Effects of different growing media on germination performance and seedling morphology of avocado (Persea americana Mill.) seeds

As global awareness of the nutritional and economic value of avocado (Persea americana Mill.) continues to grow, new commercial plantations are being established worldwide, requiring large quantities of uniform, high-quality nursery stock. In this study, the effects of four growing media on the germination capacity and morphological development of avocado seedlings were evaluated. The results showed that the first germination occurred on day 35 after sowing in perlite medium (T1) at a rate of 10%, while the latest germination initiation was observed in T4 (perlite + cocopeat + soil:farm manure:river sand) beginning on day 42, with germination completed by day 77 across all media. Although germination capacity did not differ significantly among growing media, values ranged from 91.1% (T1) to 97.7% (T4), all of which were considered adequate for practical propagation. The desired threshold of 80% germination capacity was reached earliest in T3 and T4 media (day 56) and latest in T2 (between days 70 and 77). Eight months after sowing, the greatest seedling height was recorded in T3 (soil:farm manure:river sand, 96.8 cm). Stem diameters at this time were 9.9 mm in T2, while seedlings grown in all other media exceeded 10 mm- the threshold recommended for successful grafting. Plant and root fresh and dry weights were highest in T1 (perlite). Overall, the recommended stem diameter for grafting was attained within eight months of sowing in all growing media, indicating that all four substrates support successful rootstock production.