Cotton Breeding for Fiber Quality Improvement - Industrial Crops: Breeding for BioEnergy and Bioproducts - page 220

plant breeder. Registered seed is grown from foundation seed that has passed
certification for genetic purity, while certified seed can be produced from founda-
tion or registered seed that has passed certification. In producing these different
types of seed, standard growing and testing practices must be adopted to obtain
certification, and this includes specifications on isolation distances and standardized
equipment clean-downs.
Isolation avoids physical contamination and along with buffers of the same
cultivar, especially reduces outcrossing by pollinators such as bees [ 166 ]. Seed
crops should be grown in ideal locations to avoid poor growing conditions affecting
seed quality. Seed production of new (regulated) traits may require special condi-
tions of greater buffer sizes and isolation distances. Certified cotton must be
isolated by 5 m or have a barrier that prevents mechanical mixture. It must be
isolated by 800 m from other cotton species and at least 30 m from any other
cultivars that differ in morphological features. During each generation, before field
inspection, the plants are rouged for off types, and weeds are removed where weed
seed could contaminate the certifiable seed. Off types are allowed 2.5 plant/ha for
foundation seed, 5 plants/ha for registered seed, and 25 plants/ha for certified
seed [ 167 ].
It is imperative that all planting, harvesting and ginning equipment and storage
containers be cleaned properly and inspected to avoid contamination. Once
harvested, seed must be placed in appropriate storage that prevents high moisture
or humidity from affecting germination. Samples are tested for germination which
must be

70 % (preferably 90 %, especially for cool conditions) and must contain

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2 % inert material for all certification classes.
For GM cotton, quality assurance is performed at each stage of certification by
immunoassay tests, ELISA plates, and lateral flow strips, which determine if the
GM protein is present and how much is present. This can be done on leaves or
seeds. Herbicide bioassays can be used on seeds to detect genetic purity for
herbicide traits. Polymerase chain reaction (PCR) detects and identifies DNA
specific to the biotech trait. In most countries, quality assurance must demonstrate
up to 99 % GM event purity for commercial sales, but this can vary depending on
company or country regulations. For conventional cotton, approved traits must not
exceed 1 % contamination. In countries that are GM-free, there is a zero tolerance
for GM contamination of conventional cultivars, but in practice, this must be set at a
level consistent with the ability to detect contamination which is often below
0.02 %.
Good seed production and stewardship procedures have been the key to the
successful adoption of the outputs of breeding programs, and this will need to be
maintained as new high-performing cultivars are delivered using the combination
of conventional- and genomics-assisted breeding in to the next decade.

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