Patent ID: 6521817
Filing Date: 2003-02-18
Classification: A01H

Abstract:
A process for producing a tetrasporous heterokaryotic mycelium that is isogenic with a first bisporous strain of Agaricus bisporus for at least 50% of its nuclear genome by crossing the first strain with a second wild-type strain that is interfertile with Agaricus bisporus, the second strain having fructifications that carry basidia having predominantly homokaryotic spores, to form a heterokaryotic hybrid of the first and second strains, the hybrid having fructifications that carry basidia having predominantly homokaryotic spores, wherein the process comprises:obtaining first homokaryons of the first strain and second homokaryons of the first strain by isolating protoplasts of the first strain, wherein the first and second homokaryons are intercompatible; crossing the first homokaryons of the first strain with homokaryons of the second strain, to obtain a first hybrid having a majority of homokaryotic spores; subjecting homokaryons of the first hybrid to a series of backcrosses with the first homokaryons of the first strain and selecting tetrasporous hybrids at each backcross to obtain a second hybrid having a desired proportion of the genome of the first strain; crossing homokaryons of the second hybrid with the second homokaryons of the first strain to obtain a third hybrid, the third hybrid having the desired proportion of the genome of the first strain and a nuclear and chromosomal distribution of alleles of the first strain; and culturing the third hybrid to produce the heterokaryotic mycelium.