Sweet Corn Cultivation

Wednesday, June 2, 2010

Super sweet corn Cultivaton

Sweet corn (Zea mays convar. saccharata var. rugosa also called Indian corn, sugar corn, and pole corn) is a variety of maize with a high sugar content and prepared as a vegetable. Sweet corn is the result of a naturally-occurring recessive mutation  in the genes which control conversion of sugar to starch inside the endosperm  of the corn kernel. Unlike field corn varieties, which are harvested when the kernels are dry and mature (dent stage), sweet corn is picked when immature (milk stage) and eaten as a vegetable, rather than a grain. Since the process of maturation involves converting sugar into starch, sweet corn stores poorly and must be eaten fresh, canned, or frozen before the kernels become tough and starchy.

The fruit  of the sweet corn plant is the corn kernel, a type of fruit called a caryopsis. The ear is a collection of kernels on the cob. Because corn is a monocot, there is always an even number of rows of kernels. The ear is covered by tightly wrapped leaves called the husk. Silk or is the name for the styles of the pistillate flowers, which emerge from the husk. The husk and silk are removed by hand, before boiling but not before roasting, in a process called husking or shucking.
Super sweet corn is a warm season crop. It germinates best at the temperature range from 20°C - 25°C. The weather should not be too cold; otherwise, it will be caused slow germination, bad growth,bearing few and small ears and even died when damaged by the frost.
It can be suitable for growing at different kinds of soil conditions, but best at deep fertile and good drainage loam or sandy loam soil. It could be cropped continuously at same place, but better to rotate with rice sweet potato, sugarcane, soyabean and vegetable.
Super sweet corn fields must be isolated over 100 meters (the father the better) from field corns or other super sweet corn with different color of kernels or planted in different period in order to avoid the same flowering stage for obtaining the best and uniform quality of the ears and kernels.

2. Varieties &  Sowing:
Bright Jean- This super sweet hybrid is vigorous, medium early (70-80days), high-yielding, and suitable for summer planting. The ears are uniformly well-fitted, with an average ear weight of 200-250g. Excellent light-yellow kernels are tender, crispy, and taste almost shell-less. It ships and stores well too. Bright Jean is especially tolerant to heat, wetness, and damping-off, resistant to virus,Helminthosporium maydis, and Ostrinia durnacalis. The plants are 30-40cm higher than Honey Jean No. 2 for easier harvesting of the ears.

Fertilization: Any fertilizer recommendation should be based on soil condition and local experience.For basal fertilizer, manure should be applied in rows before chemical fertilizer, and then a layer of soil should be covered before seeding.
Side dressing for super sweet corn must be applied earlier than sweet corn or field corn namely,before 30 – 40 cm height of plants.

4. Weeding and Pest Control:
Hand or hoe weeding must be careful without causing damage to the root system and should be finished before side dressing of fertilizer application.
77.3 % Sutan EC at the rate of 4 L/ ha (dilution 1: 300) is recommended as pre- emergence herbicide to apply on the surface of soil after seeding. It will be last effective for one month to control weeds.
Downey mildew (Peronosolerospora sacchari): Seed treatment with 35% Apron at the rate 3g / kg have been treated  and it will control the downy mildew at seedling stage.
Helminthosporium leaf spot (H.maydis and H. turcicum): Spray with 80 % maneb or 65 % Zineb.
Rust (Puccinis sorghi and P. Polysora): Same as to Helminthosporium leaf spot.
Bacterial stripe and leaf bright (Pseudomonas andropogonis and P. avenae): Avoid to plant in hot and humid season.
European corn borer (Ostrinia nubilalis): Apply with 45% EPN or spray 50% carbaryl after the male flower tasselling or spray 40.6 % carbaryl before the earning.
Cotton bollworm (Helicoverpa armigera): Same as to European corn borer.
Corn leaf aphid (Rhopalosiphum maidis): Spray with 24% Lannate or 40.64% Furadan.

5. Thining:
Thin the seedling to 1 plant each hill when 20 cm height. Retain 1 ear at upper part of each plant for becoming full ear and carefully pick the other for using as baby corns (within 8cm long). Do not damage the leaves when picking the baby corns.

6. Irrigation:It is desirable to have the soil well supplied with water in growing stages, especially right before or after earing and tassel stages. Too dry before earing stage will cause un uniform ears, sterilization,short ear, small kernels, hard skin of kernels, low sugar content and bad taste.

7. Harvest:The ears should be harvested at full and tender stage. General speaking, Honey Pearl can be harvested at 70-75 days depending on the weather conditions, or 20 days after silking of the ear for both varieties. Anyway, when the silks are turning brown and dry, the kernels are full and the milk like liquid can be squeezed out by fingers from the kernels,that is ready for harvest.
For maintaining the high quality of the product, cold storage (0 – 5 °C) is recommended. It is better to transport with frozen container when export.
Storage in high temperature condition will decrease the sugar content promptly.

Health benefits
Cooked sweet corn has significant antioxidant activity, which has been suggested to reduce the chance of heart disease and cancer, although this has not been definitively proven in practice. "There is a notion that processed fruits and vegetables have a lower nutritional value than fresh produce. Those original notions seem to be false, as cooked sweet corn retains its antioxidant activity, despite the loss of vitamin C," says Rui Hai Liu assistant professor of food science at Cornell University. The scientists measured the antioxidants' ability to quench free radicals, which cause damage to the body from oxidation. Cooked sweet corn also releases increased levels of ferulic acid, which provides health benefits, such as battling cancer. "When you cook it, you release it, and what you are losing in vitamin C, you are gaining in ferulic acid and total antioxidant activity.

Compiled By Harsh Saxena

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