Genetic variation among non-oil sunflower cultivars related to water deficit stress tolerance

الملخص EN

Water deficit stress is one of the most prominent factors that limits yield of many crops in the world.

This will hold true under rain fed and irrigated agriculture.

This research targeted identification of the plant traits that are more related to water deficit tolerance.

Three non-oil sunflower (Helianthus annuus L.) cultivars were compared; shumoos , select 1, and select 2.

Seed of the cultivars were planted on the farm of Field Crops Station of the College of Agric., University of Baghdad in 2013.Three irrigation levels of water were used ; 320, 400, and 560 mm/season.

A randomized complete block design of four replications in a factorial arrangement was used.

When cultivars compared, select 2 gave higher number of seeds (1366/capitulum), 21.2 cm capitulum diameter, 99.7 days to physiological maturity, higher seed yield (144g/plant) and high seed weight (119.2mg/seed).

Crop growth rate of cultivar was increased with increased level of irrigation water.

At 320 mm, crop growth rate was 5.5 g/plant/day, increased to 7.1 g/plant/day at 560 mm/season.

Seed filling period and plant height had higher ratio of genetic to environmental variance than other traits.

Chlorophyll index, percent water loss (PWL) and days to 90% flowering had higher ratio of genetic to environmental variance than the rest of other studied traits.

These five traits had at least 76% h2b.s, and they were similar in P.C.V% and G.C.V%, so, they were recommended to be used as parameters to select sunflower genotypes tolerant to water deficit stress studies in a specific geographic area.

Meanwhile, genotypic resultant values were coincided with many traits detected for drought stress tolerance by genetic to environment variance ratio.