ISHS Acta Horticulturae 175: Symposium on Physiology of Productivity of Subtropical and Tropical Tree Fruits
THE INFLUENCE OF BANANA (CV. WILLIAMS) PLANT DENSITY AND CANOPY CHARACTERISTICS ON RATOON CYCLE INTERVAL AND YIELD |
| Authors: | J.C. Robinson, D.J. Nel |
| Keywords: | banana, density, cycle interval, leaf area index, radiation, yield per annum |
| Abstract:
In a Williams banana density trial at Burgershall in the Eastern Transvaal, a high density of 2222 plants ha-1 retarded plant crop (P) cycle interval by only one month compared to 1000 plants ha-1. In the first ratoon (Rl) cycle, the canopy of the P crop caused a lengthening of total R1 cycle interval from 15.5 months at 1000 plants ha-1 to 21.3 months at 2222 plants ha-1. The greater canopy cover of the R1 crop caused even longer R2 cycle intervals of 21.6 and 30.9 months respectively. Analysis of leaf production during the R2 vegetative phase showed that cycle delay at high density was a function of slower leaf emergence rate combined with more leaves per plant before flowering. These components were in turn related to lower stem temperatures and reduced light interception by the suckers. At 1000 plants ha-1, 38.3 leaves plant-1 were produced at the rate of 27.5 leaves year-1 whereas at 2222 plants ha-1, 44.8 leaves plant-1 were produced at the rate of only 22.9 leaves year-1. Total radiation transmission through the canopy was 30 and 14 per cent respectively. In the Rl cycle, potential leaf area index (LAI) at flowering increased from 3.2 at 1000 plants ha-1 to 6.3 at 2222 plants ha-1. At the highest density, LAI increased from 2.5 immediately after P crop harvest, to 6.3 at flowering, diminishing again to 5.0 at harvest. Yield per annum is a function of total bunch yield per ha and cycle interval. At 2222 plants ha-1, yield per annum was significantly higher than at 1666 ha-1, for the P cycle separately, and for all 3 cycles cumulatively, but not for the R1 and R2 cycle separately. More ratoon cycles are required to determine the optimum density. | |
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