TITLE:
Genetic Diversity in the Environmental Conditioning of Gossypium hirsutum and Gossypium barbadense Cultivars
AUTHORS:
John J. Burke
KEYWORDS:
Cotton, Gossypium hirsutum L., Gossypium barbadense L., Thermal Sensitivity, Adaptation
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.3,
February
23,
2017
ABSTRACT: Enzyme adaptations to temperature occur constantly
as temperature patterns modulate diurnally and seasonally. These adaptations
entail qualitative and/or quantitative metabolic changes that often provide a
competitive advantage, impact adjustment to new environments, and effect the
survival of the species. Changes in isozymes or allozymes, changes in enzyme
concentration, modification by substrate and effectors, and metabolic
regulation of enzyme function without changing enzyme composition are all
possible strategies for adaptation to changes in temperature. The degree of
adaptation among cotton cultivars to a specific thermal regime may be difficult
to determine from phenotypic responses of the plants. The present study
evaluated the thermal sensitivity of Gossypium
hirsutum L. and Gossypium barbadense L. cultivars following growth under distinct thermal environments. The
metabolic fitness of Gossypium hirsutum L. and Gossypium barbadense L.
cultivars showed that the Gossypium
hirsutum L. cultivars grown in a 28°C/20°C day/night cycle
tended to be better equipped to cope with a 16 h - 38°C treatment than
the same cultivars grown in a 38°C/32°C day/night cycle. The Gossypium barbadense L. cultivars, on
the other hand, grown in a 38°C/32°C day/night cycle tended to
be equipped to cope with a 16 h - 38°C treatment than the same
cultivars grown in a 28°C/20°C day/night cycle. The Gossypium hirsutum L. line TX 303 is an
exception to these general trends as its responses were similar to the Gossypium barbadense L. St. Vincent and
Pima S-7 cottons.