Fertility of doubled monoploids ofSolanum phureja

Thirteen anther-derived doubled monoploids and their heterozygous diploid anther donor were evaluated in the greenhouse for flowering, fruit set, seed set and pollen fertility. Doubled monoploids varied for number of days to flower, duration of flowering, abundance of flowers and general flower quality. Fruit set on the doubled monoploids in controlled crosses with diploid male-fertile clones varied from 0 to 73% with a mean of 33% compared to the anther donor with 58%. Seed set varied from 9 to 210 seeds per fruit and was significantly lower than the anther donor (377 seeds/fruit). Five doubled monoploids that shed low quantities of pollen exhibited significantly less pollen stainability (10-30%) than the anther donor (88%). However, pollen of doubled monoploids did not germinatein vitro. 2n pollen frequencies of 20–55% were observed for the doubled monoploids compared with 22% for the anther donor. It was concluded that doubled monoploids had lower female fertility compared to the anther donor but that they produced sufficient seed to facilitate utilization in a breeding program as female parents. However, they were considered to be male-sterile for practical purposes.