2. COTTON
King of fibres, White Gold
65%fibre used in textile industry
Fibre – elongation of single cell in sub epidermal layer of seed.
4 cultivated species
1.G.hirsutum – American upland cotton (90%)
2.G.barbadense-Egyptian cotton (8%)
3.G.arboreum-tree cotton (2%)
4.G.herbaceum-Asian cotton(<2%)
3. COTTON QUALITY CHARACTERS
1.Percent of good and bad Kapas:
• Kapas of fully opened and spoiled and not opened properly are collected and
weighed separately. Then the percentage of both good and bad kapas calculated
and expressed in percentage.
2.Barlett's earliness index:
B.I. = P1 + (P1 + P2) + (P1 + P2+P3) + (P1 + P2+P3 ----- Pn)
N (P1 + P2 + P3 + ---- Pn)
Where,
• B.I. = Barlett's index
• P1, P2, P3…. Pn = Seed cotton picked in first, second third and at then picking
respectively.
• N= Total number of pickings.
4. COTTON QUALITY CHARACTERS
3.Ginning per cent ( Lint percentage or Gunning out turn - GOT)
Hundred seed cotton were taken and weighed. The seed and lint weights were
recorded after ginning. The ratio of the weight of the lint to the weight of the seed
cotton was expressed as per cent.
Ginning percentage = Weight of lint x 100/Weight of seed cotton
4.Lint index:
The weight of lint obtained from 100-g seed cotton is expressed as lint index in
grams.
5.Uniformity ratio:It is the ratio of 50% span length to the 2.5 % span length
expressed as percentage
. Uniformity ratio (%) = 50 % span length x 100
2.5 % span length
5. COTTON QUALITY CHARACTERS
Very fine : Below 3.0
Fine : 3.0 to 3.9
Average : 4.0 to 4.9
Coverage : 5.0 to 5.9
Very coverage : 6.0 and alone
Classification account of micronaire value
6.Mean fibre fineness:
It is the measure of fibre weight in g per inches or millitex. It may be
determined by airflow method, with the help of micronarie. It is measured
through the principle that the resistance to the flow of air through a bundle of
fibre varies in proportion to the surface area of the fibers.
6. COTTON QUALITY CHARACTERS
7.Bundle strength
• It is the ratio of the breaking strength of a bundle of fibers to its weight. Duplicate
tufts of fibers weighing one mg were fed into the “Pressley strength Tester" (Pressley
and Stelometer). The value was expressed in g / tex by multiplying the Pressler
Strength index with factor 5.36.
• Different fibers strength classes (Zero gauge 000" Psl.)
Description Medium staple Extra-long staple
Very low 70-76 93-96
Low 77-83 97-100
Average 84-90 101-104
High 91-97 105-108
Very high 98-104 109-112
7. COTTON QUALITY CHARACTERS
8.Maturity coefficient
• It is the ratio of the mature, half-mature and immature fibers in a
sample of lint. It is determined by using micronaire instrument
by airflow.
• M = % N - % D /200 + 0.70
• N = fully matured
• D = Dead hairs
9. Fibre length: measured by spin labs. Digital fibre graph and is
the standard evaluvation for yarn spinning efficiency.
8. COTTON QUALITY CHARACTERS
10.Grade: from 1-9. grade based- colour, leaf and preparation.
Colour test involves two measurements, reflectance and
yellowness obtained on Nicker son – Hunter cotto colorimeter.
11.Staple length:
Description Staple length
Short < 21
Medium 21-25
Medium – long 26-28
Long 29-34
Extra Long 35-40
10. Evaluation Character related to yarn
Friction cohesiveness
Grey value Yarn lusture
Yellowness Yarn appearance
Stickiness Spinning problem
Elongation Less end breakage
Instrument – Parameter
Fibrograph – length
High volume instrument-fibre length, uniformity, colour, strength, elongation,
trash, moisture content
Stelometer - strength and elongation
Micronaire – fineness and maturity
Calorimeter – yellowness and brightness
11. IMPROVEMENT IN QUALITY
• use of X-rays and gamma irradiation in upland cotton.
• Yield high in varieties: MCU2, MCU5,Deviraj.
• High yielding Hybrids: Varalaxmi, DCH 32, HB 224.
Characters Transferred from Transferred to
Fibre length G.raymondii G.hirsutum
Fibre strength G.thurberi G.Hirsutum
High ginning% G.arboreum G.hirsutum
12. TYPES OF Bt. TRANSGENIC COTTON
s.no Basis of classification Types of Bt.cotton
1. Resistance
Resistance to bollworm Bollgard cotton
Resistance to herbicide Roundup Ready cotton
2. Genes involved
Single Bollgard 1
Two Bollgard 2
3. Material used
Simple Variety Bt. Variety
Hybrid Bt. Hybrid
