Materials required

Materials required
    A. Substratum
    • The substratum serves as moisture reservoir and provides a surface or medium for which the seeds can germinate and the seedlings grow.
    • The commonly used substrata are sand, paper and soil.
    I. Sand
    a. Size of sand particle
    • Sand particles should not be too large or too small.
    • The sand particles should pass thorough 0.80 mm sieve and retained by 0.05 mm sieve.
    b. Toxicity
    • Sand should not have any toxic material or any pathogen.
    • If there is presence of any pathogen, found, then the sand should be sterilized in an autoclave.
    c. Germination Tray
    • When we use the sand, germination trays are used to carry out the test.
    • The normal size of the tray is 22.5 x 22.5 x 4 cm.
    • They tray may either zinc or stainless steel.
    B. Method of seed placement
    1. Seeds in sand(s)
    • Seeds are planted in a uniform layer of moist sand and then covered to a depth of 1 cm to 2 cm with sand.
    2. Top of sand (TS)
    • Seeds are pressed into the surface of the sand
    C. Spacing
    • We must give equal spacing on all sides to facilitate normal growth of seedling and to avoid entangling of seed and spread of disease.
    • Spacing should be 1 5 times the width or diameter of the seed.
    D. Water
    • The amount of water to be added to the sand will depend on size of the seed.
    • For cereals, except maize, the sand can be moistened to 50% of its water holding capacity.
    • For large seeded legumes and maize sand is moistened to 60% water holding capacity.
    II. Paper
    • Most widely used paper substrates are filter paper, blotter or towel (kraft paper).
    • It should be have capillary movement of water, at vertical direction (30 mm rise / min.).
    • It should be free from toxic substances and free from fungi or bacteria.
    • It should \ hold sufficient moisture during the period of test.
    • The texture should be such that the roots of germinating seedlings will grow on and not into the paper.
    A. Methods
    a. Top of Paper (TP)
    • Seeds are placed on one or more layers of moist filter paper or blotter paper in petridishes.
    • These petridishes are covered with lid and placed inside the germination cabinet.
    • This is suitable of those seeds which require light.
    a. Between paper (PP)
    • The seeds are placed between two layers of paper
    b. Roll towel method
    • The seeds are placed between two layers of paper and rolled in towels.
    • The rolled towels are placed in a water source and kept in germinator or germination room
    c. Inclined plate method
    • Germination on glass plate with germination paper and kept at an angle of 45°
    III. Soil
    • Should be non-caking, free from large particles. It must be free from weed seeds, bacteria, fungi, nematode and other toxic substances. Soil is not recommended for reuse.
    B. Temperature
    • Normally most of the seeds germinate between 20-30° C
    C. Light
    • Light requirement seeds should provided with light eg. Lettuce
    Germination requirements for different crops

    Crop

    Substratum

    Temp 0 C

    First count
    ( Days)

    Final count
    (days)

    Pre - treatment
    Brinjal TP,BP 20-30 7 14 EthreI (25 ppm) 48 hrs.
    Tomato TP,BP 20-30 5 14

    Chillies TP,BP 20-30 7 14 (Hot water 85° C 1 min)
    Bhendi BP,S 20-30 4 21

    Onion TP,BP 15-20 6 21 KN03
    Carrot TP,BP 20-30 7 14 KN03
    Radish TP,BP 20-30 4 10 Pre chill
    Cabbage



    		Pre chill
    Cauliflower TP 20-30 5 10 Pre chill, KN03
    Ash gourd S 30-35 5 14 light
    Biter gourd BP,S 20-30 4 14

    Bottle gourd BP,S ' 20-30 4 14 -
    Germination apparatus
    1. Germination Cabinet / Germinater
    • This is called chamber where in temperature and relative humidity is controlled. We can maintain the required temperature
    2. Room germinator
    • It works with same principle of germinator. This is a modified chamber of larger one and the worker can enter into it and evaluate the seedlings. Provisions are made to maintain the temperature and relative humidity. This is used widely in practice.
    3. Counting Board
    • This is used for accurate counting and spacing of seeds. This consists of 2 plates. The basal one is stationary and top one is movable. Both top and basal plates are having uniform number of holes viz., 50/100, when the plates are in different position. After taking the sample, the top plate is pulled in such a way that the holes are in one line so that the fixed number of seeds falls on the substratum.
    4. Vacuum Counter
    • Consists of a head, pipe and wall. There are plates of 50 or 100 holes which can be fitted to the head. When vacuum is created the plate absorbs seeds and once the vacuum is released the seeds fall on the substrate.
    5. Impression Board
    • Made of plastic / wood with 50 or 100 holes/pins. Here the knobs are arranged in equal length and space. By giving impression on the sand it makes uniform depth and spacing for seed.
    D. Seedling Evaluation
    • ISTA classified the seedlings into different categories based on the development of essential structures
    Categories of seedlings
    1. Normal seedlings
    2. Abnormal seedlings
    3. Hard seeds
    4. Fresh ungerminated seeds
    5. Dead seeds
    1. Normal seedlings
    • Seedlings which show the capacity for continued development into normal plant when grown in favorable conditions of soil, water and temperature.
    Characters of normal seedling
    1. A well developed root system with primary root except in certain species of graminae which normally producing seminal root or secondary root
    2. A well developed shoot axis consists of elongated hypocotyls in seedlings of epigeal germination.
    3. A well developed epicotyls in seedlings of hypogeal germination.
    4. One cotyledons in monocots and two in dicots
    5. A well developed coleoptile in graminae containing a green leaf
    6. A well developed plumule in dicots
    7. Seedlings with following slight defects are also taken as normal seedlings. Primary root with limited damage but well developed seminal root system in leguminaceae (Pisum), graminae (maize), cucurbitaceae (cucumis) and malvaceae (cotton)
    8. Seedlings with limited damage or decay to essential structures but no damage to conducting tissue
    9. Seedlings which are decayed by pathogen but it is clearly evident that the parent seed is not the source of infection.
    2. Abnormal Seedlings
    • Seedlings which do not show the capacity for continued development into normal plant when grown in favorable conditions of soil, water and temperature
    Types of abnormal seedling
    A. Damaged seedlings
    • Seedlings with any one of the essential structures missing or badly damaged so that the balanced growth is not expected. Seedlings with no cotyledons, with splits, cracks and lesions or essential structures and without primary root.
    B. Deformed seedlings
    • Weak or unbalanced development of essential structures such as spirally twisted or stunted plumule or hypocotyls or epicoptyl, swollen shoot, stunted roots etc.
    C. Decayed seedlings
    • Seedlings with any one of the essential structures showing diseased or decayed symptoms as a result of primary infection from the seed which prevents the development of the seedlings.
    3. Hard seeds
    • Seeds which do not absorb moisture till the end of the test period and remain hard (e.g.) seeds of leguminaceae and malvaceae
    4. Fresh ungerminated seeds
    • Seeds which are neither hard nor have germinated but remain firm and apparently viable at the end of the test period.
    5. Dead seeds
    • Seeds at the end of the test period are neither hard nor fresh or have produced any part of a seedling. Often dead seeds collapse and milky paste comes out when pressed at the end of the test.
    Retesting
    • If the results of a test are considered unsatisfactory it shall not be reported and a second test shall be made by the same method or by alternative method under the following circumstances.
    1. Replicates performance is out of tolerance
    2. Results being inaccurate due to wrong evaluating of seedlings or counting or errors in test conditions.
    3. Dormancy persistence or phytotoxicity or spread of fungi or bacteria. The average of the two tests shall be reported.
    Use of tolerances
    • The result of a germination test can be relied upon only if the difference between the highest and the lowest replicates is within accepted tolerances.
    • To decide if two test results of the same sample are compatible again the tolerance table is used.
    Reporting results
    • The results of the germination test is calculated as the average of 4 x 100 seed replicates. It is expressed as percentage by number of normal seedlings. The percentage is calculated to the nearest whole number. The percentage of abnormal seedlings, hard, fresh and dead seeds is calculated in the same way. These should be entered on the analysis of certificate under appropriate space. If the result is nil for any of these categories it shall be reported as '0'.
    Seed standards for germination
    S.No. Crop Class of seed


    		Foundation Seed Certified seed
    1. Brinjal 70 70
    2. Chillies 60 60
    3. Bhendi 65 65
    4. Tomato 70 70
    5. Cabbage 70 70
    6. Cauliflower 65 65
    7. Carrot 60 60
    8. Radish 70 70
    9. Beet root 60 60

Last modified: Saturday, 24 March 2012, 7:30 PM