الفهرس 
Effect of water stress on agronomic,
Superiority percentage.Only 14 pages are availabe for public view
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Abstract
Plant breeders have extensively used and exploited superiority to improve seed and oil yield in sunflower. In a systematic breeding program, it is essential to identify superior parents for hybridization and crosses to expand the variability reservoir for selection of superior genotypes under drought tolerance because it is becoming an important challenge in sunflower. If drought tolerant cultivars are developed, sunflower can be grown successfully in areas where water is a limiting factor. Combining ability analysis helped the breeder in selecting desirable parents and provided information or the relative importance of GCA and SCA for interpreting the genetic basis of important traits. The present work was carried out at Sakha Agricultural Research Station, ARC, Kafr El-sheikh governorate, Egypt during the two growing summer seasons (2015 and 2016). The main objectives of the present investigation were: 1. Evaluation of the performance of fifteen crosses and a check cultivar grown under different water treatments using diallel analysis. 2. Studying the effect of general and specific combining abilities in parents and their F1 crosses. 3. Studying the superiority over the check cultivar (Sakha 53) in the F1 crosses. 4. Estimation of water consumptive use for the crosses and a check cultivar under the three irrigation treatments. 5. Estimation of water use efficiency for the crosses and a check cultivar under the three water treatments. 6. Estimation of predicted cultivated area, seed and oil yields from saved water used in T2 irrigation treatment instead of T1 irrigation treatment. The material used included six parents namely; Line 4, Line 10, Line 16, Line 17, Line 63 and Giza 102, respectively. Also included a check cultivar namely; Sakha 53. In 2015 summer season, all possible combinations without reciprocals were made among the six parents to give fifteen crosses. In 2016 summer season, the F1 crosses and the check cultivar were planted under normal irrigation and two water stress treatments using a randomized complete blocks design (RCBD) with three replications in each experiment. In the normal irrigation treatment (T1), the plants received irrigation every 14 days, in the second treatment (T2), the plants received irrigation every 21 days and in the third treatment (T3), the plants received irrigation every 28 days. Data were recorded on ten individual guarded plants, chosen randomly for the crosses (F1) and the check cultivar. The following measurements were recorded; number of days to first flowering, number of days to half flowering, number of days to full flowering, number of days to physiological maturity, plant height, stem diameter, head diameter, seed yield/plant, 100-seed weight, seed yield/fad., seed oil percent and oil yield/fad. The obtained Data were analyzed on plot mean basis. An ordinary analysis of variance and superiority were performed for F1 half diallel.