Physiological studies on Earliness in Musk Melon (Cucumis melo L.) II. Changes in leaf Carbohydrates, Soluble Nitrogen Peroxidase, Catalase, Gibberellin A₃ and Abscissic acid Levels Indifferent Varieties*

Early varieties of musk melon (Cucumis melo L.) were found to contain lower leaf N, catalase activity and endogenous GA₃ like promotors but a higher carbohydrate, nitrogen (C: N) ratio, peroxidase activity and endogenous ABA-like inhibitors during pre-flowering growth period viz. 40 days after seed sowing than the late varieties. The number of days to first female flower opening was positively correlated to total leaf N, endogenous GA₃ but negatively to per cent carbohydrates, C: N ratio and endogenous ABA at 40 days after seed sowing. It also showed a positive correlation with total carbohydrates per plant at 54 days and C: N ratio at 68 days after seed sowing. Since, peroxidase and catalase activity (cm⁻²) showed a negative and positive correlation, respectively with the number of days to first female flower, these can be exploited as efficient selection indices for earliness in musk melon at early growth stages.