Growth Analysis of ‘Florigraze’ Rhizoma Peanut: Shoot and Rhizome Dry Matter Production

Abstract

Abstract‘Florigraze’ rhizoma peanut (Arachis glabrata Benth.) is a perennial tropical forage legume grown in Florida and the southern Gulf Coast. It is vegetatively propagated with rhizomes and regrows from rhizomes in the spring following winter frost‐kill, but little is known about its growth and development. Two studies were conduced near Gainesville, FL, on Arredondo loamy sands (loamy, siliceous, hyperthermic Grossarenic Paleudults) in 1980 and 1981 to characterize aerial and underground growth of Florigraze. The establishment‐year study used spaced‐planted hills (three to five rhizomes per hill) in 1980 and 1981. The defoliation‐frequency study (undefoliated vs. defoliated every 2, 6, or 8 wk) was conducted in 1981 on plants (hills) that were undisturbed at the 1980 site. Entire hills were dug every 3 to 8 wk, and separated into shoots and primary and secondary rhizomes. In the establishment year, accumulated dry matter (DM) of shoots and rhizomes increased until September, when shoot growth plateaued or declined while rhizome growth continued. During cooler autumn months, photosynthate produced in shoots was partitioned into rhizome growth. Secondary rhizomes (smaller non‐branched rhizomes) constituted the bulk of rhizome mass. Shoot/rhizome ratios increased from zero at planting to about 1.5 to 2 by late summer, then declined to about 0.5 in autumn. Defoliation treatments decreased rhizome DM production by one‐half (8 wk) to two‐thirds (2 and 6 wk) that of the undefoliated control. Our results indicate that defoliation should be avoided for establishing plants and plants that will be used as a source of rhizomes for propagation.