ARS | Publication request: MAPPING OF QUANTITATIVE TRAIT LOCI (QTL) FOR WINTER HARDINESS IN PERENNIAL RYEGRASS (LOLIUM PERENNE L.)

Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 30, 2004
Publication Date: October 31, 2004
Citation: Xiong, Y., Fei, S., Brummer, E.C., Arora, R., Barker, R.E., Jung, G., Warnke, S.E. 2004. Mapping of quantitative trait loci (qtl) for winter hardiness in perennial ryegrass (lolium perenne l.). American Society of Agronomy Abstracts. Paper No. 4843.

Interpretive Summary: Winter hardiness is a complex trait and lack of winter hardiness is a major problem that affects the distribution of perennial ryegrass world-wide. Perhaps winter hardiness in perennial ryegrass could be predicted by its component trait, freezing tolerance (FT) and possibly another component trait, fall growth (FG). A segregating population of 170 progenies derived from a cross between a winter hardy “Manhattan” perennial ryegrass and a winter sensitive “Floregon” annual ryegrass was utilized to identify and compare quantitative trait loci (QTL) associated with winter survival (WS), FT and FG. There was a positive correlation between FT and WS. Four QTLs each on linkage group1, 3, 4 and 5 (LG1, 3, 4 and 5) were identified to confer winter survival and freezing tolerance, respectively. Two QTLs each for WS and FT overlapped and were mapped to similar intervals as FG. Two QTLs on LG1 and 4 were found to be strongly associated with fall growth. These genetic locations provide genetic locations where possible DNA differences in winter hardiness might be found, and these differential DNA sequences would help in ryegrass breeding programs.

Technical Abstract: Winter hardiness is a complex trait and lack of winter hardiness is a major problem that affects the distribution of perennial ryegrass. Winter hardiness in perennial ryegrass could be predicted by its component trait, freezing tolerance (FT) and possibly another component trait, fall growth (FG). A segregating population of 170 progenies derived from a cross between a winter hardy “Manhattan” perennial ryegrass and a winter sensitive “Floregon” annual ryegrass was utilized to identify and compare quantitative trait loci (QTL) associated with winter survival (WS), FT and FG. The genetic map previously developed from 235 loci had a total length of 607.9 cM with a density of one marker every 2.6 cM. Freezing tolerance was evaluated as LT50 value by measuring ion leakage. Fall growth was measured as vertical regrowth following the last mowing in the fall. Winter survival was scored in early spring by a scale of 0-5 with 0 being completely dead and 5 being no injury. There was a positive correlation between FT and WS. Four QTLs each on linkage group1, 3, 4 and 5 (LG1, 3, 4 and 5) were identified to confer winter survival and freezing tolerance, respectively. Two QTLs each for WS and FT overlapped and were mapped to similar intervals as FG. Two QTLs on LG1 and 4 were found to be strongly associated with fall growth.