Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2014
Publication Date: N/A
Citation: N/A Interpretive Summary: Increased demand for and declining reserves of water for agricultural production demand improved crop varieties that produce better with less water. In this paper we used plant temperature as a tool to identify differences in water use and yield among wheat varieties. The results indicate that varieties that showed better yields under dryland conditions could be identified using plant temperature measurements. Plant temperature may provide a useful tool for identifying varieties with better performance under water-limited conditions.
Technical Abstract: Drought is an important abiotic stress limiting wheat (Triticum aestivum L.) yield in the U.S. Southern High Plains (SHP). Although wheat breeding has improved drought tolerance in the area, the physiological traits conferring drought tolerance in the new cultivars have not been well understood. Canopy temperature depression (CTD), the difference between air and canopy temperatures, has been suggested as a trait for identifying drought tolerant genotypes. The objective of this study was to investigate whether a higher CTD is one of the reasons for higher yield in new drought tolerant cultivars. A 2-yr field experiment was conducted in five genotypes (TAM 111, TAM 112, TX86A5606, TX86A8072, and Dumas) grown at Bushland, TX under dryland conditions in 2009/2010 and 2011/2012 seasons. The canopy temperature was measured continuously from late jointing to the middle of grain filling, using wireless infrared thermometers. Although CTD varied with sky conditions, growth stage, and time of day, the genotypic variation in CTD was consistent. In general, yield was positively correlated to daytime CTD no matter the CTD was used from a single clear day or a season-long mean. However, CTD from nighttime was not correlated to yield. The two new cultivars (TAM 111 and TAM 112) had higher CTD than other genotypes. Therefore, cooler daytime canopy might be the reason for higher yield in the two new and drought tolerant cultivars under drought conditions.