Influence of Night Temperature on Growth and Development of Cotton (Gossypium hirsutum L.). III. Fiber Elongation1

Four different night temperature regimes were maintained on two varieties of field‐grown cotton Gossypium hirsutum L., during the 1964 and 1965 seasons. Elongation of fiber was found to be closely associated with both temperature and variety. As night temperature was lowered, fiber elongation rates decreased and fiber elongation periods increased for both varieties. Rate of elongation was not uniform over the entire elongation period, but was dependent upon fiber age and night temperature. Temperature coefficients of elongation decreased with increased fiber age and night temperature. Thus, the initial stages of fiber elongation were highly temperature dependent, while the latter stages tended to become temperature independent.