Therefore, to achieve multiplication, we note that a low dosage of BA (2.22มิวM) applied to the medium containing 5.37 มิวM NAA strongly inhibited this undesirable saprophyte development but had less effect on increasing GGB diameter. Although this medium also contained 5.37 มิวM NAA, this auxin was obviously not the PGR conductive to the inhibition of saprophyte formation, since the medium containing only this same level of NAA showed no evidence of inhibition at all (Table 4; Combination 1). The naturally produced 2ip (2.22 มิวM๗ +/- NAA (5.37 มิวM) may also depress saprophyte formation. In contrast, it has a positive effect on GGB multiplication, as seen in Table 4. Obviously, cytokinin is required during this stage to depress sporophyte formation, as well as to promote GGB multiplication.