Presence Of Insect Pollinators In Abundance

Published Date: 02 Nov 2017

Pure and healthy seed is of paramount important for vegetable production. It requires a special technique and perfect acquaintance with various fundamental principles of vegetable seed production.

Different parts such as mature fruits ( tomato, watermelon , muskmelon and pumpkins ),immature fruits/pods( Brinjal, okra , capsicum ,green chillies , peas , beans , bottle gourd, ridge gourd ,sponge gourd, squash, tinda, cucumber),leaves, (palak , spinach ) ,bulbs(onion) roots( carrot, radish, turnip beet root) ,stems (cole crops) are used as vegetables. Hence unlike in cereal or pulse crop, the agro-techniques market production as well as for production in vegetable varieties a great deal depending upon the type f vegetable crops.

With some vegetable it may be a simple job but for relatively a large number of other vegetable it requires special cares in agro-techniques at various stages of flowering and seed production.

I. Selection of the area

- Grow the seed crop in semi-arid areas, as the seed born inoculums cannot transfer to the new seed in a dry atmosphere.

- for some disease the production of healthy seed means that grower can concentrate on growing rather than crop protection.

II. Cultural practices:

In majority of the cases cultural practices are same both for market production of vegetable and seed production.

Furrow irrigation; reduce the incidence of foliage diseases and fruit rot in some cases.

Replanting of selected heads (cole crops), roots (carrot, radish) and bulbs (onion).

Seed to seed method (in situ).

Root to seed method.

More spacing between plants:

Avoid quick spread of diseases.

Crop inspection and spry treatment is easier.

Leaves and pods will dry more quickly and the chance of successful infection will be reduced.

III. Planting season :

Summer for watermelon and muskmelon.

Summer and rainy season for cucumber, pumpkins and gourds.

More number of female flowers are produced during summer ,More number of fruit/plant – maximum seed yield.(Nobel and Davis,1949)

Foliage diseases are minimized during summer months.

Summer and rainy season for tomato and brinjal ( warm season crops)

They cannot withstand frost.

High temperature (more then 38o c) results in reduced pollen production in tomato.

Low temperature during cool season causes loss of pollen viability and leads to parthenocarpic set in brinjal. Also results in abnormal ovary development.

_ Rainy and summer season for Amaranth (warm season crop, requires 15-16 hr day length for Optimum growth).

Winter (September-October) for beet root / palak (cool season crop).

Winter for cole crops.

Throughout vegetative growth temperature must be 15o C. for 2 months. Hence, possible only in hills.

Winter for root crops (radish and carrot) .

European / temperate type in hills.

Short duration

Do not withstand transplanting.

Require chilling temperature during root growth and long photoperiod (14 hrs) during flowering.

Asiatic / tropical types in plains.

Long duration.

Can withstand transplanting.

Do not require chilling temperature during root growth for seed production.

Winter planting for onion and carrot.

All cultivars of onion are long day plant with respect to bulb formation. Day neutral with respect to flowering. Bulbs are more quickly at warm temperature than cool temperatures.

10 – 15 - 100 % bolting

15 – 20 - < 10 % bolting.

20 – 25 - No bolting .

Sowing: October

Transplanting : January

Bulbing : April –May

Store bulbs in fairly cool temperature or over wintering the field conditions the plants for seed stalk formation . Temperature of 5 – 14o C are favorable for the conditioning process.

Bulbs – Planted in October , November – December , there will be chilling temperature. While, the onions are in flower, clear , bright days are necessary to ensure insect activity for pollination.

IV . Proper isolation of seed fields:

Highly self pollinated crops: Tomato( Lycopersicon esculentum), Garden pea( Pisum sativum) , French bean ( Phaseolus vulgaris ) , Cow pea ( Vigna unguiculata) , Hayacinth bean( avare) ( Dolichos lab lab var. typicus).

Often cross pollinated crops: Brijal ( Solanum melogena) , Chillies ( Capsicum frutescence), bell pepper( C. annum) , Okra( Abelmoschus esculentus).

Highly cross pollinated crops: Cabbage ( Brassica oleracea var. capitata), Cauliflower ( B.oleracea var.botrytis), Knol khol ( B.o. var.gongylodes) , Turnip ( B. rapa) , Radish ( Raphanus sativus) , carrot ( Daucus carota) Garden been/ palak( Beta vulgaris), Amaranths(Amaranths tricolor) , Onion( Allium cepa ) , Watermelon(Citrullus lanatus) muskmelon ( Cucumis melo) Pumpkin ( Cucubita maxima, C.moschata, C.mixata), squash ( C.pepo) , Bottle gourd ( Lagenaria sicerarea), Sponge gourd ( Luffa cylindrica) , Ridge gourd (L.acutangula) Bitter gourd( Momrdica charantia) , Ash gourd ( Benicasa hispida) ,Round gourd ( Citrullus vulgaris var. fistulosus) , Cucumber ( Cucumis sativus) , Longmelon ( C.melo var. utilissimus).

Isolation is essential to:

Minimize cross pollination between two varieties.

Minimize parthenocarpic fruit set in certain cases .

Minimize mechanical mixtures of seeds of two species.

Isolation distance suggested for:

Crop

Foundation

Certified

Highly self pollinated

50 - 200 m

25 – 100 m

Often cross pollinated

400 m

200 m

Highly cross pollinated

1600 m

1000 m

Skillful and intelligent rouging of seed fields :

Plants that are off type diseased ( eg. Squash mosaic is seed borne) or off type fruits should be removed as early as possible to reduce the amount of off type pollen in the field .

preflowering rouging with regard to morphological characters, early bolters, heads, root and bulb characters.

Post flowering rouging with regard to flower colour, fruit or pod characteristics.

Post harvest stage rouging with regard to seed colour and shape.

VI . Presence of insect pollinators in abundance:

_ Majority are cross pollinated, honey bees being the chief pollinating agents.

_ For maximum fruit set and seed yield, these insects should be present in relative abundance in seed fields at the time of flowering.

Even in self fertile, perfect flowers of muskmelon and watermelon self pollination is rare unless necessary mechanical aid is given by bees or by hand.

Assured pollination has been found to increase 22 -100 % seed yield in radish.

Insufficient pollination has been reduce the seed yield.

Insufficient pollination also results in (D) shaped fruits in case of watermelon.

Extension of " Trained bees" to field pollination has been suggested .

Bee pollination can undoubtedly be applied to all members of the cultivated vegetable crops excepting a few species such as bottle gourd and ridge gourd which are pollinated by moths as anthesis takes place during evening or night hours.

VII . Stage of seed maturity and harvesting :

Allow the fruits , pods , capsules, umbels atc. , to reach the full maturity .

- Stage of harvest has a drastic effect upon germination of the seed.

If the crop is not harvested immediately after reaching proper stage, deterioration may occur in the field.

( 1 ) In crops like tomato , Brinjal , Muskmelon , watermelon , cucumber , bitter gourd , pumpkins and squash the seeds are extracted as follows :

Fermentation method: Crush or cut the fruit, collect the seed + pulp+ mucilagenus material in a container. Add some water. Allow for fermentation at room temperature for 24 hours to 48 hours. Wash the seeds and dry.

Acid method: 8 - 10 ml commercial HCl or 3 ml commercial H2SO4 per kg of freshly threshed material . Add some water and stir vigorously. Seeds separate within half an hour. Wash and dry the seeds. Germination is good.

Mechanical method: Mechanical harvesting and crushing of the fruits takes place in the field. Seeds are separated, washed and cleaned.

In crops like okra, legumes, cole crops and radish, the plants are harvested when 90% of the pods are ripened (Yellow or brown pods) and left in the threshing yard for 4-5 days before threshing.

In crops like onion carrot, and leafy vegetables, seed ripening not uniform. Dry seed stalks or umbels are cut periodically and dried an threshed.

I n bottle gourd, ridge gourd, and sponge gourd dry fruits are broken open and seeds are extracted.

In chillies and capsicum, red rip fruits are harvested, dried and beaten and seed are separated.

VIII. Seed drying:

Unless the seed is dried fairly rapidly to safe moisture content level of storage, the high rate of respiration and mould growth will cause over heating resulting in loss of viability.

1. Sun drying

2. Drier or dehydrator drying.

Moisture content should be reduced to 6 – 8 % for safe storage.

Estimated seed yield (Q/ha)

Sl. No.

Crop

Yield (Q/ha)

Sl. no.

Crop

Yiel (Q/ha)

1

Tomato

1.5- 2.0

12

Amaranths

2.0

2

Brinjal

1.0

13

Peas

14.0 -15.0

3

Carrot(temp.)

5.0 – 6.0

14

Watermelon

1.0 – 2.0

4

Carrot(Asiat.)

15.0 – 20.0

15

Muskmeon

1.0

5

Radish

6.0- 8.0

16

Pumpkins

3.0 – 4.0

6

Turnip

4.0 -5.0

17

Bitter gourd

7.0 – 8.0

7

Knol kohl

5.0 – 6.0

18

Cucumber

3.0 – 4.0

8

Cauliflower

2.0- 2.5

19

Cpsicum

0.7 – 0.8

9

Cabage

2.0 – 2.5

20

Chillies

0.7 - 0.8

10

Onion

7.0 – 8.0

21

French bean

30.0-35.0

11

Beet root/Palak

5.0 – 6.0

22

Okra

10.0- 25.0