Media and gelling agent effect on cotton callus initiation from excised seed hypocotyls

A factorial experiment was performed to develop a medium which would support initiation and proliferation of callus in a diverse group of exotic lines of Gossypium hirsutum. Seed hypocotyls of T1, T25 and T133 were cultured on Linsmaier and Skoog (LS) basal medium (1965) with NAA or 2,4-D tested in combination with BA or kinetin. The best medium from this study was then compared to five published media for support of callus initiation and growth of the varieties Acala 1517-75, Coker 500, Dunn 120, Paymaster 303 and TM1. Furthermore, the effects of two gelling agents, Difco-Bacto agar and Kelco Gelrite, were investigated with each of the six media. Significantly more callus was initiated on media solidified with Gelrite than with agar. The best callus production occurred on LS medium supplemented with 30gl^-1 glucose, 0.1 mgl^-1 BA and 0.1 mgl^-1 2,4-D.