|02-172AL Project Manager: D. C. Jones|
BREEDING COTTON FOR YIELD AND QUALITY IN ALABAMA
David B. Weaver, Auburn University
A cotton breeding project was initiated at Auburn University in 2001. Most of our work is centered on four primary objectives: Development of cotton germplasm or cultivars with improved yield and fiber properties; evaluation and development of cotton germplasm for resistance to reniform nematode; evaluation and development of cotton germplasm for resistance to abiotic stresses, particularly heat and drought; and evaluation of effects of broadening the genetic base of upland cotton. In 2012, we evaluated experimental lines for yield and fiber properties at Tallassee and Prattville. We tested 74 new F4:5 lines in preliminary tests at Tallassee, and 30 lines in advanced tests at Prattville and Tallassee. All these tests have also been evaluated for fiber quality. Selection for future testing will be based primarily on lint yield and fiber quality. Fiber quality at Tallassee was excellent: QS2 (Quality Score 2, where fiber strength is the major factor in determining the score) of lines were commonly greater than 80, with some selections having a QS2 score of more than 90. Eight F2, 7 F3, and 8 F4 generations of various populations were grown at Tallassee, and F4:5 progeny rows were grown, individual rows selected and submitted for fiber quality analysis. Crosses were made to create new populations for future work. All these populations have involved crosses between advanced experimental lines from Auburn and other public programs, and newly released sources of resistance to reniform nematode including BARBREN. Complete yield and fiber quality data are now available from the 2011 Regional Breeders Testing Network at 12 yield locations and two disease evaluation locations. Auburn experimental lines ranked 2nd, 5th, and 8th and 10th in the 27-entry test (24 experimental lines plus 3 checks). Fiber quality of these lines was not up to expectations. None of these lines was continued in the 2012 RBTN test, with all new lines being evaluated in 2012. Complete data on performance of these lines is not yet available, but preliminary data show some of the lines performed well at some locations, particularly in the southeastern U.S.
We have made significant progress in incorporating and evaluating the LONREN source (RENlon gene) of resistance to reniform nematode into adapted germplasm and testing of advanced lines in both nematode-infested and nematode-free fields. Most of the detailed information on this project will be covered in a separate final report. Complete data on yield and fiber quality of these lines is included as a manuscript recently accepted to Crop Science and is included as a part of this report.
Examining the G. hirsutum wild collection for heat tolerance using chlorophyll fluorescence has been an on-going project. We have made some progress in this area that has continued through 2012. Our main focus is to identify techniques that can be used to evaluate genotypes in the growth chamber and field using chlorophyll fluorescence as an assay. We evaluated a select group of 44 accessions that had shown some promise of having heat tolerance from previous work, and compared those to checks and a group of 44 randomly chosen accessions in the growth chamber. Data demonstrate a linear relationship between chlorophyll fluorescence and a heat tolerance index in the growth chamber. In summer of 2011 we compared the top ten accessions with four commercial adapted lines. Lines were compared on hot days (temperatures > 35 °C) and normal days (termperatures < 35 °C). We believe we have identified a core group of genotypes that can tolerate and recover more rapidly from exposure to high temperatures than non-tolerant genotypes. In 2012 field studies, we tested selected F2:3 lines from crosses involving two of the accessions. Not enough hot days were observed to collect meaningful data. We are continuing to evaluate these materials in growth chamber studies as we prepare for more field work in 2013. In the meantime, a manuscript has been submitted for publication in Crop Science that details our work to date. It is still in review as of the writing of this document.
We will continue to inbreed, select, and test experimental lines in the field for yield and fiber quality properties. Lines with superior performance will be advanced and tested at multiple locations in Alabama and possibly the Southeast, with the eventual goal of identifying and releasing superior cultivars or germplasm for production in Alabama. Advanced lines with the LONREN and BARBREN sources of resistance to reniform nematode will continue to be tested in the field in 2012. We will continue pursuit of the RENlon gene as a possible qualitative gene for fiber strength, and continue our investigations into discovery of heat tolerant accessions. We have initiated a project to evaluate cotton genotypes for resistance to Corynespora leaf spot. Our primary objectives are to develop a protocol for evaluation in controlled environments and apply the protocol to various cotton germplasm pools.
|Project Year: 2012|
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