THE GENETICS OF TRIPLOID FORMATION AND ITS RELATIONSHIP TO ENDOSPERM BALANCE NUMBER IN POTATO

The ability of Solanum tuberosum Group Andigena clones to produce trip loids (2n = 3x = 36) in 4x(4 endosperm balance number (EBN)) X 2x(2EBN ) crosses was investigated. The difference in triploid production amon g the clones tested, though large, appears to be the result of low her itability. The triploids produced in the 4x X 2x crosses did not seem to bear heritable factors that improved triploid production in 2x and 4x populations derived from them. Yet, the seeds/fruit data from a sim ilar 4x X 2x cross fit a Poisson distribution. It was argued that the low probability nonheritable random events responsible for the triploi ds from 4x X 2x and 2x X 4x crosses were misfertilzations, mitotic abn ormalities in the gametophyte, and (or) mitotic misdivisions in the en dosperm.