Showing 3 results for Qtl
M. Mohammadi, M. Baum,
Volume 12, Issue 45 (10-2008)
Abstract
Improving the drought tolerance of barley varieties through the integrated efforts of plant biotechnology and conventional breeding is an important objective in barley breeding. One hundred and fifty eight doubled haploid lines of barley were mapped with 50 SSR and 93 AFLP markers. Agronomic traits such as early growth vigor, plant height, peduncle length, extrude of spike from flag leaf, spike length and kernel per spike were evaluated at ICARDA research stations, Tel Hadya and Breda, during 1382-1383. Genetic correlation between grain yield and considered traits suggested that important traits for high yield in both stations were rapid early growth, short plant height, more extrude of spike from flag leaf, and more kernel per spike. But peduncle length exhibited a different roles in both environments. For plant height, eight Atlas on chromosomes 2, 3, 4, 5, 6 and 7 were identified in Tel Hadya and Breda. Two of these QTLs were shown co-located with peduncle length QTLs. The QTLs which is linked with Bmag13 marker on chromosome 2, explained 42 percent of phenotypic variation for kernel per spike in Tel Hadya. Identification of these QTLs for agronomic traits is the first step to analyse and dissect more complex characters for barley adaptation to drought stress conditions.
A.h Hosseinzadeh, I Bernousi, M Mardi, M Bihamta, S Omidi, B Yazdi Samadi,
Volume 13, Issue 47 (4-2009)
Abstract
Fusarium head blight (FHB) is one of the most destructive diseases of wheat causing significant reduction in grain yield and quality. Development of resistant varieties is an effective, economical and enviromentally safe way to control FHB disease. A major QTL (quantitative trait locus) for Fusarium head blight resistance, Qfhs.ndsu-3BS, derived from cv. Sumai 3, has been identified and verified by several research groups via molecular marker analysis. The resistant cv. Sumai 3 was crossed to susceptible cv. Falat, then three backcrosses were followed by one self-fertilization. Three simple sequence repeat (SSR) markers, Xgwm 389, Xgwm493, Xgwm533, were used for marker assisted selection (MAS) in BC1 and BC2 generations.The probability of linkage between markers and Qfhs.ndsu-3BS was calculated using a binomial probability function based on the assumption that a molecular marker at a specific distance from Qfhs.ndsu-3BS in the population would carry the donor-parent allel as a function of the distance between marker and QTL and the number of backcrosses/selfs used in deriving the population. Microsatelite locus Xgwm 493 was significantly associated with Qfhs.ndsu-3BS.
B Siahsar, A Taleei, A Peyghambari, M Naghavi, A Rezaee, Sh Kohkan,
Volume 13, Issue 47 (4-2009)
Abstract
In order to map the genomic regions affecting barley forage quantity and quality, two experiments were conducted with 72 doubled haploid lines and their two parents (‘Steptoe’ and ‘Morex’), at the Research Farms of the Faculty of Crop and Animal Sciences, University College of Agriculture and Natural Resources, University of Tehran and Agriculture and Natural Resources Research Station of Sistan, in 2007. The experiments were arranged in a randomized complete block design with two replications. Each plot consisted of six rows that were 3m in length and spaced 25cm apart. QTL analysis was conducted by Composite interval mapping (CIM) method separately for each trait in each location. The main effect of genotype was high significant for all the studied traits. Transgressive segregation in both directions (positive and negative) was observed for all the studied traits. There was a negative relationship between forage qualityrelated with quantity-related traits. Thirty-three QTLs controlling different studied traits were identified. Phenotypic variance explained by these QTLs varies from 7.07 to 39.04%. Highest LOD scores were obtained for the leaf to stem ratio on chromosome 2H. QTLs of forage quality (total digestible nutrient, dry organic matter digestibility, leaf to stem ratio, seed to forage ratio and number of tiller per plant) and quantity (plant height, forage wet and dry matter) indexes were found on chromosomes 1H, 2H, 3H, 4H, 5H, 6H and 7H. Most of mapped QTLs appear to be fairly stable between locations and can become candidates for marker-assisted selection.
