Producing Seeds of Biennial Vegetables in Temperate Regions

PRODUCING SEEDS OF BIENNIAL VEGETABLES IN TEMPERATE REGIONS

T S Verma and

S C Sharma IARI, Regional Station, Katrain (Kullu Valley), Himachal Pradesh, 175 129

w&sm ICAR

Published by Directorate of Knowledge Management in Agriculture INDIAN COUNCIL OF AGRICULTURAL RESEARCH New Delhi 110 012

PRINTED : MAY 2000 REPRINTED : MARCH 2011

Project Director (DKMA)

Incharge (English Editorial) Editing

Chief Production Officer Technical Officer (Production) Senior Artist

Dr T P Trivedi Dr R P Sharma Dr Sudhir Pradhan V K Bharti Punit Bhasin Narendra Bahadur

Š 2011 , All Rights Reserved Indian Council of Agricultural Research New Delhi

ISBN : 81-7164-101-7

Price: ?100

Published by Dr T.P. Trivedi, Project Director (DKMA), Directorate of Knowledge Management in Agriculture, Indian Council of Agricultural Research, Krishi Anusandhan Bhavan, Pusa, New Delhi 1 10 012 and printed at M/s Chandu Press, D-97, Shakarpur, Delhi 110 092.

CONTENTS Chapter No.

1.

2.

3.

4.

5.

Title

Page No.

Foreword

iii

Preface Introduction Climate Soil Principles of Crop Production Cole Crops Cabbage Cauliflower

iv

Knol-khol

Brussels sprout Sprouting broccoli Kales and Collards

1

3

7 10 26 26 51 64 71 78 85

6.

Root Crops Carrot Radish Turnip Beet

90 90 105 116 125

7.

8.

9.

Maintenance Breeding Breeders’ Seed Production Seed Processing

137 145 151

10.

Plant-Protection Measures

155

11.

Bibliography

169

Annexures

I. II. III. IV.

Mean Meteorological Observations (1975-1992) Seed Standards Crop Standards Average seed-yield and multiplication ratio

172 173 174 175

Subject Index

176

.

I

Introduction TN Vegetable Crops seed production has been divided into two groups: A(i) those vegetables which can produce seeds satisfactorily in the vast plains and lower mountaineous tracts of India termed tropical, annual or Asiatic eg. tomato, brinjal, capsicum, chillies, cucurbits, okra, peas, beans, spinach, amaranthus, onion, fenugreek, basella (poi), lettuce, leek, celery, Indian (Asiatic) cauliflowers, tropical or Asiatic types of radish, turnip and carrot; (ii) European or biennial or temperate vegetables requiring temperate climate especially during a specific stage of their growth for successful seed production. During this period that these vegetables meet the vernalization (chilling) requirement, a precondition necessary for breaking the dormancy of the plant thus stimulating the conversion of the vegetative phase into the reproductive phase i.e. induction of bolting and flowering. The vegetables under this category belong to two groups viz. cole and root groups. In the cole group the different vegetables are cabbage (Brassica oleracea (L.) var capitata L.) late cauliflower/ snowball group (Brassica oleracea (L.) var. botrytis L.), knol khol (Brassica oleracea (L.) var. gongylod.es L.), brussels sprouts (Brassica oleracea (L.) var. gemmifera DC), sprouting broccoli (Brassica oleracea (L.) var. italica Plenck), kale (Brassica oleracea (L.) var. acephala DC) and collards (Brassica oleracea (L.) var. viridis (L.) (Tanwer and Singh, 1988). With the exception of snowball or late group of cauliflower, all other cole crops need a low temperature of 4.4°-10°C for 60 days to stimulate inflorescence stalk development whereas the late cauliflower does not require chilling for flowering but its seed production is possible only in the temperate regions which offer the favourable temperature for good seed setting in April-May when the crop is in flowering stage. The root crops comprise of beet (no asiatic type) and temperate types of radish, turnip and carrot.

For the first time in 1942-43, the then Imperial Government encouraged the 'seed production of European types of vegetables at Quetta in Baluchistan (now in Pakistan). At about the same time initial trials on seed production were also initiated in Kashmir. The Department of Agriculture, Punjab also opened a small farm at Katrain (Kullu Valley), in Himachal Pradesh (the then a part of Punjab) during 1942-43. In 1945, the seed production in Kashmir and Kullu Valley was mainly in the hands of private seed growers. These growers paid little attention to the scientific procedures to be followed in the production of quality seeds comparable to the imported seeds. The reasons being lack of expertise available in India at that time, lack of technical knowhow, time taken for standardization of agrotechniques for quality seeds and the difficulty in the adaptability of the new materials (varieties of different crops to the new environment which took some time (few years) to get acclimatized to the changed climatic conditions. The varieties suitable

2

PRODUCING SEEDS OF BIENNIAL VEGETABLES

for a particular region may not perform well at some other location with a similar set of climatic conditions due to ‘nicking’ behaviour. They will become adapted in the course of time or need modifications in the cultural techniques.

With the partition of India in 1947, Quetta centre of temperate vegetable seed production went to Pakistan and the supplies were cut off. The Kashmir seed industry which was still in infancy was also considerably affected by disturbances in 1948. Thus it became necessary to strengthen the temperate seed programme also at some other suitable locations in India. After taking the results from the preliminary trials carried on since 1940-43, the Ministry of Food and Agriculture, Government of India started a Research Station (Central Vegetable Breeding sub Station) at Katrain (Kullu Valley) Himachal Pradesh in 1949. This station in 1955 was transferred to Indian Agricultural Research Institute, New Delhi with the sole objective of intensifying the improvement work on temperate vegetables and was renamed as IARI Vegetable Research Station and later on as IARI, Regional Station.

_

Climate Kullu Valley stretches over a distance of about 80 km between Based on the altitude the valley is divided into lower Kullu valley and upper Kullu valley. The altitude of lower Kullu valley stretching between Aut and Kullu ranges from 800 m to 1200 m. This part has more plain area than the upper part of the valley. The altitude of the upper Kullu valley ranges between 1200 m and 2000 m. Katrain situated at 1500 m in the centre of the upper Kullu valley has good irrigated and rain-fed agricultural land in the vicinity. For seed production the areas, between 1200 and 1450m altitude, are considered the best due to minimum fluctuations in temperature. The lower Kullu valley is relatively warmer but quite suitable for growing winter vegetables for local consumption and supply to plains as off-season vegetables. A part of this valley with irrigation facilities has now become specialized in off-season production of vegetables. Also mild winter facilitates a continuous growth of the winter vegetables sown or planted during autumn. The temperatures during the winter meet the chilling requirement of temperate vegetables. The seed maturity and harvesting is a bit earlier than the upper Kullu valley.

The upper Kullu valley due to high altitude and its nearness to snowline represents the true temperate climate in having snowfall, frost and severe winter. Comparison of climatic conditions of Indian locations with that of foreign countries based upon Singh et al., (1959) is given in Tables 1 and 2.

1 Aut and Rahla (25 km north-east of Manali).

Table 1. Major seed production areas in the world Region

Climate

North-Western Europe Eastern and South-Eastern UK, Holland, Western Denmark

Maritime climate, mild winters, cool summers, 50 - 100 cm rainfall throughout the year.

ii. Central Europe Southern Sweden, Eastern Denmark Northern Germany, Switzerland

Transitional climate, cold winters, warm summers, 50-100 cm rainfall throughout the year.

iii. Mediterranean area Southern France, Southern Italy

Mediterranean climate, warm wet winters, hot dry summers, 50-100

i.

cm rainfall iv. North America and Canada Western USA (Pacific North West), Canada (British Columbia)

Maritime climate, mild winters, cool summers, 50-100 cm rainfall distriÂŹ buted throughout the months maxiÂŹ mum in autumn and winter.

v. California

Mediterranean climate

Besides Kullu and Kashmir valleys, fulfilling the necessary requireÂŹ ments for seed production of temperate vegetables, there are other areas

4

PRODUCING SEEDS OF BIENNIAL VEGETABLES

also in India (Table 2) which would widen the scope for expanding this seed industry not for indigenous consumption but also for exports to even some European and Western countries where seed production is becoming expensive day by day with the increase in costs of labour.

Seed production enterprise, on a commercial scale, will be profitable in India where labour is cheap and should also simultaneously generate employment opportunities. Identification of other pockets with suitable climatic conditions will also overcome the problems of many diseases and insect pests which have become quite predominant due to continuous growting of vegetable seed crops in the same land/tract.

Table 2. Temperate vegetable seed production regions in India

i.

Region

Climate

Srinagar Valley (Jammu and Kashmir)

Transitional climate, cold winters,

ii. Upper Kullu Valley (Himachal Pradesh)

iii. Lahaul Valley (Himachal Pradesh) iv. Kalpa Valley, Kinnaur (Himachal Pradesh) v. Saproon Valley, Solan (Himachal Pradesh) vi. Kumaon Hills (Uttar Pradesh) vii. Kalimpong-Daijeeling Hills (West Bengal) viii. Nilgiris (South India)

warm summers, 50-75 cm rainfall distributed over about 60 days Cold winters, warm summers, 1DO125 cm rainfall distributed throughout the months, maximum in rainy season and spring Severe cold winters, cold summers, 10-25 cm rainfall Severe cold winters, cold summers, 10-25 cm rainfall Cold winters, mild summers, 75-100 cm rainfall Cold winters, mild summers, 100-125 rainfall Cold winters, warm summers, 200250 cm rainfall Cool winters, warm summers, rainfall upto 110 cm

The chief features of European or temperate climate are as follows: (i) Low temperature: A low temperature of (4.4°-10°C) for 60 days during winter provides the necessary requirements for breaking the dormancy of biennial vegetables which otherwise will not induce to bolting and flowering. A low temperature within this range, duration of exposure to low temperature and the stage of growth of the plant have an interacting effect on bolting. For a plant to respond to the inductive reaction of low temperature, it must attain a particular stage of growth. (ii) Mild summer: The temperate vegetables after getting the necessary requirement of low temperature for breaking their dormancy, enter into the flowering stage. There will be no seed setting at high temperature due to pollen sterility and mortality. It is only the mild summer with day temperature below 30°C that favours efficient pollination, fertilization

CLIMATE

5

and seed setting. (iii) Low rainfall: Low rainfall of 50 to 75 cm is well distributed over the year. Generally the ripening and harvesting period of biennial vegetables coincides with dry or low rainfall in summer.

It is obvious that the upper Kullu valley from Katrain to Manali, meets the requirements of a typical temperate climate except that the annual rainfall is slightly high ranging from 100 to 150 cm (Annexure I). This rainfall is distributed over the months invariably more during rainy and spring seasons from the July to September and February to April, respectively. These two seasons are important for seed production.

Rains during rainy season interfere with the sowing/transplanting of cole crops, sowing of root crops and also harvesting and seed extraction of preceding year rabi crops if the rains commence early. During spring almost all the crops are in the flowering stage and the rains during this period affect seed-setting by reducing bee-activity (the main pollinating agent) and also damage the pollen grains. Inspite of these bottlenecks standardization of agrotechniques viz. adjustment of so wing/planting dates, protection from frost/snow, tackling of diseases and insect pests has made it possible to grow seed crops satisfactorily provided proper attention is given. In a cloudy weather, efficiency of pollination can be increased by keeping more bee-hives in the fields so that the honey bees remain confined to a limited area with an increase of visiting bees per unit area. The climate in the vicinity of Manali is, however, not suitable for seed production under open field conditions on account of persisting colder winters for longer durations, high snowfall and rainfall.

The climate of Kashmir valley is nearer to the European climate than Kullu valley. The climate of Kashmir valley, however, differs in one respect of distribution pattern of rainfall because a greater portion of total rainfall is received during the monsoon. The winter temperatures of Kullu and Kashmir valleys are so congenial that neither protection from cold in the field nor provision of storage facilities for overwintering is required. The crops under these climatic conditions can be left in the open for overwintering without any damage. Winter and summer suit to produce seeds of not only the European /temperate /biennial vegetables but also of summer vegetables (tropical/ sub-tropical) like tomato, brinjal, capsicum, chillies, cucumber, summer squash, okra and french bean for optimum utilization of land and labour. This forms a sort of intensive type of seed farming system and can be practised more profitably by the seed growers.

Lahaul Valley, situated on the other side of the Rohtang Pass, has an ideal climate resembling to that of Quetta (Pakistan). However, this valley has heavy snowfall than Quetta but is complete dry because of very low rainfall during the winter. As a result of this, overwintering of cabbage heads or roots is not possible under open field conditions because of prolonged period of snow-cover leading to winter/ snow injury.

For seed production in such areas, it is necessary to overwinter the heads/roots under proper storage conditions as is done in some parts of Central Europe and Kalpa Valley of Kinnaur district in Himachal

6

PRODUCING SEEDS OF BIENNIAL VEGETABLES

Pradesh. At present seed production of temperate vegetables in Lahaul Valley is not done because of main above mentioned bottlenecks except Kalpa Valley (Himachal Pradesh). Due to confined tracts of seed production in the mountain areas, a great population of harmful pathogens and insect-pests is being built up constantly in these areas and this may pose a grave challenge to the seed industry, if suitable measures to evolve resistant stocks of the crop are not taken up seriously right now or the seed industry will have to be shifted to some other areas not prone to diseases and pests e.g. black rot (cole crops), downy mildew (cole crops) and sclerotinia rot (cauliflower) . Mere shifting of a site within a particular region will take care of only the soil borne pathogens. However, due to increasing awareness among the people regarding the role of vitamins, minerals, proteins and carbohydrates in their diet (food) and the growing of off-season vegetables for supply to the plains, there is hardly any patch remaining without growing of one or other kind of vegetables. These areas, of course, will definitely be advantageous to meet immediate challenge. However for long term planning, location of new pockets confined by high mountain ranges will be the only answer in the absence of resistant varieties. It is worthwhile to make a mention of some diseases/crops which are having a grave concern on the part of the seed grower/ government. For example, sclerotinia rot of cauliflower is found in Saproon valley of Solan (Himachal Pradesh), Kullu valley, Kashmir valley and the Uttar Pradesh hills and black-rot and downy mildew in cole crops in temperate and subtropical zones.

3 Soil "1VT ORMALLY the soils suitable for fresh vegetable growing will defii. N nitely meet the requirements of seed production also. Generally well-drained loam soils are preferred. Since most of the temperate crops take more than 1 year for seed production, soil should either have sufficient organic matter and nutrient content or be supplied externally.

It is advisable to get the soil analysis carried so as to make judicious use of organic manures and chemical fertilizers. Among the organic manures, Farmyard manure (FYM) as cattle dung is mostly used.

Besides many advantages, FYM also increases the water-holding capacity and improves aeration in the soil. But owing to the non-availability of FYM in sufficient quantities to meet all the nutritional requirement of the crops, the use of other sources of essential minerals either singly or in combined form is essential to boost up the production. Clay soils are difficult to prepare and normally not considered suitable particularly for root crops. On heavy soils, maturity of seed crops is delayed considerably whereas light soils hastens the maturity and seed ripening.

The soils in the upper Kullu valley vary from sandy loam to clay loam.

The land on the bed of the Beas river particularly near Katrain is generally of sandy-loam type which can be easily worked out after rains and irrigation. The soils are, however, poor in plant nutrients and require considerable quantity of organic manure to make them fit for vegetable seed production. Maturity of seed crop in such soil is also advanced by 2-3 weeks than the heavier soils. With adequate manuring these soils become more suitable for seed production than the clayloam soils. The soil analysis of 3 farms namely Naggar, Baragraon and Sarsai of IARI Regional Station, Katrain (Kullu Valley), situated above 1 500 m above mean sea level showed that these soils contain sand, silt, clay contents (Table 3a) and organic carbon, P2Os and K2Q (Table 3b).

These soils show acidic reaction with pH ranging between 4.8 and 5.3.

Table 3a. Mechanical analysis of soils of 3 farms Clay

Height above mean sea level (m)

Sand content (%)

Silt content

content

(%)

(%)

Naggar

1,688

90.5

8.5

1.0

Baragraon

1,560

84.0

13.0

3.0

Sarsai

1,650

89.0

8.5

2.5

Name of the farm

8

PRODUCING SEEDS OF BIENNIAL VEGETABLES

Table 3b. Chemical analysis of soils of 3 farms Name of the farm

EC (in mm hos/cm)

Organic Organic nitrogen carbon

CaC03

P205

k2°

(kg/ha)

(kg/ha)

Naggar

0.07

Low

0.40

Nil

95.8

196.0

Baragraon

0.07

Low

0.38

Nil

153.9

308.0

Sarsai

0.16

Low

0.46

Nil

89.1

218.5

Analysed by the Division of Soil Science and Agricultural Chemistry, IARI, New Delhi.

Soil preparation Due to hilly terrain, the fields have to be properly levelled to facilitate irrigation and should also have proper drainage. The fields are usually terraced and made into convenient sizes. The land should be thoroughly prepared to make it loose and friable. The land preparation must start between 45 and 60 days before the actual transplanting period by giving 3-4 ploughings. All the stubbles and weeds should be removed to make the field clean. FYM should be thoroughly incorporated into the soil during field preparation. Vegetables grow best in fairly deep soils. The tilth or physical condition of the soil is important in relation to plant growth. If the soil is poor in physical condition, it will be hard and crusty when dry, and sticky when wet. Under such conditions, vegetables will not grow and develop properly. The physical properties of soil may be improved by adding soil amendments, which improve the chemical and/or physical conditions of the soil and consequently improve the plant growth. The best ones commonly used are organic amendments which affect soil structure and fertility. The rate of decomposition of organic matter depends upon water, nitrogen and temperature.

The deeper the soil prepared, the greater is its capacity for holding air and moisture. One of the purposes of turning over the soil is to separate soil particles and allow air to come into contact with as many particles as possible and thereby provide good growing media for the growth of roots and soil microorganisms. The fall ploughing has several advantages in soils vacated by root crops after their replanting in November-December. i. Organic matter decomposes more rapidly. ii. Insect and disease problems are reduced by burying them in the soil or exposing them to the unfavourable environment. iii. More water is absorbed. iv. The physical conditions of clay soils are improved by exposing them to frost action. v. The trapped air acts as insulator for increasing the survival of earthworms.

SOIL

9

The fall ploughing is particularly desirable when soil, manure or a large amount of organic matter is to be turned under.

Soils should not be worked with when they are wet. For testing, a handful of soil is squeezed by hand, it should readily crumble and not feel sticky when the pressure is released. If the soil forms a compact, muddy ball, it is too wet to be worked with, and such soil sticks to the showel or other tool. Shiny unbroken surfaces of spaded soil is another indication of a wet soil condition. Clay soils low in organic matter, loose their crumbly texture if they are worked with when wet and become hard, compact and unproductive. Soils should also not be worked to such a fine consistency that crusting occurs after rains. Clay soils particularly crust easily and prevent emergence of seedlings. These soils should be left comparatively rough and cloddy to reduce crusting of the soil surface. Ploughing is the basic operation in land preparation and should be done very carefully to prepare bedding for the germination of seed and establishment, growth and development of the plant.

4 Principles of Crop Production T VEGETABLE CROPS grown for fresh market are short duration in

V nature and need optimum fertilization for their proper development.

Rich fertile soils are considered to be the most suitable for them.

MANURING AND FERTILIZATION

For seed production, heavy doses of manures and fertilizers are required because several vegetable crops have to be grown through two stages, vegetative and reproductive with the result that in some cases the fields remain occupied for more than a year. For the second phase to complete its development smoothly, extra manuring than required for vegetable crops need to be applied. It will not be advantageous to apply fertilizers during the vegetative phase and ignore the reproductive phase. But it does not mean that bolting and flowering will not take place. The reason is that in the absence of proper manuring, the plant will not be able to bear the sufficient load of flowers and seed. The early set pods and seeds will not allow further development of buds and opening of flowers as a consequence of physiological imbalance of nutrition. This affects the maturity, quality and vigour of seed produced.

In Kullu valley, the availability of FYM is not satisfactory due to small farm-holdings and less number of cattle. Other main reason is increasing area under apple cultivation in this belt which is very remunerative although less labour and expense oriented. The orchardists divert major portion of FYM to apple trees. Use of inorganic fertilizers is the only alternative left to tackle the problems of soil fertility.

The FYM available in this valley primarily consists of cattle dung and dried leaves of conifers such as deodar ( Cedrus deodara) and other Pinus spp. According to Singh et al. (1959), the possibility of green manuring requires consideration. In the intensive cultivation of cereals and vegetable crops, this may not be feasible due to less time in between the two consecutive crops. However, only in seed production of temperate vegetable crops, it may be possible to grow a short and quick growing green manuring crop after the harvest of seed crops of turnip, knolkhol, cabbage, cauliflower, etc. in June. The green manure crop can be ploughed in by the end of August or early September when sufficient moist conditions in the soil is present and high temperature facilitates rapid decomposition of the green matter. This green manured land would be available for transplanting of mature root crops for over-wintering in the field during November and December. If land is vacated by cole crops after harvesting, it can be utilized for replanting of root crops after raising green manuring crop. In the second year cole crops can be transplanted during August-September on the land vacated after seed harvesting of root crops without following green manuring due to

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