About

Larry Stein, Ph.D., is a professor and Extension Horticulturist at Texas A&M University. He received his B.S. in Horticulture from Texas A&M University in 1979, followed by an M.S. in 1981 and a Ph.D. in 1985 in Horticulture from the same institution. Stein was appointed as an Extension Horticulturist at the Texas A&M Research and Extension Center in Stephenville in 1985, where he worked on pecans, fruit crops, and vegetables. In 1992, he transferred to the Research and Extension Center in Uvalde to continue his work in these areas and was promoted to Professor. His research focuses on production horticulture, developing best management practices for pecans, fruits, and vegetable crops. He has authored numerous Extension publications, is a co-author of the Texas Peach Handbook, and an editor of the Texas Pecan Handbook. Additionally, he assisted with the release of a new table grape, ‘Victoria Red’, and two bluebonnets, ‘Texas Maroon’ and ‘Ladybird Johnson Royal Blue’.

Research topics

• Botany
• Biology
• Horticulture
• Genetics
• Biotechnology

Selected publications

• Legacy effect of non‐native <scp> <i>Eucalyptus</i> </scp> trees on the regeneration of coastal plant communities

  Restoration Ecology · 2025-10-28

  articleOpen access

  Abstract Introduction When the elimination of a non‐native plant is insufficient to promote the regeneration of indigenous vegetation, secondary interventions, such as the removal of non‐native plant litter, may be appropriate due to legacy effects. Eucalyptus species are known to create legacy effects following control due to litter accumulation, which hinders seed germination and the establishment of native species. Objective We experimentally assessed the potential for natural regeneration after the elimination of planted non‐native Eucalyptus trees on coastal dunes in Southern Brazil, taking into consideration the legacy effect of Eucalyptus litter. Methods We compared richness, diversity, and cover of native species in three conditions: (1) Reference: native vegetation without Eucalyptus ; (2) With Litter (WL): Eucalyptus trees eliminated, litter not removed; and (3) No Litter (NL): Eucalyptus trees eliminated, litter removed. All data were collected in November 2022, April 2023, and October 2023. Results Species richness and vegetation cover were consistently higher in the Reference condition throughout all sampling months compared to the WL and NL conditions. Native species richness was higher in the NL condition, while vegetation cover increased faster compared with the WL condition. Species composition differed between NL and WL areas, with NL changing more rapidly over time compared to WL. In the last month of sampling, higher similarity of species composition was observed in conditions NL and WL. Conclusions The establishment of native species is facilitated once Eucalyptus litter is removed, with faster gains in species richness and vegetation cover.

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• Effect of Warm Temperature Interruption on the Accumulation of Winter Chilling in Kiwifruit (Actinidia chinensis Planch. and A. deliciosa A. Chev.)

  HortScience · 2024-04-22 · 4 citations

  articleOpen access

  Warm temperature exposure during winter has reportedly resulted in the apparent negation of chilling in several fruit species. This study was conducted to investigate the floral and vegetative response of two pistillate kiwifruit cultivars to intermittent warm temperature interruption during chilling accumulation. Dormant 1-year-old canes of Actinidia chinensis ‘AU Golden Dragon’ and Actinidia deliciosa ‘AU Fitzgerald’ were collected in December 2018 and 2019 (334 and 360 chilling units, respectively), shortly after leaf abscission. Canes were cut to 10 nodes after removing the first six basal nodes, placed in jars filled with distilled water, and transferred to respective chilling treatments. Treatments included continuous chilling (CC) (in addition to base chilling) at 1-week (168 chilling units) increments (0–5 weeks) and chilling exposure at the same increments with intermittent warm temperature (WT). For the WT treatments, each week of chilling was followed by 3 days of exposure to warm conditions. Chilling and warm temperature exposure were simulated by 7/4 °C and 25/17.2 °C (day/night) air temperatures, respectively, using separate climate-controlled growth chambers. After treatments, canes were forced in a third chamber at 21.1 to 25.0 °C with light-emitting diode lighting. Vegetative budbreak, floral bud number (from here on defined as floral response), and floral development stage were recorded for each cane at 2-day intervals. For ‘AU Golden Dragon’, WT did not result in any reduced floral response at any of the observed chilling levels. However, lower mean floral response was observed with WT, as compared with CC for ‘AU Fitzgerald’ at 5 weeks of chilling over the 2 years ( P = 0.05). WT also lessened the effect of apical dominance with respect to vegetative/floral response to node position for both cultivars. Chilling type had no significant effect on vegetative response in either cultivar. Estimated chilling requirements (CC) in this experiment were similar to those reported previously for these cultivars. Results suggest that A. chinensis cultivars may respond more favorably than A. deliciosa to the erratic winter temperature patterns experienced in the southeastern United States.

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• Phenotypic diversity and population structure of Pecan (Carya illinoinensis) collections reveals geographic patterns

  Scientific Reports · 2024-08-10 · 11 citations

  articleOpen access

  Pecan (Carya illinoinensis) is an economically important nut crop known for its genetic diversity and adaptability to various climates. Understanding the growth variability, phenological traits, and population structure of pecan populations is crucial for breeding programs and conservation. In this study, plant growth and phenological traits were evaluated over three consecutive seasons (2015-2017) for 550 genotypes from 26 provenances. Significant variations in plant height, stem diameter, and budbreak were observed among provenances, with Southern provenances exhibiting faster growth and earlier budbreak compared to Northern provenances. Population structure analysis using SNP markers revealed eight distinct subpopulations, reflecting genetic differentiation among provenances. Notably, Southern Mexico collections formed two separate clusters, while Western collections, such as 'Allen 3', 'Allen 4', and 'Riverside', were distinguished from others. 'Burkett' and 'Apache' were grouped together due to their shared maternal parentage. Principal component analysis and phylogenetic tree analysis further supported subpopulation differentiation. Genetic differentiation among the 26 populations was evident, with six clusters highly in agreement with the subpopulations identified by STRUCTURE and fastSTRUCTURE. Principal components analysis (PCA) revealed distinct groups, corresponding to subpopulations identified by genetic analysis. Discriminant analysis of PCA (DAPC) based on provenance origin further supported the genetic structure, with clear separation of provenances into distinct clusters. These findings provide valuable insights into the genetic diversity and growth patterns of pecan populations. Understanding the genetic basis of phenological traits and population structure is essential for selecting superior cultivars adapted to diverse environments. The identified subpopulations can guide breeding efforts to develop resilient rootstocks and contribute to the sustainable management of pecan genetic resources. Overall, this study enhances our understanding of pecan genetic diversity and informs conservation and breeding strategies for the long-term viability of pecan cultivation.

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• Evaluation of Spinach Cultivars for Resistance to Stemphylium Leaf Spot (Stemphylium vesicarium) and White Rust (Albugo occidentalis)

  HortScience · 2023-12-15 · 4 citations

  articleOpen access

  Stemphylium leaf spot, caused by Stemphylium vesicarium , and white rust, caused by Albugo occidentalis , can cause significant losses in spinach production. Management of these foliar diseases of spinach has become increasingly challenging with the development of fungicide resistance in some pathogen populations, high planting density and overhead irrigation used for baby leaf spinach production, and the fact that &gt;60% of fresh market spinach production in the United States is certified organic. To identify spinach cultivars with resistance to Stemphylium leaf spot and white rust, a field trial was performed near Crystal City, TX, USA, in 2021 (79 cultivars), 2022 (87 cultivars), and 2023 (63 cultivars). Each year, the plants were inoculated with S. vesicarium and rated for disease severity. Plants were also rated for white rust severity that resulted from natural infection during the 2021 and the 2022 trials. During each trial, 11% to 27% of the cultivars were identified as resistant to Stemphylium leaf spot, and another 29% to 48% had moderately resistant reactions. In contrast, only 5 of 79 cultivars (6%) in the 2021 trial did not develop symptoms of white rust, and all 87 cultivars evaluated in the 2022 trial had symptoms of white rust. Although there was no significant correlation between mean Stemphylium leaf spot ratings and mean white rust ratings during these trials, the cultivars Colusa, Kodiak, PV-1569, and PV-1664 displayed resistant or moderately resistant responses to both diseases in at least two trials. Therefore, processing and fresh market spinach growers have resistant cultivars from which to select to reduce the economic impacts of Stemphylium leaf spot and white rust.

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• Southern Sensation™ Seedless Grape (cv. ‘A-1400’)

  HortScience · 2022-01-20

  articleOpen access
  PublisherOA PDFDOI

• Genome-wide association study and genomic prediction of white rust resistance in USDA GRIN spinach germplasm

  Horticulture Research · 2022 · 40 citations

  • Biology
  • Genetics
  • Biotechnology

  ) in some major commercial production areas, particularly in southern Texas in the United States. The use of host resistance is the most economical and environment-friendly approach to managing white rust in spinach production. The objectives of this study were to conduct a genome-wide associating study (GWAS), to identify single nucleotide polymorphism (SNP) markers associated with white rust resistance in spinach, and to perform genomic prediction (GP) to estimate the prediction accuracy (PA). A GWAS panel of 346 USDA (US Dept. of Agriculture) germplasm accessions was phenotyped for white rust resistance under field conditions and GWAS was performed using 13 235 whole-genome resequencing (WGR) generated SNPs. Nine SNPs, chr2_53 049 132, chr3_58 479 501, chr3_95 114 909, chr4_9 176 069, chr4_17 807 168, chr4_83 938 338, chr4_87 601 768, chr6_1 877 096, and chr6_31 287 118, located on chromosomes 2, 3, 4, and 6 were associated with white rust resistance in this GWAS panel. Four scenarios were tested for PA using Pearson's correlation coefficient (r) between the genomic estimation breeding value (GEBV) and the observed values: (1) different ratios between the training set and testing set (fold), (2) different GP models, (3) different SNP numbers in three different SNP sets, and (4) the use of GWAS-derived significant SNP markers. The results indicated that a 2- to 10-fold difference in the various GP models had similar, although not identical, averaged r values in each SNP set; using GWAS-derived significant SNP markers would increase PA with a high r-value up to 0.84. The SNP markers and the high PA can provide valuable information for breeders to improve spinach by marker-assisted selection (MAS) and genomic selection (GS).

  PublisherDOI

• Young Field-grown Kiwifruit Plants’ Response to Early Autumn Frost Injury in Texas

  HortTechnology · 2020-12-16 · 2 citations

  articleOpen access

  Two-year-old, field-grown golden kiwifruit ( Actinidia chinensis ) and fuzzy kiwifruit ( Actinidia deliciosa ) plants were evaluated for injury following an early freeze event of −4.1 °C on 14 Nov. 2018 in Burleson County, TX. Plant material included seven cultivars: one seed-propagated [Sungold™ (ZESY002)] and three cutting-propagated golden kiwifruit (AU Golden Dragon, AU Golden Sunshine, CK03), and one seed-propagated (Hayward) and two cutting-propagated fuzzy kiwifruit (AU Authur and AU Fitzgerald). Observations were made 5 weeks after the frost event. Base trunk diameter (BD) and maximum trunk diameter damaged (MDD) provided a reference of plant size and crude measurement of damage intensity, as evident by presence of water-soaked necrotic and/or dehydrated tissue following the removal of a thin slice of periderm, vascular cambium, phloem, and xylem. Percent of base diameter damaged (PBDD) was calculated as MDD divided by BD and provided an assessment of damage, unbiased by plant size. Percent of shoot damaged (PSD) was visually evaluated as the percentage of entire shoot system exhibiting damage. In addition, presence of basal damage (DB) and basal cracking (CB) were recorded. A strong cultivar response was observed for BD, MDD, PBDD, and PSD. Mean cultivar values for PSD ranged from 79% and 19% for AU Authur and Sungold™ seedlings, respectively, which represented extremes among cultivars. Fuzzy kiwifruit exhibited greater injury (PBDD, PSD, DB, and CB) as compared with golden kiwifruit cultivars. Basal damage and basal cracking proved unique to fuzzy kiwifruit, as DB ranged from 0% in Sungold™ seedlings to 100% in fuzzy kiwifruit ‘AU Authur’ and ‘AU Fitzgerald’. In spite of having greater vigor, golden kiwifruit plants sustained less injury. Method of propagation had no effect on injury. PBDD and PSD proved to be reliable field assays for documenting injury, based on their strong correlation value ( r = 0.92). Greater relative autumn frost tolerance of golden kiwifruit over fuzzy kiwifruit cultivars is previously unreported.

  PublisherOA PDFDOI

• Three New Fungal Leaf Spot Diseases of Spinach in the United States and the Evaluation of Fungicide Efficacy for Disease Management

  Plant Disease · 2020 · 11 citations

  • Biology
  • Horticulture
  • Botany

  caused symptoms of intermediate severity. Fungicide efficacy tests demonstrated that chlorothalonil, mancozeb, pyraclostrobin, fluxapyroxad + pyraclostrobin, and penthiopyrad were completely effective at preventing leaf spots caused by any of these pathogens when applied 24 h before inoculation of 'Viroflay' plants in greenhouse trials.

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• Characterization of Leaf Spot Pathogens from Several Spinach Production Areas in the United States

  Plant Disease · 2020 · 24 citations

  • Biology
  • Horticulture
  • Botany

  , when inoculated individually and in combination.

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• The Texas Superstar® Program: Success through Partnership

  HortTechnology · 2011-12-01 · 1 citations

  articleOpen access

  T exas Superstar is a marketing assistance program that involves the promotion of outstanding plants that have proven performance in most regions of Texas. From the beginning, this program has represented a partnership between the Texas AM 2) must be unique and offer desirable and ornamental characteristics (i.e., the ability to perform in the heat of a Texas summer or pest resistance) not usually available in commonly sold plants; 3) must consistently perform well for most Texas consumers regardless of their gardening expertise and growing locations; 4) must be as pest resistant as possible (deer proof an added bonus); 5) must be able to be propagated and massproduced in sufficient numbers to meet increased consumer demand; and 6) preferably is so attractive in the sales container that it sells itself to consumers who have never heard of the many attributes of the plant. Conservatively, Texas Superstar marketing promotions have been estimated using informal surveys of producers to have resulted in $15 million of increased sales at the major wholesaler level not including value-added components or smaller wholesaler production. Texas is a climatic microcosm of much of the United States (Mackay et al., 2001). The state spans four U.S. Department of Agriculture hardiness zones, has 15 unique land resource areas and eight major soil orders, and has annual precipitation rates ranging from 8 inches per year in the far west to 56 inches per year in the far east. The trial sites for the program are in College Station, Lubbock, Overton, and San Antonio. These sites represent major differences in ecological zones near the vast majority of the population centers in the state. All decisions concerning plants selected for trialing or designated for promotion based upon trial site performance are made by the Texas Superstar Executive Board. Members are: B. Pemberton (Chair), Texas AgriLife Research, Overton; M. Arnold, Texas AM T. Davis, Texas AM D. Lineberger, Texas AM C. McKenney, Texas Tech University, Lubbock; D. Rodriguez, Texas AgriLife Extension Service, San Antonio; and L. Stein, Texas AgriLife Extension ServiceUvalde. B. Pemberton directs the trial site at Overton. M. Arnold directs the trial site at College Station. T. Davis serves as an administrative liaison to the Executive Board. D. Lineberger maintains the website for the program. C. McKenney directs the trial site in Lubbock. D. Rodriguez and L. Stein direct the trial site in San Antonio. All of the Executive Board members are engaged in the search for new and unique plants for the program, provide research support when needed for production aspects of a promotion, and are involved in industry relations. In many cases, these efforts have been integrated into teaching and student research programs (Arnold et al., 2001). The Texas Superstar program grew out of regional marketing promotions coordinated by J. Parsons in the San Antonio region in the 1980s. From the beginning, these promotions of plants with proven performance were coordinated with industry to insure an adequate retail supply at the time of the promotion. In 1989, the first statewide marketing promotion was accomplished featuring the Texas bluebonnet. By the mid 1990s, the acronym CEMAP, which stands for Coordinated Education and Marketing Assistance Program, was used for the program. In 1997, the term Texas Superstar was coined by the Executive Board. All promotions were retroactively designated Texas Superstar plants. Texas Superstar was trademarked at the time. Later, the trademark was registered, and the rights were assigned to the Texas Agricultural Experiment Station (now Texas AgriLife Research). In 1998, Texas Superstar tags were first used; $0.05 per tag sold was designated for the program. Horticultural Marketing and Printing (Mesquite, TX) helped develop the brand by donating artwork and the patent search. Wal-Mart (Bentonville, AR) purchased the first tags. The tag revenue is used to support all aspects of the program as approved by the Executive Board. In the mid 1990s, D. Lineberger created the Aggie Horticulture website. The CEMAP Program folder was

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Frequent coauthors

• George Ray McEachern

  9 shared

• Jerry Parsons

  Frimley Park Hospital

  6 shared

• Lindsey J. du Toit

  Washington State University

  5 shared

• J. Benton Storey

  Texas A&M University

  5 shared

• Tim D. Davis

  Centers for Disease Control and Prevention

  5 shared

• John A. Lipe

  5 shared

• Wayne A. Mackay

  University of Arkansas at Fayetteville

  4 shared

• Calvin G. Lyons

  4 shared

Education

• B.S., Horticulture

  Texas A&M University

• M.S., Horticulture

  Texas A&M University

• Ph.D., Horticulture

  Texas A&M University