Temperature, Nitrogen and Light Effects on Hybrid Bermudagrass Growth and Development

Abstract

‘Tifdwarf’ bermudagrass [C. dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] is one of the most widely used cultivars on golf course putting greens in the southern USA because of its superior putting green quality. This study evaluated the effects of photosynthetic photon flux density (PPFD), temperature, and nitrogen fertilization on growth and development of Tifdwarf bermudagrass. In controlled environment studies, increasing N increased bermudagrass internode length, leaf length, and shoot weights. Increasing N had no significant effect on the chronological appearance rate of successive leaves and axillary buds. The phyllochron was positively correlated with day/night temperature. The internode and leaf length were greatest at the 27/19°C treatment and least at the 35/27°C treatment. Internode length increased from 20 to 40 mm as the PPFD decreased from 975 to 300 μmol m−2 s−1 at 27/19°C but only increased from 10 to 22 mm long at 35/27°C. Leaf lengths responded similarly. Leaf and internode length were greater at low than at high day/night temperatures regardless of incident light. The alteration in growth form occurred within 3 to 4 d of treatment initiation. Results indicated that temperature as well as light levels regulated expression of dwarfness in Tifdwarf bermudagrass. In regions that typically have long periods with daytime temperatures of 27°C or less and a PPFD of 600 μmol m−2 s−1 or less, the growth form of Tifdwarf bermudagrass may change dramatically, resulting in plants with longer internode spacings and longer leaves. Because of this change in growth form, one may expect faster coverage from newly planted sprigs and faster recovery from disruptive cultural activities when the daytime temperatures are 27°C or less as compared with periods when the daytime temperatures are 30°C or above and the PPFD is >1000 μmol m−2 s−1 as is typical of summer in southern climates.