Locations In Texas Research Articles

Registration of ‘Red River Runner’ Peanut

‘Red River Runner’ (Reg. No. CV‐116, PI 665474) peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) is a high‐oleic‐oil cultivar with the experimental designation TX994313 that was cooperatively developed and released by the USDA‐ARS, Texas AgriLife Research, and the Oklahoma Agricultural Experiment Station in 2011. Sustainable peanut production in the southwestern United States is driven by the availability of cultivars possessing high oleic fatty‐acid oil content, high yield, and superior grade. The objective of this work was to develop a high‐oleic peanut cultivar with acceptable yield and superior grade potential (near or above 70%) that would increase the peanut producer's profit per hectare. Red River Runner was selected from progenies derived from a three‐way cross between ‘Tamrun 96’, breeding line TX901639‐3, and ‘Sun‐Oleic 95R’ and cooperatively tested for several years. Red River Runner has an excellent yield and moderate tolerance to Sclerotinia blight (caused by Sclerotinia minor Jaggar). Red River Runner is similar to the existing high‐oleic runner cultivar ‘Tamrun OL07’ in many agronomic characteristics such as yield, seed size, and weight. However, Red River Runner was released because it consistently exhibits a higher grade potential than Tamrun OL07 in some locations in Texas (averaging 5.4 points higher) and in most locations in Oklahoma (averaging 4.6 points higher); therefore in those locations, production of Red River Runner will significantly increase the crop value per hectare for peanut growers.

Perennial Biomass Grasses and the Mason–Dixon Line: Comparative Productivity across Latitudes in the Southern Great Plains

Understanding latitudinal adaptation of switchgrass (Panicum virgatum L.) and Miscanthus (Miscanthus × giganteus J. M. Greef & Deuter ex Hodk. & Renvoize) to the southern Great Plains is key to maximizing productivity by matching each grass variety to its optimal production environment. The objectives of this study were: (1) to quantify latitudinal variation in production of representative upland switchgrass ecotypes (Blackwell, Cave-in-Rock, and Shawnee), lowland switchgrass ecotypes (Alamo, Kanlow), and Miscanthus in the southern half of the US Great Plains and (2) to investigate the environmental factors affecting yield variation. Leaf area and yield were measured on plots at 10 locations in Missouri, Arkansas, Oklahoma, and Texas. More cold winter days led to decreased subsequent Alamo switchgrass yields and increased subsequent upland switchgrass yields. More hot-growing season days led to decreased Kanlow and Miscanthus yields. Increased drought intensity also contributed to decreased Miscanthus yields. Alamo switchgrass had the greatest radiation use efficiency (RUE) with a mean of 4.3 g per megajoule intercepted PAR and water use efficiency (WUE) with a mean of 4.5 mg of dry weight per gram of water transpired. The representative RUE values for other varieties ranged from 67 to 80 % of Alamo’s RUE value and 67 to 87 % of Alamo’s WUE. These results will provide valuable inputs to process-based models to realistically simulate these important perennial grasses in this region and to assess the environmental impacts of production on water use and nutrient demands. In addition, it will also be useful for landowners and companies choosing the most productive perennial grasses for biofuel production.

Increasing Hard Winter Wheat Yield Potential via Synthetic Wheat: I. Path‐Coefficient Analysis of Yield and Its Components

ABSTRACTSynthetic hexaploid wheat, created from a cross between durum [Triticum turgidum L. (syn. Triticum durum Desf.)] and Aegilops tauschii Coss., is a good source of new genes for bread wheat (Triticum aestivum L.) improvement. The purpose of this research was to evaluate the potential and performance of synthetic wheat in Texas. Ten elite primary synthetics from the International Maize and Wheat Improvement Center (CIMMYT) were backcrossed to two Texas cultivars, TAM 111 and TAM 112. Populations were bulked and “modified bulked” to advance generations. Yield‐related agronomic traits were measured on the BCF4 and BCF5 populations across five Texas locations. Improvement was observed in South Texas and the Blacklands, which had more disease pressure and fewer intermittent dry spells than locations in the Texas Rolling and High Plains. Selected bulks were not superior to nonselected bulks. Head number per unit area had the highest correlation with yield. Similar to crosses with spring wheat, synthetics contributed to yield through an increase in seed weight. Synthetic populations that produced higher grain yield than both TAM 111 and TAM 112 maintained their large seed size and weight but had increased number of heads and grains per head. Poorer performance in environments with harsh winters could be because of a lack of winter‐hardiness in the primary synthetics. Improved yield could result from selecting for increased number of heads per unit area and grains per head in lines derived from these populations.

Genetic Diversity ofHepatozoonspp. in Coyotes from the South-Central United States

To better define the strains and species of Hepatozoon that infect coyotes in the south-central United States, whole blood and muscle samples were collected from 44 coyotes from 6 locations in Oklahoma and Texas. Samples were evaluated by a nested polymerase chain reaction (PCR) using primers amplifying a variable region of the apicomplexan 18S rRNA gene as well as histopathology (muscle only) for presence of tissue cysts. Hepatozoon spp. infections were identified in 79.5% (35/44) of coyotes tested including 27 of 44 (61.4%) whole blood samples and 17 of 44 (38.6%) muscle samples tested by PCR and 23 of 44 (52.3%) muscle samples evaluated by histological examination. Analysis revealed 19 distinct sequences comprising 3 major clusters of Hepatozoon spp., i.e., 1 most closely related to Hepatozoon americanum, another most closely related to Hepatozoon canis , and the third an intermediate between the 2 groups. The diversity of Hepatozoon spp. in wild canids appears greater than previously recognized and warrants further investigation.

Seasonal Population Dynamics of the Potato Psyllid (Hemiptera: Triozidae) and Its Associated Pathogen “<I>Candidatus</I> Liberibacter solanacearum” in Potatoes in the Southern Great Plains of North America

The potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), and its associated pathogen "Candidatus Liberibacter solanacearum" (Ca. L. solanacearum), the putative causal agent of zebra chip (ZC) disease in potatoes (Solanum tuberosum L.), were sampled in commercial potato fields and untreated control plots for 3 yr in multiple locations in Texas, Kansas, Nebraska, and Colorado. Populations of the potato psyllid varied across years and across potato growing regions. However, the percentage of potato psyllids infected with Ca. L. solanacearum although variable across years, was consistently highest in the Lower Rio Grande Valley of Texas (LRGV), the reported overwintering location for this pest. The numbers of Ca. L. solanacearum-infected psyllids collected on field traps and large nymphs counted on leaf samples were both positively correlated with the final percentage of ZC in tubers. In the LRGV, where vector and disease pressure is the highest, population levels of immature life stages of the psyllid and percentage of ZC differed greatly between commercial and untreated fields. These results show that the pest management program that was used can be effective at controlling development of the psyllid and ultimately reducing the incidence of ZC.

Effect of genotype and environment on flavonoid concentration and profile of black sorghum grains

In recent years, colored sorghum genotypes high in flavonoids have been developed. Flavonoid levels of eight black sorghum genotypes grown in four locations in Texas were evaluated to assess the relative genotype, environment and genotype × environment effects. Levels of total 3-deoxyanthocyanidins ranged from 292 μg/g to 499 μg/g and 251 μg/g to 804 μg/g across environments and genotypes, respectively. Total 3-deoxyanthocyanidins in sorghums from Halfway were low (178–694 μg/g) due to the reduction of their non-methoxylated forms. This reduction is likely due to significant grain weathering which was observed only at Halfway. In addition, flavanone and flavone levels were the lowest at Halfway with levels of 12 μg/g and 78 μg/g, respectively. For all flavonoids there was a genotype by environment interaction (p < 0.01) which suggests that environment had a different effect on flavonoid levels depending on the genotype. Color values L*, a* and b* did not correlate with flavonoid content. Due to genotype, environment and their interactions, sorghum breeders must evaluate these traits in multiple environments to identify genotypes with high and stable production of flavonoid compounds.

Environmental and Genotypic Variation of Capsaicinoid and Flavonoid Concentrations in Habanero (Capsicum chinense) Peppers

Habanero peppers have become increasingly popular in the United States for supplying unique flavors and high levels of pungency. As consumption of this product increases, development of improved cultivars with elevated phytochemicals will likely result in additional demand from consumers. This study evaluated fruit size, capsaicinoid, and flavonoid concentrations in six Habanero (Capsicum chinense) genotypes grown at three different Texas locations: College Station, Uvalde, and Weslaco. Five of these Habanero experimental hybrids (H1-red, H2-orange, H3-orange, H5-dark orange, and H6-yellow) were developed at Texas A&amp;M University with genetic improvement in numerous traits of interest, and Kukulkan F1 (Kuk-orange) was included as a commercial control. In general, H1-red had the largest fruits in these locations. Capsaicin and dihydrocapsaicin (DHC) concentrations were highest in Kuk-orange followed closely by H5-dark orange and were lowest in H6-yellow. Fruit at Weslaco was larger and contained more capsaicin and DHC than those produced in Uvalde or College Station. Although flavonoid contents were variable and low in all genotypes and locations, H3-orange showed the most stability for use in future crossing schemes to compete against Kuk-orange for this characteristic. Our results suggest that variation in phytochemicals in fruit tissue of Habanero genotypes can be exploited by selecting in an appropriate environment.

Geographic pattern of host‐associated differentiation in the cotton fleahopper, Pseudatomoscelis seriatus

AbstractHost‐associated differentiation (HAD) is the occurrence of genetically distinct, host‐associated lineages. Most of the cases of HAD in phytophagous insects have been documented in specialist insects inhabiting feral ecosystems or in generalist parthenogens in agroecosystems. Herein we report HAD in the cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae), a native, generalist, non‐parthenogenetic insect feeding on native wild hosts [horsemint, Monarda punctata L. (Lamiaceae) and woolly croton, Croton capitatus Michx. (Euphorbiaceae)] and on cotton [Gossypium hirsutum L. (Malvaceae)] in the USA. Examination of genome‐wide genetic variation with AFLP markers and Bayesian analyses of P. seriatus associated with three different host plant species at five locations in Texas revealed a geographic pattern of HAD. The geographic pattern of HAD corresponded with differences in precipitation among the locations studied. In three locations, two distinct lineages of P. seriatus were found in association with horsemint and cotton/woolly croton, whereas in two other locations, populations associated with the different host plants studied were panmictic. We suggest that precipitation differences among locations translate into heterogeneity in vegetation distribution, composition, and phenology, which altogether may contribute to the observed geographic pattern of HAD.

Peanut (Arachis hypogaea L.) Response to Lactofen at Various Postemergence Timings1

Abstract Field experiments were conducted at nine locations in Texas and Georgia in 2005 and 2006 to evaluate peanut tolerance to lactofen. Lactofen at 220 g ai/ha plus crop oil concentrate was applied to peanut at 6 leaf (lf), 6 lf followed by (fb) 15 days after the initial treatment (DAIT), 15 DAIT alone, 6 lf fb 30 DAIT, 30 DAIT alone, 6 lf fb 45 DAIT, 45 DAIT alone, 6 lf fb 60 DAIT, and 60 DAIT alone in weed-free plots. Lactofen caused visible leaf bronzing at all locations. Yield loss was observed when applications were made 45 DAIT, a timing that would correspond to plants in the R5 (beginning seed) to R6 (full seed) stage of growth. At all locations except the Texas High Plains, this application timing was within the 90 d preharvest interval. Growers who apply lactofen early in the peanut growing season to small weeds should have confidence that yields will not be negatively impacted despite dramatic above-ground injury symptoms; however, applications made later in the season, during seed fill, may adversely affect yield.

Castor (Ricinus communisL.) Tolerance to Postemergence Herbicides and Weed Control Efficacy

Potential US castor production is limited due to only one labeled herbicide (trifluralin). Field studies were conducted at two Texas locations during 2008 and 2009 to evaluate postemergence herbicides for castor tolerance and weed control efficacy. Clethodim and fluazifop-P-butyl caused no castor stunting while acifluorfen, bentazon, imazethapyr, and lactofen caused stunting which ranged from 5 to 46%. Imazapic and 2,4-DB caused the greatest stunting (44 to 99%) and resulted in castor yields of 0 to 45% of the untreated check. Acifluorfen, imazapic, imazethapyr, lactofen, and 2,4-DB controlled at least 80% smellmelon (Cucumis meloL. var. Dudaim Naud.) while clethodim and fluazifop-P-butyl controlled at least 98% Texas millet [Urochloa texana(Buckl.) R.Webster]. Imazapic and imazethapyr provided 57 to 75% Texas millet control. Results suggest that castor tolerance to the graminicides, clethodim, and fluazifop-P-butyl is high; however, castor injury and yield reductions with the postemergence applications of broadleaf herbicides suggest that these herbicides should not be used in castor production.

Distribution of the threatened lace hedgehog cactus (Echinocereus reichenbachii) under various climate change scenarios

Climate change predictions for the Great Plains region of North America include increased temperatures and changes to annual precipitation patterns. We used ecological niche modeling (Maxent) to assess how three climate change scenarios published by the Intergovernmental Panel on Climate Change might affect the distribution of the threatened lace hedgehog cactus (Echinocereus reichenbachii) by the 2050s and the 2080s. Under all scenarios investigated, the total land area of suitable habitat for the species increased relative to the current land area predicted as highly suitable by the model. However, under all scenarios, the center of the most suitable area for this species shifted by 160–604 km from the current location in northwest Texas, changing at a rate 20–75 km per decade. While the rate of dispersal in this species is not known, Echinocereus spp. seeds are typically spread by small mammals and it seems unlikely that this species will be able to disperse rapidly. Consequently, the range may initially contract during the coming century, especially in southern Texas where it is most imperiled and where the climate is predicted to become increasingly unsuitable. The current patchiness of distribution of the species suggests that microhabitat characteristics and limitations to dispersal might reduce its actual realized niche relative to the fundamental niche indicated by the models. In addition, land use for agriculture, grazing, and urbanization might further reduce the success of this species in a changing climate.

Triticum mosaic virus Isolates in the Southern Great Plains.

In 2006, a previously unknown wheat (Triticum aestivum) virus was discovered in Western Kansas and given the name Triticum mosaic virus (TriMV). TriMV has since been found in wheat samples isolated all across the Great Plains. Even though it can infect singularly, TriMV is mostly found with Wheat streak mosaic virus (WSMV) as a co-infection. The potential for TriMV to cause economic loss is significant, but very little is known about the virus. The objective of this study was to survey the TriMV population for genetic variation by nucleotide sequencing of isolates across a geographical region. A secondary objective was to characterize the WSMV isolates that are being co-transmitted with TriMV. Fourteen different TriMV isolations were taken from locations in Texas, Oklahoma, and Kansas, and the coat protein cDNA was sequenced. Thirteen nucleotide differences were found in the TriMV isolates, of which three induce amino acid changes. WSMV isolates had 65 nucleotide changes when compared to WSMV Sydney81. Our results indicate the TriMV virus population has minimal amounts of sequence variation and no singular WSMV genotype is specifically associated with TriMV co-infection. Based on the isolates analyzed, it appears that the field population of TriMV is very homogeneous.

Sesame (Sesamum indicumL.) Growth and Yield as Influenced by Preemergence Herbicides

Studies were conducted during the 2007 and 2008 growing seasons under weed-free conditions in South Texas and the High Plains region of Texas to evaluate preemergence herbicides for sesame tolerance. No reduction in sesame stand was noted with any herbicide at south Texas location; however, at the High Plains location, linuron at the 2X rate reduced stand counts 28 days after treatment (DAT) in 2007 and diuron reduced sesame stand 147 DAT in 2008 when compared with the untreated check. At the 1/2X rate all herbicides exhibited minimal stunting while at the 1X rate stunting was variable and varied between locations. At the 2X rate, all herbicides caused sesame stunting compared to the untreated check. No herbicide, with the exception of linuron at the 2X rate in 2008 at the High Plains location, reduced sesame yield when compared with the untreated check. Although some herbicide treatments resulted in sesame stunting, this did not result in any yield reductions and this can be attributed to the ability of the sesame plant to compensate for injury and/or reduced stands.

Registration of TAM 04WB‐33s Upland Cotton with Improved Fiber and Yarn Properties

TAM 04WB‐33s upland cotton (Gossypium hirsutum L.) germplasm line (Reg. No. GP‐940, PI 662041) was developed by the Cotton Improvement Laboratory, Department of Soil and Crop Sciences, Texas A&amp;M AgriLife Research and released in 2010 as part of an ongoing effort to create germplasm with combinations of improved fiber‐quality parameters, especially upper half mean length (UHML) and fiber bundle strength (FBS), that contribute to the production of improved yarn. TAM 04WB‐33s exhibited high volume instrument (HVI) UHML and FBS greater than the comparison cultivars when grown under irrigated culture at multiple locations in central and south Texas during 2007, 2008, and 2009. Limited yarn evaluation indicated that TAM 04WB‐33s produced 30‐count carded yarn that was 27% stronger and required 43% more force to break than either ‘DP 491’ or ‘FiberMax 832’. This germplasm line is competitive in all other fiber properties and in yield potential with current upland cotton cultivars adapted to central and south Texas.

Flavonoid composition of lemon-yellow sorghum genotypes

Flavonoid composition of lemon-yellow sorghums grown in two locations in Texas, USA was evaluated and compared with that of white and red sorghums using high performance liquid chromatography (HPLC-PDA). Sorghums from Lubbock were brighter in colour and had minimal weathering compared to those from College Station. Sorghums with red/purple secondary plant colour had the highest levels of 3-deoxyanthocyanidins (8–187μg/g) and their levels were highest in grains from College Station (39–187μg/g). Pericarp colour did not have any effect on 3-deoxyanthocyanidin levels (p>0.05). The tan plant lemon-yellow sorghum Tx2953 had the highest levels of flavones (268–362μg/g). Among the genotypes, lemon-yellow sorghums had the highest levels of flavanones (134–1780μg/g), which are located in the pericarp and their levels were increased in the grains with a bright yellow pericarp and minimal weathering. The high flavanone levels in lemon-yellow sorghums makes this sorghum genotype a good source of those compounds.

The Diabetes Symptom Self-Care Inventory: Development and Psychometric Testing with Mexican Americans

Context Type 2 diabetes is prevalent throughout the world. In previous studies of Mexican Americans with type 2 diabetes, 95%–97% of those sampled reported having symptoms they believe were caused by diabetes and most self-treated their symptoms. To more accurately capture Mexican Americans’ symptom prevalence and their self-treatments, the Diabetes Symptom Self-Care Inventory (DSSCI) was adapted from the Diabetes Self-Care Instrument. Objectives This article describes the modification process used to perfect the DSSCI for use in improving self-care among people with type 2 diabetes. Methods This instrumentation study used qualitative and quantitative methods. The study was completed in four phases that used focus groups, cognitive interviews, and survey administration. Four convenience samples were drawn from community-dwelling Mexican American adults, aged 25–75 years, with type 2 diabetes in an urban area and a rural location in Texas. Results Phase I: Seven focus groups ( n = 45) generated data for revising items. Phase II: Cognitive interviews with 16 participants were used to evaluate four revisions of the questionnaire. Phase III: Surveys were administered to 81 participants. Total number of symptoms on the DSSCI correlated with scores on the Centers for Epidemiological Studies-Depression scale ( r = 0.65, P < 0.001), Illness Perception Questionnaire-Revised Diabetes Symptom subscale ( r = 0.57, P < 0.001), and Audit of Diabetes-Dependent Quality of Life scale ( r = −0.42, P < 0.001). Minor revisions followed. Phase IV: Test-retest stability was demonstrated ( n = 44). Conclusion The DSSCI is a culturally relevant, sound measure of Mexican Americans’ diabetes symptoms and the actions they take to address them.

Effects of Applying Nitrogen on Yield of Introduced Perennial Summer Grass Cultivars in Oklahoma

Effects of Applying Nitrogen on Yield of Introduced Perennial Summer Grass Cultivars in Oklahoma

GROWTH AND WATER USE OF GARDEN ROSES IN TWO CLIMATES IN THE SOUTHWESTERN UNITED STATES

Roses are considered high water use plants although little is known about their quantitative water use in different climates. The objective of this study was to determine growth and water use of two cultivars of landscape roses in two locations in the Southwestern United States. Rosa L. 'WEKbepmey' [Strike It Rich™ (SIR)] and 'RADtko' [Double Knock Out® (DK)] were grown in 15.5 L containers in a substrate consisting of 60% compost and 40% soil to simulate a well amended garden soil. From July to November 2008 plants were grown in Tucson, Arizona (32°16'49 N 110°56'45 W) in a retractable roof greenhouse and in Overton, Texas (32°17'39 N 94°58'31 W) outdoors. DK was the larger of the two cultivars and produced 132 g shoot dry weight averaged over the two locations versus 92 g shoot dry weight for SIR after 16 weeks. Average shoot dry weight of roses in Arizona was 130 g and in Texas 92 g. The greater growth rate of plants in Tucson, Arizona, a semi-arid subtropical climate, is likely due to warmer temperatures in fall which supported continuous shoot mass increase until mid November, while the growth rate in Overton, Texas, a humid subtropical climate, was slower throughout the study. Reference evapotranspiration (ETo) was 30 to 120% greater at most sampling dates at the Arizona compared to the Texas location. Water use per plant was approximately two to three times greater in Arizona than in Texas and water use per leaf area followed this pattern. Water use of plants was significantly affected by climate, specifically temperature, but was not a direct function of local reference evapotranspiration.

Evaluation of Renewable Energy as a Source of Power for Desalination of Remote-Oilfield Brines

Summary A hybrid system of wind, solar, and diesel generators could provide an efficient alternative for powering water-desalination projects in remote-oilfield locations in Texas, USA. Disposal of produced water from oil and gas wells is a costly procedure for production companies, but water-to-oil production ratios exceed 10:1 (by volume) at many wellsites. Much of the petroleum produced in the United States and elsewhere is found in arid regions that could benefit greatly if the produced water could be purified sufficiently for agricultural, industrial, or potable use. Our previous research identified and validated treatment options capable of recovering a high proportion of fresh water from oilfield brine. In this paper, we extend the earlier research further by examining the possibility of using renewable energy to power the units in "off-the-power-grid" situations. A macro-driven spreadsheet was created to allow for quick and easy cost comparisons of renewable energy sources for a variety of scenarios. Using this tool, wind and solar costs were compared for cities in regions throughout Texas. The renewable energy resource showing the greatest potential was wind power, with the analysis showing that in windy regions such as the Texas Panhandle, wind-generated-power costs are lower than those associated with diesel-fuel generation.

Acculturative and neighborhood influences on subjective social status among Spanish-speaking Latino immigrant smokers.

Subjective social status (SSS) reflects an individual's perception of her/his relative position in the social hierarchy. However, little is known about culturally-relevant, multilevel predictors of low SSS among low socioeconomic status (SES), minority populations. The goal of this study was to identify individual- and neighborhood-level variables predicting SSS among 297 Spanish-speaking Latino immigrant smokers living in several locations in Texas, with an emphasis on the association of SSS with acculturative and socioeconomic variables. Participants were recruited and enrolled through the National Cancer Institute's Cancer Information Service from August 2002 to March 2004. Determinants of SSS were explored using a series of linear regressions. In analyses adjusting for demographics (including objective indicators of SES), speaking Spanish at home and work and living in economically disadvantaged neighborhoods, respectively, were associated with low SSS. However, in analyses including demographics, acculturation, and neighborhood characteristics, only income, education, and acculturation remained associated with SSS. Consistent with results from a previous study in the area (Franzini & Fernandez-Esquer, 2006), less acculturation predicted low SSS among immigrant Latino smokers. However, unlike previous research, these associations were maintained after controlling for SES. Results suggest that the density of less acculturated Latinos within economically deprived neighborhoods might account for the disappearance of neighborhood effects in the final model.