Submitted to: Journal of Cotton Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/13/2003
Publication Date: 12/1/2003
Citation: PERCY, R.G. COMPARISON OF BULK F2 PERFORMANCE TESTING AND PEDIGREE SELECTION IN THIRTY PIMA COTTON POPULATIONS. JOURNAL OF COTTON SCIENCE 7. 2003. 170-178 Interpretive Summary: Plant breeders are continually striving to increase the efficiency and efficacy of their breeding methods. Early generation testing is a technique that has as its objective the early identification of superior heterogeneous populations. Despite the relatively long history of early generation testing, it is only in recent years that it has been employed in cotton breeding in the form of bulk F2 testing - with little data to support its efficacy. In the present investigation the results of bulk F2 performance tests have been compared with the results of a traditional pedigree-breeding program. The correspondence between the two methods was very weak, suggesting that the two methods are not complementary in identifying superior populations for selection. Public and private breeding programs currently using or considering using F2 testing as a component of their breeding efforts should test its efficacy in their own germplasm and in their own programs prior to its adoption.
Technical Abstract: The objective of early generation testing is to increase breeding efficiency through early identification of superior heterogeneous populations. Bulk F2 testing is a method that has gained adherents among the cotton breeding community ' with little data to support its efficacy. The goal of this study was to compare F2 performance data with historical pedigree selection records to determine the degree of correspondence between the two methods in identifying superior hybrid populations. Thirty hybrid populations, originally created in 1983 and 1984, were recreated and their F2 populations were tested for yield and fiber performance in randomized complete block tests at Maricopa and Safford, AZ in 2000 and 2002, respectively. Pedigree selection records of the 30 populations were summed across F2, F3, and F4 generations, and correlations were run between the summed selection records and F2 population performance data. Comparisons were made between F2 performance and the number of lines each population contributed to advanced, replicated testing. Significant correlations were almost entirely lacking between F2 performance data and summed selection records of 1983 crosses. A greater number of correlations were observed between field and fiber quality selection numbers of 1984 crosses and their F2 populations' yield and fiber performance. These correlations were not consistent between the Maricopa and Safford locations. The F2 yield and fiber performance of the 30 populations had a poor correspondence to the number of progeny these populations contributed to advanced, replicated testing. In the present investigation, the use of F2 testing would yield results that vary considerably from those obtained by pedigree breeding.