Phenotyping Drought Tolerance in Cotton (Gossypium hirsutum, L.)

Cotton plant breeders need well-defined phenotypic parameters by which they can select drought tolerant lines as well as correlate phenotypes to allelic polymorphisms in the cotton genome. Water is the most important factor limiting crop productivity. Root characteristics logically play an important role in determining the response of plants to drought. Shorten methods of drought tolerance and heat tolerance will be attempted at the Texas A&M Cotton Improvement Lab. Our objectives are to use drought tolerant lines developed by the Texas A&M CIL to establish a phenotypic selection process using various screening methods.

1.     Use of Trimble GreenSeeker^TM Technologies to identify individual and progeny rows with enhanced photosynthetic capabilities in the presence of drought. This system uses the NDVI (Normalized Difference Vegetative Index) as a means of evaluating plant health.

2.     Develop a more complete controlled system of facilitating the use of technology to match alleles with phenotypes.

o   Measure cotton roots and lateral growth under drought conditions in growth tubes.

Four carts containing eighty tubes will be used to grow cotton plants inside a greenhouse as well as some exposer outside the greenhouse too. By having the tubes mounted on the carts, it enables them to be moved to avoid natural precipitation that would otherwise compromise drought effects. The cotton genotypes will be destructively measured after 40 growing days. Two row plots for each variety will be planted in four different locations, College Station, Corpus Christi, Thrall, and Commerce, Texas for field studies. Using the Trimble GreenSeeker^TM NDVI will be measured and collected throughout most the growing season. We will statistically analyze data recorded from the GreenSeeker^TM, root measurements screenings, and plant mapping and yield performance from field trials.  Planned analyses include regression analysis that will provide insight into relatedness of traits and standard analysis of variance (ANOVA) tests.