Study on Maturity Indices and Effect of Growing Substrates on Seed Germination of Litsea glutinosa

Aim: Litsea glutinosa is a multipurpose, fast-growing tree widely exploited due to its multipurpose utilisation. Species reported low seed viability, hence generally propagated through vegetative methods. We studied the maturity indices of fruits and seeds to determine the optimal collection stage. Studied the effect of different growing substrates and Gibberellic acid (GA3) treatment on the germination percent (GP), mean germination time (MGT), germination value (GV), peak value (PV), and germination index (GI).

Study Design: Study was conducted at Forest Tree Seed Laboratory, ICFRE-FRI. The change in fruit colour from green, dark brown purple, and dark blue stages was compared with the seed parameters, germination percent, mean germination time, germination value, etc. to obtain the most suitable stage for fruit and seed maturity. Seed germination experiment was conducted in Complete Randomized Design with four replications of 25 seeds for each treatment. Seeds were sown directly on different germination substrates, such as filter paper, sand, and vermiculite, without treatment and also with 0.05% GA3 pretreatment. Seeds were kept in the seed germinator at 25±1ºC with a 24-hour photoperiod and high relative humidity (RH > 90%).

Results: The highest germination rate was observed in vermiculite with GA3 soaking . i.e., 80±3.26%, followed by vermiculite 68±8.64%. The lowest germination percent of 5±4.08% was observed in seeds plated on filter paper with GA3 soaking. No germination was recorded in the seeds plated on the filter paper.

Conclusion: Most suitable germination medium to maximise the germination of L. glutinosa seed is vermiculite. Furthermore, the pretreatment of seeds in GA3 (0.05%) for 24 hours and sowing in vermiculite improves overall performance with respect to GP, MGT, GV, PV, and GI. In the context of maturity indices, the dark blue stage with a moisture content of around 50% is the right stage for the collection of seeds of the species. This stage is characterised by high GP, GV, and low MGT values as compared to other growth stages.