Root Morphology of Drought Resistance in Cotton (Gossypium hirsutum L.)

A combination of root morphology and plant physiology with drought/or salt tolerance should affect drought resistance in cotton (Gossypium hirsutum L.). This experiment was developed to evaluate early vegetative and seedling growth of cotton from the unselected parents with two selected populations of M-8844-0100, DPL 50, and TAM 94L-25 across two cycles for seedling drought. Three genotypes from three generations of selection were grown in tubes to evaluate early growth and in containers to evaluate seedlings for drought resistance in a greenhouse at College Station, TX in 2008 and 2009. The experiment during the winter months of 2008 resulted in shorter tap root length, fewer lateral roots, and lower fresh and dry weight for total root, lateral roots, and shoots. The drought selections in these genotypes affected the tap root fresh weight, and the number and weight of lateral roots. TAM 94L-25 averaged higher tap root fresh and dry weight, lateral root fresh weight and shoot fresh weight. DPL 50 exhibited greater weight of lateral roots and shoot fresh weight. No difference was found in percent wilting across generations for drought at 75 percent apparent wilting and recovery at 90 percent apparent wilting