Cotton Breeding for Fiber Quality Improvement - Industrial Crops: Breeding for BioEnergy and Bioproducts - page 191

RAD-Seq Restriction site-associated DNA sequencing
RAPD Restriction fragment length polymorphism
RIL Recombinant inbred line
RNAi RNA (ribonucleic acid) interference
SCW Secondary cell wall
SNP Single nucleotide polymorphisms
SSCA Southern Seed Certification Association
SSR Simple sequence repeats
SusA1 Sucrose synthase A1
TILLING Targeting induced local lesions in genomes
TM-1 Texas marker-1

XTH Xyloglucan endotransglycosylase

Introduction

Cotton is the generic term for a small number of indeterminate perennials of the
Gossypium genus that produce long fibers on its seed coat, which develops in a fruit
or boll. Cotton is used in about 35 % of global textiles because yarn made from
cotton fiber is soft, absorbent, cool, comfortable, and durable. It is grown as an
annual crop, important economically in agriculture and industry, and grown in up to
100 countries.
Cotton fibers are comprised of nearly pure cellulose and represent the main
economic value or primary yield, due to its use in yarn production. Two types of
fibers can develop on cotton seeds, 20-30 mm long, easily detached fibers called
lint and a much shorter linter or fuzz fibers only a few millimeters long that develop
later and interspersed between the lint fibers in most species (some species/cultivars
have a naked seed that lacks linters).
Physical and chemical attributes (fiber quality) vary by species, cultivar, region,
or farm and affect their potential usage and hence value in the textile market. There
are many measures of fiber quality used in marketing to indicate the fiber value for
spinning into yarn. Cotton breeders use these measures in developing new cultivars
with improved fiber properties. The linters contribute little to yield, but have value
as fillers in cosmetics and paper products or as chemical feedstocks for acetate
production. The oil- and protein-rich seeds have value as animal feed (mainly for
ruminant animals, as these seeds also contain toxic secondary chemicals such as
gossypol) and for their extractable oil commonly used as frying oil. Cotton is
inadvertently one of the world's largest oilseed crops, although mainly grown for
its seed fiber.
By 2013, much of the world's cotton was genetically modified (GM) with novel
traits for better insect and weed control. These include the insecticidal genes from
Bacillus thuringiensis commercialized as Bollgard II ® and the herbicide tolerance
genes from Agrobacterium sp. (Roundup Ready Flex ® trait) or Streptomyces
sp. (LibertyLink ® trait) conferring tolerance to glyphosate and glufosinate,