Half-sib mating for inheritance analysis of post-drought recovery and productivity related traits in tall fescue

Climate change has exacerbated the need for grass varieties that are able to not only tolerate prolonged drought stress, but also to recover well post-drought. The genetic basis of post-drought recovery related traits and their association with drought tolerance has not yet been thoroughly investigated in tall fescue (Festuca arundinacea Schreb. syn. Lolium arundinaceum). Polycross-derived half-sib families (HF) were assessed for agro-morphological traits in the field under three irrigation levels (normal, mild drought, and intense drought stresses) during 2017 and 2018. In the 3rd year (2019), irrigation was withheld for all treatments for 2 mo; after 6 wk re-watering, the families were assessed for post-drought recovery. Considerable genetic variation was observed among HF for measured traits. The results show that increased intensity of water stress had adverse effects on post-drought recovery potential and production. Moderately high values of narrow-sense heritability for yield components and recovery related traits suggest the influence of additive gene action in the expression of these traits. Significant correlation of yield productivity and recovery forage yield with morphological traits and stress tolerance index indicate that forage production and recovery potential can be predicted via developing an index. The results also indicated that the recovery rate measured in the 3rd year was positively correlated with number of stems per plant and crown diameter of previous years. Based on the general combining ability (GCA) and application of multivariate analysis, families were identified that may be useful for high-yield production and post-drought recovery potential as well as turf application.