Exogenous Application of Paclobutrazol and Potassium Nitrate in Growth and Survival of Waterlogged Tomato

Abstract

The general objective of this study was to evaluate the effects of exogenous application of PBZ and KNO₃ in tomato subjected to different water regime. Specifically, it aimed to determine the response of tomato under different water regime as affected by application of PBZ and KNO_3, and identify the optimum concentration of the two PGRs that will give highest survival of tomato in different water regime. Waterlogging caused reduction in %survival of tomato; however no further decreased from 24hrs to 48hrs waterlogging. This trend was similar to plant height, number of leaves, leaf dry weight, stem dry weight, plant dry weight, and days to flowering. In terms of PGRs, across WR, no significant effect was observed in chlorophyll content, stem dry weight, and root dry weight. Application of PBZ at any concentration caused reduction in plant height while increased leaf dry weight and plant dry weight was observed at 250 ppm. However, PBZ at 500 ppm decreased leaf dry weight. Increased plant dry weight and earlier days to flower was achieved by KNO₃ application. Combined application of 500 ppm PBZ and 8% KNO₃ decreased the survival rate and the number of adventitious roots and caused delay in initiation of adventitious roots and induction of flower. Exogenous application of PGRs at lower concentrations (4% KNO₃ + 500 ppm PBZ) showed positive results in the growth and survival of waterlogged tomato plants however, further study focused in timing of application and combination with other PGRs is also recommended.