Effects of water deficit on growth and yield of cotton cultivar Sri Sumrong 60

The objectives of this study were to determine the effects of water deficit on growth yield and yield components of cotton (Gossypium hirsutum L). The study has been conducted in the dry season of 1996 (January-July, 1996) at National Corn and Sorghum Research Center, Pak Chong, Nakhon Ratchasima. The experimental design was Randomized Complete Block with 4 replications. The cultivar Sri Sumrong 60 was used in this experiment. Treatments composed of full irrigation applied weekly (T1), stress period at the beginning of square producing stage (T2) and stress period at the early blooming stage (T3). Midday leaf water potential (T1) was used as an indicator for water deficit, when T1 reached about -2.5 MPa, the irrigation was resumed again. The results revealed that plant height, number of nodes per plant and height to node ratio of T2 and T3 were statistically lower than of T1 during stress period. The production of reproductive organs of T2 and T3 was significantly reduced. Ten days after reirrigation, the recovery and rapid growth occurred in T2 and T3. Thus, total seed cotton yield of T2 and T3 was not significantly different from T1. However, T3 gave the greatest seed cotton yield, approximately 3 ton ha-1. (Résumé d'auteur