Severe Drought Stress Influences the Success of Madura Tangerine Flower Induction
Off-season tangerines flower induction through drought stress is one of the efforts to meet the availability of tangerines throughout the year. The level of drought stress that can induce flowering has a certain threshold so that severe stress can affect the success of flower induction. This study aims to prove that severe drought stress can affect the success of induction of Madura lowland tangerines. The study was conducted in the PKHT-IPB Tajur Experimental Field with ± 300 meter above sea level from March-October 2017 and designed with a Randomized Block Design (RBD) of one factor, namely the level of drought stress with three levels: without drought stress as control (routine irrigation with 100% field capacity water content), 50% field capacity water content drought stress (no irrigation to 50% field capacity water content) and 40% field capacity water content drought stress (no irrigation to 40% field capacity water content). The results showed that the water content of 50% and 40% of the field capacity did not induce Madura tangerine flower as evidenced by very high levels of gibberellins. 50% and 40% field capacity water content is too low so that the plants have severe drought stress and disrupt the flower induction process. The severe drought stress is characterized by high leaf and soil water potential, high leaf proline content, decreased stomata density, and leaf rolling.
Keywords: field capacity water content, lowland tangerine, off-season, Randomized Block Design (RBD), rewatering