Date of this Version
Chapter 7, from Forages: The Science of Grassland Agriculture, Volume II, Seventh Edition. Edited by Kenneth J. Moore, Michael Collins, C. Jerry Nelson and Daren D. Redfearn. Published 2020 by John Wiley & Sons Ltd.
The growth and development of forage plants is an amazing process. In some annual grasses such as cereal rye, plants can go from the late vegetative stage to fully-flowered in less than two weeks. Conversely, some perennial grasses like indiangrass can go from the vegetative stage to the elongation stage, then enter a quiescent phase for several weeks until adequate moisture is available which then moves plants into the flowering stages to complete the seed production process. Understanding the developmental morphology of forage plants is important for making good management decisions. Many such decisions involve timing the initiation or termination of a management practice at a specific stage of development in the plant’s life cycle. Physiologic responses to defoliation and subsequent growth potential are affected by growth stage and strongly influence subsequent developmental morphology (Parsons 1988; Brueland et al. 2003). Leaf appearance rate during seedling development has been used to evaluate stand establishment and is strongly related to seedling root development (Moser 2000). Leaf development on established tillers of perennial grasses can be used to time management practices such as defoliation, burning, fertilization, and growth regulator and pesticide application (Moore et al. 1991). Decisions regarding grazing and harvest management are often based on plant development (Frank et al. 1993; Brueland et al. 2003). This chapter addresses the initiation, expansion, and maturation of leaves, stems, and roots and how they regulate the transition from vegetative to reproductive growth and subsequent production of reproductive tissues. The interaction of these processes has profound effects on forage yield, quality, and stand longevity. Emphasis is given to the interactions of developmental morphology on these processes. The authors thank Dr. Howard Skinner for his work on the previous edition of this chapter.