The effectiveness of the honeycomb selection method for herb and total
Alkaloid content yields was evaluated in a population of Hyoscyamus muticus, L.
(Egyptian henbane) grown at a plant spacing of 80x80 cm. Three cycles of selection
were conducted using selection pressure of 14.3% and the traits of plant height,
primary branching, fresh and dry herb yield and total alkaloid contents were
evaluated. The plant were harvested two times. The mean single plant of the studied
traits showed an increasing trend from the base population to the third cycle of
selection in each harvest. The populations developed by honeycomb selection
beside the base population were evaluated in yield test experiment using a
randomized complete block design at high plant density (50 x 50 cm). The results of
the yield test showed that honeycomb selection was effective in increasing the
studied traits and the major constituents of alkaloid content; hyoscyamine and
hyoscine. Improvement in each studied trait did not adversely affect any other studied
trait. The estimates of realized heritabilities between successive cycles of selection
showed an increasing trend from the base population to the third cycle of selection.
In the 151 and 2nd harvests, the realized heritabilities ranged from 0.34 to 0.57 and
from 0.47 to 0.53 for plant height, from 0.46 to 0.53 and from 0.45 to 0.58 for primary
branching, from 0.40 to 0.57 and from 0.44 to 0.59 for fresh herb yield, from 0.42 to
0.58 and from 0.43 to 0.57 for dry herb yield and from 0.47 to 0.62 and from 0.47 to
0.59 for total alkaloid yield; respectively. The results indicated the presence of
additive genetic variation for yield traits in the base population.