Breaking Seed Dormancy in Indian Tree Species: Pre-sowing Treatments and Carry-over Effects on Germination and Seedling Morphology

Abstract

Seed dormancy is both an adaptive ecological trait and a persistent operational constraint in Indian forestry nurseries. The practical literature contains numerous treatment comparisons, yet the term dormancy is often applied to any low-germinating seed lot, and treatment success is usually judged from final germination or a short-term vigour index. This critical narrative review evaluates the mechanistic fit, efficacy and limitations of pre-sowing treatments used for Indian tree species, with particular attention to whether treatment effects carry beyond radicle emergence into seedling morphology and nursery performance. Literature was selected from accessible scholarly indexes and verified journal records through 26 May 2026, supplemented by backward and forward citation searching. Evidence was organised around dormancy diagnosis, treatment class, species functional group, germination dynamics, morphological outcomes and methodological quality. The strongest and most reproducible evidence supports targeted disruption of water-impermeable coverings in hard-coated legumes, especially by carefully controlled mechanical scarification, whereas responses to hot water and sulphuric acid are highly sensitive to temperature, concentration, duration, seed moisture and lot history. Gibberellic acid, nitrate, stratification and biological priming can improve germination in selected taxa, but their apparent superiority is frequently confounded by weak diagnosis, inadequate viability testing and direct effects on early elongation. Across the Indian evidence base, genuine carry-over effects remain less certain than germination effects because most studies measure seedlings on a common calendar date, thereby favouring treatments that germinate earlier, and rarely follow plants through hardening or outplanting. Height alone and arithmetic vigour indices do not establish seedling quality; root-collar diameter, biomass partitioning, root architecture, abnormality, survival and field establishment are more informative. A mechanism-led workflow that separates dormancy from empty seed, ageing and seed-covering constraints can reduce unnecessary chemical treatment and improve protocol transfer. Future work should use factorial, seed-lot-replicated designs, equal-age as well as equal-date comparisons, transparent dose reporting and longer follow-up. Current evidence supports species- and lot-specific optimisation rather than universal prescriptions.