Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 11, 2000
Publication Date: N/A
Technical Abstract: All high specific gravity cultivars in the U.S.are very closely related, which increases their genetic vulnerability and results in inbreeding as efforts are made to improve specific gravity. The purposes of this study were to estimate narrow-sense heritability/phenotypic variation for yield and specific gravity in random-mating diploid hybrid populations of S. phureja x S. stenotomum (PHU-STN) during two cycles of recurrent selection for specific gravity. Four clones from each of 72 maternal half-sib families were evaluated for yield and specific gravity in two selection cycles in replicated field tests in 1990-1991 (cycle 1) and 1995-1996 (cycle 2). Narrow-sense heritability for specific gravity was estimated as 0.37 +/- 0.25 (cycle 1) and 0.43 +/- 0.27 (cycle 2), with a 27% decrease in phenotypic variance between cycles. Narrow sense heritability for yield was estimated as 0.60 +/1 0.26 (cycle 1) and 0.06 +/- 0.24 (cycle 2), with a 73% decrease in phenotypic variance between cycles. The results indicate that additional breeding efforts in this PHU-STN population could improve specific gravity. However, the amount of variation for yield is decreasing rapidly, and may indicate that the yield potential of this population is approaching its limit.