May 2020 FINAL STUDY REPORT USDA NRCS East Texas Plant Materials Center Nacogdoches, Texas Evaluation of Swamp sunflower Accessions of the Western Coastal Plain Melinda Brakie ABSTRACT Swamp sunflower (Helianthus angustifolius L.) or narrow leaf sunflower is a native warm season perennial prevalent in longleaf pine habitat. Swamp sunflower blooms in late summer to fall and is used by migrating Monarch butterflies (Danaus plexippus) and other pollinators. The study objective was to develop a swamp sunflower composite for pollinator and wildlife habitat in East Texas and western Louisiana in the Western Coastal Plain region. The study was conducted from March 2017 to November 2019 at the USDA NRCS East Texas Plant Materials Center near Nacogdoches, Texas. Thirty-one collections (accessions) from east Texas were tested for seed germination and evaluated for seedling vigor in the greenhouse and shadehouse. Accessions exhibiting poor seedling vigor were eliminated from the evaluation. Twenty-two accessions were transplanted to field evaluation in June 2017. Accessions were evaluated for insect and disease resistance, mature plant height, leaf width, reproductive stem number, bloom dates and survival in spring and fall. Survival, percent seed germination, and reproductive stem number were used to select eleven accessions for a composite release in 2021. Selected accessions crossed and set seed in the study plot while nonselected accessions were clipped regularly to minimize bloom and seed set in summer and fall 2019. Seed of selected accessions was harvested and combined proportionately in a composite seed mix in winter 2019. The seed mix was used to start transplants in the greenhouse to establish a seed increase field in spring 2020. INTRODUCTION Swamp sunflower is a native, warm season perennial understory forb found in the longleaf pine bluestem range of the southeastern US (Grelen and Duvall, 1966). This plant along with grassleaf goldaster (Heterotheca graminifolia) are the two most frequently occurring composites in Louisiana longleaf pine sites (Haywood and Harris, 1999). Swamp sunflower grows in low, open flatwoods, moist sites and upland range sites on sandy loam and clay loam soils (Ladybird Johnson Wildflower Center, 2017). Wildlife and pollinators use swamp sunflower year-round. Whitetail deer browse the foliage, which contains 10% or more crude protein in full leaf stage, during summer (Grelen and Hughes, 1984). Silvery Checkerspot (Chlosyne nycteis), Gorgone Checkerspot (C. gorgone), Bordered Patch (C. lacinia) and Painted Lady (Vanessa cardui) butterfly caterpillars use swamp sunflower as a host (New Moon Nurseries, 2017). Southern migrating Monarch butterflies use this forb as a fall nectar source when passing through longleaf pine habitat of southern Louisiana and East Texas (USDA NRCS, 2015 and Texas A&M Forestry, 2017). Quail and dove utilize the seeds as a winter food source (Grelen and Hughes, 1984). Swamp sunflower was chosen for evaluation because of its importance to wildlife and pollinators and wide distribution throughout pine forests. The study Melinda Brakie, Soil Conservationist, East Texas Plant Materials Center, 6598 FM 2782, Nacogdoches, Texas 75943. Phone: (936) 564-4783 objective was to develop a composite of best performing swamp sunflower accessions for future release for wildlife and conservation plantings. MATERIALS AND METHODS The initial study evaluation was conducted from March 2017 to November 2019 at the East Texas Plant Materials Center (ETPMC). The study included germination testing, seedling emergence ratings, and field evaluations. Thirty-one swamp sunflower accessions were collected by NRCS USDA and US Forest Service personnel from native stands in East Texas (Table 1). One accession with immature seed was eliminated from evaluation. Table 1. East Texas Plant Materials Center swamp sunflower (Helianthus angustifolius) assembly accession numbers and county of origin for initial evaluation. USDA NRCS East Texas Plant Materials Center, Nacogdoches, Texas. Accession County of Accession County of Accession County of number origin number origin number origin 9094901 Hardin 9095068 Angelina 9095078 Angelina 9094902 Hardin 9095069 Sabine 9095079 Angelina 9094904 1/ Jasper 9095070 Angelina 9095080 Angelina 9094940 Nacogdoches 9095071 Angelina 9095081 Sabine 9095007 2/ Polk 9095072 Jasper 9095082 Jasper 9095029 Houston 9095073 Sabine 9095083 Sabine 9095030 Houston 9095074 Angelina 9095084 Jasper 9095060 2/ Hardin 9095075 Angelina 9095085 Sabine 9095066 Angelina 9095076 Sabine 9095086 Angelina 9095067 Angelina 9095077 2/ Angelina 9095087 Jasper 2/ 9095088 Not known 1/=eliminated from evaluation due to immature seed, 2/=not tested for seed germination. Twenty-six accessions were tested for germination beginning on 27 March 2017. Four replications of fifty untreated seeds were used per accession. The seeds were placed between two layers of moistened white blotter paper (Anchor Paper Company, Saint Paul, MN) in a clear square plastic boxes. The boxes were placed in a SG30 controlled environment chamber (Hoffman Manufacturing Co., Albany, OR) set at alternating temperatures of 30°/20°C (86°/68°F) and 8 hours light (AOSA, 2007). Germination counts were conducted at 3, 7, and 14 days. Germinated seedlings with a radicle and plumule were counted and removed from the boxes. Total germination of each replication was multiplied by two to calculate percent germination then the four replications/accession were averaged to determine mean percent seed germination at 14 days. Seeds of thirty accessions were planted into Hiko HV93 transplant trays (Stuewe and Sons, Inc., Tangent, OR) containing a mixture of Pro-mix BX media (Premier Tech Horticulture, Quakertown, PA) and fine sand on 8 March 2017. The trays were placed in the greenhouse and watered as needed to encourage seedling emergence. Accession seedling vigor was visually rated thirty days after seeding using a scale of 1=excellent, 3=good, 5=fair/average, and 7=poor. Transplant trays were moved to the shade house to harden off for three weeks before transplanting to the field. Transplant vigor was visually rated three days before field planting, and the eight lowest rating accessions were eliminated from the study (Table 4). 2 Twenty-two accessions were transplanted into a Woden fine sandy loam soil on 2 June 2017 at the ETPMC. Experimental design was a randomized complete block with four replications. Each plot consisted of 10 plants on 2-foot centers. Transplants were watered as needed in the first year of establishment. Transplant survival was recorded 30 days after planting (DAP), 60 DAP, and end of the growing season in 2017. Spring and fall plant survival were recorded in 2018 and spring survival in 2019. Transplant vigor was visually rated 60 DAP using a scale of 1 to 9 where 1=excellent and 9=very poor/dead. Bloom date for each accession was recorded when at least 50% of the plants in a replication were in open bloom in 2017, 2018, and 2019. Beginning or first bloom and peak bloom dates were recorded in 2018 and 2019. Disease resistance, insect resistance, and plant vigor were visually rated based on a scale of 1 to 7 where 1=excellent and 7=poor and recorded at 50% bloom date in 2017 and 2018. Plant height, number of reproductive stems, leaf width, and plant lodging score were measured from three plants chosen at random from each plot at 50% bloom in 2017 and 2018. Plant height was measured in inches from ground level to top of the tallest inflorescence. Number of reproductive stems was a direct count. Three leaves per plant were chosen at random and the width of each leaf measured in millimeters with digital calipers. Plant lodging was based on a visual scale of: 1=majority of plants reproductive stems are upright or about 90º angle; 3=majority of plant reproductive stems are about 45° angle; 5=majority of plants reproductive stems are less than 45° angle. Study data for percent germination, 30 and 60 DAP transplant survival and vigor, number of reproductive stems, leaf width, stem lodging, mature plant height, disease and insect resistance, and spring and fall plant survival was analyzed in Statistix10 (Analytical Software, Tallahassee, FL) using mean and standard deviation to determine variation among swamp sunflower accessions. Eleven accessions were chosen for future release as a composite of the best performing accessions from the study. Selected accessions bloomed and produced seed while blooms of undesirable accessions were clipped regularly to prevent pollination in 2019. Seed of selected accessions was collected and cleaned in fall 2019. The same number of seed from each accession were counted and combined to form a composite mix (Fehr, 1987) for transplant production and eventual large-scale seed increase. In February 2020, Hiko V93 seeding trays (Stuewe and Sons, Tangent, OR) were filled with a mix of fine sand and Pro-Mix BX (Premier Tech Horticulture, Quakertown, PA) and about six seeds planted per tray cell. The trays were placed in the greenhouse and watered as needed. RESULTS AND DISCUSSION Seed Germination Tests The untreated swamp sunflower seeds germinated quickly as twenty-two of twenty-six accessions had 25% or greater germination at 7 days. This result contrasts with Nichols (1934) who observed New Jersey collections took 64 days to germinate without stratification. Mean seed germination varied from 89% for accession 9095083 to 0.5% for accession 9094901. Five accessions (9095083, 9095084, 9095073, 9095072, and 9095076) had 80% or greater mean germination (Tables 3 and 4). 3 Seedling Vigor in Greenhouse and Shadehouse Accessions were not replicated in the greenhouse or shadehouse. Greenhouse and shadehouse seedling vigor ratings were visually ranked on a scale where 1=excellent to 7=poor. Greenhouse ratings varied from 1 to 7 with a mean of 5 (Table 4). Accessions 9095073 and 9095069 received excellent ratings while four accessions were rated at good and the rest received average or poor ratings. Seedling vigor ratings for the shadehouse also ranged from 1 to 7 with a mean of 3 (Table 4). Ten accessions received excellent vigor ratings and eight received good vigor ratings.