Plant & Animal Genome IX Conference

Workshop: Forest Tree Genome Mapping
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POLYMIX BREEDING COMBINED WITH PARENTAL ANALYSIS (PMX/WPA) OF PROGENY: AN ALTERNATIVE TO FULL-SIB BREEDING AND TESTING

¹ Weyerhaeuser Company, 810 Whittington Ave., Hot Springs, AR, 71902, USA

² Weyerhaeuser Company, P.O. Box 420, Centralia, WA, 98531, USA

³ North Carolina State University, College of Forest Resources, 840 Main Campus Drive, Raleigh, NC 27695, USA

Implementation of most traditional full-sib crossing and testing designs is logistically difficult, costly and genetic gain is constrained by resource availability. An alternative to full-sib crossing and testing can ameliorate all these constraints. The solution alternative is to apply a pollen mix (PMX) of many male parents rather than a single pollen for each cross. PMX breeding is easy to implement, ensures good estimates of breeding values of the parent being pollinated, and provides for increased genetic gain opportunity because of the significantly increased number of effective parental combinations tested. However, PMX breeding has found limited use because inbreeding and pedigree control is lost. The development of relatively inexpensive molecular markers allows paternity analysis of progeny, thus allowing full pedigree control. We call this system PMX breeding with parental analysis (PMX/WPA). The feasibility of PMX/WPA was evaluated in a loblolly pine (Pinus taeda) third-generation population of 45 select individuals, among which there was considerable relatedness. All parental trees were genotyped at seven chloroplast and three nuclear microsatellite loci. Unique fingerprints were obtained for all 45 individuals but accurate paternal determinations for progeny from a complete pollen mix would not be possible due largely to relatedness in the breeding population. The inclusion of more markers and/or the creation of polmixes and breeding groups that avoid relatedness would resolve this problem. Key Words: Polymix crossing, mating design, genetic fingerprinting, genetic markers, genetic gain Note: Patent Pending