An empirical rule for breeding high-optimum-temperature strains of Flammulina velutipes

Abstract

　An experiment was conducted to establish empirical genetic rules for breeding high-optimum-temperature hybrids of Flammulina velutipes. Optimum temperatures of monokaryotic stocks from commercial strains showed a normal distribution ranging between 20.0°C and 25.7°C with a mean of 22.5°C. Monokaryotic stocks having A2 incompatibility factor showed a higher optimum temperature than A1 factored stocks. Optimum temperatures of hybrids between compatible monokaryotic stocks also showed a normal distribution with a mean of 23.4°C, which was 0.9°C higher than the monokaryon's mean. When the monokaryons were classified into high-(H), medium-(M) and low-(L) optimum-temperature groups, the results of H×H, H×M and H×L matings yielded high-optimum-temperature dikaryons at the rates of 64%, 58% and 42%, respectively. In the case of H×H mating, the A1B1×A2B2 hybridization produced more than 80% high-optimum-temperature dikaryons, but the A1B2×A2B1 hybridization produced only 50% high-optimum-temperature dikaryons. The rate of high-optimum temperature hybrids between reciprocal dikaryon isolates of A1B1×A2B2 and A2B2×A1B1 showed no significant difference in temperature characteristic. However, a difference in the rate of high-optimum-temperature stock production was recognized between A2B1×A1B2 and A1B2×A2B1 reciprocal isolates. As a result of this work, a dikaryon with an optimum temperature of 25.9°C was produced.