Effect of different water regimes and organic manures on indole acetic acid (IAA), oxidase activity, leaf area, light transmission ratio, chlorophyll stability index, relative water content and yield attributes of noni (Morinda citrifolia L.)

An experiment was conducted at Horticultural College and Research Institute, Tamil Nadu Agricultural University, Periyakulam in split plot design with irrigation regimes on main plot (four levels) and organic manures on sub plot (eight levels) with two replications. Among the different treatment combinations, M2S4 (100% WRc through drip irrigation + 50% farmyard manure + 50% vermicompost) exhibited superior performance for leaf area, light transmission ratio, chlorophyll stability index, relative water content and fruit yield as against the poor performance by M4S8 (check basin method of irrigation + no manures and no fertilizers) at different growth phases.  Indole acetic acid (IAA) oxidase activity was found to be the lowest in M2S4 (100% WRc through drip irrigation + 50% farmyard manure + 50% vermicompost) as against the highest in M4S8 (check basin method of irrigation + no manures and no fertilizers).   Key words: Morinda citrifolia, IAA oxidase, leaf area, light transmission ratio, chlorophyll stability index, relative water content, yield.