Sypium hirsutum ) production. Genetic resistance could drastically {benefit
Sypium hirsutum ) production. Genetic resistance could considerably benefit US growers. Furthermore, the removal of chemicals from the market for nematode handle is accentuating the need for genetic resistance to cotton nematodes. Years ago, screening of cotton germplasm collections revealed no higher resistance to reniform nematodes among 52-chromosome Gossypium species, but revealed pretty high resistance in the 26-chromosome cotton relative G. longicalyx, a spindly African relative (2n=52). Excellent resistance levels were noted for other 26-chromosome species, also. Innovative breeding and collaborative efforts helped us circumvent ploidy and genomic barriers to introgression with the African species’ resistance. We subsequently utilised breeding supplies to localize and map the introgressed gene (Renlon) to chromosome-11, and to establish a system for marker-assisted choice that contributed considerably to the improvement PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/20060468 LONREN-1 and LONREN-2, two very resistant lines that had been jointly “released” towards the public. Subsequent field-tests, however, revealed that the LONREN lines endure from variable levels of “stunting”, and that stunting was really extreme in some locations. Different tests recommend that the severity of stunting is related with nematode population density, and that LONREN lines are hypersensitive to the nematode combined with other soil pathogens. Several lines of proof also indicate that genes linked towards the introgressed gene (Renlon) impact resistance to other pathogens, and others have an effect on field and fiber efficiency. Genetic dissection and characterization of this area is desirable for scientific and practical motives. Towards these ends, we’ve got mounted a map-based strategy for high-resolution recombination, mapping, and minimization of the alien segments get BIBS 39 flanking the resistance gene. Our hypotheses regarding the “stunting” and approaches to analyze it will be discussed, like our breeding tactics, efforts to develop new sequence-based markers in the flanking region along with the strategies to recover informative recombinants.Meeting Abstracts 493 GOSSYPIUM ACCESSIONS RESISTANT TO ROTYLENCHULUS RENIFORMIS Vary IN SENSITIVITY For the HERBICIDE FLUOMETURON. Stetina1, Salliana R. and W.T. Molin2. 1USDA ARS, Crop Genetics Research Unit, PO Box 345, Stoneville, MS 38776, 2USDA ARS Crop Production Systems Research Unit, PO Box 350, Stoneville, MS 38776. Reniform nematode (Rotylenchulus reniformis) resistance is getting transferred to Upland cotton (Gossypium hirsutum) from its distant relatives. Anecdotal observations of fluometuron damage to LONREN lines with resistance from G. longicalyx raised issues about introducing herbicide sensitivity from other resistance sources. The analysis objective was to evaluate fourteen sources of reniform nematode resistance for their reaction to fluometuron inside a replicated greenhouse trial: G. herbaceum accessions A1-017 and A1-024; G. arboreum accessions A2-083, A2-100, A2-190, and A2-194; G. barbadense accessions Pima PHY 800, GB 713 and TX 110; G. hirsutum accessions T19, T1347, and T1348; and 3 G. hirsutum lines with resistance introgressed from G. barbadense (FR-05) or G. longicalyx (LONREN-1 and LONREN-2). The manage was G. hirsutum cultivar Deltapine 161 B2RF. Six seeds of every line had been planted on top of a mixture of sandy loam soil and sand (3:1 by volume) in 10 cm square pots. Fluometuron added to one hundred cm3 added soil mix (1:1, sandy loam:sand) at prices of 0, 0.34, 0.67, 1.