Abstract: The current study was conducted at College of Agriculture and Veterinary Medicine, Jimma University, Ethiopia to identify nutrient media that support optimum germination of Ficus vallischaude seed. Six media and media mixes and a control were tested in a completely randomized design. The result has clearly revealed that early germination of seeds was observed with the use of media containing a mixture of forest soil, cow dung and sand in 3:1:1 ratio and with the use of cow dung alone. The germination percentage of Ficus vallischaude varies significantly among different media. Accordingly the germination percentage was 100% for the control followed by sand and forest soil with 88 and 72%, respectively. This study revealed sand as the most appropriate nutrient medium for the germination of Ficus vallischaude.
INTRODUCTION
Fig is among the oldest fruits and is known to man from time immemorial. Fig. has a significant religious and cultural value in different societies mainly among the Oromo people, the largest ethnic group in Ethiopia (Williams-Linera and Lawton, 1995; Aksoy, 1998; Dibaba, 2002). It is also used as a live statue since it has a long life span (more than 100 years) to remember the locally famous individuals in the society. It is also called after the name of market and the occasions held under its shade and after the name of residents (tribes) living close to the tree. Fig. tree is also widely valued for spiritual and sacred properties and as a focal point for resolving conflicts (FAO, 2001). On top of the above-mentioned uses of fig, Ficus vallischaude is also used as an ornamental plant.
According to Milton et al. (1982), Ficus seedlings were rarely found in the forest except in light gaps or along the banks of river and lakes. The minute size of the seeds presumably put Ficus at a disadvantage when in direct competition with seedlings from species with larger seeds (Milton et al., 1982). According to Slocum and Horvitz (2000), despite the frequent and abundant arrival of small seeds, their arrival was probably not as influential on forest regrowth relative to the arrival of large seeds. This is because small seeds have difficulty of overcoming seed predation and competition with vegetation. Another plausible reason could be some species with small seeds need specific microsites to establish, for instance exposed soils or arboreal sites for some Ficus species. Smaller seeds have limited food reserves. If germination is to take place from too deep in the soil the seed reserve may be exhausted before seedlings emerge and begin to photosynthesize. This might be fatal germination (Bewely and Black, 1994; Hartmann et al., 1997).
So far, there are very few research findings on fig. Furthermore, the scanty literatures available to date are mainly on its ecological and economical uses. Less attention was given to propagation methods. It was with this idea in mind that the study on the effect of different nutrient media on germination of Ficus vallischaude seed under laboratory condition was conducted. The main objective of the study was therefore to identify growing media that support optimum germination of Ficus vallischaude seed.
MATERIALS AND METHODS
The experiment was conducted at College of Agriculture and Veterinary Medicine, Jimma University (JUCAVM), Ethiopia in the soils laboratory for three months from September to November, 2009. JUCAVM is located at about 7o, 33'N and 36o, 57'E at an altitude of 1710 m above sea level. The temperature in the laboratory during the experiment ranges from 21 to 22°C. The relative humidity ranges from 31.2 to 91.4%.
Seven treatments namely Forest Soil (FS), Cow Dung (CD), sand (SN), Forest soil + sand (3:1), Cow dung + sand (3:1), Forest soil + Cow dung + sand (3:1:1) and Control (germinating seeds in Petri dish lined with blotting paper) (CON) were tested. The experiment was laid down in Completely Randomized Design (CRD) (Montgomery, 2008) with four replications. Fig. seeds were obtained from Boterbocho forest project area, Southwest Ethiopia. Fifty seeds were sown per pot or per Petri dish. Watering was performed regularly and uniformly.
Date of germination and number of seed germinated per day starting from seventh day after sowing was recorded for 52 days. Germination percentage was determined based on the final day count of germinated seeds. Data were subjected to analysis of variance and means were compared using GenStat computer software, GenStat for Windows 11th Edition (VSN International, 2008).
RESULTS AND DISCUSSION
For date and percentage of germination, significant effects of nutrient media were observed (p<0.05). Next to control, cow dung and a mixture of forest soil, cow dung and sand (3:1:1) resulted in earlier (Fig. 1) germination whereas sand followed by forest soil and a mixture of forest soil, cow dung and sand (3:1:1) resulted in higher germination percentage (Fig. 2).
For date (initiation) of germination a significant effect of nutrient media was observed (p<0.05) (Fig. 1). Cow dung alone and a mixture of forest soil, cow dung and sand (3:1:1) gave early germination next to control. For instance, seed germination on cow dung and mixture of forest soil, cow dungs and sand started on 19 days after sowing. This could be due to a favorable condition created by these media in retaining good moisture and providing good aeration. The main conditions required for seed germination include water, air (oxygen) and temperature.
| Fig. 1: | Mean F. valliscude date of germination as affected by different nutrient media (CON = Control, FS = Forest soil, CD = Cow dung and SN = Sand). Means followed by different alphabets differ significantly (p<5%) as established by an LSD-test (LSD = 5.71) |
| Fig. 2: | Mean F. valliscude germination percentage as affected by different nutrient media (CON = Control, FS = Forest soil, CD = Cow dung and SN = Sand). Means followed by different alphabets differ significantly (p<5%) as established by an LSD-test (LSD = 12.1) |
Therefore, media that have good aeration and water holding capacity should be selected for germination of Ficus vallischaude seed. Previous reports indicated that moisture availability is vital factor for fig seed germination and establishment (Galil and Meiri, 1981; Titus et al., 1990).
For germination percentage 52 days after sowing, a significant effect of nutrient media was observed (p<0.05) (Fig. 2). Compared to control, all nutrient media resulted in significantly lower germination percentage. From the nutrient evaluated, sand resulted in a higher percentage of germination (88%) followed by forest soil (72%). However, the percentage germination achieved on forest soil was not significantly different from that of a mixture of forest soil, cow dung and sand (66%) and that of cow dung (65%). This result clearly demonstrated that regular water supply and good aeration promotes higher germination of the fig seeds. This is congruent with previous reports. For instance Herrera (2004) indicated that sand is one of the popular germinating media for Fig. He also further suggested that any medium used for germination of fig should be well drained.
As shown in Fig. 1, 100%of fig seeds sown in the Petri dishes (control) germinated within three weeks (21 days) and demonstrated a sharp trend. Whereas, the other media although started germination almost at the same time with that of control, they did not show regular trend like that of control. This may be attributed to the differences in moisture retention capacity of the medium, temperature and other abiotic factors. Milberg et al. (2000) reported that abiotic factors like light also determine the germination capacity and energy of fig seeds. Garcia et al. (2005) has also demonstrated the role of abiotic factors like temperature, photoperiod on germination of Ficus lundellii seeds. These authors found significant effect of light on germination of Ficus lundellii under all temperature regimes. Another study by Laman (1995) reported abiotic and biotic factors limiting the population density of other Ficus species such as F. stupenda. For all nutrient media, there was an increasing trend of germination as the days proceed. Fig. seed germination was completed with in eight weeks after sowing for all media. A medium with a mixture of cow dung and sand (3:1) was an exception as in this case germination was completed within seven weeks. This may be due to optimum moisture holding capacity enhanced by cow dung and proper aeration due to sand.
In conclusion, the results of this study clearly showed the importance of media composition for seed germination of fig tree (Fig. 3). Accordingly, early germination of Fig. seed was enhanced by the use of cow dung alone and a mixture of forest soil, cow dung and sand in a 3:1:1 ratio. The study also revealed sand as the most appropriate media for the germination F. vallischaude and would be an interesting option to be exploited in nursery production.
| Fig. 3: | Number of seeds germinated every seven days after sowing on different nutrient media: CON (closed square), FS (open square), CD (closed triangle), SN (open triangle), FS: SN (closed diamond), CD:SN (open diamond) and FS:CD:SN (open circle) |
However, further research is required to assess the seedling performance under field conditions to recommend suitable media for F. vallischaude seed germination, seedling growth and field establishment.
ACKNOWLEDGMENTS
My sincere thanks go to Gezahegn Berecha for his unreserved support during data collection and analysis and Hirko Dibaba who supplied me the seeds used for the experiment. Etetu shiferawu also deserves special thanks for looking after the experiment daily in the laboratory. I also thank the Jimma College of Agriculture for allowing me to use the laboratory facilities.