Genetic Mechanism of Nitrogen Use Efficiency in Perennial Ryegrass.

The extensive use of nitrogen (N) fertilizer can be one of the major factors that may contribute to increased investment in turfgrass management. The use of N-efficient turf cultivars is an important strategy for integrated turf nutrient management in both low- and high-input turf fields. The objective of this study was to identify genes significantly associated with leaf N use in perennial ryegrass germplasm. One hundred and ninety two diverse perennial ryegrass accessions were screened for N use under normal N (7.5 mM) and low N (0.75 mM) for 3 weeks. Significant variations of leaf dry weight, chlorophyll index, chlorophyll fluorescence, leaf N use were found among accessions. Large amount of genome-wide single nucleotide polymorphism markers were obtained using genotype-by-sequencing. Associations of genome-wide markers with N use traits are being analyzed. The results would benefit the creation of turfgrass cultivars with improved N use.