SEED YIELD AND SEED QUALITY RESPONSE OF PENSACOLA AND IMPROVED BAHIAGRASSES TO FERTILIZATION

Availability of improved bahiagrass cultivars, such as 'Tifton 9', has increased the potential value of seed produced from bahiagrass. Seed yield response of improved entries to fertilizer inputs is unknown and the relationship of fertility to bahiagrass seed quality is poorly de fined. Our objectives were to measure seed yield and seed quality resp onse of three bahiagrass (Paspalum notatum Flugge var. saurae Parodi) entries, varying in forage yield, to fertilizer inputs, Bahiagrass was established in 1991 on Clarendon loamy sand (fine-loamy, siliceous, t hermic Plinthaquic Paleudults) near Tifton, GA. Forage production had been evaluated from 1992 to 1994. In 1995 and 1996, seed was harvested from 'Pensacola', Tifton 9 (T9), and RRPS Cycle 18 (T18) in July. Eig ht fertilizer treatments, identical to the 3-yr forage yield study, in cluded rates of 56, 112, 224, and 448 kg N ha(-1); 25 and 49 kg P ha(- 1); and 47, 93, 139, 186, and 279 kg K ha(-1). Seed yield was lower (P < 0.01) in 1995 than in 1996 and year and fertilizer treatment intera cted (P < 0.01), Seed yield achieved with 224 kg N ha(-1) and the lowe st P and K rates was not improved by higher rates, Although fertilizer treatment and entry interacted (P < 0.01), optimal fertilizer inputs among entries were similar, Seed weight was greater in 1995 and was in creased (P < 0.05) by spring application of 112 kg N ha(-1) compared w ith 56 kg N ha(-1), but not by higher rates. T18 seeds had greater (P < 0.05) emergence 7 or 14 days after planting (DAP) than Pensacola or T9. Emergence 14 DAP was greater with the highest N rates than the low est rate. Emergence 35 DAP was only influenced by year (1996 > 1995), Moderate levels of N enhanced seed yield. Fertilizer treatment had no important effect on seed emergence or dormancy. Seed production and cu mulative emergence of the three entries were similar.