Fungi will attack the carob seed and germinating carob seedling. The fungi of importance in
Australia are:
• Rhizupus nigricons and Mucor hiemalis which will cause carob seed rot preventing the
germination of seed; and
• Rhizoctinia solani and Fusarium species will kill germinating seedlings.
Grazing animals may damage immature plants by browsing the growing tip. When this
occurs the plant must be replaced as it will never renew a vigorous main leader. When
mature, stock browsing of the lower branches does not seriously harm the carob (Esbenshade
& Wilson 1986).
3.7 Propagation techniques
Direct seeding
Carobs are traditionally direct seeded in the autumn or early spring (Esbenshade and Wilson
(1986). The seeds may be:
• Pre-soaked in water and planted to a depth of 5 cm; or
• Pre-germinated and planted to a depth of 2.5 cm where supplementary irrigation is
available.
In Spain, the entire pod is usually fed to livestock and stock manure is then buried in the
fields. The carob seed, which is undigested by the livestock, sprouts directly from the
manure.
With the above techniques, care must be taken to protect the seedling from frost and grazing
animals. Particular care must be taken during establishment as the carob seed is susceptible to
fungal attack.
Nursery Production
Due to the susceptibility of carob seedlings to disease, grazing animals and environmental
factors, nursery production and subsequent transplanting is the method preferred by the
Project Team.
The preferred greenhouse production time is during early spring and autumn, when
temperatures are not extreme. To aid germination and to break seed dormancy, the seeds are
scarified by soaking for 1 hour in concentrated sulphuric acid and then thoroughly washed
and soaked in water at room temperature for 24 hours. According to Esbenshade and Wilson
(1986), this process obtains the greatest germination rates, although germination is still below
40%. Soil sterilisation to prevent fungal infection may double the seedling survival rate.
Alternatively, Gebhardt (1996) prefers soaking seed in hot water (about 80o
C) for 4 hours and
collecting the seeds that have swollen for planting. This treatment is repeated for the seeds
that have not begun to swell.
Seeds are sown into germination trays or directly into individual containers (and transplanted
into larger containers before the tap root is restricted by the container). Transplanting from
small individual containers will usually occur at the second true leaf stage.
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Roots grow between 2 and 5 times the length of the above ground shoots. Care must be taken
to prevent root damage, particularly ‘J’ rooting, which will slow growth rates in the field.
Esbenshade and Wilson (1986) state that no procedure has been developed which will
prevent damage of the taproot prior to field planting.
hans muster wrote:About olives: in Morocco, near Agadir, I saw wild olives in unirrigated places. The fruits were 5 by 7 mm in size, black when ripe.
Maybe they sprout easilier than cultivated olives, because there is a selection towards sexual reproduction? Or because they are more likely to be swallowed by birds?
They could still be grafted later on if good fruits are required.