Authors:R. Singh, L. Ram, R.K. Singh, and D. Singh Jakhar
Maize protein quality is deficit in essential amino acids, lysine and tryptophan. These constraints of o2 (opaque2) are corrected in genetically improved, hard endosperm QPM (Quality Protein Maize). An integrated strategy of phenotypic selection for endosperm modifiers and molecular marker-assisted foreground and background selection has been used in present study. The QPM donors were, CML 161, DMRQPM 58, CML 176 and CML 141 whereas, normal maize inbreds were CM 212, V338, V361, V336, V341, V351, CM 141 and V335. The inbreds were subjected to parental polymorphism survey between non-QPM and QPM using CIMMYT based three SSR markers, viz. phi057, umc1066 and phi112. Two markers, viz. phi057 and umc1066 exhibited co-dominant reactions, while phi112 was dominant in nature. Finally, two combinations V335 × CML 141 and V351 × CML 141 were considered for conversion program. Foreground selection was exercised using o2 specific marker umc1066 in BC1 and BC2 generations, while background as well as foreground selection was exercised in BC2F3 generation to recover the genome of recurrent parent up to extent of 80 to 100% with the help of SSR markers distributed across the whole maize genome. The tryptophan concentration in endosperm protein was significantly enhanced and the converted maize lines had almost twice the amount of lysine and tryptophan than normal maize inbreds.
Authors:F. Akfirat, Y. Aydin, F. Ertugrul, S. Hasancebi, H. Budak, K. Akan, Z. Mert, N. Bolat, and A. Uncuoglu
Prasad, M., Kumar, N., Kulwal, P.L., Röder, M.S., Balyan, H.S., Dhaliwal, H.S., Gupta, P.K. 2003. QTL analysis for grain protein content using SSRmarkers and validation studies using NILs in bread wheat. Theor. Appl. Genet.
Authors:L. Wang, Z. Zhang, H. Liu, S. Xu, M. He, O. Veisz, and Z. Xin
Stripe rust, caused by
(PST), is one of the most serious diseases of wheat (
L.) worldwide. Of 94
Triticum durum/Aegilops tauschii
synthetic wheat accessions tested, CI142 (Garza/Boy//
271) was found to be resistant to 6 Chinese PST races. The resistance to stripe rust in CI142 was proven to be controlled by a single dominant gene, tentatively designated
. Gene postulation showed that the pathogenic specificity of CI142 is different from 21 other lines possessing known resistance genes, such as
Yr10, Yr15, Yr24
, located on chromosome 1B. Bulked segregant analysis (BSA) and F
segregation analysis of the CI142/Mingxian 169 cross were used to analyse the SSR markers linked to
. Five SSR markers were found to be closely associated with
in the order
, in which the relative genetic distances of these SSR loci to the gene
were 5.4, 0.8, 0.8, 1.0, and 2.4 cM, respectively. Two SSR markers (
Yr10, Yr15, Yr24
, suggesting that these 2 SSR markers may be used as diagnostic ones for the gene in a wheat breeding program against stripe rust. Based on these findings,
is most likely a new gene or a new allele at the
locus, which provides an opportunity to diversify stripe rust-resistant resources for wheat breeding programs.
The bread wheat germplasm comprising of 222 accessions was evaluated for tolerance to Sitobion avenae. A 1000-kernel weight loss rate and an unbiased test of the tolerance were used to quantify tolerance trait. The population structure analysis revealed three subpopulations in this wheat collection. After 103 SSR loci which evenly covered all wheat chromosomes were scanned for association, eight SSR loci significantly associated with S. avenae tolerance. The information reported in this study would be helpful for wise utilization of the S. avenae tolerant germplasm and selection of parental lines in wheat breeding programs.
Genetic diversity of 74 T. urartu genotypes was studied using 11 SSR (simple sequence repeats) markers. The number of alleles ranged from 4 to 15, with an average of 8 alleles per primer. The mean values for the expected heterozygosity (He) and polymorphism information content (PIC) over all loci and populations were 0.56 and 0.52, respectively. From a geographic viewpoint the higher diversities were observed in Jordan, followed by Syria and Turkey. Diversity revealed within countries was higher than among them, even in the same regions of the relevant countries. The analysis of molecular variance revealed that most of the genetic variability was accounted for by differences within populations (90%), with less variability among them (10%). The dendrogram generated based on Nei’s dissimilarity matrix revealed three main clusters for which the grouping patterns were not clearly associated with the geographic origins, indicating the gene flow among different countries. Principal coordinate analysis (PCoA) confirmed subgrouping obtained by cluster analysis. In general, genetic distances between geographic regions were low or moderate, which was also supported by low values of pairwise Fst. Our findings can direct the sampling strategies on T. urartu in studied regions to find beneficial alleles. The heterotic groups detected by cluster and PCoA analysis in the present study can serve as effective candidates in crossing programs to broaden the genetic base in T. urartu.
Authors:Mária Höhn, L. Hufnagel, Klára Cseke, and G. Vendramin
We investigated the diversity pattern of nine Swiss stone pine (Pinus cembra L.) populations along the Carpathian range including the High Tatras, by using six chloroplast DNA microsatellites (cpSSR). Our aim was to detect genetically distinct regions by clustering of populations, and to tackle possible historical colonization routes. Our analysis referred to an investigated geographical range with the two most distant populations situated at about 500 air km. We found that the most diverse populations are situated at the two edges of the investigated part, in the Retezat Mts. (South Carpathians) and the High Tatras, and diversity decreases towards the populations of the Eastern Carpathians. Hierarchical clustering and NMDS revealed that the populations of the South Carpathians with the Tatras form a distinct cluster, significantly separated from those of the Eastern Carpathians. Moreover, based on the most variable chloroplast microsatellites, the four populations of the two range edges are not significantly different. Our results, supported also by palynological and late glacial macrofossil evidences, indicate refugial territories within the Retezat Mts. that conserved rich haplotype composition. From this refugial territory Pinus cembra might have colonized the Eastern Carpathians, and this was accompanied by a gradual decrease in population diversity. Populations of the High Tatras might have had the same role in the colonizing events of the Carpathians, as positive correlation was detected among populations lying from each other at a distance of 280 km, the maximum distance between neighbouring populations.
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.
( Manju et al . 2012 ), analysis of source of colonising moss propagules and dispersal of moss species ( Skotnicki et al . 2002 ). The SSRmarkers were widely used in several species of bryophytes to study reproductive biology and its effect on genetic
Authors:L. Brbaklić, D. Trkulja, A. Kondić-Špika, S. Mikić, M. Tomičić, and B. Kobiljski
Chen, X., Min, D., Yasir, T.A., Hu, Y.G. 2012. Genetic diversity, population structure and linkage disequilibrium in elite Chinese winter wheat investigated with SSRmarkers. PLoS one 7 (9):e44510. doi: