Location: Insect Control and Cotton Disease Research
Project Number: 3091-22000-040-004-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Jan 1, 2022
End Date: Dec 31, 2022
Objective:
1. Develop germplasm lines with Fov4 resistance from SA-3208 and the reniform and root-knot nematode resistances from the BAR 32-30 breeding line. Continue the effort of further stacking the Fov4 resistance from SA-3208 with the insect and nematode resistance from a line derived by introgression of insect resistant trait from triple species hybrids into BAR 32-30 that is homozygous for Ren2,3 and Mi1,2. Identify and evaluate homozygous Fov4 and nematode resistant lines or Fov4, insect, and nematode resistant line in growth chamber and field tests. 2. Advance the introgression of Fov4 resistance from G. barbadense ‘Pima S-4’, ‘Pima S-6’, and from G. arboreum accession # 190 into the BAR 32-30 line. Identify and evaluate homozygous Fov4 resistant lines in growth chamber and field tests. Identify markers associated with the resistance. 3. Advance the introgression of Fov4 resistance from triple species hybrids derived from G. arboretum (4 accessions), G. herbaceum, G. armourianum, or G. turneri into the BAR32-30 line. Identify and evaluate homozygous Fov4 resistant lines in growth chamber and field tests. 4. Characterize genetic variation, virulence, and nematode interactions of Fov1 and Fov4, and elucidate virulence determinants and host resistance mechanisms through functional genomic approaches.
Approach:
1. The F2 plants with the Fov4 resistance from the cross between SA3208 and BAR 30-30 will be further propagated to F3 to identify the F2 plants that are homozygous for both the Fov4 and the reniform and root-knot nematode resistances. The F3 plants from the identified F2 plants will be evaluated for the Fov1/nematode and Fov4 resistances in growth chamber and field tests. For stacking Fov4, nematodes, and insect resistances, SA 3208 was crossed to 7 insect-resistant BC5 lines derived by introgression of caryophyllene oxidase gene from triple species hybrids into BAR 32-30 resistant to reniform and root-knot nematodes. Fov4 resistant F2 plants will be further propagated to F3 to identify Fov4, insect, reniform and root-knot nematode resistant plants. These plants will be evaluated for Fov1/nematode, Fov4, and insect resistances in growth chamber and field tests. 2. Fov4 resistance from Pima S-4, Pima S-6, G. arboreum accession # 190 have been introgressed into BAR 32-30 line to BC5S2-5 levels. The top performing lines will be tested for Fov1/nematode and Fov4 resistance in growth chamber and filed tests, selected, and released. 3. Fov4 resistance from seven triples species hybrid will be further introgressed into BAR 32-30 to BC5S3 levels. These plants will be evaluated for Fov4 and nematode resistances and yield performances. 4. SSR and SNP markers associated with Fov4 resistance will be identified and mapped using DNA from susceptible and resistant backcross lines derived from different sources of resistance. The developed markers will be utilized for marker assisted breeding. 5. Determine genetic variation among different VCGs of Fov, and their interaction with nematodes on disease development on the resistant and susceptible cotton lines carrying Mi1, Mi2, or Mi1/Mi2 root-knot nematode resistance gene(s). Elucidate the role of gossypol and lacinilene defense pathways on cotton host resistances against Fov utilizing the RNAi P450 hydroxylase and the dHG-OMT RNAi suppression lines in G. barbadense backgrounds.
