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Radiata Pine

Genetic ranking of seedlots

Two systems used for genetic ranking of Pinus radiata seedlots in New Zealand and Australia are summarised below. More information is given in a bulletin published by the Radiata Pine Breeding Company (RPBC) Rating The Genetic Quality of Radiata Pine (PDF 3.4Mb.)

Growth and form (GF) rating system

In 1987 the then Forest Research Institute (now Scion) introduced the Growth and Form (GF) rating system to provide a means of comparing genetic quality of different radiata pine seedlots.

The GF system is a single number rating for a combination of growth and form traits, enabling you to see what performance you can expect in relation to unimproved seed. Higher GF numbers have a greater level of genetic improvement. The GF system also allows you to compare the relative merits of one seedlot with another.

Information in the table below is taken from "Whats New in Forest Research No 157" and compares the performance of OP seed against unimproved seed. Note that this a guideline only and that improvement ratings can vary considerably within a seedlot class.

Table 1: Comparison of performance of some typical seedlots from different genetic improvement classes with that of unimproved seed.

Unimproved

0

45

1

Climbing Select

5-10

50

7

850 orchard

13-18

65

14

268 orchard

15-20

70

16

Top 16 268

19-23

70

19

Control-pollinated 268

27-32

80

23

DOTHISTROMA RESISTANT (DR)

13-18

65

LONG INTERNODE (LI)

8-13

55

The GF system is only used now for OP seedlots. CP seedlots are rated under the GF Plus™ rating system which provides more detailed information.

GF Plus™ rating system

GF Plus™ seedlots registered under GF Plus™ are rated for six traits, each using a 1 - 30 scale:

Growth (Gro): Based on Diameter. The higher the number the better the anticipated growth rate. See the RPBC bulletin Radiata Pine Growth (PDF 3.3Mb) for a more full description of this trait.

Stem Straightness (Str): The higher the number the better the expected average straightness of the trees.

Branching (Br): The higher the number the more multinodal the seedlot. See the RPBC bulletin Radiata Pine Branching Habit (PDF 3.3Mb).

Dothistroma (DR): The higher the rating the greater the resistance to Dothistroma needle blight. Ratings for this trait are based on assessments of relative proportions of live crown in Dothistroma prone areas. See the RPBC bulletin Radiata Pine Dothistoma Resistance (PDF4.6Mb)

Wood Density (WD): Based on values for growth rings 6-10. The higher the number the higher the expected juvenile wood density. See the RPBC bulletin Radiata Pine Wood Density (PDF 1.5Mb) for a fuller discussion of this trait.

Spiral Grain (SpG): The higher the number the lower the average incidence of spiral grain.