvested for the single row planting and the four center rows harvested for the twin row planting. Soil types for the study were Dragston fine sandy loam (coarse‐loamy, mixed, thermic, Aerie Ochraquults) in 1979, Dragston loamy fine sand in 1980, and an Eunola loamy fine sand (fine‐loamy, siliceous, thermic Aquic Hapludults) in 1981. NC 7 produced a higher percentage of extra large kernels (ELK), sound mature kernels (SMK), total meat (TM) and had a higher dollar value ha−1 than Florigiant. No differences were found between the two cultivars for yield or percentage of fancy size pods (FP). The two row patterns had no effect on yield, value or any grade characteristic. Skip‐row planting produced a significantly (P < 0.01) higher yield and value on a planted hectare basis than did solid planting, while no differences were recorded for any grade characteristic. The highest yield (4599 kg ha−1) and value (2266 dol ha−1) were recorded for NC7 in the twin‐row pattern with skip‐row planting.