ZILLI alex leonel
congresos y reuniones científicas
Ecophysiological Responses of Tetraploid Bahiagrass to Nitrogen Fertilization
San Antonio, Texas
Congreso; International Annual Meeting 2019; 2019
Dramatic increases in forage yield are commonly observed after nitrogen fertilization in warm-season perennial grasses. However, the ecophysiological mechanisms involved are not sufficiently understood in this group of plants. Novel apomictic hybrids have been generated in tetraploid bahiagrass, and their response to N availability is crucial for selection. In addition, bahiagrass could be used as a model species. The objective was to determine the effect of nitrogen fertilization on forage production, light interception and tillering in ten apomictic tetraploid bahiagrass genotypes (eight advanced breeding lines and cultivars Argentine and Boyero UNNE). Two N fertilization rates (0 and 150 kg N ha-1 year-1) were applied after cutting the plots at 5 cm stubble height in 2018. Intercepted photosynthetically active radiation (iPAR) was measured weekly, and plots were harvested in summer 2019. Previously, total tiller density (TTD), vegetative tiller density (VTD) and reproductive tiller density (RTD) were measured; and tiller weigh was estimated. Nitrogen fertilization increased biomass production, achieving an average increment of 23.2 g dry matter per g N applied. No statistical differences among genotypes where found. The iPAR increased rapidly after cutting the plots, reaching 78% and 45%, and 92% and 63% 20 and 50 d after cutting for fertilized and non-fertilized plots respectively. Nitrogen fertilization increased TTD (50.1%) and RTD (257.7%), but it did not affect VTD neither tiller weight. Genotypes differed for TTD and RTD, varying between 972 and 1396, and between 160 and 507 tillers m-2 respectively. Nitrogen fertilization increased biomass production by increasing RTD, which could increase seed production as well. In addition, N fertilization significantly improved iPAR, which will allow better efficiency in the use of radiation, together with greater ability to compete with weeds. Finally, the information generated will be used for selecting the advanced breeding lines to be released to the market.