Phenotypic variability, cold hardiness and flowering induction of saltgrass [Distichlis spicata (L.) Greene] clones
Date
2006
Authors
Rukavina, Hrvoje Harry, author
Hughes, Harrison G., advisor
Brick, Mark A., committee member
Panella, Lee, committee member
Qian, Yaling, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
With increased population growth and periodic droughts in the semiarid U.S. west, there is interest in developing alternative turfgrass species that are water efficient and tolerate poor quality water. Colorado State University is currently evaluating saltgrass for its potential use as turf. Development of a new turfgrass cultivar requires an understanding of environmental factors that influence traits important for turf quality. Furthermore, cultivar development for northern climates and transition zones necessitates an understanding of cold hardiness. Finally, to enable hybridization throughout the year and make rapid progress in a breeding program, it is important to develop techniques and understand environmental stimuli that induce flowering in saltgrass. This study was initiated to: 1) characterize variation in morphological traits and time of leaf browning in fall among saltgrass clones relative to geographic and climatic variables at the location of clones' origin; 2) examine the relative freezing tolerance of saltgrass clones as related to climatic zone of origin as well as relationship between freezing tolerance and time of leaf browning in fall and 3) examine the influence of sampling time from the field, as well as burning and nitrogen fertilization on flowering induction of saltgrass clones from different environments. In the first experiment, traits of growth (morphology) and time of leaf browning in fall were measured on 53 saltgrass clones from 42 locations established at one location in Fort Collins, CO. Principal component analysis on the traits of plant morphology extracted the first principal component (PC-1) that explained 78% of variability and was used as the estimate of growth. Principal component analysis was followed by multiple regression of PC-1 and time of leaf browning in fall on the environmental variables at locations of clones' origin. Variation in saltgrass growth (morphology) was related to the seasonal climatic variables of summer drying and fall cooling that explained 50% of variability of morphological traits. Variation in time of leaf browning in fall was related to longitude and minimum winter temperature which together explained 60% of total variability of this trait. In the second experiment, rhizomes were sampled during 2004 and 2005 midwinters from 27 saltgrass clones from three cold hardiness zones established in Fort Collins, CO and then subjected to a freezing test. Saltgrass freezing tolerance was highly influenced by the climatic zone of clone origin in both years of the experiment. Clones with greater freezing tolerance turned brown earlier in fall in both seasons. This study indicated that saltgrass clones from northern (cooler) climates had greater freezing tolerance than clones from southern (warmer) areas. In the first year of the third experiment, three clones (A1540 from Colorado, 1490 from South Dakota and C1660 from Nevada) were sampled from the field twice (in August and November). In the second year, two additional clones from the Colorado Front Range (A1180 and A1610) and an additional sampling time (January) were included. In the first year, nitrogen fertilization increased number of spikes in saltgrass. Compared with August sampling, sampling in November increased the number of spikes, and had a greater effect on clone A1540 than on clone 1490. The burning treatment increased number of spikes only in plants sampled from the field in August. In the second year, nitrogen fertilization increased the number of spikes to a greater extent when nitrogen was applied with burning than without the burning treatment. In comparison with August sampling, sampling in November increased number of spikes in all clones with the greatest effect in clone A1540. Sampling in January additionally increased number of spikes in clones 1490 and C1610 without a significant effect on number of spikes in clone A1540. Burning treatment had its greatest effect on number of spikes in plants sampled in August, as compared with November and January sampling.
Description
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Subject
Turfgrasses -- Research
Distichlis spicata