Incomplete block design in plant tissue culture research

Most experiments in tissue culture employ either completely randomized or randomized complete block designs. The ability of orchardgrass (Dactylis glomerata L.) leaf halves and segments from individual leaves of chrysanthemum (Dendranthema grandiflora Tzvelev.) to respond similarly in vitro to identical treatments allows application of an alternative experimental design based on blocking by leaf. Incomplete block designs conserve experimental materials and reduce labor while maintaining the statistical power and efficiency of more conventional designs. They also allow combination with nesting (hierarchal designs) to monitor different sources of variability or with factorial studies. Application of incomplete block designs for orchardgrass (somatic embryogenesis) and chrysanthemum (shoot organogenesis) leaf cultures are presented.