Generation of Pest Resistant, Diploid Potato Germplasm with Short-Day Adaptation from Diverse Genetic Stocks.

Abstract

A broad range of diploid potato breeding stocks were employed to generate 2x X 2x true seed families, and subsequently, clonal selection was made under short-day conditions. The diploid parental lines used were: 1) (di)haploids from short-day adapted 4x varieties; 2) 2x wild species which are cross-compatible with cultivated diploid potatoes and (di) haploids; 3) their hybrids with 2x breeding lines which were selected under short-day conditions; 4) diploid cultivated species; and 5) Iong-day adapted breeding lines from programs in North America and Europe. Thirty-three diploid true seed families consisting of a total of 990 seedlings were grown in an irrigated coastal desert at La Molina, Peru in 1990. Occurrence of 2n gametes were surveyed using the seedling plants. Three hundred-fifty plants from a total of 640 evaluated by acetocarmine glycerol stain, indicated the occurrence of 2n pollen grains at various frequencies. Eighteen of 108 plants, which were crossed by 4x males, had seed sets as female, indicating occurrence of 2n eggs. Resistance to bacterial wilt (Pseudomouas sola-nacearum), potato tuber moth (Phthorimaea oper-culella), root-knot nematode (Meloidogyue incognita. race 3), Potato Virus Y (PVY) and potato leaf roll virus (PLRV) was evaluated.