Study of compact dwarf pigeonpea's response to photoperiod and exogenous gibberellic acid

Pigeonpea [Cajanus cajan (L.) Millsp.] is the second most important pulse crop of India known for its rich protein and versatile uses. Pigeonpea exhibits differential genotypic response to varying photoperiods, while its response to exogenous gibberellic acid (GA₃) has rarely been studied. ‘TDT2004-1’ is an interspecific derivative with D₀ type compact dwarf plant type. The present investigation was conceived, with a view to studying the response of compact dwarf plant type ‘TDT2004-1’ to varying natural photoperiod and exogenous GA₃. The flowering response to photoperiod was studied by conducting a monthly sowing trial in pots, while the response to GA₃ was assayed in vivo under controlled conditions in growth chamber. ‘TDT2004-1’ exhibited a qualitative short day photoperiodic response, while it was insensitive to exogenous GA₃ up to concentrations of 100 ppm. The study connotes that short-duration pigeonpea is also photoperiod-sensitive unlike otherwise and that ‘TDT 2004-1’ could be used to evolve rabi/rice fallow cultivable varieties. It also serves as a valuable genetic material for providing insight into GA₃-mediated processes.