Combining Ability of Agronomic Traits in Sunflower (Helianthus annuus L.) Through Line x Tester

The Journal of Environmental studies (JES) 
Vol.22: 1-12 (22), 12 pages
Author:Attia M. A., Bakheit B. R., Abo-Elwafa A. 'and El-Shimy A. A.
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 Twenty three inbred lines (selfed) were top-crossed with two testers. The 46 top crosses along with their parents were planted in Randomized Complete Block Design (RCBD) with three replications. The results showed highly significant mean square of crosses was observed for all the traits including days to 50% flowering, days to maturity, plant height, stalk diameter, head diameter, 100-achene weight, achene yield/plant, achene yield/plot and oil content, indicating significant variation for these traits. The mean squares due to lines were highly significant. While, variance among testers were highly significant only for plant height, head diameter and oil content. The results revealed that ten S1 lines (S1, S3, S5, S7, S8, S11, S13, S15, S17 and S23) exhibited positive GCA effects. Nine lines out of ten were significant or highly significant GCA effects. These lines should be considered as good combiners for oil content, and its implies that these lines possess favorable alleles with additive genetic effects for this trait. The same result was found by the analysis of half-sib families. Whereas, that the respective S1 lines would have good g.c.a for oil content and selected as parent to produce the first cycle of recurrent selection for the population H.S. Concerning the SCA values for oil content, the results indicated that thirteen crosses were positive and significant or highly significant. These crosses were suitable combination and can be superior candidate for improving high oil content genotypes. Therefore, we are selected the best 10 crosses  exhibited  positive  significant  or  highly  significant, (S1 × A21, S3 × A3, S4 × A3, S5 × A21, S8 × A3, S14 × A21, S15 × A21, S17 × A3, S20 × A3 and S23 × A21) as parents to produce the first cycle of recurrent selection for population top crosses. 


Sunflower, Helianthus annuus, GCA, SCA, Inbred lines, line x tester.