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Showing 2 results for Tester
Rasoul Banaei, Amin Baghizadeh, Saeid Khavari Khorasani,
Volume 3, Issue 1 (9-2016)
Abstract
In order to estimate the components of genetic variance and general and specific combining abilities of maize lines, an experiment was done using 8 S6 inbred lines as female parents and 2 male inbred lines as testers consisted of K1264/5-1 (early mature) and K3615/1 (late mature) using line by tester mating design based on randomized complete block design with three replications in two different conditions (Salt stress with Ec=5 dsm-1 and non-salt conditions) in research field of graduate university of advanced technology (Kerman, Iran) in 2014. Analysis of variance results showed significant differences among inbred lines for some of measured traits in both salt and non-salt conditions. Significant differences observed for line × tester mean-squares in non-salty condition for all measured traits except days to silking and physiological maturity. In salt stress condition, just for leaves number per plant and days to silking, line × tester effects were not significant. Additive variance for days to silking and physiological maturity in non-salt condition was more than dominant variance, therefore the additive to non-additive variance ratio was more than 1 and indicating emphasis on this matter too. Inbred line L6 had a significant positive GCA and the highest grain yield with 1455.785 and 789.107 kg/ha in non-salt and salt stress condition, respectively. The crosses (L4×T1=428.460 and L7×T1= 438,345) in non-salt condition and (L3×T1=438.345) in salt stress conditions had a positive significant specific combining ability. Finally, from all existed variation, the lines and line × tester effects were more important than tester effects that indicates transmission of diversity from lines to hybrids.
Seyede Sharare Arianezhad, Hamid Hamid Najafi Zarini, Mehdi Ghaffari, Gholamali Ranjbar,
Volume 9, Issue 1 (9-2022)
Abstract
This research was carried out to estimate the genetic variance components for sunflower fatty acids in two separate optimum and drought stressed conditions in Karaj during 2020 and 2021 growing seasons. The plant materials consisted of 12 hybrids derived from crossing of four restorer lines by three cytoplasmic male sterile lines (Testers) that were evaluated in two separate experiments as randomized complete block design with three replications. Drought stress made a reduction in oil yield (34 percent), oil content (six percent), stearic acid (4.7 percent) and oleic acid (10.6 percent) and an increase in palmitic acid (12 percent) and linoleic acid (2.8 percent). Line × tester interaction effect had a major role in explanation of the variance of the hybrids in terms of fatty acid content in both conditions, indicating the critical role of non-additive effects in genetic control of these traits. Under optimum irrigation, oil yield, oil content and stearic acid content were under control of both additive and dominant gene action and palmitic, oleic and linoleic acids were under control of dominant gene action. Under drought stress, except oil content which was under control of additive effects, all the other traits were under control of dominant gene action. According to the results of this study, fatty acid composition of sunflower was under control of non-additive genetic effects and the crossing-based methods and hybrid breeding could be used for improvement of sunflower in terms of fatty acid composition.
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