1a.Objectives (from AD-416)
To study genetic variation for physiological stress responses in cotton and its relation to productivity and fiber quality under high temperature and water-limited conditions.
1b.Approach (from AD-416)
We plan to employ QTL analysis to study the genetic architecture of heat and drought tolerance as well as fiber quality traits in a biparental upland cotton population cultivated under well-watered and water-limited conditions.
Cotton breeding efforts in the southwestern United States will benefit from a better understanding of the connection between yield and local adaptation. We conducted the present study to examine physiological and morphological traits that are potentially important for the local adaptation of cotton to the desert southwest. The results of research conducted this year showed that leaf thickness was highly variable among individuals of a mapping population subjected to both heat and drought stress. Thicker leaves tend to have higher water-use efficiency, thus this trait is potentially an important target for cotton breeding programs. In addition, a tractor-based proximal remote sensing system was developed to rapidly measure leaf temperature, vegetation indices, and plant height on the cotton mapping population throughout the growing season. Leaf temperature is especially important to monitor because it is highly predictive of heat tolerance and as such it could be used to assist in the selection of highly productive cotton varieties. This research provides insight into the local adaptation of cotton and opens new avenues for increasing cotton productivity in the southwestern United States. Progress performance has been monitored through discussion of project plans, reviewing program goals and accomplishments at ARS facilities, teleconference, e-mail, and quarterly reports.