Estimation of Genetic Variability and Heritability in Lettuce (Lactuca sativa L.)

Abstract

Twenty-five genotypes of lettuce were evaluated to study the variability and heritability parameters at Experimental
Farm, Division of Olericulture, Sher-e-Kashmir University of Agricultural Sciences and Technology (K), Shalimar,
Srinagar during 2006 and 2007. The analysis of variance showed significant differences for all the characters.
Variability revealed that phenotypic coefficient of variation (PCV) in general were higher that the corresponding
genotypic coefficient of variation (GCV) for all the characters. The high phenotypic as well as genotypic variance
were observed for carotenoids only, while the characters like number of leaves per plant, leaf yield per plant, vitamin
C, average leaf weight, calcium, plant spread and potassium exhibited moderate PCV as well as GCV. High estimates
of heritability ranging from 69.90% to 94.10 % were recorded for most of the characters. However, days to first
picking (45.60), duration of picking (50.20), leaf breadth (56.20) and plant height (58.70) exhibited low heritability.
The characters like carotenoids (50.81%), leaf yield per plant (33.53), number of leaves per plant (32.25%), vitamin
C (30.67), calcium (26.03), average leaf weight (23.24), duration of picking (22.67) and potassium (22.42) recorded
maximum genetic gain as percent of mean. High heritability associated with high genetic advances was obtained
in the case of number of leaves per plant, leaf yield per plant, vitamin C and carotenoids, which further suggested
substantial additive gene effect governing these characters and phenotypic selection may be useful in improving
these traits.