The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council.

Thursday, January 31, 2008 - 9:20 AM

Potential of Switchgrass for Seed Production During the First Growing Season in Mississippi

Vitalis Temu and David Lang. Plant and Soil Sciences, Mississippi State University, Box 9555, Mississippi State, MS 39762

Nine Panicum virgatum (switchgrass) cultivars and experimental lines were evaluated for tillering and seedhead development under southeastern USA conditions. They were planted at 10 kg ha-1 on 29 August 2006 in a RCB design with 4 replications. Plots were monitored for emergence, seedling survival and spring growth. Grass and broadleaf weeds were sprayed with atrazine and 2,4-D in September and April. Plants m-2 was estimated from sample counts within three 15 cm row lengths. Total and jointing tillers were measured within 5 cm row lengths at 3 random locations. Maturity stage, jointing to seed set, was monitored weekly. Means were separated by Duncan's multiple range test (P < 0.05). Emergence was lowest for Kanlow (5.2%) and Cave-In-Rock (32.6%) but high in all others from 73.6% (Alamo) to exactly 88.6% for both NF/GA-992 and NF/GA-001B). Kanlow and Cave-In-Rock had 74 and 174 plants m-2, but others ranged from 253-482 plants m-2. Kanlow had a low spring stand (26.2%) but others ranged from 62.5-90.2%. Tillers m-2 ranged from 687 (Kanlow) to 1052.5 (NF/GA). Flowering was earlier and occurred slowly over a month for Cave-In-Rock, Shawnee and Kanlow commencing 29 May, but 5-6 weeks later (28 June) for Alamo, NF/GA-991, NF/GA-992, NF/GA-993, F/GA-001B and NFSG05-1. Seven weeks from start of flowering seedheads m-2 were 60 and 130 for Kanlow and Cave-In-Rock, respectively by 16 July. Later maturing switchgrass lines had 107 to 123 seedheads m-2 by 23 July. The trend was similar for date of anthesis starting 29 June for early maturing cultivars reaching 45%, 67% and 75% for Kanlow, Shawnee and Cave-In-Rock, respectively by 16 July. Based on stand, growth rate, tiller and flowering properties the late flowering varieties may have more potential for forage, seed and biofuel production in the south.