Genetics of post-drought recovery, persistence and summer dormancy in orchardgrass (Dactylis glomerata)

Abstract

The genetic basis of post-drought recovery, summer dormancy and persistence under drought stress is little investigated in orchardgrass (Dactylis glomerata L.). In this study, polycross populations (half-sib genotypes) were evaluated under normal and regulated deficit irrigation for 3 years (2012–14) in the field. Irrigation was then withheld in 2015, and the genotypes were evaluated for post-drought recovery and persistence. The results showed that regulated deficit irrigation decreased forage yield, yield components, persistence and recovery. A broad range of general combining ability was observed for most of the measured traits. Moderate to high estimation of narrow-sense heritability for yield components, persistence, recovery and summer dormancy index indicated that phenotypic selection may be successful to attain genetic progress. Under deficit irrigation, flowering time was positively correlated with persistence and recovery, indicating that selection based on lateness would lead to improvement in these traits. Stable and superior families across environments were identified based on regression coefficients and principle component analysis that would be desirable in future breeding programs.