Pairing tests in the Phellinus pini group

Abstract

Pairing tests were used to determine patterns of sexuality and to define species in the Phellinus pini group. Intrastock pairings demonstrated a unifactorial pattern of sexuality in 48 of the 54 samples from Europe, Morocco, North America, and Asia. Irregular patterns were observed in two stocks from North America and four stocks from Asia. Using interstock pairings, 19 stocks from Europe were identified as P. pini and three as P. chrysoloma. Two compatible stocks from Morocco were intersterile with isolates from all other areas and possibly represent P. vorax. Seven intersterility groups were apparent among the 25 stocks from North America. Three intersterility groups were evident among the five stocks from Asia.

Intercontinent pairings demonstrated that North American collections were fully intersterile with P. chrysoloma and usually intersterile with P. pini. One North American stock was identified as P. piceinus. It seems unlikely that the remaining intersterility groups represent known taxa. The same is true for the stocks from Asia.

Speciation is considered allopatric between European, North American, and Asian stocks. Sympatric speciation is evident in North America and perhaps also in Asia.

Key Words:

• intersterility groups
• pairing tests
• Phellinus
• speciation
• unifactorial compatibility