Genetic improvement of western larch: Series 1 progeny tests for East Kootenay seed planning zone

Project number: EP 1020.02.01

District: Rocky Mountain Forest District

Objectives

• To evaluate the growth and adaptability of local and non-local (including North Idaho) western larch families in the East Kootenay seed planning zone
• To estimate breeding values of parents included in first generation seed orchards in order to remove genetically inferior parents
• To estimate components of genetic variance/covariance, heritabilities and genetic gain for traits relating to tree growth, form, adaptability and wood properties

Experimental design

Genetic entries included in test (208 in total)

Zone	Number of wind-pollinated families
East Kootenay	140
West Kootenay	31
North Idaho	31
Controls	6 (5 local operational EK seedlots plus 1 Siberian larch seedlot from Russia)

Layout

• Randomized complete-block design with 10 replicate blocks
• The 208 genetic entries were randomly subdivided into 8 sets of 26 entries
• Sets were randomly assigned to positions in blocks
• Genetic entries were randomly assigned to four-tree row plots within sets
• Sampling units are individual trees spaced at 2 x 2 m. White stakes identify set corners

History

• 1991 plantations established
• 1993 manual brushing, third-year tree height and condition recorded
• 1996 manual brushing and sixth-year height and condition recorded
• 2000 tenth-year height and condition asessment (including range-wide provenance test at Lamb Creek)

Publications

Jaquish, B., G. Howe, L. Fins and M. Rust. 1995. Western larch tree improvement programs in the Inland Empire and British Columbia. In Ecology and management of Larix forests: a look ahead. Proc. of an international symposium; 1992 October 5-9; Whitefish, MT, U.S. Schmidt, W.C. and K.J. McDonald (comps). Gen. Tech. Rep. INT-GTR-319. Ogden, UT: U.S.D.A., Forest Service, Intermountain Research Station. pp. 452-460.

Comments

The Lamb Creek installation also includes a plantation of a western larch provenance test. Seedlings from 129 seedlots from throughout the natural range of western larch were planted in four replicate blocks of 10-tree row plots. Test seedlings were grown by Dr. G. Rehfeldt, USDA, Forest Service, Moscow, ID who used the seedlots in his studies genetic variation in western larch. This planting represents the only long-term field testing of the 129 provenances. Three­ year test results indicated that provenance effects were minimal for provenance mean height, survival and damage.

The hot, dry summer of 1994 resulted in considerable mortality on the Lussier River site. The Lussier River site was abandoned in 2000, due to low survival.