Clone variation of seed traits, germination and seedling growth in Dalbergia sissoo Roxb. clonal seed orchard

A clonal seed orchard (CSO) of Dalbergia sissoo Roxb. at Hoshiarpur, India consisting of 20 clones originating from different agro-climatic conditions of four northern states (Uttar Pradesh, Rajasthan, Haryana and Uttarakhand) was the source of seeds for variability studies. There was lot of variation in seed size, seed weight, germination percent, germination value and growth rate in nursery of different clones over the years. Seed length, seed width and seed weight were positively correlated to each other but seed size had no effect on germination percent and germination value under laboratory conditions. However, seed weight was found positively correlated with germination percent in nursery with the seed lot of 2008 collection. The genetic parameters for seed traits and seedling growth also showed a wide range of variations in the orchard clones. Heritability values were found to be over 50 percent for seed weight and seed length. However, only seed weight showed high heritability value coupled with more genetic gain across the years, which indicate the presence of good amount of heritable additive component in seed weight. There was no consistency in the seed characters, germination and seedling growth parameters studied across the two years. Effect of clones was dominant and accounted for variation in seed size, seed weight, seed germination and growth parameters. Seed size or seed weight should not be used as criteria for grading of bulked seed lots of different clones, as it can narrow down genetic diversity by rejecting small seeds. The impact of these genetic differences in handling of seed lots during bulking and grading for mass propagation of nursery planting stock of D. sissoo is also discussed.