Susceptibility of Populus deltoides Bartr. to Melampsora larici-populina and Melampsora allii-populina. II. Quantitative Analysis of a 6x6 Factorial Mating Design

1993

S. 188-199

29 Lit. Ang.

Unselbständiges Werk

200051406

Quantitative susceptibility to Melampsora spp. was observed in a 6x6 Populus deltoides factorial mating design. Artificial inoculation in the nursery proved inefficient for estimating partial resistance. However, in the laboratory test, susceptibility was efficiently partitioned into number of uredia size of uredia and latent period, and these 3 traits were correlated to natural rust infestation in the nursery. Partial resistance to rust caused by Melampsora larici-populina was highly heritable in Populus deltoides. No correlations between growth and susceptibility were observed in our study. Additive variances estimated from the half sib effect overpassed additive variances estimated from clonal effect in the full sib families, which suggested that genetic differentiation occured between stands within the natural range of Populus deltoides. The large amount of intra- and inter-specific partial rust resistance must be futher studied and categorized to better understand the Populus-Melampsora system and to optimize the use of these natural resources in poplar improvement.