Response of mature sapodilla (Manilkara zapota) trees to shoot heading
M. Malip
Abstract
Effect of shoot heading on flushing, flowering and fruit setting of sapodilla was studied in MARDI Kuala Linggi, Melaka. The study was carried out on five-year- old sapodilla trees cv. Jantung. At three months after heading the softwoods, semi-hardwoods of the current year, and hardwoods of the previous year, the shoot diameter showed a declining trend i.e. 5.10, 4.70 and 4.40 mm, respectively. However 6 months after heading, the reverse occurred when the shoot diameter of the softwoods, semi-hardwoods and hardwoods showed an increasing trend i.e. 5.4, 6.90 and 7.80 mm, respectively. The significant differences (p <0.05) for shoot diameter and shoot length were only detected at 6 months, and not 3 months after heading. A positive and strongly linear correlation at 6 months after heading was established between shoot sizes and flush diameter (y = 4.11 + 0.26x, r2 = 0.98) as well as shoot sizes and shoot (flush) length (y = 10.61 + 2.01x, r2 = 0.93). Flowering shoots, fruit setting and fruit number were significant (p <0.05) between softwoods, hardwoods and to that of semi-hardwoods. The number of flowering flushes, fruit setting and fruit number were highest for the semi-harwoods compared to the softwoods and hardwoods. Subsequent experiment shortly after the secondary peak season with 25%, 50%, 75% and 100% degree of heading severity imposed on the semi-hardwoods of the current year showed that there is no significant difference (p <0.05) in shoot number appeared immediately after heading. However, significant difference (p <0.05) between pruning severity was detected in flowering shoot number and fruit set per pruned shoot at 9 months after heading. Comparisons between total number of fruits from the flushes of the unpruned shoots showed that the 25% heading severity treatment had the highest fruit number (113.8 fruits).
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