Effect of autumn water stress in combination with ethephon on flowering and yield of litchi, 'Mauritius', in a warm production area of South Africa
Poor litchi flowering is a worldwide problem, especially in areas where temperatures during the flower induction period are not low enough. The effect of autumn water stress in combination with ethephon application to control late autumn flush in order to improve flowering and yield was investigated over a four year period. The study was carried out on the cultivar 'Mauritius' grown on heavy clay soil in a warm production area of South Africa. The trees were subjected to four irrigation treatments and those were, two stress-inducing irrigation treatments and two optimum irrigation treatments without water stress. Water stress treatments were applied during autumn, either between March and April (early stress), or between April and June (late stress). Up to 50 and 70% of the optimum tree water requirement was withheld for the early and late water stress periods, respectively. Ethephon was applied to both water stress treatments as well as to one of the optimum irrigation treatments whenever young flushes appeared. The second optimum irrigation treatment was not treated with ethephon. Water stress in combination with ethephon application successfully controlled vegetative flushing and increased flowering and yield compared to optimum irrigation in combination with ethephon application. Optimum irrigation without ethephon caused the trees to flush in all four trial years. Differences in tree reaction with regard to treatment and climatic effects are discussed.
Cronje, R.B., Ratlapane, I.M. and Froneman, I.J. (2016). Effect of autumn water stress in combination with ethephon on flowering and yield of litchi, 'Mauritius', in a warm production area of South Africa. Acta Hortic. 1130, 503-510
flower induction, autumn flush, irrigation