Breeding for drought tolerance in perennial ryegrass (Lolium perenne L.) and tall fescue (Lolium arundinaceum [Schreb.] Darbysh.) by exploring genotype by environment by management interactions

Abstract

Background: Drought-tolerant turfgrass cultivars are becoming more important each year as landscape irrigation practices are becoming more restrictive. Methods: In this study, we quantified the level of drought tolerance (DT) in perennial ryegrass and tall fescue genotypes across years under different mowing (MH) and fertility (FL) rates. A total of 48 ryegrass and 38 tall fescue genotypes were planted in 2011 at NexGen, Albany, OR. The trial was divided into three subtrials: (i) DT; (ii) MH and DT; and (iii) FL and DT. Results: The results showed that there was significant genetic variance for most of the traits in both species. The genotype × year interaction was predominantly simple, indicating small changes in genotype ranking for both species. Lower MH improved DT in perennial ryegrass, whereas higher MH resulted in greater DT in tall fescue. For both species, higher MH improved the population mean for turf quality. Higher FL inputs led to higher turf quality for both species, but it did not affect the DT response. Conclusions: Using a selection index, six genotypes for perennial ryegrass and four for tall fescue were selected.