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Showing 2 results for Water Deficit Stress
Dr Mohammad Motamedi, Ms Parviz Safari,
Volume 4, Issue 2 (3-2018)
Abstract
Drought stress is one of the most important factors involved in reducing wheat production and identifying genetic structure and gene action type in controlling grain yield in water stress condition is essential for choosing appropriate breeding methods. In this study, 9×9 one way diallel crosses were used to study the genetic structure of wheat grain yield at stress and non- stress conditions. Combining ability analysis by the second Griffing method for both conditions resulted in significant GCA and SCA variances, representing grain yield may be controlled by additive and non- additive effects of genes. The results of applying combining ability analysis indicated that among the parents, genotypes Ghods and Bam had the highest GCA for grain yield and the best specific crosses were Arg × Ghods, Navid × Moghan, Bam × Alvand (for both irrigation regimes) and Bam × Ghods (in stress condition). Biplot analysis of diallel data was used to display GCA and SCA for parents and to determine heterotic groups and the best crosses. In general, according to the results, Bam, Ghods and Arg were tolerant cultivars and had the ability to maintain yield in drought stress condition as well as to transfer these properties to the hybrids. So these genotypes can be used to improve stress tolerance in breeding programs.
Mozhgan Shirinpour, Ehsan Atazadeh, Ahmad Bybordi, Saeid Aharizad, Ali Asghari, Ashkboos Amini,
Volume 10, Issue 1 (9-2023)
Abstract
Considering the importance of maize production and the impact of water deficit stress on reducing the yield of maize, estimating the genetic components and heritability of traits for determine the breeding method under water deficit stress is essential in breeding programs. The generations drived from a cross between two inbred lines of maize including B73 (maternal line) and MO17 (paternal line), SC704 (F1) as well as F2, BC1, BC2 and F3 generations in order to estimate the genetic effects and heritability of yield, yield components and morphological traits were studied. Seven maize generations using the generations mean analysis under the full irrigation, mild and severe water deficit conditions were evaluated. The experiment was conducted in the form of randomized complete block design with 20 replications per experimental unit during two cropping seasons (2018-2019) at the Agricultural Research Station of University of Tabriz. The results of two-year combined analysis of variance and mean comparisons under three different irrigation regimes showed that water deficit stress significantly reduced all of the studied traits (except root/shoot ratio). The generations mean analysis showed the high contribution of non-additive gene effects for the genetic control of grain yield, ear diameter, number of kernel row, ear weight (in full irrigation conditions), 100 grain weight, plant height, fresh shoot weight and biological yield traits. According to these results, selection in the advanced generations and the breeding method based on hybridization can be effective to improve these traits. Also, the significant contribution of additive gene effects in controlling the inheritance of ear length, ear weight (in both stress conditions) and root/shoot ratio traits indicated that selection in early segregating generations and inbred parents can be effective for breeding of these traits and taking advantage of additive variance. Hybrid SC704 and inbred MO17 compared with the inbred B73 showed the lowest variation percentage under the water deficit stress conditions, which indicated their high yield potential and stability in the stress conditions.
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