Effects of nine different propagation media on seed germination and the initial performance of papaya (Carica papaya L.) seedlings

Abstract

SummaryAn experiment was undertaken in July and August in two consecutive years (2009 and 2010) to test the efficiency of nine propagation media of varying composition. Significant differences in germination percentages and in the initial performance of papaya (Carica papaya L.) seedlings were observed. The results showed that medium M9, consisting of a 1:1:1 (v/v/v) mix of vermicompost: sand: pond soil with a 20 mm-thick cocopeat layer, was characterised as having a lower bulk density, particle density, electrical conductivity and pH, as well as a higher water-holding capacity and plant nutrient content than all of the other media tested. Medium M9 was found to be optimal for the initial performance of papaya seedlings and gave the maximum rate of seedling emergence, the highest germination percentage, the highest seed vigour, and the shortest time for seed imbibition. Medium M9 was also found to be best for the subsequent growth of papaya seedlings. It gave the best performance in terms of seedling height, total leaf area per plant, number of leaves, stem diameter, number of roots, root length, total production of biomass, and the lowest root:shoot ratio. Medium M9 also significantly reduced seedling mortality and produced the healthiest seedlings (92.2% survival in 2009; 93.2% survival in 2010) in the shortest time (38.3 d in 2009; 38.1 d in 2010) with the highest net profit (approx. US$ 64.0 per 1,000 seedling in both years) and benefit:cost ratio (1.85 in 2009; 1.84 in 2010) compared to the other eight media tested in both years of experimentation.