Genetic variation within and between populations of Pinus sylvestris L. (Scots pine) for susceptibility to Melampsora pinitorqua Rostr. (pine twist rust)

Abstract

The genetic variability of Scots pine (Pinus sylvestris L.) for twist rust susceptibility and the consequences for genetic improvement of the species were evaluated after arti®cial inoculation of 1-year-old seedlings in greenhouse tests. Wind-pollinated progenies, factorial and incomplete diallel mating designs were used to compare two natural populations of Scots pine (Haguenau, France, and Taborz, Poland) and their hybrids (Haguenau´Taborz). Families from Taborz were signi®cantly (P < 0.001) less susceptible to twist rust than those from Haguenau. Inter-population hybrids were as susceptible as the Haguenau population. No clear relationship between severity of infection, shoot length and phenological stage at time of inoculation was observed in intra-and interpopulation crosses. Dierences observed between the two natural populations for their response to twist rust are suggested to be the consequence of local adaptation simultaneously for climatic conditions and pathogen pressure. Within each of the two populations, the eects of general combining abilities (GCA) for rust susceptibility were predominant, although estimation of individual heritabilities remained at a moderate level (0.30±0.54). In interpopulation crosses, GCA eects of Haguenau and Taborz populations were still predominant. Moreover, hybrid performance could be predicted with con®dence based on the intrapopulation GCA values of parents. Genetic gain on twist rust resistance could be achieved quickly through intrapopulation mass or backward selection based on windpollinated progeny tests.

Genetic Variation of Lodgepole Pine, Pinus contorta var. latifolia, Chemical and Physical Defenses that Affect Mountain Pine Beetle, Dendroctonus ponderosae, Attack and Tree Mortality

“…Some studies categorize heritability values as high if the estimated value is ≥0.45 (King et al, 1997;Alfaro et al, 2000). Quencez and Bastien (2001) characterize moderate levels of heritability as between h 2 =0.30-0.54. Whereas Roberds et al (2003) state moderate levels of heritability are h 2 =0.44 to 0.59, Hamilton et al (2001) stated that the degree of genetic control or heritability of secondary defenses varies widely among plant species, but that it is generally thought to be in the order of 0.3.…”

Clonal plant production from self- and cross-pollinated seed families of Pinus sylvestris (L.) through somatic embryogenesis

“…In France, gains in the genetic quality of Scots pine plantations are expected from improved breeding populations created from natural populations. Scots pine plantations at Haguenau, in eastern France, are appreciated for their superior height and diameter growth (Quencez and Bastien 2000). In this context, our study was undertaken to improve existing protocols of P. sylvestris SE and apply these enhancements to embryogenic lines derived from immature zygotic embryos of the natural population of Haguenau for clonal plant production.…”