Optimization of Organic Rooting Media for Clonal Propagation of Apple Rootstock “M.9 T337”

Standardizing organic rooting media is vital forthe mass propagation of dwarfing apple rootstock M.9 T337via stooling to meet the growing demand for high‐density planting. Eight different organic rooting media treatments viz; T 1 : Cocopeat, T 2 : Farm Yard Manure, T 3 : Sawdust, T 4 : Cocopeat + Farm Yard Manure (1:1), T 5 : Sawdust + Cocopeat (1:1), T 6 : Sawdust + Farm Yard Manure (1:1), T 7 : Cocopeat + Sawdust + Farm Yard Manure (1:1:1) and T 8 : Control (Soil) were evaluated under a factorial randomized block design with three replications under open‐field conditions to assess their influence on rooting performance. Among all treatments, T 1 : Cocopeat was significantly superior over control (T 8 ), producing 117% longer roots, 65% longer rooted stool portions, 360% more adventitious roots, 112% greater total root length, 114% higher fresh root biomass and 160% higher dry root biomass. Correspondingly, T 1 also recorded the highest absolute values for length of longest root (49.67 cm), number of adventitious roots (53.67), total root length (2.73 m), fresh (5.32 g) and dry (2.70 g) root biomass, length of rooted stool portion (23.10 cm), and proportion of graftable daughter stools per mound (75.39%). Total root length exhibited strong positive correlations with electrical conductivity ( r = 0.52), organic matter content ( r = 0.57), leaf area ( r = 0.87), and volumetric water content ( r = 0.95), indicating that media with superior physical and chemical properties enhanced rooting outcomes. These results suggest that cocopeat alone or in combination with Farm Yard Manure, optimized root development yielding more graftable daughter stools.