The botanical name of pawpaw is Carica papaya L.; it belongs to the Caricaceae
Varieties: CO 1, CO 2, CO 3, CO 4, CO 5, CO 6 and CO 7.
CO 3 and CO 7 are gynodioecious (bisexual + female) types highly suitable for table purpose and CO 2, CO 5 and Co 6 are dual-purpose varieties for table and papain production.
Soil and climate: It is a tropical fruit and grows well in regions where summer temperature ranges from 350 C - 380
C. Tolerates frost and comes up to an elevation of 1200 m. Well drained
soils of uniform texture are preferable. If drainage is not adequate, collar - rot disease may occur.
Sowing: 500 g of seeds is required for planting one ha. June-September is the best season for planting. Avoid planting in rainy season.
Nursery: Treat the seeds with Captan @ 2 g/kg of seeds. Dibble four seeds in polythene bags in depth not exceeding one cm. Provide partial shade. Water the bags in rose can. Seedlings will be ready in about 60 days.
Planting: Plant the seedlings at 1.8 m either ways in pits of 45 cm x 45 cm x 45 cm size.
Irrigation: Irrigate copiously after planting. Irrigate the field once in a week.
Application of fertilizers: Apply FYM 10 Kg/plant as basal. Apply 50 g in each of N, P and K per plant at bi-monthly intervals from the third month of planting after removing unwanted sex forms. Apply 20 g in each of Azospirillum and Phosphobacterium at planting, again six months after planting.
Aftercultivation: Male trees should be removed after the emergence of inflorescence maintaining one male tree for every 20 female trees for proper fruit-set. In each pit only one vigorously
growing female/hermaphrodite tree should be retained and other plants should be removed. In gynodioecious type like (CO 3, & CO 7) keep one hermophrodite type/pit and remove female trees.
Micronutrients: Spray ZnSO4
0.5% + H2 BO3
0.1% during 4th and 8th month to increase growth and yield characters.
Plant protection
Nematodes: To control in the nursery, apply carbofuran 3 G @ 1 g/polythene bag after germination.
Diseases
Root rot and wilt: In water stagnated areas root-rot may appear. It is advisable to drench the soil with 1 % Bordeaux mixture or Metalaxyl 0.2%, 2 or 4 times at fortnightly intervals. Good drainage is vital.
Crop duration: 24 – 30 months.
Harvest: Fruits should be picked at colour break stage.
Yield: The average yield is as follows
CO 2 : 200-250 t/ha
CO 3 : 100-120 t/ha
CO 5 : 200-250 t/ha
CO 6 : 120-160 t/ha
CO 7 : 200-225 t/ha.
Papain extraction: Papain has several industrial uses, the important one being in brewing industries. It is used as “meat tenderiser” and in textile and leather “sanforization” processes and drugs.
The method of extraction of papain from papaya fruits is simple. The latex should be tapped from immature papaya fruits. Select 75 to 90 days old fruits. On the selected fruit, give incisions (cut) with a razor blade or stainless steel knife. The cuts should be given from stalk to tip of the fruit. The depth of the cut should not be more than 0.3 cm. Four such cuts are given spaced equally on the fruit surface. Tap the latex early in the morning and complete the tapping before 10.00 a.m. Repeat the tapping four times on the same fruit at an interval of three days. The cut
should be given on the fruit surface in places not covered by previous cuts. The latex collected from all the trees in a day should be pooled, shade dried in an aluminium pan or tray and passed
through a 50 mesh sieve to remove all foreign matter. In large plantations, vacuum driers can be adopted with advantage. Papain produced by artificial heating will have better colour and
high quality. Add potassium meta-bi-sulphite (KMS) at 0.5 % for better colour and keeping quality.
The latex should be dried very rapidly at temperatures of 500 to 550 C. Stop drying when the dried product comes off as flakes having a porous texture. Powder the dried papain by means
of wooden mallets or in electrically operated granulators and sieve the powder through 10 mesh sieve. Pack the powder in polythene bags in convenient quantities and seal them. Put the sealed bags in a tin container and seal it after evacuating air. Exposure to air deteriorates the quality of papain and vacuum sealing is therefore necessary. For large scale manufacture of
papain, vacuum sealing machine and a granulator will be useful.
The green papaya fruits after extraction of papain can be used for pectin manufacture and “tooty – fruity” or they can be allowed to ripen and made into other products. The CO 2 and CO 5
varieties of papaya released by Tamil Nadu Agricultural University, Coimbatore are ideal for papain production. Tamil Nadu Agricultural University, Coimbatore, supplies pure seeds of these varieties.
Yield: The yield of crude papain is as follows:
CO 2 : 600 kg/ha
CO 5 : 800 Kg/ha.
Seed Production Technology
Germination improvement: Soak seeds in 100 ppm GA3 for 16 hours or in 2% fresh leaf extract of arappu or 1% pungam leaf extract or pellet the seeds with arappu leaf powder.
Optimum depth of sowing: Sow seeds at 1 cm depth for better germination and seedling growth.
Seed extraction: Fruit size or weight has no association with seed quality except that the seed content is more in large fruits and less in small fruits. The seeds from different fruit weight or size
classes did not differ in their quality. Hence, all ripened fruits can be used for seed extraction.
Grading: BSS 6 wire mesh sieve.
Storage: Dry seeds to 8-10% moisture and treat with halogen mixture containing CaOCl2, CaCo3 and arappu leaf powder (at 5:4:1 ratio) @ 3g/kg and pack in cloth bag to maintain viability upto 5 months.
Invigoration of old seeds Stored seeds can be invigorated by soaking them in dilute solution of disodium phosphate (10-4 M) adopting 1:8 seed to solution ratio for 4 hours followed by drying back to original moisture content.
