White Clover Clone Response to Alternative Defoliation Methods

Abstract

While clover (Trifolium repens L.) is often evaluated under clipping during selection of germplasm but is ultimately utilized in grazed pastures. The objective of this study was to determine the effect of defoliation method on morphological characters that serve as selection criteria for improving white clover productivity and persistence. Vegetative clones of 14 plants of Southern Regional Virus Resistant germplasm were space‐planted in a common bermudagrass [Cynodon dactylon (L.) Pers.] sward in each of 2 yr on a Savannah fine sandy loam (fine‐loamy, siliceous, thermic Typic Fragiudnlt). Clones were defoliated the following year by continuous stocking with cattle or by clipping or rotational stocking on a monthly basis. Lateral plant spread of all clones increased from April to June, but declined from July to October due to death of stolon apices, and was reduced up to 50% by continuous stocking compared with clipping and rotational stocking. In July, plant leaf area, stolon length, and number of stolon apices of all clipped and rotationally‐stocked clones were twice that of continuously‐stocked clones. Morphological response to defoliation method in October, however, was genotype‐dependent; clones that exhibited superior growth in response to one defoliation method did not exhibit the same response to either of the other methods. The differential effect of defoliation method on white clover morphology demonstrates the sensitivity of these characters to harvest management, and because of their association with persistence, the need to evaluate germplasm in the environment in which it will be utilized.