Worldwide interest about using sweet sorghum （sorghum bicolor L. Moench） as bio-fuel stock is booming and a little has been focused to it is grain flour composition, whereas sorghum is important for the economy of semiarid regions since it thrives and produces both grain and forage. Eight sweet sorghum and four grain sorghum were investigated for chemical composition and physico-chemical characterization. The result showed that amylose content for some sweet varieties was high （YT, 27.10%） as that of grain varieties （GL-1, 27.19%）. Total phenolic content of most sweet varieties was high relative to the grain, whereas most of the grain varieties showed thick gel. Total starch showed significant variation among varieties with higher values obtained from sweet ones （80.20% GL-6 and 82.60% GL-13）. For pasting properties all of sweet varieties clotted upper to the grain varieties in the RVA viscogram. Sweet varieties ranked lower for most of thermal properties than the grain varieties. Current result reflected that sweet varieties studied have prospective future for starch industries and generally characterized by low grain quality in respect to protein content. Among parameter studied protein content, pasting properties and thermal properties clearly exhibited different trends between sweet and grain varieties studied.
利用118对 SSR 分子标记对2012年云南哈尼梯田的47份水稻材料进行多态性检测,分析其遗传多样性,并利用Structure 2．3．4软件进行群体结构分析.结果显示,118对 SSR 标记共检测到255个等位变异,变幅为2～4个,平均每个标记2．161个.基因多样性指数变异范围为0．043～0．656,平均0．303.多态信息含量（PIC）变异范围为0．042～0．583,平均0？256.其中高度多态位点（PIC＞0．5）有2个,中度多态位点（0．25＜PIC＜0．5）有66个；通过遗传相似系数及基于数学模型的群体结构分析均将供试材料分为偏籼和偏粳2个类群；聚类结果和海拔高度总体上没有明显规律,但偏籼类群中的偏籼红米亚群按海拔高低分别聚在一起.研究表明,云南哈尼梯田现有栽培水稻以偏籼水稻为主,但本研究估测的遗传多样性低于前人报道.
Understanding genetic characteristics in rice populations will facilitate exploring evolutionary mechanisms and gene cloning. Numerous molecular markers have been utilized in linkage map construction and quantitative trait locus （QTL） mappings. However, segregation-distorted markers were rarely considered, which prevented understanding genetic characteristics in many populations. In this study, we designed a 384-marker GoldenGate SNP array to genotype 283 recombination inbred lines （RILs） derived from 93-11 and Nipponbare Oryza sativa crosses. Using 294 markers that were highly polymorpbic between parents, a linkage map with a total genetic distance of 1,583.2 cM was constructed, including 231 segregation-distorted mark- ers. This linkage map was consistent with maps generated by other methods in previous studies. In total, 85 significant quanti- tative trait loci （QTLs） with phenotypic variation explained （PVE） values〉5% were identified. Among them, 34 QTLs were overlapped with reported genes/QTLs relevant to corresponding traits, and 17 QTLs were overlapped with reported sterili- ty-related genes/QTLs. Our study provides evidence that segregation-distorted markers can be used in linkage map construc- tion and QTL mapping. Moreover, genetic information resulting from this study will help us to understand recombination events and segregation distortion. Furthermore, this study will facilitate gene cloning and understanding mechanism of in- ter-subspecies hybrid sterility and correlations with important agronomic traits in rice.
Accumulating evidence has suggested that epigenetic marks including DNA methylation,small RNA and histone modification may involve hybrid vigor in plants.However,knowledge about how epigenetic marks in hybrids regulate gene expression is still limited.Based on genome-wide DNA methylation landscapes of Arabidopsis thaliana Ler and C24 ecotypes and their reciprocal F1 hybrids which were obtained in our previous work,we analyzed allele-specific DNA methylation and distinguished cis-and trans-regulated DNA methylation in hybrids.Our study indicated that both cis-and trans-regulated DNA methylation played roles in hybrids,when cis-regulation played a major role in CG methylation and trans-regulation played major roles in CHG and CHH methylation.In addition,we observed correlations between trans-regulated DNA methylation and siRNA densities.Enriched siRNA regions were significantly concurrent with highly trans-regulated DNA methylation regions.Our results illustrated DNA methylation regulation patterns integrated with siRNAs in Arabidopsis hybrids,and shed light on understanding the mechanism of epigenetic reprogramming for hybrid vigor.
