Five cycles of recurrent selection for increased essential oil content in East Indian lemongrass: response to selection, and effects on heritabilities of traits and intertrait correlations

Abstract

AbstractFive cycles of phenotypic recurrent selection for increased essential oil content were carried out in East Indian lemongrass, Cymbopogon flexuosus. In each cycle, the top 5% of plants for essential oil content were selected and their ramets were planted in isolated polycross blocks to produce the seed of the next cycle. Response to selection for essential oil content and its effect on three unselected traits, leaf yield, dry matter content in leaves and citral content in the essential oil, were determined by evaluating C0‐C5 populations in a replicated trial. Genetic variation, heritability estimates and intertrait correlations for essential oil content, leaf yield, leaf width, tiller number and citral content in the essential oil in C4 were determined, by evaluating 40 clones and their half‐sib progenies produced from 40 randomly selected C4 plants, in a replicated experiment. These were compared with those determined in C0 earlier. The mean essential oil content increased from 0.66% in C0 to 1.67% in C5 (i.e. by about 31% per cycle over C0). Selection for essential oil content did not affect leaf yield and its effect on dry matter content in leaves was marginal. The first three cycles of selection for essential oil content did not affect citral content in the oil but two further cycles significantly decreased citral content. Heritabilities and intertrait correlations between all traits studied, except citral content and essential oil content, were similar to those found in C0.