Response of Selected and Unselected Bahiagrass Populations to Defoliation

Recurrent restricted phenotypic selection (RRPS) has increased spaced‐plant yield of ‘Pensacola’ bahiagrass (Paspalum notatum Flügge var. saurae Parodi) and led to higher‐yielding, more erect genotypes. Response to defoliation was examined in three entries: selection Cycle 0, Pensacola; Cycle 9, ‘Tifton 9’, and Cycle 14. In a 3‐yr plot study, two cutting heights (15 or 100 mm) in combination with three regrowth intervals (2, 4, or 8 wk) were imposed throughout 24 wk. A split‐split plot arrangement of regrowth interval (whole plot), cutting height (subplot) and entry (sub‐subplot) was used, with six replications. In a 2‐yr grazing study, response of the same entries to defoliation from continuous stocking was evaluated. In the plot study, yield (7030 kg ha−1) was maximized by low cutting height and 8‐wk regrowth interval during the first year. In Year 2, a 4‐wk regrowth interval and low cutting height produced the highest yield (11220 kg ha−1). Mean yields of Tifton 9 (7650 kg ha−1) and RRPS cycle 14 (7320 kg ha−1) were greater than Pensacola (6500 kg ha−1), but response of entries to cutting height and regrowth interval varied among years. In the grazing study, herbage mass was greater for Tifton 9 (1670 kg ha−1) and RRPS Cycle 14 (2000 kg ha−1) than for Pensacola (1420 kg ha−1). Carrying capacity of Tifton 9 (935 d ha−1) was greater than Pensacola (855 d ha−1). Daily gains were similar (0.34 kg) for all germplasms. Bahiagrass stand declined rapidly for RRPS Cycle 14. Continuous stocking at high grazing pressure was not suitable for RRPS Cycle 14.