Guava Guava under the genus Psidium. This genus have about 150 species. 'The genus Psidium guajava' grown in our country.

The origin of guava is tropical America. Its extended rapidly from Peru to Mexico. Nowadays guava grown all over the tropics and subtropics. The major producing countries are India, Mexico, Brazil, Pakistan, Sri Lanka, Bangladesh, Burma, Rhailand, Malaysia, Indonesia, Hawaii, Philippine, Florida. Optimum growing temperature for guava is 23-28 °C., but the matures trees can tolerate up to 45°C.

Guava is the major source of vitamin C and Pectin. Guava contains moisture 80-83%; acid 2.45%; reducing sugar 3.5-4.45%, non-reducing sugar 3.97-5.23%, TSS 9.73-14.23; Potassium 0.48%, vitamin C 260mg per 100 g of edible' potion (Rahim, 2008). However, nutrients contents depend on variety, season, maturity etc. Guava can be eaten both as in green and ripe stages. Fresh fruits used as salad, pudding etc. Jam, jelly, juice, pickles, ice cream can be made from guava through processing. Tea can be made from leaves of guava.

Guava is the medium height (2 to 10m) trees with shallow roots. Flowers arises from the axils of the leaves either as solitary or in cymes (2-3 flowers in cluster). Flowering going on from 25-45 days during the production season. Flowers are hermaphrodite often pollinated by air or insects. About 80-86% flowers set fruits but finally 50-60% fruits reached to maturity as initial shredding of flowers are usual. Unripe fruits are green in color and turned in yellow when it ripe.

Temperature has great influenced on flowering. High temperatures enhances shredding of flowers and fruits. Dry weather during flowering is desirable. Guava grown well under mild sunlight or partial shade. Major flowering found in summer and less in autumn. But under irrigated conditions flowers may come in off season (January-March).

Rain is one of the important factors for guava production. 100cm rain per annum distributed throughout year is ideal for guava. Guava can be grown any kind of soils, but well drained rich in organic matter clay loam to sandy loam is best. Soils should have enough moisture for better production. Optimum pH from 4.2-8.2.

Propagation Guava can be propagated both by sexual and asexual means. Plants grown from seed does not show mother characters and also delayed fruiting. Vegetative propagation like air layering, grafting and budding easily be done. For rootstock production, seeds should be collected from the ripe fruits and then sown to the bed. Seeding raising in the poly bag is better. Germination enhances almost a week if seeds soaked for 2-3 days in water.

Varieties There are lost of varieties in the world. Varietal variations like small, large, round, oblong, oval, pear shaped, white or red flesh also found in our country. Brief description of some of the varieties are as follows:

Kazi piyara This variety was collected from Thailand in and around nineteen hundred eighties and named as Kazi Piyara. Fruits are oblong, flesh are crispy, light sour, tasty. Seeds are hard and profuse. Average fruit weight 500g. Quick growing and about 5-7m height.

Sawupkanti This variety grown extensively in Sawupkanti areas of Barisal district. Medium size tree, fruits oval to round, slightly rough surface. White flesh, very sweet and soft and less seeded.

'Kanchannagar This variety grown Kanchannagar areas of Chittagong district. Less seeds than other varieties. Pear shaped fruits, much pulp and highly tasted.

FTIP BAU Piyara 1 (Misti) This variety collected from BAU campus. All season regular bearing semi-dwarf variety. Fruits round, glossy, very sweet, soft seeded. No disease and pest noticed in the BAU Germplasm center (Rahim, 2008).

FTIP BAU Piyara 2 (Ranga) Semi-dwarf regular bearing variety. Fruits are almost round to oval, yellowish green, red flesh, large size (300-600g), crispy, sweet, rough surface, seed medium hard. As the flesh is red, and high yielder this variety is highly acceptable to everyone.

FTIP BAU Piyara 3 (Choudhury) Local collection. Fruits round, greenish yellow, flesh reddish pink, medium crispy, sweet, soft seeded, less seeds. This variety is attractive, sweet and tasty. No disease and pest are noticed.

FTIP BAU Piyara 4 (Apple) Fruits round to oval, shiny green, smooth surface, attractive, soft, sweet flavored, seed medium hard. Infested by fruits fly. This variety is attractive, tasty and high yielder.

BAU Piyara 5

FTIP BAU Piyara 5 (Oval) Collected from abroad. Fruits are round and sinus, white fleshed, soft seeded, crispy, highly sweet, flavored. Plants are spreads like umbrella. Average fruit weight 300.5g. No disease and pest noticed. Fruits produced in the both season.

FTIP BAU Piyara 6 (Jelly) Collected from Hawaii. Pectin high, so jam and jelly prepared from this variety. Flesh bright red. Fruit size 120-250g. Fruits oblong, attractive, seed soft, crispy, heavy sour. No disease and pest noticed. Fruits produced in the both season.

Apart from these, there are other varieties like Mukandapuri, Angur, IPSA, BARI Piyra 2 and 3, Syedi, Allahabad, L-49, Cherry, Kashi also grown in Bangladesh.

Cultivation procedure Before rainy season, like other fruits pit size of 75-100cm to be done with a spacing of 4-5m. Hexagonal system should be followed. 25-30kg well decomposed cowdung should be applied in each pit 3 weeks before planting. Urea, TSP and MP @ 100g per pit sjould also be applied 1 week before planting. Rainy season is the best planting time but plants in poly bag can be planted any time of the year. After planting soil should be slightly raised at the base of the plants so that no water stand at base of the plant. After planting staking and protection is essential. Doses of manures and fertilizers should be increased with increase of the age of the plants.

Insects and pests

Mealy bug Most of the guava plant affected by mealy bug. White insects in cluster attacked plants. They eat young leaves, twig and flowers. Infected fruit dry out. Infected twig may pruned to control it. Malathion @ 20ml/10l water should be sprayed.

White fly This is a serious pest. Spiraling cotton wool white fly look like blocks of cotton. Sucking the leaves and finally the leaves die. Detergent powder @ 10g/l water should be sprayed.

Diseases Wilt, Anthracnose, canker leaf rust, die back, seedling blight are the major dieses of guava.

Anthracnose Leaves, branches fruits everything affected by anthracnose. Die back of twig is the symptom of the disease. Cool and hot both weather favored the disease. Black spots are formed in infected fruits which become non marketable. Infected branches should be pruned. Fungicides like Bordeaux mixture (4:4:50) or Dithane M-45 should be sprayed.

Wilt' Plants in acidic soil susceptible to this disease. Leaves in diseased plants become yellow and finally shredded. All branches wilted and finally the plants die. Only the remedy is to used wilt resistant rootstock. FTIP-BAU GPC succeed on controlling this disease through grafting on wilt resistant root stock (Farooque et al., 2000).

Yield' Full bearing started from 3-4 years of planting. Fruits can be harvested after 4-5 months of flowering. Yield depends on variety, age, growing conditions etc. Full bearing trees may yield 400-800 fruits and 20-30t/ha. [MA Rahim]