Post on 06-May-2015
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Seed: Types and Quality
Dr. Tauqeer Yasir
What is seed?In broad sense
Seed is a material which is used for planting or regeneration purpose.
scientifically
Seed is a fertilized matured ovule together covered with seed coat is called
seed or it is a propagating material.
Technological point of view
Seed is a fertilized ripened ovule consisting of three main parts namely
seed coat, endosperm and embryo, which in due course gives rise to a
new plant.
It also refers to
Propagating materials of healthy seedlings, tuber, bulbs, rhizome, roots,
cuttings, setts, all types of grafts and vegetatively propagating materials
used for production purpose.
Basic Parts of a Seed1. Embryo2. Endosperm3. Seed Coat
The embryo is the baby plant.
It consists of plumule, radicle and cotyledon. The embryo is the
young multicellular organism before it emerges from the seed.
The endosperm is a source of stored food, consisting primarily of
starches. It is the structure that has been formed to provide
nutrition for embryo in germination.
The seed coat consists of one or more protective layers that encase
the seed. The seed coat is tough and waterproof. It covers and
protects the embryo and the food supply
GerminationThe emergence and development from the seed embryo of those structures
which seed indicate the ability to produce a normal plant.
Conditions Necessary for Germination
Water
Air
Temperature
Light
Modes of Germination
Seeds present two modes of germination based on the behavior of the
cotyledons or storage organs.
Epigeal Germination
Hypogeal Germination
Types of SeedsMONOCOTS DICOTS
Embryo with single cotyledon Embryo with two cotyledonsUsually endospermic Usually non-endospermic (Except Castor seed)Germination usually hypogeal (Except in onion) Germination usually epigeal (except in pea, gram)Flower parts in multiples of three Flower parts in multiples of four or fiveMajor leaf veins parallel Major leaf veins reticulatedStem vacular bundles scattered Stem vascular bundles in a ringRoots are adventitious Roots develop from radicleSecondary growth absent Secondary growth often present
Grains, (wheat, corn, rice, millet) sugarcane, banana, ginger, onions, grass
Legumes (pea, beans, lentils, peanuts) mint, lettuce, tomato, oak, tree, etc.
1.Epigeal GerminationThe cotyledons come out above the soil surface and generally turn green and act as first foliage leaves. This type of germination present in groundnut, bean, cotton, sunflower and cotton seeds.
1.Hypogeal GerminationThe cotyledons do not come above the soil surface. This type of germination is found in wheat, barley, maize and pea.
Classes of Seed1. Breeder’s Seed2. Pre-basic seed3. Basic Seed4. Certified Seed
1. Breeder’s seed
Progeny of nucleus seed
Directly supervised by a breeder
Genetically and physical pure
Not available for commercial distribution
2. Pre-basic seed
Progeny of breeder’s seed
Handled so as to maintain specific genetic purity and identity
Produced in the defined regions
Must be approved by the Federal Seed Certification Department.
White label with diagonal violet line
Classes of Seed
3. Basic seed
• Progeny of pre-basic seed
• Produced on extension farms ,
research farms and by progressive farmers
• Must be certified by the FSCD
• white label
4. Certified seed
• Progeny of basic seed
• Produced by registered growers
of seed producing agencies
• Quality is controlled by the FSCD
• Certified Seed-I has Blue label and
certified seed-II (improved seed) has red label
a. Species (botanical name)
b. Cultivar name
c. Category
d. Reference number
e. Date of issue of certificate
Information on the Label
ANALYSIS TAGA-1 Seed Co.Location, USA
Variety & Kind Vernal AlfalfaLot No. 307-98
Pure seed 98.90%Inert matter 01.05%Other crop seed 00.00%Weed seed 00.05%Noxious weeds 00.00%
Germination 90.00%Hard seed 05.00%Date tested Jan. 2001Net weight 60 lbs.
Seed QualitySeed quality is the sum of all properties contributing to seed performance. The quality of seed can decide whether a farmer’s crop will be good, bad or indifferent. Seed quality is determined by the following characteristics:
1. Physical Attributes
2. Physiological Attributes
3. Genetic Attributes
4. Storability
A minimum of damaged seed A minimal amount of weed seed or inert matter A minimum of diseased seed Near uniform seed size
1. Physical Attributes
Seed Quality
2. Physiological Attributes
Germination Percentage or ViabilityThe germination percentage or viability is an indicator of the seed’s ability to emerge from the soil to produce a plant in the field under normal conditions Seed VigourSeed vigour is the capacity of seed to emerge from the soil and survive under potentially stressful field conditions and to grow rapidly under favourable conditions
Seed of the same variety
Adapted to the local conditions
Pest and disease tolerance
High yielding ability
3. Genetic Attributes
Seed Quality
4. Storability
Moisture content
Temperature of the environment
Seed treatment