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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Research Project #436116

Research Project: Genetic Improvement and Cropping Systems of Warm-season Grasses for Forage, Feedstocks, Syrup, and Turf

Location: Crop Genetics and Breeding Research

Project Number: 6048-21000-030-000-D
Project Type: In-House Appropriated

Start Date: Mar 25, 2019
End Date: Jan 8, 2024

1. Characterize and improve internode length and stem maggot resistance in bermudagrass. 1A. Using RNA Sequencing, identify candidate genes that regulate internode length in bermudagrass. 1B. Develop integrated pest management strategies for mitigation of the Bermudagrass Stem Maggot (BSM). 2. Develop genetic markers and biocontrol agents to reduce root-knot nematode and aphid damage in sweet sorghum. 2A. Determine if the root-knot nematode resistance gene can be moved from Honey Drip to susceptible or moderately resistant sorghum cultivars by marker-assisted selection and thus confer or improve resistance. 2B. Identify new genetic loci for root-knot nematode resistance and develop markers associated with resistance. 2C. Investigate the use of entomopathogenic fungi to control sugarcane aphid in sorghum. 3. Assess lupin and carinata as renewable bio-based products and soil enhancement cover crops. 3A. Assess the economic and environmental impact of lupin as a winter crop cover within a summer row crop rotation. 3B. Determine the effects of Brassica carinata grown as a winter crop on soil quality and subsequent summer row crop production. 4. Develop genomic technologies for centipede grass and use those technologies to understand and improve desirable ecological and aesthetic traits for this species. Work may include, but is not limited to, water and nutrient efficiency, resilience to foot traffic, color, and pollinator support.

Objective 1: For characterization of internode length in turf bermudagrass, total ribonucleic acid (RNA) will be extracted from the leaf and stem tissue of bermudagrasses. RNA samples will be sent for library preparation and sequencing. The transcriptome will be reconstructed and differentially expressed genes will be identified and then confirmed for internode length via real-time Polymerase chain reaction (PCR). For stem maggot resistance, forage bermudagrass germplasm will be selected from the bermudagrass core collection for further evaluation for yield, quality and tolerance to Bermudagrass Stem Maggot (BSM) and tested in the field in two side by side plots (one sprayed and one not sprayed) and replicated four times in a randomized complete block design. Most tolerant lines for further analysis for yield and quality traits will be determined and used for release and use for crosses. Objective 2: The root-knot nematode resistance gene will be moved from ‘Honey Drip’ to susceptible or moderately resistant sorghum cultivars by marker-assisted selection. Furthermore, new genetic loci for root-knot nematode resistance will be identified by creating a mapping population using a source of resistance different than ‘Honey Drip’. In collaboration with ARS fungal curator, naturally occurring entomopathogenic fungal isolates will be obtained from sugarcane aphids. Entomopathogenic fungi will be applied to susceptible sorghum to determine if these strains can control sugarcane aphids. Objective 3: The economic and environmental impact of lupin with and without rye as a winter crop cover within a summer row crop rotation will be determined using rotating main crops of peanut and cotton over years with different cover crops during the winter (narrow leaf lupin, white lupin, white lupin + cereal rye, narrow leaf lupin + cereal rye, cereal rye, and fallow. Half the covers will be harvested and the other half rolled. Changes in soil fertility and yields will be determined. The effects of Brassica carinata grown as a winter crop on soil quality and subsequent summer row crop production an experiment will be determined by rotating carinata and rye planted as a winter cover with sorghum and soybean as rotating summer crops. Objective 4: For the genetic mapping of desirable turf traits in centipedegrass, a genome-wide association study will be conducted using a population of approximately 300 vegetatively propagated lines replicated in the field. Morphological traits will be measured for two years after establishment. Single nucleotide polymorphisms (SNPs) will be created from each line using genotyping by sequencing and the genome of a centipedegrass line will be sequenced. SNPs will be aligned to the reference sequence and SNPs will be identified that are associated with the traits. For the identification of pollinators of centipedegrass inflorescences, a collection of centipedegrass lines will be grown in large field plots. In collaboration with an entomologist, pollinators will be documented that transit into each plot and those directly pollinating the inflorescences.