|Hanneman Jr, Robert|
|Ramon, Miguel - DEPT HORT,UNIV WI MADISON|
Submitted to: National Potato Council Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 8, 1997
Publication Date: N/A
Technical Abstract: Efforts to generate hybrids from crossing Mexican diploid species x Tuberosum haploids by embryo rescue and double were conducted. After 3,077 pollinations were made during 1995, 31 hybrids were obtained by embryo rescue 20 days after pollination (DAP)from crosses between 2x(1EBN) species and 2x(2EBN) haploids. None were the desired hybrids. In 1996, 3,288 pollinations were made, resulting in 184 fruit. Embryo rescue was performed between 14 and 20 DAP and resulted in 3,867 embryos, of which 530 developed into seedlings. A unique diploid hybrid between the haploid US-W 1818 (Chippewa) x S. pinnatisectum (PI 275233) has been confirmed. It has extreme field resistance to late blight equivalent to that of S. pinnatisectum. Cold chipping, 828 accessions representing 98 species have been screened for chipping from 34-36F storage. The best clones and families have been used in crosses to haploids to incorporate cold chipping ability. 28 haploid-species families were screened for their ability to chip directly after 3 months of 34-36F storage and after 6 days of 68-72F reconditioning. Three families had 2, 6 and 13% acceptable clones direct, increasing to 4, 32 and 27% after reconditioning and in 1995 they chipped at 0, 16, and 18% direct and 3, 34, and 23% when reconditioned. Families containing S. raphanifolium, PIs 296126 and 310998, consistently ranked in the top 5 over two years. Extremely promising materials have resulted from this work and are being used to transfer this trait to tetraploids.