Genetic variation in ectomycorrhiza formation by<i>Pisolithus arhizus</i>on<i>Pinus pinaster</i>and<i>Pinus banksiana</i>

Abstract

summary The ability of 28 monokaryons and 78 reconstituted dikaryons of Pisolithus arhizus (Scop, pers Pers.) Rauchert [Syn.: Pisolithus tinctorius (Pers.) Coker &amp; Couch] to form ectomycorrhizas on Pinus pinaster (Ait.) Sol. and Pinus banksiana (Lamb.) was studied using the growth pouch method. The ability to form mycorrhiza and promote growth of P. pinaster differed both between and within monkaryons and dikaryons. Some monokaryons and dikaryons failed to form ectomycorrhizas. Monokaryons formed fewer ectomycorrhizas on P. pinaster than dikaryons. The heterokaryotic state was necessary for the full expression of ectomycorrhiza‐forming ability. Growth of P. pinaster was more strongly correlated with ectomycorrhiza formation by dikaryons than by monokaryons.