Influence of potting media types and weights on emergence and shoot growth of avocado (Persea americanaMill.) seedlings

Abstract

Influence of potting media types and weights on emergence and shoot growth of avocado (Persea americana Mill.) seedlings. Abstract — Introduction. In Ethiopia, avocado is cultivated in many traditional homesteads. For the nurs- eries, there is a need for standardized formulas for potting media constituting locally available sowing media. Materials and methods. Our study was undertaken at the Jimma Agricultural Research Center (Ethiopia) to evaluate the effect of different media types and weights on the emergence and the seedling shoot growth of avocado trees. The study focused on addition of various proportions of locally available organic sources (farm- yard manure and coffee pulp) and sand to topsoil. Eight media mixes were prepared. Those media mixes were combined at three media weights ((1.5, 2.5 and 3.5) kg) and studied with a factorial block design com- pletely randomized with four replications. The data on mean days to emergence (Mde) and shoot growth were destructively collected from four sample plants per plot at 30-day intervals (duration) starting from 30 days after emergence (Dae) up to 180 Dae (six months after emergence). An analysis of variance was done at each sampling. Results and discussion. Avocado seeds took about 70 Mde. The different media types significantly influenced the total fresh and dry weight of the seedlings. Plant height, fresh and dry weight and shoot diam- eters were highly and significantly affected by media type and weight interactions. MT6 (topsoil 3 vol. + farm- yard manure 2 vol.) gave a significantly higher total dry weight than MT1 (topsoil 4 vol. + sand 1 vol.) and MT8 (topsoil). Media weights affected all shoot growth characters. As the media weight increased, most shoot growth characters increased. All growth characters were highly influenced by the growth duration, and by the medium weight and growth duration interactions. Conclusion. At the initial growth stages, the dry matter increase was similar on all media weights up to 60 Dae; as the seedlings developed, the effect of higher weights was clearly seen, showing the importance of using larger medium containers for optimizing growth, which is due to the contribution of a larger supply of nutrients and no restriction on root growth. Based on this study, the seedling growth was stabilized between (90 and 120) Dae and responded well to additional nutrients and media weight as growth advanced in the nursery. Ethiopia / Persea americana / plant propagation / growing media / growth / agronomic characters