Influence of argel, micro-elements and growth regulators on flowering and fruit set of mango

Abstract

This study aimed to enhance flowering and fruit set in three mango cultivars introduced to Sudan from South Africa. The age of trees was five years. All trees showed symptoms of vegetative malformation. The severity differed with cultivar i.e. very severe in Tommy Atkins, intermediate in Kent and slight in Keitt. To alleviate the vegetative and the expected floral malformation, in mid November, all trees were pruned at least 5 cm below the distorted shoot tips, the cut surfaces were sprayed with Stroby (fungicide/ acaricide) in concentration of 50 mg/l, and each tree received a soil fertilizing treatment composed of 100 g urea and 100 g calcium super phosphate. In three separate experiments, each cultivar was assigned for a specific test. Each experiment was accomplished in a complete randomized block design with 8 replicates, where each tree was considered a replicate. Argel was tested for the effects of its different forms and modes of application on Tommy Atkins cultivar in the first experment . Soil application of ground stems and the foliar application of leaf water extract enhanced the percentage of flowering branches significantly. Soil dressing with grounded argel stems improved the characteristics of the inflorescence. All argel treatments improved fruit set compared to the control, but the best fruit retention was obtained from the foliar application of the leaves water extract. In the second experiment argel, Fe, and Mn were tested singly and combined on “Kent” mango cultivar. Mn alone, or Mn + argel, or argel alone increased the number of flowering branches per tree significantly. All treatments increased fruit set over the control, but the best fruit retention resulted from the combination of argel and Fe, or the single application of argel. In the third experiment where argel, BA and NAA were tested singly or in combinations, NAA and its combination with argel reduced the number of flowering branches compared to the control and the other treatments that performed alike. On the contrary the argel + NAA treatment increased the length of main spike, the distance between secondary spikes, the number of flowers per tertiary spike and retained the highest number of fruits per inflorescence although it depressed the initial fruit set to a level resembling the control in which fruit set was the least.