Authors:M. Golabadi, A. Arzani, and S. Mirmohammadi Maibody
Grain protein content (GPC) in durum wheat is a crucial determinant of pasta quality and as such is an important economic factor. This study was carried out to determine the microsatellite markers (SSRs) as associated with GPC in durum wheat grown under normal and moisture stress conditions. F3 and F4 population derived from 151 F2 individuals developed from a cross between Oste-Gata (drought tolerant) and Massara-1 (drought susceptible) genotypes, were used. The population was evaluated under four environmental conditions (two irrigation regimes in two growing seasons). The results of single marker regression analysis (SMA) revealed that 2, 4 and 10 markers to be associated with GPC, test weight (TW) and 1000 grain weight (TGW), respectively. These markers explained between 4.4 and 21.8% of the phenotypic variation in either environmental condition. The most significant marker observed for GPC was located on 5B chromosome near Xgwm408 under normal conditions and the other marker was observed on 1A, explaining about 15% of phenotypic variance. However, it was not recognized any marker related to GPC under drought stress conditions. Xgwm408 marker was coincident with the markers identified for TW, TGW and components of grain yield under drought stress conditions. In spite of 5B, the other chromosomes such as 2B and 3B were related to quantitative traits like TW and TGW. Composite interval mapping (CIM) identified 4 and 5 putative minor and major QTL for TW and TGW, respectively. Two QTL near Xbarc101 and Xbarc124 markers on 3B and 2B chromosome, explained up to 45.2 and 6% of phenotypic variations of TGW and TW, respectively.
Authors:F. Rafiei Boroujeni, A. Arzani, F. Afshari, and M. Torabi
The objectives of this research were to examine the inheritance of leaf rust resistance genes in the Iranian wheat cultivar ‘Marvdasht’, which is highly resistant to leaf and stripe rusts, and to identify Lr genes present in this cultivar using molecular markers. The genetic basis of resistance to the leaf rust pathogen (Puccinia triticina) in ‘Marvdasht’ was studied in F2:3 populations derived from crosses of Bolani (susceptible cultivar) × Marvdasht. Isolates 84-1 and 85-28 of P. triticina, which are the predominant isolates in Iran, were used to examine the segregation of resistance originating from ‘Marvdasht’. The results indicated that resistance in ‘Marvdasht’ to Puccinia triticina isolate 84-1 was governed by two dominant seedling resistance genes Lr1 and Lr17a. Allelism studies using an F2 population derived from a cross between ‘Falat’ (Seri 82) and Marvdasht indicated that resistance in Marvdasht was not due to the resistance gene Lr26 present in ‘Falat’. With the application of a previously developed molecular marker for Lr1, the STS marker RGA-567-5, the presence of Lr1 was verified in Marvdasht. Based on bulk segregant analysis, Lr17a was mapped to the distal end of chromosome 2AS and was closely linked to microsatellite marker Xbarc212 at a distance of 3.7 cM. In conclusion, the presence of Lr1 and Lr17a was confirmed in the cultivar Marvdasht.