Breaking seed dormancy and optimization of seedling substrate of red sandal wood (Adenanthera pavonina L.)

Abstract

Red sandal wood (Adenanthera pavonina L.) is a useful ornamental, forage and medicinal tree
which is becoming less common in some areas. Hard-seed dormancy inhibits germination. The objectives
of this research were to identify a treatment to break seed dormancy and to find an optimal substrate
for the growth of seedling for use in the Plant Genetic Conservation Project area of Pibulsongkram Rajabhat
University. Plant characteristics are in Family Leguminosae, Subfamily Mimosoideae. It was divided into
2 experiments: 1) To induce seed germination. Five seed treatments were tested to break dormancy:
soaking in water, soaking in HCl, soaking in NaOH, soaking in plant hormone, wounding and compared
with untreated seeds (control). One hundred seeds per treatment were placed in seedling trays for 1 week
in greenhouse, 2 replications per treatment. 2) To investigate suitable substrates for growth

Three centimeter high seedlings were grown in 8 substrate types: loam mixed with chicken manure, loam
mixed with chicken manure and marigold, loam mixed with dove manure, loam mixed with dove manure
and marigold, loam mixed with bat manure, loam mixed with bat manure and marigold, loam mixed with
marigold and loam (control). Nine seedlings were planted in each substrate and 3 of each were placed in
each of 3 greenhouses for 4 weeks. The results were shown that the HCl treatment gave highest seed
germination (91%). Seedlings grown in loam mixed with bat manure, with or without marigold, had significantly
better growth (P ≤ 0.5) than the other treatments. Adding marigold into the substrate can decrease
the amount of manure required and increase the height of seedlings.