Standardization of Quick Seed Viability Protocol for Pinus roxburghii Sarg. Using Tetrazolium Assay

Chir pine (Pinus roxburghii) is one of the important tree species among five indigenous pine species of the Himalayan region and is widely distributed throughout the Himalaya. It is used as a commercial timber, fuel wood and pulpwood and also provide resin for various utilities. For the ecological, silvicultural and economical significance, the regeneration of this species is required for restoration and conservation purposes. Before seed sowing in nursery, there is need to know the actual seed vigour and quality of seeds. Therefore, the present experiment was conducted at Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh of India to standardized a quick seed viability testing protocol using tetrazolium (TZ) and confirmed with laboratory seed germination testing. The tetrazolium test and germination test were conducted with 100 seeds in 4 replications in CRD design as per the procedure devised by ISTA and analyzed with OPSTAT statistical software. After pre-moistening, chir pine seeds were cut longitudinally into two parts away from the radicle end to expose the embryo. The seeds of the species stained with 0.5, 1.0, 1.5 and 2.0 % solution of TZ and incubated at 25, 30 and 35 °C temperature in the darkness for 12, 24 and 36 hours. The result of TZ test showed that the seeds of chir pine soaked in 0.5 % tetrazolium solution at 25 °C temperature for 24 hours found to be the best one for the seed vigour and seed quality testing. For predicting the accurate seed viability, RMS (root mean square) method was used and recognized six staining seed categories distinguished 1 to 6. Seed category 1 denoted as viable seeds and category 6 as non-viable seeds. Result showed that the topographical staining categories 1, 2 and 3 provided least root mean square value and recommended these as viable seed categories for TZ seed viability test. Furthermore, it is also compared with laboratory seed germination test to standardize the seed viability protocol and result in line with the conformity. Overall, the results of the present study fulfilled all the gaps and criteria of quick seed viability testing in chir pine species and standardized protocol could be used for future seed vigour testing within a short period of time for the forest restoration and conservation purpose.