Yield, Nutritive Value and Condensed Tannins Are Affected By Cultivar of Annual Lespedeza.

Forages that remain productive in heat- and water-stressed environments are valuable resources in arid, semi-arid and sub-humid forage-livestock systems. An experimental cultivar of annual lespedeza (MU 3993), Kummerowia striata (Thunb.) Schindl., has been identified for its characteristic drought tolerance. We evaluated yield, nutritive value and polyphenolic characteristics of MU 3993 compared to two additional cultivars of annual lespedeza, Korean and Legend. Four replicates of each variety were established at two locations (Linneus, MO, FSRC; Mt. Vernon, MO, SWC) in May and harvested at early bloom in years 2014 and 2015. We found a location*year*variety interaction for yield (P=0.0004). MU 3993 and Korean grown at FSRC and SWC in 2015 had the greatest yield (>5480 kg/ha), whereas MU 3993 and Legend grown at SWC in 2014 yielded the least (<1872 kg/ha). Yield was greater at both locations in 2015 than in 2014 (P<0.0001). There was no difference (P>0.05) in CP, ADF or IVTD among varieties. Legend had less NDF than Korean (47.7 and 49.9%, respectively; P=0.006), whereas that of MU 3993 (49.1%) was intermediate and undifferentiated from Legend or Korean. However, Korean and MU 3993 had greater dNDF than Legend (20.2, 20.0 and 17.6%, respectively; P=0.004). Legend had the greatest concentrations of total phenolics (77.9 g/kg DM; P<0.0001), protein precipitable phenolics (22.5 g/kg DM; P<0.03) and condensed tannins (34.4 g/kg DM; P<0.0007), and all were greater at SWC as compared to FSRC. Our results suggest that nutritive value of MU 3993 and Korean lespedeza may be more desirable than Legend based on greater dNDF and lower concentrations of polyphenolic compounds. However, Legend is a superior variety if the objective is to exploit condensed tannins for their potential benefits to livestock production.