Early Scarlet Research Articles

Laboratory Assessment of Host Plant Selection of the Brown Marmorated Stink Bug (<i>Halyomorpha halys</i>)

The behavioral response of brown marmorated stink bug, <i>Halyomorpha halys</i> (Hemiptera: Pentatomidae), to various phenological growth stages (leaf, flower and pod/seed/kernel) of six host plants (soybean, corn, sunflower, Early Scarlet and Mississippi Silver cowpeas, and princess tree leaf) was investigated in a Dual Choice Arena Test (DCAT) and Multiple Choice Arena Test (MCAT). In DCAT, each experiment consisted of one of the growth stages of each plant with princess tree leaf as the standard. In MCAT, two experiments were conducted using: (1) similar growth stages from the different plants and (2) different growth stages from the same plant. <i>Halyomorpha halys</i> distribution was observed at time intervals up to 24 hours after insects were released. Results from MCAT and Preference Index (PI) from the DCAT indicated that more <i>H. halys</i> were recorded on princess tree leaves. Mississippi Silver (PI=1.59±0.05) and Early Scarlet (PI=1.49±0.08) flowers were preferred over princess tree leaves and other flowers (PI≤1). Sunflower seed was the least preferred (PI=0.43±0.18) among similar growth stages. Overall, the reproductive stages were preferred over the vegetative stage. Our findings can be useful in developing management programs such as trap cropping for this pest.

Response of Advanced Cowpea (Vigna unguiculata) Breeding Lines to Halosulfuron-Methyl

Studies were conducted in Oklahoma and Arkansas to evaluate the tolerance of nine advanced cowpea breeding lines and one cultivar treated PRE with halosulfuron at 1× (0.054 kg ha−1) and 2× (0.107 kg ha−1) rates. The breeding lines, developed by the University of Arkansas, included 01-103, 01-111, 01-117, 01-140, 01-174, 01-180, 01-181, 01-184, and 01-198. ‘Early Scarlet’ was also included as the standard commercial cultivar. Halosulfuron did not reduce the emergence of the breeding lines and Early Scarlet in Oklahoma, but reduced cowpea emergence 14% at the 2× rate in Arkansas. All breeding lines and Early Scarlet had similar emergence capacity in both locations. Higher injury (crop stunting, up to 59% at the 2× rate) and reduction in flowering (up to 83% points at the 1× rate) were observed in Arkansas, but not in Oklahoma. Averaged over herbicide rate, yield was higher and did not differ among cultivars in Arkansas (0.89 to 1.18 Mg ha−1) versus Oklahoma (0.36 to 0.82 Mg ha−1). The highest yield in Oklahoma was obtained from 01-174, 01-103, and 01-117. Despite the observed phytotoxicity symptoms, halosulfuron did not reduce cowpea yield. Halosulfuron is safe to use with these breeding lines and cultivar, at the 0.054 kg ha−1rate, but may delay cowpea maturity almost 1 wk in soils of close to neutral pH or higher.

Tolerance of Selected Advanced Cowpea (Vigna unguiculata) Breeding Lines to Fomesafen

Chemical options for weed control in commercial cowpea production are limited. Repeated long-term use of the acetolactate synthase (ALS) inhibitor, imazethapyr, has resulted in selection for ALS-resistant populations of Palmer amaranth. Experiments were conducted at Bixby, OK, and Kibler, AR, from 2001 to 2003 to evaluate the tolerance of cowpea cultivars and advanced breeding lines to fomesafen, a potential alternative for controlling ALS-resistant Palmer amaranth and other problematic broadleaf weeds. Eight commercial cultivars and 42 advanced breeding lines were entered in the preliminary screening, using 0.84 kg/ha fomesafen. Six breeding lines were selected for the first replicated trial and three (00-582, 00-584, and 00-609) were advanced to across-location experiments. Fomesafen doses of 0, 0.17, 0.34, and 0.67 kg/ha were tested across locations. ‘Early Scarlet’ was used as commercial standard. The advanced lines had equal or higher yield potential (1,182 to 1,936 kg/ha) than Early Scarlet (1,108 kg/ha) across locations. Of the cultivars tested, line 00-609 was the best yielder, whereas 00-584 had the highest tolerance to fomesafen. At the commercial fomesafen rate of 0.34 kg/ha, 00-584 had higher yield (974 and 1,735 kg/ha, respectively, at Bixby, OK, and Kibler, AR) than the nontreated, weed-free, Early Scarlet. Thus, fomesafen can be used on the tolerant line, 00-584, without reducing yield potential relative to Early Scarlet.

COWPEA TOLERANCE TO SANDEA HERBICIDE

Southernpea is a major vegetable crop in Arkansas and Oklahoma for commercial production and home gardens. Complete weed control is necessary for this crop in commercial production to keep the peas free of contaminants and achieve high harvest efficiency. Several weeds like pigweed, cocklebur, velvetleaf, lambsquarters, hophornbeam copperleaf, nightshade, nutsedge, and morninglories are difficult to control in this crop because of limited herbicide options. Sandea (halosulfuron) is an excellent herbicide for nutsedge control and has activity on most of the weeds mentioned above. It has both soil and foliar activity. Sandea is labeled for several vegetable crops and southernpea may have enough tolerance to Sandea to warrant a label expansion. Experiments were conducted in Arkansas and Oklahoma between 2002 and 2005 to determine the tolerance of southernpea to Sandea and its efficacy on some weed species. In Oklahoma, trials were conducted in LeFlore County and at the Bixby Research Station in 2002 and 2003. Treatments consisted of various herbicides applied preemergence (PRE) or postemergence (POST), among which were some Sandea treatments. The doses of Sandea tested ranged from 0.024 to 0.048 lb a.i./A with some treatments applied with Basagran (bentazon), POST. Preemergence treatments were applied at 20 GPA and POST treatments at 30 GPA. Experimental units were arranged in randomized complete block design with four replications. The cultivar used was Early Scarlet. Plots were comprised of four rows, spaced either 30 or 36 inches, depending on location, 15 ft long. The crop at Bixby was irrigated, but not at LeFlore. In Arkansas, two experiments were conducted in 2005 at the Vegetable Station in Kibler. One experiment was setup in a split-plot design, with four replications, with cultivar as mainplot and Sandea treatments as subplot. Eleven advanced breeding lines and Early Scarlet were used. Four Sandea treatments, using doses of 0.048 and .096 lb ai/A applied either PRE, at 1 to 2-trifoliate (early POST), and at 3- to 4-trifoliate (late POST) were tested. The second experiment compared the responses of 16 advanced breeding lines and Early Scarlet to 0.096 lb a.i./A Sandea applied PRE. Plot size at Kibler consisted of 4 rows, spaced 36 inches, 20 ft long. Herbicide treatments were applied at 20 GPA spray volume and the crop was sprinkler irrigated as needed. In Oklahoma, the commercial rate of Sandea (0.032 to 0.048 lb a.i.) did not cause any injury to southernpea when applied PRE regardless of availability of irrigation. However, when applied POST, significant stunting (up to about 20%) of plants was observed in both locations. This level of injury did not cause significant yield loss. The trial at Bixby could not be harvested due to excessive pigweed biomass later in the season. Sandea controlled Palmer amaranth and carpetweed &gt;90% when applied PRE, but had no activity on these species when applied POST. Conversely, Sandea had excellent activity (100%) on common cocklebur when applied POST, but ineffective when applied PRE. Trials in Arkansas were strictly for tolerance evaluation so no weed control data was collected. In Arkansas, the PRE timing was also safer than POST when 0.096 lb ai Sandea was used. The 11 advanced lines tested in trial 1 were among the top 15 lines selected for tolerance to Sandea from a preliminary screen. These selected lines still showed different levels of tolerance to high rates of Sandea, but may not show any difference among each other at the recommended rates. The best lines were 00-609 and 00-178, which showed no yield reduction when treated with 0.096 lb ai Sandea PRE. All advanced lines had higher yield than Early Scarlet without herbicide treatment. In trial 2, 01-103, 01-180, and 01-181 had 0% to 10% yield loss when treated with 0.096 lb ai Sandea, PRE. All three had similar or greater yield than Early Scarlet. The commercial standard incurred about 20% to 30% yield loss from the high dose of Sandea applied PRE in both trials in Arkansas. Sandea is safe for cowpea, PRE at recommended doses. However, some advanced lines can tolerate high rates of Sandea. Some weeds are controlled by Sandea PRE, but not POST and vice versa.

Effect of Storage Conditions and Genotype on Shelf-life of Fresh Southernpea

Fresh-shelled southernpeas [Vignaunguiculata(L.) Walp.] is a popular vegetable. Postharvest storage of fresh-shelled peas is a crucial step in the production process. Farmers strive to produce a product that is high in quality and freshness with appropriate texture and appealing color. Improper storage and handling of southernpeas will result in deterioration. In an effort to prevent potential losses of southernpeas, this study was conducted to determine the best method to ship and store shelled peas. Five southernpea varieties: `Early Acre', `Early Scarlet', `Excel Select', `Coronet', and `Arkansas Blackeye #1' were planted in a randomized block design at the University of Arkansas. Twelve mature green pods of each variety were subjected to a sweated and unsweated treatment and then shelled. After shelling, seed were subjected to four different environmental conditions, and each treatment was evaluated for changes in physical appearance. Objectives of the study were to determine the best variety and environmental condition to maintain a quality marketable product. The study showed that a refrigerated environment at or near 3 to 5 °C allowed the crop to be stored for up to 2 weeks. It also appeared that sweating assisted with the shelling process and maintained appearance of each variety longer.

EFFECT OF STORAGE CONDITIONS AND GENOTYPE ON SHELF-LIFE OF FRESH SOUTHERNPEA

Postharvest storage of southernpeas, Vigna unguiculata (L.) Walp., is a crucial point of the production process. Governed by consumer demands, farmers strive for a product that is high in quality and freshness, and has an appropriate texture and appealing color. Improper storage of southernpeas will result in their eventual deterioration, unacceptance, and possible loss of profit. Because of this, an appropriate storage facility and temperature should be devised that will benefit both farmer and consumer. In an effort to prevent potential losses of southernpeas, a study was conducted to determine the best environmental condition at which to store them to potentially extend their shelf-life. In 2004, five southernpea varieties—`Early Acre,' `Early Scarlet,' `Excel Select,' `Coronet,' and `Arkansas Blackeye #1'—were planted in a randomized block design on the University of Arkansas horticulture farm. Upon maturity, 12 green pods of each variety were subjected to a sweated and unsweated treatment and then shelled. After shelling, the seeds were subjected to four different environmental conditions evaluating each on the basis of changes in physical appearance. Further objectives of the study were to determine the best variety, environmental condition, and treatment to maintain product quality in a manner that would relate to growers on a commercial basis. Results showed that a refrigerated environment at or near 3 to 5 °C is a good environment to store this particular crop for nearly 2 weeks. It also appeared that the sweated treatment assisted with the shelling process and maintained the appearance of each variety longer. From the results, temperature and percent relative humidity are arguably two important components of postharvest storage that have the potential of negatively affecting the crop.

608 Super-elevated CO2 Concentrations Reduce Growth of Radish and Lettuce

Radish (Raphanus sativus cv. Giant White Globe) and lettuce (Lactuca sativa cv. Waldmann's Green) plants were grown for 25 days in growth chambers at 23 °C, ≈300 μmol·m-2·s-1 PPF, and 18/6 photoperiod, and four CO2 concentrations: 400, 1000, 5000, and 10,000 μmol·mol-1. Average total dry mass (g/plant) at the 400, 1000, 5000 and 10,000 μmol·mol-1 treatments were 6.4, 7.2, 5.9, and 5.0 for radish and 4.2, 6.2, 6.6, and 4.0 for lettuce. Each species showed an expected increase in yield as CO2 was elevated from 400 to 1000 μmol·mol-1, but super-elevating the CO2 to 10,000 μmol·mol-1 resulted in suboptimal growth. In addition, many radish leaves showed necrotic lesions at 10,000 μmol·mol-1 by 17 days and at 5000 μmol·mol-1 by 20 days. These results are consistent with preliminary tests in which radish cvs. Cherry Belle, Giant White Globe, and Early Scarlet Globe were grown for 16 days at 400, 1000, 5000, and 10,000 μmol·mol-1. In that study, `Giant White Globe' produced the greatest total dry mass at 1000 (3.0 g/plant) and 5000 μmol·mol-1 (3.0 g/plant), and the least at 10,000 μmol·mol-1 (2.2 g/plant). `Early Scarlet Globe' followed a similar trend, but `Cherry Belle' showed little difference among CO2 treatments. Results suggest that super-elevated CO2 can depress growth of some species, and that sensitivities can vary among genotypes.

213 Effects of Air Temperature and Carbon Dioxide Concentration on Growth of Radish

The RASTA (Radish Assimilation in Spaceflight Testbed Atmospheres) space flight experiment is being designed to evaluate effects of spacecraft environment on carbon partitioning in radish. Carbon dioxide concentration and air temperature effects on radish partitioning are being evaluated to optimize conditions on orbit. Determining effects of these stresses on growth will allow environmental stress effects to be isolated from microgravity effects during the mission. Three cultivars, Cherriette, Cherry Belle, and Early Scarlett Globe, have been grown at 23 °C at 400, 1500 and 10,000 ppm CO2 to determine effects of super-elevated CO2 on growth. Total biomass production was greatest at 1500 ppm CO2, with a decline at 10,000 ppm CO2. Harvest index of all cultivars was also highest at 1500 ppm. `Cherry Belle' and `Early Scarlet Globe' were grown at ambient CO2 under temperatures ranging from 18 to 30 °C. Total biomass production was greatest at 22 °C, with significant declines in total dry mass and harvest index with increasing temperatures. Temperatures less than 22 °C resulted in decrease in total biomass, but partitioning to storage roots was enhanced. (Supported by NASA NCC10-0034)

Evaluation of Southernpea Breeding Lines and Varietie for Earliness, Yield, and Maturity

Evaluation of new southernpea cultivars and advanced breeding lines for spring and fall cropping is important for both producers and processors of this crop in South Texas. The spring trial included three commercially available cultivars and 17 advanced breeding lines from the Univ. of Arkansas breeding program. Foliage color ratings taken in the spring correlate with similar ratings taken in 1995 and indicate that Arkansas 435-87-68 may be tolerant to high pH soils that caused yellowing in several other cultivars. The highest producing varieties, Arkansas 87-435-68 and Arkansas 92-552, produced net yields &gt; 1000 lb/acre. The fall trial included the same material as the spring trial plus four more commercially available cultivars. Maturity ratings taken in early October varied widely between cultivars and breeding lines. Recorded ratings represented growth stages ranging from cultivars with no flowering to those that had set pods that were filling. The most mature types included Arkansas breeding lines 96-593, 95-368, 96-556, and 95-301, which had maturity ratings of 3.8, 3.5, 3.5, and 3.3, respectively. Net yields varied widely among cultivars in the fall trial. Yields ranged from 23.8 to 522.8 lb/acre. Those with the highest net yields included 'Early Scarlet', Arkansas 91-285, Arkansas Blackeye #1, and Arkansas 95-368, with yields of 522.8,402.2, 401.2 and 400.5 pounds per acre, respectively. Although yields in the trial were considerably lower than expected, several cultivars produced 400 or more pounds of peas per acre compared to many commercial fields that were not harvested.

Effect of Silver Nitrate on In Vitro Regeneration of Cowpea (Vigna unguiculata) Cotyledon Explants

Cowpea (Vigna unguiculata L.) is an important grain legume that is grown extensively in Africa, South America, India, and in the United States. This study investigated the effects of silver nitrate (AgNO3) on regeneration of cowpea cotyledon explants. Silver nitrate at 50 μm significantly increased percent regeneration in comparison to the control. The effect of duration of exposure was also determined with the ethylene inhibitor AgNO3. By exposing explants to 59 μm AgNO3 during different stages of culture, significant increases were actualized in percent regeneration and shoot number. The greatest percent regeneration was obtained when 59 μm AgNO3 was augmented to both the initiation and regeneration media or to only the regeneration media. These results indicate that the low percentage of regeneration of this genotype may be related to ethylene biosynthesis or metabolism. This study resulted in an improved regeneration system for the commercial cowpea cultivar Early Scarlet, and will be useful in developing a cowpea transformation system.

`Excel', `Early Scarlet' and `Arkansas Blackeye #1': New Southernpea Varieties

Southernpea (Vigna unguiculata) is an important crop in the southern United States. The Arkansas Agricultural Experiment Station announces the release of three varieties. `Excel' produces a compact bush plant, from 45–60 cm tall with no basal runners. Pods are deep purple, 20–25 cm long and shell easily at the green mature stage. Flowering and fruiting are concentrated, with the pods produced at the top of the plant on medium-length peduncles. Seed has a bright pinkeye and is similar in size to pinkeye purple hull BVR but matures 3–4 days earlier. `Early Scarlet' produces a medium sized plant, from 60–75 cm tall with no basal runners. Pods are light red, 20–25 cm long and shell easily at the green mature stage. Flowering and fruiting are concentrated at the top of the plant with pods produced on medium-length peduncles. Seed has a light pinkeye and is similar in size to `Pinkeye Purple Hull BVR' but matures 2–3 days earlier. `Arkansas Blackeye #1' produces a bush plant, from 50–65 cm tall with no basal runners. The pods are silver, 20–25 cm long and shell easily. Flowering and fruiting are concentrated with the pods produced in the top of the plant on medium-length peduncles. Seed has a distinct medium-sized blackeye and the seed are very similar in size, type and eye pattern to `California #5 Blackeye'. Maturity is normally 2–3 days earlier than `Pinkeye Purple Hull BVR'.

Effect of Peat : Vermiculite Mixes Containing Trichoderma harzianum on Increased Growth Response of Radish

Abstract The effects of peat: vermiculite mixes on increased growth response of radish (Raphanus sativus L. ‘Early Scarlet Globe’) induced by Trichoderma harzianum Rifai (isolate T-12) were investigated. Canadian sphagnum peat and vermiculite were mixed in various ratios to form 0-100% peat mixes. Four levels of T-12 amendment were added to these mixes—0%, 2%, 5%, and 10% (v/v) or 0%, 0.1%, 1%, and 10%. In general, increasing levels of T-12 amendment induced linear increases in radish dry weights after 4 and 5 weeks. Greatest increases were seen in mixes containing 20% peat or 80% peat. The smallest increases were observed when T. harzianum was added to 0% peat or 100% peat mixes. There was no effect on the population densities of T-12 after it was introduced into the mixes. No Pythium spp. or root disease were detected in the mixes, suggesting that T. harzianum, a biological control agent, can increase plant growth independent of any detectable root pathogens.

NITRATE ACCUMULATION IN GREENHOUSE VEGETABLE CROPS

Four cultivars each of lettuce (Lactuca sativa L.), radish (Raphanus sativa L.) and spinach (Spinacia oleracea L.) were grown at three NH4NO3 levels (0, 14.7 and 29.4 g N/m2) in a muck soil as a commercial greenhouse crop under winter conditions (low light intensity and short photoperiod). Analysis of the tissues for NO3-N showed that all three vegetable crops contained high concentrations of NO3-N when grown under these conditions: radish highest, followed by lettuce, then spinach. Total N and NO3-N were increased by N fertilizer only in radish roots, and yield was promoted by the additional N only in lettuce. Lettuce cultivars Domineer and Korrekt contained significantly less NO3 than Grand Rapids or Noran and were higher yielding than the standard cultivar Grand Rapids. The NO3 content of radishes was extremely high, especially in the root of the white cultivar Icicle (1.68% NO3-N). Yield of roots from Icicle was not significantly different from Champion, Early Scarlet Globe and Red Boy, cultivars which did not contain as much NO3-N. Smooth-leaf spinach cultivar Northland was higher yielding with significantly less NO3 than savoyed cultivars America, Winter Bloomsdale or Savoy. High NO3 tissue concentrations can be reduced in these crops by growing cultivars that accumulate less NO3.

Experiments on carrot seed growing. (II)

1. The studies were undertaken in 1955 at Kurume to make a survey of the bolting period, the flowering period, the form of ramification, the yield and germination percentage of the carrot seed using twelve leading varieties which are cultivated commonly in Japan. 2. The varieties cultivated in the southern part of Japan (Yokono-sanzun, Nagasaki-gosun, Kuroda-gosun and Tohsoh) showed the earlier habit in bolting and flowering period, the larger yield and better germination of seeds than the northern varieties(Early Scarlet Horn, Senko-sanzun, Chanteney, Ogatagosun, Nakamura-senko-futo, Kokubu and Sone). In general, the seeds from the primary umbels showed the highest percentage in germination, the secondary umbels the second, and the tertiary umbels the lowest, respectively. A consideration may be taken into account from the facts mentioned above that, at Kurume, the later the flowering time the more incident to summer rainy season the fruiting time is and the severer fungus diseases and physiological domages are. 3. In Kintoki variety native at Kurume, the yield of seed is smaller and the percentage of germination is lower than in the other native varieties in southern Japan. It is considered that one reason for these results depends on the time for flowering and fruiting later than that in the others. 4. The form of ramification of carrot is differents in each group of varieties. The oriental varieties show a standing habit of ramification with strong main shoot, large diameter of the primary umbel, and poor lateral shoots. On the contrary, the occidental varieties have a spreading habit with well developed lateral shoots and the secondary umbels large in diameter. 5. In the oriental varieties, the amount of seeds collected from the primary umbels showed a high proportion to the total yield. While, it was low in the occidental varieties. 6. In order to facilitate the selection and make good quality of seeds, it is desirable to collect the seeds from the primary and the secondary umbels, which are earlier in flowering and large in diameter, and to cut off the tertiary umbels. 7. The bolting percentage was investigated in some strains of Sanzun and Gosun varieties sown at different times (Aug. and Nov., 1954, Mar. 1955). There was a trend that the early bolting strains have a higher bolting rate. 8. For the purpose of surveying the difference of bolting among the individual plants within one variety, the seeds collected from different plants bolted at different periods were sown in Aug. and Nov., 1954. Then, the bolting time and bolting percentage were observed next spring. From these experiments it was recognized that the progenies from early bolted plants showed an earlier bolting and a higher percentage of bolting.