Microspore development stage No. of Proliferative Loci/Explant Pathway Callus formation rate(%) No.of Plantlet obtained/ explant Remarks Tetrad - - - - - Early-uinucleate 4 Callus mediated 12.5 - Callus is non-organogenetic Late- uninucleate 4 Callus mediated Plb development 12.5 4 Callus is achlorophyllous, friable&organogenetic

Table 4: Effect of Microspore Development Stage on Callus induction of Rhyncostylis retusa Anthers in BM+BAP(10mg/l)+Peptone(2mg/l).