Báo cáo nghiên cứu nông nghiệp " Flowering biology "

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Objectives of Seed Orchard Management •Early flowering; flowering can begin at 3 years for E. nitens. •Simultaneous flowering between trees; ensures out-crossing. •Promote abundant flowering and abundant seed crops.

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Nội dung Text: Báo cáo nghiên cứu nông nghiệp " Flowering biology "

Flowering biology • Differences between species • Flowering and seed development cycle. • Factors affecting seed production.
Eucalyptus nitens seed development cycle June Year 1 Feb Year 2 Nov Year 2 Feb Year 5 Feb Year 4 Jan Year 3
Objectives of Seed Orchard Management • Early flowering; flowering can begin at 3 years for E. nitens. • Simultaneous flowering between trees; ensures out-crossing. • Promote abundant flowering and abundant seed crops.
Seed yields for E. nitens • Some sites produce very little seed. Quoted seed crops are usually less than 100 g per tree. • Crops of 1 kg seed per tree are possible (200,000 seeds). • Site conditions and management important for good seed production.
Factors affecting seed production - Eucalypts • Hormone treatments • Nutrition – Fertiliser (P&K) • Spacing and topping • Irrigation • Genetics • Environment
Factors affecting seed production - Eucalypts • Hormone treatments • Nutrition – Fertiliser (P&K) • Spacing and topping • Irrigation • Genetics • Environment
Promoting seed production – Spacing • Tree crowns need plenty of light to produce seed. • Shaded branches do not produce seed. • Early thinning needed to keep crown low. • Stocking must be less than 300 stem per ha.
Mahogany • Small flowers are borne in axillary or sub-terminal inflorescences. • Flowers are unisexual, with both sexes similar, and the trees monoecious, • Each inflorescence is 10-20 cm in length
Mahogany • Pollination is by insects, bees and moths
Mahogany • The fruits are large (12-15 x 6-8 cm), woody, erect, capsules, • When dry, the 4 or 5 valved fruits split open from the base, or from the base and the apex simultaneously. • Seeds are chestnut coloured and 7.5- 12 cm in length • There are usually about 35-45 winged seeds per fruit.
Mahogany • Flowering usually takes place when trees are deciduous or just coming into new leaf and shortly before the rainy season • The fruits mature in 10-11 months.
Teak – flower characteristics • Stamens 6 (5 or 7), 3-4 mm long, • Style 4-5 mm long & stigma 2-lobbed, lobes often adpressed. • Fruit drupaceous, 1.2-1.8 cm long and wide, seeds ?
Teak – flower characteristics • Stamens 6 (5 or 7), 3-4 mm long, • Style 4-5 mm long & stigma 2-lobbed, lobes often adpressed. • Fruit drupaceous, 1.2-1.8 cm long and wide, seeds 1-4
Teak – flower characteristics • Inflorescence contains a few thousand flowers buds; • 1-3 of them bloom each day; • Anthesis for the entire inflorescence occurs over 1-2 months. • Pollen is shed within a few hours of flowers opening. • Peak receptive period is between mid-morning and early afternoon; after this time the pollen viability gradually decreases
Teak – flower characteristics • Teak is insect-pollinated mainly by bees • Flowering season varies ordinarily from June to August or September. The fruits ripen from November to January and fall gradually
Teak – seed characteristics • Fruits/seeds – for transport and storage it is useful to remove the calyx by rigorous rubbing and winnowing. • Fruit can be dry-stored in airtight sealed tins for up to 2 years. • The viability of its seeds varies from 40- 85%.
Teak – seed characteristics • Various pre-sowing treatments have shown to improve germination • Seed storage - orthodox • Vegetative propagation by cuttings; grafting; tissue culture