Evaluation of Resistance to Fusiform Rust in Loblolly Pine from East Texas

A set of 21 loblolly pine families produced by crossing trees from east Texas were tested for resistance to fusiform rust disease. The parents of these families were surviving trees in stands that experienced extensive mortality in the 1960s due to southern pine beetle infestation. Seedlings were grown in tubes in a greenhouse and artificially inoculated with C. quercuum from five different sources of inoculum, each consisting of single gall collections of aeciospores. Four of the collections originated from galls on loblolly pine (C. q. fusiforme or Cqf), whereas the remaining collection was obtained from a shortleaf pine gall (C. q. echinatae or Cqe). Two of the Cqf inocula were collected from trees in Louisiana, while the others were obtained from trees in east Texas. A single collection of Cqf in each state and Cqe were taken from round-shaped galls, while the other two Cqf collections were taken from typical fusiform-shapaed galls.