Screening jack pine seedlings for resistance to Cronartiumquercuum f.sp. banksianae and Endocronartiumharknessii

Abstract

Jack pine (Pinusbanksiana Lamb.) seedlings grown from nine seed lots were tested for resistance to two different gall rusts, Cronartiumquercuum (Berk.) Miyable ex. Shirai f.sp. banksianae Burdsall and Snow and Endocronartiumharknessii (J.P. Moore) Y. Hiratsuka. Resistance to C. quercuum f.sp. banksianae or E. harknessii was found among the seed sources tested. Resistance to one rust was not correlated with resistance to the other. Several seed sources were intermediately resistant to both rust fungi. The results demonstrate the need to screen for resistance to both gall rust fungi if seedlings are to be planted in an area where the two rusts are present.