Dormancy In Oil Palm Elaeis Guineensis

Dormancy in Oil Palm Elaeis guineensis Oil palm seeds pose difficulties in terms of commercial germination due to a strong dormancy. Dormancy could last several months or years, depending on the environmental conditions before and after harvesting. In the wild, seeds may remain viable and begin germination even after 25 years in the soil. The dormant period is affected by various factors such as moisture, light, and the concentration of gases and other substances, which can sometimes be manipulated to effect changes in dormancy. Due to these difficulties and to the importance of the crop, methods of accelerating the germination process have been the object of investigation since 1922. Dry heat method One of the most extensive reviews of methods for achieving uniform oil palm germination was carried out by Galt (1953), who had, at that time, already described the dry heat method for accelerated germination. In 1959, Rees detailed the dry heat process, a commercial method for large-scale plant production, for interrupting seed dormancy in Deli dura palms on a commercial scale in Malaysia. This method consists of subjecting the seed to temperatures of between 38°C and 40°C for 40 to 60 days, although the authors originally indicated periods of 70 to 80 days. This method can be inconvenient in terms of the high cost of maintaining the temperature, as well as the amount of time necessary to break dormancy. Chemical treatments The experiments carried out by Ramiro and Guevara (1998) identified chemical treatments stimulating different levels of germination. The best results were obtained with treatments of H2SO4 followed by immersion in 1.5 % CH2N2 for 24 hours or in 0.6% or 1.8% ethephon for 48 hours, as well as with CH 2N2 immersion only. These treatments had significant effects on germination over short, but variable, timeframes (15 to 43 days) and success rates are as high as 80%. Use of this chemical involves some difficulties, such as the quantities required to carry out largescale seed treatments, as well as the harmful effect of the residue and the danger to those handling it, all of which make it necessary to look for alternative solutions. Accelerated aging Accelerated aging (AA) performed by Murugesan et al. (2005) according to the Seed Vigour Testing Handbook of the Association of Official Seed Analysts. One subsample was AA treated without initial water soaking and another was presoaked for five days prior to the AA test. Presoaked AA treated seeds recorded 40%, 72%, and 80% germination after 50, 60, and 70 days; whereas, unaged seeds had no germination during the same period. Furthermore, the five day presoak followed by aging treatment significantly improved germination. References Addae-Kagyah, K.W. 1988. Effect of Seed Storage, Heat Pretreatment and its Duration on Germination and Growth of Nursery Stock of the Idolatrica Palm, Elaeis guineensis var idolatrica (Chevalier). Tropical Agriculture. 65(1): 77-83.

Galt, R. 1953. Methods of Germinating Oil Palm Seeds. Journal of West African Institute for Oil Palm Research. 1: 76-87. Murugesan, P., Mathur, R.K., Pillai, R.S.N., and Babu, M.K. 2005. Effect of Accelerated Aging on Seed Germination of Oil Palm (Elaeis guineensis Jacq. var. dura Becc.). Seed Technology. 27 (1): 575-587. Ramiro, J.H. and Guevara, A.E. 1998. Use of Chemical Treatments to Induce Seed Germination in Oil Palm Elaeis guineensis. ASD Oil Palm Papers. 18 (1): 1-16. Rees, A.R. 1959. Germination of Oil Palm Seed: Large Scale Germination. Journal of West African Institute for Oil Palm Research. 3:76-82.