Drought stress is one of the factors which influence sunflower (Helianthus
annuus L.) production. Breeding for tolerance to drought stress has become a
major focus. In the present investigation, combining ability, gene action and
genetic analysis of several characteristics were studied in six pure lines of
sunflower and their 15 hybrids. The materials were evaluated in two separate
experiments using a randomized complete block design (RCBD) with three
replications in two states (well-watered and water-stressed) under controlled
conditions. Comparison of mean values exhibited that under water- stressed
condition the average performance of sunflower genotypes were decreased for
all studied traits. In well-watered condition the highest value for seed
yield per plant (SY) was observed in the cross 'LR4?LR25', whereas in
water-stressed condition the highest value for this trait was observed in the
hybrid 'C104?LR25'. Combining ability analysis revealed that most of
agronomical traits such as head diameter, number of achene per head, head
weight and seed yield inherited differently in stressed and non-stressed
conditions. In water-stressed conditions, the non-additive effects played a
more important role for controlling the number of achene per head (NA), seed
yield per plant (SY), head diameter (HD), and days from flowering to
physiological maturity (DFM) than additive. Based on results yield
improvement for water-stressed conditions requires selection under drought
conditions. In well-watered condition, the cross 'LR4?C10' showed the best
SCA value for seed yield per plant (SY). In water-stressed conditions,
'RHA266?C100' had the highest SCA for seed yield per plant (SY) and number of
achene (NA) per head.
Genetic Analysis for some Economic Traits in Sunflower (Helianthus annuus L.).
