Tree crops

A number of important crops are trees: mainly for timber, and fruit.

Breeding tree crops present s particular problems because :

• they often have a long juvenility period, so take many years to flower
• the long time they need to reach full maturity means that phenotypic evaluation is slow

For example, loblolly pine takes 25 years to go from seed to seed without intervention.

Major reductions in the juvenility period can be gained by grafting.

In loblolly pine this can be reduced to 5-6 years In cocoa, grafted scions can flower within 18 months (seedlings take 36 months).