Authors:L. Wang, Z. Zhang, H. Liu, S. Xu, M. He, H. Liu, 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.
Authors:R. Uptmoor, W. G. Wenzel, A. H. Abu Assar, G. Donaldson, and et al.
A large number of sorghum landraces possessing superior grain quality but poor yield potential are cultivated in South Africa, where sorghum is of regional importance as a main staple food. Agronomic traits of landraces and newly developed breeding lines from Southern Africa were evaluated under low-input and optimal conditions. Molecular evaluation was carried out on the basis of AFLPs and SSRs. The accessions clustered into two groups. Mean genetic similarity was estimated at 0.85 using AFLPs and 0.31 using SSRs. Genetic diversity was calculated at H=0.136 and DI=0.597 for landraces and H=0.140 and DI=0.580 for breeding varieties. The most promising accessions concerning yielding ability and grain quality were selected and introduced to a breeding programme.
186Re and 188Re, two strong beta- and weak gamma-emitters having short half-lives, are intensely studied as promising radionuclides for radiotherapy. Their use for biomolecule labeling is mainly due to their similar behavior with 99mTc. This paper presents the irradiation operations in a 14 MW Triga SSR Reactor, the chemical processing for obtaining a perrhenate solution of high activity and the final characterization of the products.
Aegiolops kotschyi cytoplasmic male sterile system often results in part of haploid plants in wheat (Triticum aestivum L.). To elucidate the origin of haploid, 235 wheat microsatellite (SSR) primers were randomly selected and screened for polymorphism between haploid (2n = 3x = 21 ABD) and its parents, male-sterile line YM21 (2n = 6x = 42 AABBDD) and male fertile restorer YM2 (2n = 6x = 42 AABBDD). About 200 SSR markers yielded clear bands from denatured PAGE, of which 180 markers have identifiable amplification patterns, and 20 markers (around 8%) resulted in different amplification products between the haploid and the restorer, YM2. There were no SSR markers that were found to be distinguishable between the haploid and the male sterile line YM21. In addition, different distribution of HMW-GS between endosperm and seedlings from the same seeds further confirmed that the haploid genomes were inherited from the maternal parent. After haploidization, 1.7% and 0.91% of total sites were up- and down-regulated exceeding twofold in the shoot and the root of haploid, respectively, and most of the differentially expressed loci were up/down-regulated about twofold. Out of the sensitive loci in haploid, 94 loci in the shoot, 72 loci in the root can be classified into three functional subdivisions: biological process, cellular component and molecular function, respectively.
Authors:X.M. Fang, H.Z. She, C. Wang, X.B. Liu, Y.S. Li, J. Nie, R.W. Ruan, T. Wang, and Z.L. Yi
Waxy wheat (Triticum aestivum L.) is grown throughout the world for its specific quality. Fertilization and planting density are two crucial factors that affect waxy wheat yield and photosynthetic capacity. The objectives of the research were to determine the effects of fertilization and planting density on photosynthetic characteristics, yield, and yield components of waxy wheat, including Yield, SSR, TGW, GNPP, GWPP, PH, HI, Pn, Gs, Ci, E and WUE using the method of field experiment, in which there were three levels (150, 300, and 450 kg ha−1) of fertilizer application rate and three levels (1.35, 1.8, and 2.25 × 106 plants ha−1) of planting density. The results suggested that photosynthetic characteristics, yield, and yield components had close relationship with fertilization levels and planting density. Under the same plant density, with the increase of fertilization, Yield, SSR, TGW, GNPP, GWPP, HI, Pn, Gs, E and WUE increased and then decreased, PH increased, but Ci decreased. Under the same fertilization, with the increase of plant density, Yield, SSR, TGW, GNPP, GWPP, HI increased and then decreased, PH, Pn, Gs and E increased, PH and WUE declined. The results also showed that F2 (300 kg ha−1) and D2 (1.8 × 106 plants ha−1) was a better match in this experiment, which could obtain a higher grain yield 4961.61 kg ha−1. Consequently, this combination of fertilizer application rate and plant densities are useful to get high yield of waxy wheat.
A wheat (Triticum aestivum L.) immature spike culture system was used to expeditiously generate mutations for use in wheat improvement programs. Wheat immature spikes in culture were treated with three concentrations of ethylmethane sulphonate (EMS) to generate a spike culture derived variant (SCDV) population. EMS in a concentration dependent manner affected seed development in wheat immature spike cultures. Based on the number of seeds produced, inclusion of EMS (25 mM) for three hours in immature spike culture medium generated variants in wheat cv. AC Nanda. The wheat AC Nanda SCDV population showed variation in several phenotypic characters. Flag leaf (length, angle and sheath length), length of first and second internode, spike length, number of spikes, number of seeds per spike and seed weight, showed variation below and above the non-treated controls. A molecular screening technique combining simple sequence repeat (SSR) oligonucleotide primers with high resolution melt (HRM) PCR with EvaGreen was used to identify the variants. Screening for starch branching enzyme IIb (SbeIIb) revealed 75 lines with point mutations. Combining SSR and SbeIIb, a total of 100 Kbp portion of wheat DNA was screened. The estimated mutation frequency in SbeIIb was one per 20.8 Kbp. The spike culture system utilizes very small amounts of EMS for a brief period, thus needs minimal handling of EMS and saves one generation of plant growth in a greenhouse. The morphological variants observed are similar to those reported for seed-derived variants using EMS.
Authors:H. Sonah, R. Deshmukh, S. Chand, M. Srinivasprasad, G. Rao, H. Upreti, A. Singh, N. Singh, and T. Sharma
Flag leaf architecture is a very important trait which ensures the yield bearing capacity of plants by providing excellent source for photosynthesis. In this study, quantitative trait loci (QTLs) for flag leaf length and other traits were identified using rice recombinant inbred lines (RILs) derived from HP2216 × Tetep. A total of 12 QTLs were identified for the four traits located on seven different chromosomes of rice and analysis of interaction among the QTLs revealed additive effect for the leaf length and epistatic main effect for panicle length. More interestingly a QTL qLL12.1 responsible for the flag leaf length was identified on chromosome 12 within the marker interval RM247-RM6296 consistently at three climatic zones in India. Furthermore to saturate the qLL12.1 interval, additional 58 simple sequence repeat (SSR) markers were used for polymorphism survey which showed that qLL12.1 region was more conserved among parental lines. Finally, two polymorphic SSR markers were used for saturation of qLL12.1 region. Consequently, candidate gene approach was used to compliment QTL mapping. Co-localization of linkage map with physical map revealed 75 genes with evidence for expression. Functional annotation of these genes using in silico approaches and detailed literature search revealed nine candidate genes for flag leaf length. The stable QTL qLL12.1 identified in this study will provide starting point for map based cloning of leaf length related genes and tightly linked flanking markers can be used in marker assisted breeding programmes.
Authors:R. Singh, P. Hucl, M. Båga, and R. Chibbar
Pre-harvest sprouting (PHS) in bread wheat (Triticum aestivum L.) is one of the major abiotic constraints influencing production of high quality grain. Selection for pre-harvest sprouting (PHS) resistance in bread wheat (Triticum aestivum L.) in early generations is difficult because it is expressed as a quantitatively inherited trait and subject to environmental effects. The objectives of this study were to validate a major quantitative trait locus (QTL) for PHS resistance on chromosome 4A in bread wheat and to isolate near-isogenic lines for this QTL using marker-assisted selection. A total of 60 Canadian wheat cultivars and experimental lines were screened with three SSR markers in a QTL region for PHS resistance. The SSR markers DuPw004, barc170 and wmc650 explained 67%, 75% and 60% of total variation in germination (%), respectively, among different wheat genotypes. Marker assisted back crossing with DuPw004 reduced the population size in BC1F1 and BC2F1 generation by 41% and 59%, respectively. A survey of pedigrees of different genotypes revealed that the parental line RL4137 is a major source of increased PHS resistance in a number of western Canadian wheat cultivars. Microsatellite markers (DuPw004, barc170 and wmc650) will be useful for plant breeders to pyramid QTL from different PHS resistance sources.
The Karabakh conflict, which started in 1988, was accompanied by massive socio-political activities, different manifestations of ethnic violence, and torrents of refugees. How was the conflict manifested at the local level and in everyday life? What were the “people’s” mechanisms employed for conflict resolution in the time of crisis? Against the general background of the conflict, the case of the exchange of the Armenian village of Kerkenj and Azerbaijani village of Kzl-Shafag occupies an important place as an example of people’s diplomacy and civic initiative.The situation of conflict during 1988–1989 brought about the idea of exchange, new mechanisms of community self-organization, transformations of formal and informal relations of the authority, actualization of collective memory resulting in behavioural changes, as well as application of people’s diplomacy in the time of crisis.As a result of this, the populations of the Armenian village of Kerkenj in the Azerbaijani SSR and the Azerbaijani village of Kzl-Shafag (now Dzyunashogh) in the Armenian SSR exchanged their settlements on the basis of a mutual agreement. The agreement envisaged the exchange of houses, handing over of community property to each other, preservation of each other’s cemeteries and the possibility of reciprocal visits. The agreement still stands, and the non-formal relations between the people of the two villages continue.