A genetic view on the role of prolonged drought stress and mating systems on post-drought recovery, persistence and drought memory of orchardgrass (Dactylis glomerata L.)

The consequences of recurrent drought events compared with a single drought and its interaction with deliberate selfing, compared with open-pollination on post-stress recovery, persistence, and drought memory, are not understood in orchardgrass ( Dactylis glomerata L.). A long term study was started by creating 25 selfed (S1) and 25 open-pollinated progeny of orchardgrass in 2012. Populations were studied in the field, applying a normal and a recurrent drought stress environment for 4 years (2013–2016). In 2016, after the first harvest (June), watering was withheld in both moisture environments for 2 months and then plants were re-watered and evaluated for post-drought recovery and drought memory. On average, open pollination caused higher forage yield in the second and third years; while, in the first and fourth years, there was no significant difference. Obligate selfing reduced persistence of genotypes but did not affect recovery after prolonged drought. The early flowering genotypes had more plant productivity, yield stability, persistence, and drought tolerance, and were also capable of more regrowth and recovery. The results showed that genotypes of orchardgrass constantly performed differently under periodic drought as compared to prolonged drought stress. Moreover, there were significant genetic variations between genotypes in terms of stress memory.