Genetics of essential oil yield and their component traits in vetiver (Chrysopogon zizanioides (L.) Roberty)

The thirteen lines and five testers used for Line × tester analysis in vetiver (Chrysopogon zizanioides (L.) Roberty) to estimate the general and specific combining ability and the other allied genetic parameters with respect to physiological traits, essential oil contents, yield of essential oil and other components. The mean squares of all the eleven traits were significant for variances GCA and SCA stipulating that additive and non-additive genes control these characters. The character root yield/plot (ml), female lines L4 (g.c.a.= 71.585, x/Mean= 553.33), L13 (g.c.a.= 63.918, x/Mean= 383.33), and among testers T3 (g.c.a.= 31.149, x/Mean= 583.33) followed by T1 (g.c.a.= 26.046, x/Mean= 433.33) were the better general combiners; In the essential oil trait the female lines L1 (g.c.a.= 0.240, x/Mean= 0.80) followed by L3 (g.c.a.= 0.143, x/Mean= 0.81), L2 (g.c.a.= 0.111, x/Mean= 0.85), L9 (g.c.a.= 0.203, x/Mean= 0.78) were the better general combiners. For the character the essential oil/plot (g) the female lines L10 (g.c.a.= 1.156, x/Mean= 0.97), L7 (g.c.a.= 0.869, x/Mean= 3.50), L11 (g.c.a. = 0.802, x/Mean=5.00), L9 (g.c.a.= 0.669, x/Mean= 1.67), and L2 (g.c.a. = 0.556, x/Mean=2.57), and among testers T3 (g.c.a.= 0.391, x/Mean= 4.67) and T4 (g.c.a.=0.330, x/Mean=5.67) were the better general combiners. The heritability in the narrow sense was low in all the traits (008-3.796 %) and in most of the traits genetic advance was poor (0.008-2.93) except the two traits i.e. high namely root yield/plot (ml) 180.44 and stomatal conductance (160.99) %. The relative magnitude of SCA variance was higher than GCA for all the traits in the present investigation, depicting the predominance of non-additive gene action for inheritance of these characters. The hybrids L7× T3 followed by L10× T5, L2×T3 and L4×T5 were best for the essential oil yield of better quality and the three hybrids showed high mean performance for the khusimol content (%) namely, L8 × T4 (34.50), L3 × T1 (34.30) and L13 × T4 (34.17) % with high s.c.a. could be exploited for large area cultivation.