Genetic improvement of the Maritime Pine

Details
The Landes of Gascogne are the first European, cultivated forest, in terms of productivity and surface area.

The maritime pine genetic improvement programme led by INRA started in 1960, with the successive planting of seed orchards with different levels of genetic improvement.
The main objectives of genetic improvement are to produce trees with straighter trunks and better growth rates, although new criteria such as resistance to drought and disease are now also being studied.

Since the 1960s, successive generations of improved seeds have been used across the forest, each gradually being replaced by a new, higher-performing generation. The current programme plans the arrival of the 4th generation of genetic improvement (VF4) in 2024.

Since 1995, the improvement programmes have been coordinated by the PMF GIS (Groupe Pin Maritime du Futur – Future Maritime Pine Group), and by all forestry stakeholders (INRAE, ONF, FCBA, CNPF, CPFA and private companies)

Chronicle of the genetic improvement:
1926: Installation of the first arboretum of Maritime Pines coming from different natural areas.

1960-1969 / 1972-1974: selection campaign of trees which have superior growth and shape which lead to the planting on 246 hectares of seeds' orchards 1st generation.

The limited quantity of seeds genetically improved and their high cost has modified the reforestation method, replacing progressively the sowing by the planting. The seed is sown in a nursery to produce genetically improved plants.
Indeed, 1 hectare of sowings requires 3 kg of seeds, that is to say 45 000 seeds. In a nursery, 45 000 seeds produce 40 000 plants, or 30 hectares of forest replanted instead of 1 hectare if using seeds.

1978-2000: Gradual use in reforestation of sowing seeds coming from 1st generation, seeds 'orchards.

1986-1995: Installation of seeds' orchards of 2ndgeneration on 200 hectares.

Since 1998: Gradual use of seeds coming from 2nd generation' seeds' orchards.

2003-2006: Installation of seeds' orchards of 3rd generation (VF3)

2006: Installation by PLANFOR of a seeds' orchard of 3rd generation, 17 hectares 60 in Carcans (33). The planting chosen by PLANFOR should allow an early harvest of Pine comes in 2013.

2012: First harvest in the seeds' orchards VF3.

2013: Gradual use of seeds coming from 3rd generation seeds orchards.

2017-2019: Establishment of the 4th-generation seed orchard at Lanton (VF4.1)

2023-2024: First seed harvest from the Lanton orchard (VF4.1)

How do we create a genetically improved variety of Maritime Pine?
The main objective of genetically modifying a Maritime Pine is to increase straightness and growth of mature trees. The trees which have remarkable criteria and qualities are selected.
Crossings are done with the goal of obtaining plants which have different levels of genetic improvements.

Approximately every 15-20 years, a new generation of genetic improvement has been deployed. Each new generation shows superior characteristics compared with previous ones. Nowadays, the 1st generation is no longer planted in the forest, while the 2nd and 3rd generations are still used.

VF4, a continuously deployed genetic improvement
The 4th generation of the Landes vigour-form variety represents a turning point in the forest’s genetic improvement strategy, as it is a continuously deployed generation: small seed orchards will be regularly established through to the 2030s.

Thanks to new genetic marker models and precise knowledge of the genealogy of selected parent trees, it is now possible to predict the performance of a generation. This is possible without even needing full feedback on offsprings quality which saves several years between each selection programme.

Therefore, new generations will be introduced more quickly, with a new VF4 formulation approximately every 3 years (compared with 15 years for previous generations). In addition, selection criteria will be more rapidly adaptable from one generation to the next.

How do we create a new variety of Maritime Pine?
Cross-breeding is the genetic improvement technic which has allowed the crossing of trees from the same family so as to improve its specifications. The variety type Landes x Corse is the result of a controlled pollination between two different varieties of Pine: one originating from the Landes area and the other one coming from Corsica. Nowadays we have the varieties of type LC2.

Controlled pollination is the fecundation of a female flower by the male pollen of another variety.
1- The best female flowers are selected and the other ones are removed.
2- Afterwards, the flowers are placed in bags for three weeks and male pollen is injected in each bag.
3- The cones harvest is done 2 years after fecundation has taken place, before it starts to get hot, that is to say around March/April. The harvest is done in the presence of the SRFOB (Local Service of the forest and the wood) which certifies the seed's origin.
4- The cones are then exposed to heat in order to open themselves and to harvest the seeds.
5- The seeds are going through a 'desailleuse' so as to separate the seeds from the wings.
6- The seeds can be stored during several years before being sown but they lose their germinating power over time.

Results of the genetic improvement on the Landes Forest:
The genetic improvement has allowed increasing the average productivity in The Landes Forest since the 1960. The yield has increased going from 4.8 m3/hectare/year in 1960 to 10m3/hectare/year in 2000. We can safely say that the yield will reach 12m3/hectare/year from now to 2015.
The genetic improvement is not the only actor in this progress.
The evolution of the silvicultural technics also comes into play.
- The cleaning up and the ploughing technics;
- The phosphate fertilisation at planting time and deferred at 3-4 years;
- The control of self-propagating plants;
- Earlier thinning out and thinning out closer together;
- Stoppage of tree tapping which has reduced rotations;
- The development of the wood market which heads towards productions of more than 12 m3.
Photos (4)

Since the autumn 2013, gradual use of seeds coming from 3rd generation seeds orchards.

Author: Planfor
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Genetic improvement of the Maritime Pine

How do we create a genetically improved variety of Maritime Pine?

Author: Planfor
Copyright

Genetic improvement of the Maritime Pine

How do we create a new variety of Maritime Pine?

Author: Planfor
Copyright

Genetic improvement of the Maritime Pine

Results of the genetic improvement on the Landes Forest:

Author: Planfor
Copyright

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