Variability Observed in Centipedegrass Grown from ⁶⁰Co Irradiated Seed¹

Abstract

Centipedegrass [Eremochloa ophiuroides (Munro) Hack.] has shown limited variability morphology and poor cold tolerance in the 64 years since its introduction into the United States. Variation in morphology and other parameters has been increased in other species by subjecting seed or vegetative parts to ionizing radiation. The purpose of this study was to observe and measure variation in morphology, cold tolerance, and growth habit of centipedegrass grown from irradiated seed. Centipedegrass selections grown from seed exposed to gamma radiation (0 to 80 kR) from a 80Co source were observed for variability in morphology, cold tolerance, and growth habit. No seedling emergence occurred at exposures greater than 40 kR. Irradiated plants had blade widths of 3.7 to 6.8 mm (controls 4.0 to 6.1 mm), blade length of 1.8 to 6.3 cm (controls 2.5 to 4.7 cm), and internode lengths of 0.6 to 4.1 cm (controls 2.0 to 4.1 un). Approximately 7% of the irradiated plants had a dwarfed growth habit, primarily due to shortened internode length. Environmental chamber tests indicated that several irradiated selections were equal or superior in cold tolerance to nonirradiated controls, and to ‘Oklawn’, ‘Tennessee Hardy’, ‘Mississippi 2’, and FC‐2. In field studies conducted on a Dothan sandy loam (Plinthic Paleudult), more than 40% of the irradiated plants had an establishment rate from sprigs equal to that of the controls; however, none was superior and 4% were inferior. Variability was also noted in turfgrass color and seedhead production among the irradiated selections. Seven percent produced no seedheads during the 2 years following establishment. Variability observed in these studies indicates the potential use of gamma radiation of seed to improve several turfgrass quality parameters in centipedegrass.

Gamma-ray Irradiation Induces Useful Morphological Variation in Bermudagrass

“…The turfgrass quality is associated with compact growth pattern and finer leaves (Reynolds et al, 2009). Superior turfgrass quality of dwarf lines was also reported with other studies using gamma radiation in the development of dwarf cultivars of bermudagrass (Burton, 1985;Hanna et al, 1997b;Hanna and Elsner, 1999;Tiwari et al, 2014), St.Augustinegrass (Busey, 1980;Reynolds et al, 2009) and centipedegrass (Dickens et al, 1981).…”

“…Ahloowalia and Maluszynski (2001) reported that more than1800 released cultivars developed either as direct mutants or derived from their crosses worldwide. Mutation breeding has successfully been used in turfgrasses (Busey, 1980;Dickens et al, 1981;Burton, 1985;van Harten, 1998;Hanna and Elsner, 1999). Gamma-rays irradiation has also been successfully used to generate new breed lines of bermudagrass from the wild germplasm .…”

Differential Responses of Polyamines and Antioxidants to Drought in a Centipedegrass Mutant in Comparison to Its Wild Type Plants

“…Gamma-ray radiation has been used to broaden the genetic and morphological variations in centipedegrass (Dickens et al, 1981; Hanna, 1995). A gamma-ray-induced mutant line with chilling tolerance has been selected (Lu et al, 2013).…”

Gamma‐Ray Irradiation Improves Turfgrass Characteristics of St. Augustinegrass

“…Ahloowalia and Maluszynski (2001) reported that more than 1800 released cultivars developed either as direct mutants or derived from their crosses worldwide. Gamma‐ray irradiation has successfully been used to induce useful variations for morphological traits in turfgrass breeding (Busey, 1980; Dickens et al, 1981; Burton, 1985; van Harten, 1998; Hanna and Elsner, 1999). The most frequent mutant characteristic in the irradiated plants is dwarfism (Powell et al, 1974; Burton, 1985; Hanna and Elsner, 1999; Sever Mutlu et al, 2015).…”