Louisiana Agricultural Experiment Station Research Articles

MACRONUTRIENT AND MICRONUTRIENT CONCENTRATIONS OF SEEDED BERMUDAGRASSES1

The development and utilization of seeded cultivars of bermudagrass [Cynodon dactylon (L.) Pers.] for use in turfgrass areas such as athletic fields and golf courses has increased in recent years. There is limited data concerning the fertility requirements and the resulting nutrient concentrations for these cultivars. A study was conducted to assess the nutrient content and turfgrass quality and color of 14 seeded bermudagrasses and one vegetative cultivar, “Tifway” [C. dactylon×C. transvaalensis Burtt-Davy]. Turfgrass plots were established in 1996, maintained at a height of 2.54 cm, and fertilized at the rate of 454 g N 93 m−2 month−1 from July through October of 1996 and April through October of 1997. All other macronutrients and micronutrients were applied in equal amounts to all cultivars. Turfgrass quality and color were taken monthly. Plant tissue samples were collected, dried, ground, and analyzed for both macronutrient and micronutrient content. The study was a randomized block design with three replications. There were cultivar differences for the concentrations of nitrogen (N) and phosphorus (P) in 1997, and all the cultivars were within the sufficiency range for these two nutrients both years. There were differences for calcium (Ca), magnesium (Mg), sulfur (S), and potassium (K) concentrations among cultivars in 1996 and 1997. Although there were differences among cultivars for micronutrient concentrations, the concentrations of certain micronutrients varied widely among cultivars. Turfgrass color and quality resulted in differences among cultivars for both years. *This work was supported by the Louisiana State University Agricultural Center, Louisiana Agricultural Experiment Station, Louisiana State University, Baton Rouge, LA.

Effects of Soil Type and Soil Chemical Composition on Nutrient Content of Annual Ryegrass for Beef and Dairy Cow Nutrition#

Annual ryegrass (Lolium multiflorum Lam.) is an important crop grown on approximately 1.1 million hectares in the southeastern United States. Used primarily for winter grazing, ryegrass has considerable yield variation among production areas, possibly due to differences in ryegrass response to the range of soil properties encountered in Louisiana. The objectives of this research were: (i) to evaluate variation in soil nutrient status among a range of soil series; and (ii) to compare yield, mineral uptake, and livestock nutritional value of annual ryegrass grown on these soils. Two replicated greenhouse studies were conducted to evaluate two cultivars of annual ryegrass, Gulf and Rio, grown in seven distinct soils collected from throughout Louisiana. Soils were unamended and received no additional fertilizer during the studies. Each study was harvested twice for yield and nutrient uptake determinations. Plant tissue samples were analyzed for potassium (K), calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), zinc (Zn), and copper (Cu) concentrations using atomic absorption spectrophotometry. There were no cultivar differences or cultivar by soil interactions for yield or nutrient uptake. Yield and nutrient uptake of K, Ca, and Mn, were affected by the soil used. None of the soils produced ryegrass with sufficient Ca to meet the requirements of a dairy cow (Bos taurus), even though several of the soils had adequate to high soil test levels of Ca. All of the soils produced ryegrass with adequate Mg for beef cows (B. taurus; Bos indicus), but only half provided adequate Mg for dairy cows. All soils produced forage that met the beef cow Zn requirement, but only six provided adequate Zn for dairy cattle. All soils produced ryegrass with enough Mn to meet the requirements of both beef and dairy cattle, but there were large variations among the forages grown on the seven soils. These results indicate that mineral supplementation for beef cattle fed ryegrass grown on these soils might not be essential, but mineral supplementation for dairy cattle would be necessary. #Approved for publication by the Director of the Louisiana Agricultural Experiment Station as manuscript no. 02‐09‐0176.

Registration of ‘LA422’ Wheat

Crop ScienceVolume 41, Issue 3 p. 926-926 Registrations of Cultivar Registration of ‘LA422’ Wheat S.A. Harrison, Corresponding Author S.A. Harrison sharrison@agctr.lsu.edu Dep. of Agronomy, Louisiana State University, Louisiana Agricultural Experiment Station, Baton Rouge, LA, 70803-2110Corresponding author (sharrison@agctr.lsu.edu)Search for more papers by this authorR.D. Barnett, R.D. Barnett North Florida Research and Education Center, Florida Agricultural Experiment Station, 30 Research Rd., Quincy, FLSearch for more papers by this authorP.L. Bruckner, P.L. Bruckner Dep. of Plant Sciences & Plant Pathology, Montana State Univ., Bozeman, MT, 59717Search for more papers by this authorH.J. Mascagni, H.J. Mascagni Dep. of Agronomy, Louisiana State University, Louisiana Agricultural Experiment Station, Baton Rouge, LA, 70803-2110Search for more papers by this authorS.H. Moore, S.H. Moore Dep. of Agronomy, Louisiana State University, Louisiana Agricultural Experiment Station, Baton Rouge, LA, 70803-2110Search for more papers by this author S.A. Harrison, Corresponding Author S.A. Harrison sharrison@agctr.lsu.edu Dep. of Agronomy, Louisiana State University, Louisiana Agricultural Experiment Station, Baton Rouge, LA, 70803-2110Corresponding author (sharrison@agctr.lsu.edu)Search for more papers by this authorR.D. Barnett, R.D. Barnett North Florida Research and Education Center, Florida Agricultural Experiment Station, 30 Research Rd., Quincy, FLSearch for more papers by this authorP.L. Bruckner, P.L. Bruckner Dep. of Plant Sciences & Plant Pathology, Montana State Univ., Bozeman, MT, 59717Search for more papers by this authorH.J. Mascagni, H.J. Mascagni Dep. of Agronomy, Louisiana State University, Louisiana Agricultural Experiment Station, Baton Rouge, LA, 70803-2110Search for more papers by this authorS.H. Moore, S.H. Moore Dep. of Agronomy, Louisiana State University, Louisiana Agricultural Experiment Station, Baton Rouge, LA, 70803-2110Search for more papers by this author First published: 01 May 2001 https://doi.org/10.2135/cropsci2001.413926x Approved for publication by the Director of the Louisiana Agricultural Experiment Station, Manuscript no. 00-09-0595. Research supported in part by the Louisiana Soybean and Feedgrain Research and Promotion Board. The authors acknowledge the significant contributions of the USDA-ARS Cereal Disease Laboratory, St. Paul, MN; the USDA-ARS Soft Wheat Quality Laboratory, Wooster, OH; and the USDA-ARS Crop Production and Pest Control Research Unit, West Lafayette, IN. Registration by CSSA. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume41, Issue3May–June 2001Pages 926-926 RelatedInformation

Phytoplankton Community Structure, Biomass, and Off‐flavor: Pond Size Relationships in Louisiana Catfish Ponds

Abstract.— Many aquaculture studies are conducted in relatively small research ponds and the results are then extrapolated to larger commercial ponds. Implicit in this research is the assumption that there is no relationship between pond size and phytoplankton composition. Study objectives were to assess phytoplankton composition and biomass by several methods in 17 channel catfish Ictalurus punctatus ponds at the Aqua‐culture Research Station, Louisiana Agricultural Experiment Station in Baton Rouge, Louisiana, USA. Pond size ranged from 0.04–0.60 ha. Sampling occurred weekly from 10 September – 1 October 1997. Water temperatures coincided with a transition from summer to fall‐winter conditions. Biomass was assessed by cell counts and quantification of photopigments. Concentrations of dissolved off‐flavor compounds (2‐methylisoborneol and geosmin) were assessed by gas chromatography/mass spectroscopy of water column samples. Cell count data showed differences in dominant species, biovolume, and diagnostic pigment signatures among ponds. The smaller ponds had more diverse phytoplankton composition compared to the larger ponds, whereas chlorophyll levels were nearly an order of magnitude lower in the smaller ponds. Ultraplanktonic (2–20 μm) unicellular cyanobacteria dominated the numerical counts on most sampling dates; however, biovolume transformations of cell count data reduced the dominance of this component relative to cryptophytes, diatoms, and filamentous cyanobacteria. Pigment and microscopic analyses were well correlated. Unialgal isolates of dominant taxa from these samples indicated the presence of at least five genera of off‐flavor producers in these ponds; these taxa included Anabaena, Aphanizomenon, Pseudanabaena, as well as two species of Oscillatoria. Care in extrapolating results from smaller‐sized research ponds to larger commercial ponds is warranted, as is the potential for taxa other than Oscillatoria and Anabaena in forming off‐flavor compounds.

SOIL ARSENIC EFFECTS ON CANOLA SEEDLING GROWTH AND ION UPTAKE1*

Elevated levels of arsenic (As) often found in soils used for cotton (Gossypium hirsutum L.) production may limit growth and yield of canola (Brassica napusL.). This study was conducted to i) determine how soil-applied As affected the shoot and root dry weights, root length density, As uptake and tissue concentration, and total water use of canola and ii) evaluate the influence of soil As on phosphorus (P) uptake by and tissue concentration of canola seedlings. An experiment was conducted in a controlled-climate chamber using three soils with histories of cotton production (Commerce silt loam, Rilla silt loam, and Sterlington silt loam) and three As application rates (0, 5, and 10 mg kg−1). Four 14-day-old canola seedlings were planted three in soils with histories of cotton production (Commerce silt loam, Rilla silt loam, and Sterlington silt loam) and three As application rates (0, 5, and 10 mg kg−1). Four 14-day-old canola seedlings were planted in 3-L pots containing 2.5 kg (oven-dry-weight basis) of each soil. After 14 days, whole plants were harvested. Shoot and root tissues were dried and analyzed for As and P. Arsenic uptake by seedlings grown in both the Commerce and Sterlington soils increased when 5 mg kg−1 As were added, but did not increase with further As addition. In the Rilla soil, As uptake did not change with As addition, possibly due to the lack of change in soil solution As with As addition. Arsenic tended to remain in the roots, rather than being translocated to the shoots. Arsenic addition had no effect on shoot and root dry weights, root length density, or total plant water use in any of the soils; however, As toxicity symptoms were evident on leaves of plants in all treatments where As had been applied. Phosphorus uptake by the canola seedlings tended to decrease as soil As increased, but P concentration in tissue was not affected. A decrease in shoot P: As ratios in plants grownin Commerce and Sterlington soils indicated competition between these ions. Results of this study suggest that canola could be adversely affected if grown on soils with a fresh As application. *Joint contribution from the Department of Plant and Soil Science, Mississippi Agriculture and Forestry Experiment Station, Mississippi State University, MS, and the Department of Agronomy, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, LA. Approved for publication as Journal Article no. J9400 of the Mississippi Agricultural and Forestry Experiment Station. Approved for publication by the Director of the Louisiana Agricultural Experiment Station as Journal Article no. 98–09–0522.

Influence of Urea Alone or Combined with Fish Meal and Solubles in Liquid Supplements on Performance of Grazing Cow-Calf Pairs11Approved by the director of Louisiana Agricultural Experiment Station as publication no. 00-11-0232.

<h2>Abstract</h2> Experiments were conducted for 84 d, beginning on July 1, with cow-calf pairs grazing summer grass to determine the effects of feeding molasses containing urea or urea, fish solubles, and fish meal on BW gains, milk production, and blood metabolites. The four treatments based on a 16% CP urea-molasses mixture were no supplement, 97.8% base mixture plus 2.2% urea for cows and calves, 80% base mixture plus 10% fish solubles and 10% fish meal for cows and calves, and the supplement with fish solubles and fish meal as a creep feed for calves. The mixture contained 23% CP as fed. In Exp. 1, 60 crossbred cows with Angus-sired calves were allotted according to sex and birth date to 12, 2-ha pastures. Three pastures each with five cow-calf pairs were assigned to each treatment. In Exp. 2, 48 Hereford X Brahman F₁ cows with Angus- or Belgian Blue-sired calves were allotted as in Exp. 1 to 24, 1-ha Alicia bermudagrass pastures. Three pastures with two cow-calf pairs were assigned to each treatment for each sire breed of calf. Cows were machine-milked, and jugular blood samples were collected initially and on d 28 and 56. Cows and calves were weighed, and cows were condition-scored after a 16-h shrink at the beginning and end of both experiments. Both supplements were consumed at similar levels (1.75 kg/d) by cow-calf pairs in both experiments. Cows in Exp. 1 and calves in both experiments gained more (P<0.05) BW when cow-calf pairs had access to the supplement containing fish solubles and fish meal. Milk yield was numerically higher on d 28 (P<0.18) and d 56 (P<0.11) when cows received fish solubles and fish meal in the supplement. The decline in milk yield from initial milking tended to be less (P<0.10) on d 28 and was less (P<0.05) on d 56 when cows received this supplement. Plasma ammonia N concentrations were higher (P<0.05) when cows were fed supplement containing only urea, and both supplements increased (P<0.05) plasma urea N when compared with no supplement. Supplements containing molasses, urea, fish solubles, and fish meal appear beneficial for cow-calf pairs grazing summer forage.

Effects of Dietary Acetate and Propionate on Nutrient Digestibility, Ruminal Characteristics, and Performance by Steers Fed Diets Containing All-Concentrate or 20% Roughage11Approved by the director of Louisiana Agricultural Experiment Station as publication no. 99-11-0242.

<h2>Abstract</h2> Four experiments were conducted to evaluate the effects of dietary volatile fatty acids (VFA) on nutrient digestibility, ruminal characteristics, and growth performance by finishing steers. Diets were based on sorghum grain in Exp. 1 and 2, and corn in Exp. 3 and 4. Experiment 1 was a digestibility study with eight steers used in two 4 x 4 latin square arrangements of steers and diets. Diets in the first square were all-concentrate (C) with 1 or 2% acetate (A) or 2% propionate (P), and diets in the second square were 20% rice straw (RS) with 1 or 2% A or 2% P. In Exp. 2, steers (four per treatment) were individually fed C or RS basal diets with 1.72% A or 5.00% P added to the C diet, and 1.14% A or 3.33% P added to the RS diet based on expected intake. In Exp. 3 and 4, C diets were diluted with 1.65 or 0.55% A, respectively. These diets were further diluted with 20% rice hulls (RH) in Exp. 3, and 20% RH and 20% RS in Exp. 4. The C diet was also diluted with 20% RS in Exp. 3 and considered a positive control. Adding A, P, or RS to C diet based on sorghum grain had no effect (P>0.10) on energy digestibility or N retention. In Exp. 2, P reduced (P<0.05) DMI and ADG, compared with A. Acetate improved (P<0.05) DMI of C and RH diet in Exp. 3, but only the RH diet in Exp. 4. Likewise ADG and, in most cases, carcass weights were improved (P<0.05) by A in C and RH diets, but not in RS diets. Dietary P reduced (P<0.05) ruminal acetate levels and increased (P<0.05) ruminal propionate in Exp. 2. Acetate may have potential to improve DMI and ADG of steers consuming diets containing all-concentrate or poorly digestible roughage.

Enzymatically Digested Animal Protein as a Source of Protein for Weanling Pigs121Approved for publication by the director of the Louisiana Agricultural Experiment Station as manuscript no. 99-11-0594.2The authors acknowledge Griffin Industries, Cold Spring, KY, for financial support for this research.

<h2>Abstract</h2> Three experiments were conducted to evaluate the use of an enzymatically digested animal protein (EDAP) as a source of protein for weanling pigs. In each experiment, treatments were replicated with four (Experiments 1 and 2) or seven (Experiment 3) pens of three to five pigs each. Each experiment lasted 3 to 4 wk for the combined Phase I (1.5% Lys in Experiments 1 and 2, 1.6% Lys in Experiment 3) and Phase II (1.3% Lys) periods. In Experiments 1 (6.7 kg; 23 d of age) and 2 (6.1 kg; 22 d of age), pigs were fed one of the following Phase I diets: 1) basal (B) diet containing corn, soybean meal (SBM), whey, fish meal, and blood cells (AP-301 G; American Protein Corporation, Ames, IA); 2) B+4% spray-dried animal plasma (SDAP); or 3) B+2% SDAP + 2% EDAP (SDAP + EDAP). In Phase II, the dietary groups from Phase I were divided into two subsequent groups. One group received a diet containing corn, SBM, whey, fish meal, and 2% blood cells, and the second group received the same diet with 2% EDAP, resulting in six treatments for Phase II and overall periods. In Experiment 1, ADG and ADFI were increased (P<0.10) during Phase I for pigs fed SDAP + EDAP, and ADFI was increased (P<0.10) in pigs fed SDAP. In Phase II, the EDAP addition did not affect (P>0.10) ADG, ADFI, or the ratio of gain to feed. Also, Phase I diets did not affect (P>0.10) growth performance during Phase II. Overall, ADG (P<0.10) and ADFI (P<0.04) were increased (P<0.10) in pigs fed SDAP + EDAP during Phase I. In Experiment 2, ADG and the ratio of gain to feed were increased (P<0.10) in pigs fed SDAP + EDAP during Phase I. During Phase II, ADFI was increased in pigs fed SDAP + EDAP or B+SDAP (P<0.01) relative to those fed B only (P<0.003) in Phase I. Also in Phase II, the ratio of gain to feed was increased in pigs fed SDAP + EDAP (P<0.03) relative to those fed B+SDAP. Overall, ADG and the ratio of gain to feed were not affected (P>0.10) by diet, but ADFI was increased (P<0.03) in pigs fed SDAP + EDAP relative to those fed B. In Experiment 3, all pigs (5.7 kg; 17 d of age) were fed a common Phase I diet containing SDAP + EDAP. In Phase II, ADG, ADFI, and the ratio of gain to feed were not affected (P>0.10) by the addition of 2% EDAP or 2% blood cells. In summary, pigs fed SDAP + EDAP perform equally well compared with those fed B+SDAP.

Registration of ‘Cocodrie’ Rice

Crop ScienceVolume 40, Issue 1 p. 294-294 Registration of Cultivar Registration of ‘Cocodrie’ Rice S.D. Linscombe, Corresponding Author S.D. Linscombe slinscombe@agctr.lsu.edu Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Corresponding author (slinscombe@agctr.lsu.edu).Search for more papers by this authorF. Jodari, F. Jodari Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorP. K. Bollich, P. K. Bollich Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorD.E. Groth, D.E. Groth Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorL.M. White, L.M. White Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorQ.R. Chu, Q.R. Chu Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorR.T. Dunand, R.T. Dunand Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorD.E. Sanders, D.E. Sanders Louisiana Coop. Ext. Serv., P.O. Box 25100, Baton Rouge, LA, 70894-5100Search for more papers by this author S.D. Linscombe, Corresponding Author S.D. Linscombe slinscombe@agctr.lsu.edu Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Corresponding author (slinscombe@agctr.lsu.edu).Search for more papers by this authorF. Jodari, F. Jodari Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorP. K. Bollich, P. K. Bollich Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorD.E. Groth, D.E. Groth Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorL.M. White, L.M. White Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorQ.R. Chu, Q.R. Chu Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorR.T. Dunand, R.T. Dunand Rice Res. Stn, P.O. Box 1429, Crowley, LA, 70527-1429Search for more papers by this authorD.E. Sanders, D.E. Sanders Louisiana Coop. Ext. Serv., P.O. Box 25100, Baton Rouge, LA, 70894-5100Search for more papers by this author First published: 01 January 2000 https://doi.org/10.2135/cropsci2000.0007rcvCitations: 68 Approved for publication by the Director of the Louisiana Agricultural Experiment Station, Manuscript no. 98-86-0543. Research supported in part by the Louisiana Rice Research Board. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume40, Issue1January–February 2000Pages 294-294 RelatedInformation

036 `Quickpick': A New, Fresh-market Southernpea Suitable for Machine Harvest

The Louisiana Agricultural Experiment Station has released a new pinkeye purple hull-type southernpea cultivar for the fresh market. The new cultivar, Quickpick, originated from a cross between breeding lines LA 88-74 and LA 88-9. `Quickpick' has a bush-type plant habit with synchronous pod set and is suitable for either machine- or hand-harvest. Pods of `Quickpick' are straight, ≈20 cm long, and about 8 mm in diameter. Fresh peas are green with a light-pink eye. Yield of `Quickpick' equaled or surpassed yield of `Texas Pinkeye Purple Hull' in machine-harvested replicated tests. In hand-harvested replicated tests, yield of `Quickpick' was comparable to `Texas Pinkeye Purple Hull', `Coronet', `Pinkeye Purple Hull-BVR', `Mississippi Pinkeye', and `Santee Early Pinkeye'. `Quickpick' is immune to a Georgia isolate of blackeye cowpea mosaic virus, a major virus of southernpea in the United States.

GROWTH CHARACTERISTICS OF `BEAUREGARD' AND `DARBY' SWEETPOTATO

`Beauregard' and `Darby' sweetpotato cultivars were developed and released by the Louisiana Agricultural Experiment Station in 1987 and 1994, respectively. In total acreage, `Beauregard' is the dominant cultivar of sweetpotato grown in Louisiana and the remaining United States. However, very little is known about the growth characteristics of these two cultivars. Therefore, the objectives of this research were to examine storage root and shoot growth. Uniform transplants of both cultivars were transplanted in mid-July 1995 at the LSU Sweet Potato Research Station and sequentially harvested biweekly. Optimum leaf area of both cultivars was attained ≈60 days after transplanting. `Beauregard' had less leaf area than `Darby' at each stage of development, but partitioned more assimilates to the storage roots. At harvest, the harvest index of `Beauregard' was ≈75% compared with 50% for `Darby'. `Beauregard' had a significantly greater total yield of storage roots than `Darby'.

HIGH-SPEED CULTIVATION OF VEGETABLE CROPS WITH FINGER-WHEEL CULTIVATORS

The Precision Cultural System (PCS) developed by the Louisiana Agricultural Experiment Station allows simple and precise cultivation of vegetable crops; however, speed of the cultivators in small vegetable crops has been limited. The standard PCS sweep cultivator was limited to about 1.6–2.4 km·h–1 in small crops because it would throw soil over the crop plants at higher speed. The standard PCS rotary tiller cultivator could operate at 3.2–4.8 km·h–1 in small crops but could not be operated faster in larger crops, due to its tendency to “walk” out of the soil at higher speeds. The standard PCS sweep cultivator was modified by replacing the sweeps between the twin drills with two pairs of straight finger-wheel (“rolling cultivator”) spiders non-angled and in tandem. The finger-wheel gangs on the bed sides were also inactivated by raising them above the soil. The resulting PCS cultivator was successfully operated in very small crop plants (≤25 mm high) at speeds of 8–10 km·h–1 with no crop damage. The cultivator could then be easily refitted for standard sweep cultivation on subsequent passes. No reductions in weed control or yield of mustard, kale, turnip, or spinach were noted when using the high-speed system.

L 86-33 Sweetpotato Germplasm

Received for publication 24 May 1993. Accepted forpublication19Nov.1993. Approved forpublication by the Director of the Louisiana Agricultural Experiment Station as manuscript no. 93-28-7123. Supported by state and matching funds allocated to the Louisiana State Univ. Agricultural Center and the Louisiana Sweet Potato Advertising and Development Commission. The cost of publishing this paper was defrayed in part by the payment of page charges.Under postal regulations, this paper thereforemustbehereby marked advertisement solely to indicatethisfact. lProfessor,Dept. of Entomology. 2AssistantProfessor,Dept.ofHorticulture,towhom reprintrequests should be addressed. 3ResidentDirector,SweetPotato Research Station, P.O. Box 120, Chase, LA 71324. 4Professor,Dept.ofPlantPathologyandCropPhysiology. 5Specialist (Horticulture), Louisiana Cooperative Extension Service. 6AssociateProfessor,Dept.of Horticulture.

A Simplified Turfgrass Height-measuring Device

A simplified design for measuring the height of turfgrass (or forage) was developed and used by the Louisiana Agricultural Experiment Station (LAES). The device is similar to the common “disc meter” devices used for turfgrass and forage height measurement, but it uses a constant-force spring to simplify construction and operation. Use-of a constant-force spring allows a steady operating force on the sliding member of the device and eliminates the need for machining slots, thus greatly simplifying construction and reducing cost. The simplified device has worked well in the turfgrass research program of the LAES.

Repeatability of Stability Estimators for Grain Yield in Wheat

Stability statistics that are used to explain genotypic response to environments are not useful to plant breeders unless they are repeatable across sets of environments. The purpose of this study was to examine the repeatability of the stability estimators: regression coefficient (b1), regression coefficient away from mean regression (|b1 − 1|), mean squares for deviation from regression (Sd2i), Shukla's stability variance (σ2i), variance of genotypic means (S2i), and genotypic coefficient of variation (CVi), in addition to coefficient of determination (r2i) and mean yield (X̄i). These statistics were calculated from three sets of yield data of the Louisiana Agricultural Experiment Station winter wheat (Triticum aestivum L.) performance trials grown in 36 environments. Repeatability was estimated by Spearman's rank‐correlation coefficient and Kendall's coefficient of concordance. The |bi — 1|, σ2i, and Sd2i were not repeatable between any two subsets of environments, and repeatability of S2i and r2i s were low. Among the stability estimators, only bi and CVi were repeatable across subsets of environments. The CVi was not a reliable statistic to describe genotypic stability because the rank order of CVi was induced by the rank order of X̄.i Mean yield was the most repeatable genotypic character. Gain in selection for yield stability can be expected from the combined use of bi and X̄i. If data do not fit the linear regression model, then low values of S2i (Type 1) or Type‐4‐variance (variance of genotypic means across unpredictable environments averaged across predictable environments) may be used as an alternative criterion for yield stability.

Comparison of EPIC-WT and DRAINMOD Simulated Performance of Land Drainage Systems

Data from the Louisiana Agricultural Experiment Station Ben Hur Research Farm were used to compare the performance of EPIC-WT and DRAINMOD models in simulating the effect of subsurface drainage systems on surface and subsurface drained volumes and the fluctuations of field watertable depth. Both models overestimated the total cumulative drainage flows for the simulation period (1981-1987). The long-term cumulative values simulated by DRAINMOD and EPIC-WT were 7% and 32% greater than those observed for surface drainage volumes, and 34% and 20% greater than the observed volumes for subsurface drainage. The slope and correlation coefficients of the regression lines associated with EPIC-WT monthly flows were 0.86 and 0.85 for the surface volumes, and 0.98 and 0.92 for the subsurface volumes. The regression equation describing the linear relationships between the monthly observed flows and the flows predicted by DRAINMOD had slope and correlation coefficients of 0.95 and 0.90 for surface volumes, and 1.02 and 0.77 for subsurface volumes. The watertable fluctuations were predicted better by DRAINMOD than EPIC-WT during relatively dry periods when the watertable depth was below the root zone; however, the overall performances of the two models in simulating the watertable fluctuations over the seven-year period were about the same.

LHT24 Heat-tolerant Tomato Breeding Line

Received for publication 16 Dec. 1991. Accepted for publication 30 June 1992. Approved for publication by the Director of the Louisiana Agricultural Experiment Station as manuscript no. 91-825524. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact. 1Red River Research Station. 2Citrus Research Station. 3Dept. of Plant Pathology and Crop Physiology.

A New SAS Program for Calculating Stability– Variance Parameters

Journal Article A New SAS Program for Calculating Stability– Variance Parameters Get access M. S. Kang M. S. Kang Department of Agronomy, Louisiana State University Agricultural CenterBaton Rouge Address reprint requests to Dr. Kang, Associate Professor, Department of Agronomy, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, LA 70803-2110 Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Heredity, Volume 80, Issue 5, September 1989, Page 415, https://doi.org/10.1093/oxfordjournals.jhered.a110889 Published: 01 September 1989

Technical Notes: Experimental Verification of the Effect of Collection Pan Width on Apparent Spreader Pattern

A theoretical study of the relationship between collection pan width and apparent spreader pattern was published in the Netherlands. The mathematical relationship developed in that study has been compared to the results of an extensive experimental study on the relationship between collection pans and apparent spreader patterns conducted at the Louisiana Agricultural Experiment Station. The experimental data verify the theoretical relationship, and conversely, the theoretical relationship provides a useful explanation of the apparent pattern differences noted in the experimental study.

Alfalfa Weevil Control, 1988

Abstract Alfalfa Weevil Control, 1988: Nonirrigated alfalfa, 10 inches tall, was sprayed 14 Apr. Insecticides were applied in water (20 gal/acre) with I a CO2-powered backpack sprayer. The sprayer boom was equipped with 70° hollow-cone nozzles positioned to deliver a broadcast spray pattern. Mean wind speed was 7 mph. A randomized complete block design with 4 replicates was used. Plots measured 20 by 20 ft with unsprayed alleys separating adjacent plots. Eight stems were collected from undisturbed areas within each plot on each sample date. Samples from each plot were individually bagged, returned [ to the laboratory, and frozen. Samples were later thawed and examined under magnification for AW larvae. Pretreatment counts were taken and sampling I was repeated at 1, 4, 6, 8, 11, 15, and 21 DAT. J. B. Graves, A. M. Pavloff, and B. E. Leonard Department of Entomology Louisiana Agricultural Experiment Station Louisiana State University Agricultural Center Baton Rouge, LA 70803 (504) 388-1634