Identification of a pleiotropic QTL cluster for Fusarium head blight resistance,spikelet compactness,grain number per spike and thousand-grain weight in common wheat

Simultaneously improving Fusarium head blight(FHB)resistance and grain yield is challenging in wheat breeding.The correlations between spikelet compactness(SC),grain number per spike(GNS),thousandgrain weight(TGW)and FHB resistance remains unclear in common wheat.Identification of major quantitative trait loci(QTL)conferring FHB resistance and yield components,and development of breeder-friendly markers for the QTL are prerequisites for marker-assisted selection(MAS).Here,a recombinant inbred line(RIL)population derived from a cross between a resistant cultivar Yangmai 12(YM12)and a susceptible cultivar Yanzhan 1(YZ1)was used to map QTL for FHB resistance and yield components.A total of 22 QTL were identified;among these,six are likely to be new for corresponding traits.A QTL cluster(Qclu.yas-2D)for FHB type II resistance,SC,GNS,and TGW was detected on chromosome 2D.Breeder-friendly kompetitive allele-specific PCR(KASP)markers flanking the interval of Qclu.yas-2D were developed and validated in a diverse panel of 166 wheat cultivars and advanced lines.The YM12 alleles of Qclu.yas-2D significantly increased FHB resistance,SC,and GNS but decreased TGW in the validation population.The KASP markers developed for Qclu.yas-2D have great potential for breeding high-yielding wheat cultivars with enhanced FHB resistance.

Experimental study on the effect of H2S and SO2 on high temperature corrosion of 12Cr1MoV

Aiming at the high temperature corrosion in a coal-fired boiler,the effect of H2S and SO2 on the corrosion of 12 CrlMoV under the water wall condition has been investigated by experiments.The results indicate that H2 S can promote the corrosion significantly,and the coarse porous oxide film formed cannot stop the progress of corrosion.While SO2 presents little effect on the corrosion.The main composition of the surface of 12 CrlMoV corrosion products is Fe2 O3.With H2S in the atmosphere,the corrosion gradually develops into deeper layers by forming FeS,FeO and Fe2 O3 alternately.The corrosion rate is doubled for every 50℃ inerease in temperature at 400-500℃.

Development of T. aestivum L.eH. californicum Alien Chromosome Lines and Assignment of Homoeologous Groups of Hordeum californicum Chromosomes

Hordeum californicum （2n = 2x = 14, HH） is resistant to several wheat diseases and tolerant to lower nitrogen. In this study, a molecular karyotype of H. californicum chromosomes in the Triticum aestivum L. cv. Chinese Spring （CS）-H. californicum amphidiploid （2n = 6x = 56, AABBDDHH） was established. By genomic in situ hybridization （GISH） and multicolor fluorescent in situ hybridization （FISH） using repetitive DNA clones （pTa71, pTa794 and pSc119.2） as probes, the H. californicum chromosomes could be differentiated from each other and from the wheat chromosomes unequivocally. Based on molecular karyotype and marker analyses, 12 wheat--alien chromosome lines, including four disomic addition lines （DAH1, DAH3, DAH5 and DAH6）, five telosomic addition lines （MtH7L, MtHIS, MtH1L, DtH6S and DtH6L）, one multiple addition line involving H. californicum chromosome H2, one disomic substitution line （DSH4） and one translocation line （TH7S/1BL）, were identified from the progenies derived from the crosses of CS-H. californicum amphidiploid with common wheat varieties. A total of 482 EST （expressed sequence tag） or SSR （simple sequence repeat） markers specific for individual H. californicum chromosomes were identified, and 47, 50, 45, 49, 21, 51 and 40 markers were assigned to chromosomes H1, H2, H3, H4, H5, H6 and H7, respectively. According to the chromosome allocation of these markers, chromosomes H2, H3, H4, H5, and H7 of H. californicum have relationship with wheat homoeologous groups 5, 2, 6, 3, and 1, and hence could be designated as 5Hc, 2He, 6Hc, 3Hc and 1Hc, respectively. The chromosomes H1 and H6 were designated as 7Hc and 4Hc, respectively, by referring to SSR markers located on rye chromosomes.