Performing Department
Crop, Soil and Environmental Sciences
Non Technical Summary
This breeding project involves ,repeated cycles of selection based on the performance of half-sib progeny families (genotypic recurrent selection) to develop a ryegrass cultivar with superior yield for he Upper Coastal Plain, Piedmont, and Appalachian target area. Seed for the evaluation will be produced in Oregon but the actual selection will be based on halfsib family [erformance in Crossville, AL, Crossville, TN, and Blacksburg, VA. Two cycles of selection will be completed in the duration of this project. Selected populations (experimentasl) will be tested at multiple location as part of ongoing cultivar performance trials in and adjacent to the target area. If the first cycle show sufficient improvement, we will initate a seed increase in Oregon to produce seed for grazing evaluation.
Animal Health Component
0%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
Develop improved annual ryegrass cultivars for the Upper Coastal Plain, Piedmont, and Appalachian areas of the Eastern United States.
Project Methods
1. Target regionThe target area for this breeding project are the seven Level III eco regions between approximately 32 and 38 ? North and from the Eastern Seaboard to approximately 90 ? W, except for the Middle Atlantic Coastal Plain (63), viz .45, 65, 66, 67, 68, 69, and 7 (http://www.epa.gov/wed/pages/ecoregions/level_iii_iv.htm).2. Base populationThe base population for this regional election project is cycle seven (C7) of a recurrent phenotypic selection program for winter dry matter accumulation in annual ryegrass (Poudel, 2014). Briefly, a breeding program was initiated in 2005 to improve the winter productivity of annual ryegrass. A random-mating base population was subjected to cycles of phenotypic recurrent selection for increased biomass accumulation during winter. Single plants were raised in the greenhouse in Ray Leach Cone-tainers (Stuewe & Sons, Tangent, OR) and transplanted to a spaced-plant nursery at the Plant Breeding Unit of the E.V. Smith Research Center of the Alabama Agricultural Experiment Station in Tallassee, AL. A 1200-plant nursery was established in late October of each year with plants spaced 90 cm in all directions. The nursery was subdivided into blocks of 25 plants each (5 x 5 arrangement); beginning with C4, 1600 plants and 6 x 6 plant block pattern was adopted. Plants were harvested and evaluated for dry matter yield 750 growing degree days (GDD) after transplanting, the best entries selected from each block are then intermated in isolation and bulk-harvested seed used for the next cycle; beginning with C4 selection was based on green matter. Cycle 2 (C2) already produced higher DM yield in winter than C0, C1, Gulf, and Marshall in a two-year, five-location study (Dhaliwal, 2009). When evaluated under grazing it resulted in higher early-season gains than check cultivars Marshall and Gulf. We have breeders seed increase block in Oregon and will produce seed for a regional grazing trial beginning in autumn 2015. Thus far seven cycles of phenotypic recurrent selection have been completed. The yield was shifted approximately five percent towards earlier cuttings over these seven cycles (van Santen, 2014, unpublished results).2. Selection proceduresThe project will involve multiple selection steps within each cycle, viz. (1) phenotypic selection among parent plants n the greenhouse and the spaced-plant nursery prior to anthesis leading to the production of half-sib families (HS-families); (2) genotypic selection among HS-families forage yield; and (3) within HS-family phenotypic selection for seed production and disease resistance traits. The process begins in autumn of year 1 with raising seedlings at the Plant Science Research Center (PSRC) on the campus of Auburn University. Fifteen hundred (1500) seedlings will be established in Ray Leach Cone-tainers (Stuewe & Sons, Tangent, OR), beginning mid August of each year. The strongest 500 will be selected and shipped to Oregon in late September to establish the spaced-plant nursery for the production of HS-family seed. Plants will be monitored throughout winter and spring, eliminating approximately 200 plants based on heading date and general plant characteristics such as number of tillers; seed yield is highly correlated with number of tillers per unit area. Another selection criteria is stem rust (Puccinia graminis f. sp. lolii ). Stem rust infection reduces seed yield and quality and selection for resistance is critical. The remaining plants will be allowed to intermate and seed will harvested from each plant separately; the progeny from each plant thus constitutes a HS-family.In autumn of year 2, seedlings of each HS-family will be raised at PSRC and shipped to Oregon to establish a spaced-plant nursery there. At the same time, solid seeded (10 x 5 feet), replicated (r = 2) plots will be established in Crossville, AL, Crossville, TN, and Blacksburg, VA. At each location, extension recommendations regarding crop management and soil fertility will be followed. The first cut will be at 1000 GDD after seeding and the second at an average 50% heading for each trial, with a final cut 1000 GDD after the second cut. The most important response variable will be total seasonal yield from seeding until heading. Heading dates for annual ryegrass in Oregon range from May 1 - May 20 with anthesis occurring approximately two weeks later. This enables us to select the best HS-families the agronomic target area (AL, TN, VA) before anthesis occurs on Oregon, thereby doubling gain from selection through bi-parental control of mating. In the first stage of selection all unwanted HS-families will be mowed down and treated with a wick applicator soaked in glyphosate. In the second stage, non-thrifty plants and/or diseased plants within each HS-family will also be eliminated. At maturity, seed will be harvested separately from each plant and bulked such that each selected family contributes an equal share by mass to the next generation.In autumn of year 3 the same procedure will be followed as in year 1, beginning with raising seedling at the Plant Science Research Center (PSRC) on the campus of Auburn University. Fifteen hundred (1500) seedlings will be established in conetainers, beginning mid August of each year. The strongest 500 will be selected and shipped to Oregon in late September to establish a spaced-plant nursery. Plants will be monitored throughout winter and spring, eliminating approximately 200 plants based on heading date and general plant characteristics such as number of tillers; seed yield is highly correlated with number of tillers per unit area. Seed will be harvested. The remaining plants will be allowed to intermate and seed will harvested from each plant separately; the progeny from each plant constitutes a HS-family.In years 4 and 5 we will follow the same procedure as in year 2 and 3.3. Evaluation of progress from selectionEvaluation of progress from selection will begin in year 3 using the first synthetic generation of cycle 1 (C1SYN1), i.e., seed resulting from intermating parental plants (C1SYN0) selected from among and within half-sib families, the SYN0 generation. Because of heterosis, the SYN1 generation would be expected to have better performance than later synthetic generations and thus represents an optimistic performance expectation. In other words, if this generation does not represent a significant improvement over C0 or commercial checks, later synthetic generations of C1 are unlikely to have improved performance and no further testing would be needed.If promising, more evaluation trials will be established in participating states in year 4 using C1SYN2 seed. Furthermore, the C1SYN2 generation will also be entered OSVTs of neighboring states, such as GA, KY, MS, NC, and SC.Evaluation of progress from selection will continue in year 5 with small plot evaluation trials in the agronomic target area (AL, TN, VA) to compare C2SYN1 to C0, C1SYN1, C1SYN2, as well as commercial checks.4. Breeder seed production in OregonTime is the most limiting resource in plant breeding. In this project we aim to partially overcome by producing seed in anticipation of positive results from a small plot evaluation of the C1SYN1 population. Thus, in year 3 we will establish 0.25-acre a solid-seeded breeder seed block of the C1SYN1 population in Oregon to produce C1SYN2 seed, which will be classified as breeder seed. This should generate 300-500 pounds of seed for larger scale testing. Results from the small-plot agronomic evaluations in the agronomic target area (AL, TN, VA) will be known prior to anthesis. If positive, the seed increase block will be harvested for seed. If not, the seed increase block will be destroyed prior to harvest.Similarly in year 5 we will establish solid seeded seed increase block of the C2SYN1 population in Oregon to produce C2SYN2 breeder seed for larger scale testing.