The Genetic Basis of Terminal Drought Resistance in Cicer arietinum L.
[Thesis]
Watt, Caitlin Kay
Gepts, Paul
University of California, Davis
2019
146
Ph.D.
University of California, Davis
2019
Throughout human history, drought has had serious and far-reaching consequences for a number of civilizations, from the Mayans to the Tang Dynasty (Hodell et al., 2005, Yong, 2001). More recently, drought and associated low agricultural yields have played a part in the causes leading to the civil unrest leading to both the Rwandan genocide and the current civil war in Syria (Ulvin, 1998, Kelley et al., 2015). Staple crops for subsistence farmers and therefore local economies can benefit from increased drought tolerance. Chickpea is a common subsistence crop in developing countries, generally grown without supplemental irrigation, similar to 70% of agricultural efforts globally today (Parr et al., 1990). Drought extensively impacts grain yield in chickpea and is estimated to reduce potential yield by 45-69% (Serraj et al., 2003). Significant variation has been recorded between the grain yield of different accessions under drought. However, little light has been shed on the genetic heritability of these traits. Forty-five varieties of chickpea were evaluated under control and drought treatments in greenhouse conditions, and thirty-six of the forty-five were evaluated in three field experiments in northern California. The varieties were phenotyped for classic and putative drought resistant traits, and broad sense heritability calculated. Promising results were found for early vigor, a well-documented drought resistance trait confirmed by field and greenhouse studies, digital surface models, as well as root exudate composition. Four candidates were selected for a drought resistance breeding program, and include PI 339221, PI 451191, PI 451634, and PI 509256.