Radish

 

Climatic Requirements Radish is best suited to a cool moderate climate,especially in the vegetative stage, but due to its rapid growth it has a wider distribution. for seed rpoduction, a less humid climate is desirable. Long spells of hot dry periods are not suitable for seed production. Temperatures of 32C or above, can cause the stigma to dry and the pollen may fail to germinate.
For seed production, the radish varieties can broadly be divided into the following three groups:
a) Temperate varieties(e.g. Chinese types) which produce satisfactory seed in the temperate hills by overwintering. These varieties flower very late in the plains. Seed of these varieties is produced only in the hills.
b) those temperate varieties (e.g. White lcicle, Rapid Red, Woods long Frame, Scarlet Globe, French Breakfast) which are very quick in root development in the plains, but behave just like winter varieties for seed produced in the hills. In the hills, the seed for these varieties can be produced both from autumn and spring sowings. The autumn sown crop gives higher seed yields and matures earlier.
c) Tropical varieties (e.g. Pusa Reshmi, Pusa Chetki, Japanese White, etc.) which produce seed freely in the plains. The seed of these varieties is usually produced in the plains. but good quality seed of some of these varieties (e.g. Japanese white) can also be produced in the hills.		  

 

Land Requirements Land to be used for seed production shall be free of volunteer plants. The soils of selected fields should be deep, light and friable and the fields well-drained.  

 

Isolation Requirements

Radish is corss-pollinated by insects, chiefly honey-bees, seed fields should not be located too close to clover crops, since bees tend to visit clover in preference. Seed fields must be isolated form other vareity fields of radish, and fields of the same variety not conforming to varietal purity requirements of certification, by at lest 1600 metres for foundation seed, and 1000 metres for certified seed production.


Method of Seed Production Both seed to seed and root to seed methods can be employed for raising seed of radish. Seed to Seed method, for varieties which do not stand transplanting well, is preferred forraising certified seed. The nucleus seed,however, is invariably produced by root to seed method.  

Cultural Practices

ROOT TO SEED METHOD

FIRST SEASON - Raising of Stecklings

Time of Sowing a) For hills - The autumn sowings preferably may be done in ealry October. Spring sowing can also be done in March, as soon as the land can be prepared. However, the autumn sowings gives higher seed yields.
b) Plains: The sowing is done at normal time, that is, early october.
  


Preparation of Land For transplanting prepare the field to a fine tilth by ploughing and 3to 4 harrowings followed by leveling.


Source of Seed Obtain breeder's/foundation seeds from source approved by a seed certification agency.


Seed Rate Asiatic Varieties            10kg/ha
Temperate varieties         12kg/ha


Sowing of Seeds The seed should be sown on ridges.


Fertilisation Apply 20-25 tonnes of well-rotted farmyard manure at the time of land preparation; At the time of final levelling mix in the soil 35 kg nitrogen, 50 kg phosphorus and 50 kg potash per ha as basal application. another dose of 35 kg nitrogen be top-dressed when the roots just start growing.


Thinning Thin the crop after 20-25 days to maintain a plant to plant distance of 10-15 cm.


Spacing Row to row spacing for Asiatic types is 45 cm and for temperate types 30 cm


Irrigation Irrigate at eight to 10 days interval depending on the weather conditions and requirements. During early warm weather it may be necessary to irrigate at four to five days interval.


Interculture One weeding and one earthing-up during the early stages of growth is necessary for proper development of roots.


Insect and Disease Control Adopt recommended IPM methods


Harvesting of roots Uproot the plants (stecklings) when they have attained edible maturity (30-70 days, depending upon the vareity)


Selection of roots for transplanting

After harvesting , each steckling is critically examined for foliage and root characteristics namely, size, shape, colour, texture,sponginess etc. Stecklings having off-type foliage or roots not conforming to vareity characteristics must be rejected. Also, the diseased, malformed, forked or any other undesirable types are also rejected.

SECOND SEASON

Preparation of selected roots for transplanting After selection the tops are cut off in a such a way as to leave the small undeveloped leaves together with about 2 cm of the petioles of older leaves. It is the usual practice to cut 1/3rd of the lower root protion in asiatic types, but the whole roots are set in European varieties. These are then reset in a well-prepared field.  

 

Brief Cultural Practices

1. Preparation of land: For transplanting prepare the field to a fine tilth by ploughing and 3to 4 harrowings followed by leveling.

Method of transplanting: The stekclings selected and prepared in the manner described earlier are reset in the field at a distance of 60 x 45 cm. The soil is then firmed and tapped around the roots. Soon after transplanting the field is irrigated. The fields are then checked after 10-15 days for mortality and the gaps are filled well in time to have uniform crop stand.

Manuring:Apply 20-25 tonnes of well-rotted farmyard manure at the time of land preparation; At the time of final preparation mix in the soil 40kg nitrogen, 5 kg phosphorus and 100 kg potash per ha as basal application. Topdress 40kg nitrogen per ha at the time of bolting and preflowering stage.

 

 

 

Roguing The palnts with off-type foliage and the direct bolters are eliminated from the field prior to flowering and the crop is left to set seeds. when the roots are lifted they are critically examined for trueness to type. Besides, small sized or oversized stecklings, diseased, forked and off types should be discarded. Normally three roguings should be done, namely, before mturity of roots for off-type foliage, at the time of replanting for verifying root characteristics, such as size, shape, colour, texture etc. and thelast at flowering stage for early and late bolters and off-types. Also, at all times, check carefully for plants affected by designated diseases (black-leg and black rot) and eliminate them.  

 

Harvesting and Threshing The crop is cut when plants are fully mature. the drier the pods, the more easily will they break open during thethreshing process. The crop is cut by sickle and brought to threshing floor for threshing. there is more often considerable difficulty in threshing the seed from the pod. Frequently, the pod will not greak and let the seed escape. It is, therefore, important to thoroughly dry them before commencing the threshing. Threshing can be done by beating with sticks. the seed after sifting should be dried to six per cent moisture, before storage.  


Seed Yield The average seed yield is about 600 to 800 kg per hectare.