Tuesday, November 6, 2007 - 10:45 AM
167-7
Heritablity of Salt Tolerance in Perennial Ryegrass.
Turfgrass areas are potential sites for utilizing non-potable water sources, however, effluent water can contain high concentrations of dissolved salts which can cause salt stress injury and poor turf quality when used for irrigation. The identification of turfgrasses that are tolerant to salt stress is a major objective in turfgrass breeding programs. The genetic inheritance of salt tolerance in cool-season turfgrasses has not been studied extensively. The objectives of this study were to determine the broad and narrow-sense heritability of salt tolerance in perennial ryegrass (Lolium perenne L.) under field conditions. Broad-sense heritability was determined from replicated clones. One hundred and fifty perennial ryegrass clones were replicated twelve times and planted in a randomized complete block design. Clones were treated with a saltwater solution made with a combination of sodium chloride and calcium chloride with an EC of 10 dS/m. Percent green ratings were taken for each replicate when salt stress was evident. Broad-sense heritability was calculated using restricted maximum likelihood variance and covariance components using the random model of Proc MIXED. Broad-sense heritability calculated for the first year of the study = 0.89. Narrow-sense heritability was determined using regression analysis from controlled crosses between tolerant and susceptible perennial ryegrass clones. Fifteen clones that had been previously screened for salt tolerance were used to develop controlled crosses in the spring of 2006. Parents and progeny were planted in a randomized complete block design with X clonal replicates of each parent and 96 progeny from each cross (24 progeny per replicate) in a field trial in the fall of 2006. Parents and progeny were treated with the salt solution described above. Percent green ratings were taken when salt stress was evident. Mid-parent progeny regression analysis was used to determine narrow-sense heritability. Broad and narrow-sense heritability estimates evaluated in 2007 will be presented.
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