The transfer of a gene for glutinous endosperm to Oryza glaberrima Steud. From a japonica variety of O. sativa L.

Summary In common rice, Oryza sativa L. (n=12), the gene Am for non-glutinous is dominant over the gene am for glutinous. In African rice, O. glaberrima Steud. (n=12), no spontaneous glutinous strain has been found, but recently a glutinous strain of glaberrima was induced by EMS-treatment.The interspecific cytoplasm substitution line with sativa cytoplasm and glaberrima nucleus is male sterile. It has been confirmed that the complete restoration of pollen fertility in this male sterile line is attributed to a single dominant nuclear gene Rf _j.Trial to transfer gene am from sativa to glaberrima was commenced with backcrosses of the F₁ hybrid (glutinous sativa cv. Iwai-mochi × glaberrima ) to glaberrima type plants of the substitution line homozygous for Rf _j,using the latter as the pollen parent. At the B₁ step, highly fertile glaberrima type Am/am plants were obtained. Thereafter plants of this type were backcrossed to normal glaberrima as the recurrent pollen parent to complete the nuclear substitution. It was confirmed that the EMS-induced glutinous character of glaberrima was a monogenic recessive and that the same gene controls the expression of glutinous character in the different rice species, sativa and glaberrima.     

Carbon Accumulation and Fossil Fuel Substitution During Different Rotation Scenarios

Accumulation of carbon (C) in biomass and soil, and using forest residues for bioenergy are examples of forestry’s contribution to reducing the enhanced concentration of greenhouse gases in the atmosphere. The aim of this report was to study the effect of rotation length on carbon accumulation in biomass and soil, and on the amount of forest residues that could substitute fossil fuel during 2000–2100. Two models, based on inventory data from the Swedish National Forest Inventory, were used to simulate the effects of a changed rotation length in the region of Dalarna (1.8 × 10⁶ ha), in central Sweden. During the studied period, the accumulation of carbon in biomass was 32 kg C ha^?1 yr^?1 larger for the prolonged rotation period and 105 kg C ha^?1 yr^?1 smaller for the shortened rotation period compared with the base scenario. The build-up of carbon in forest soil was 23 kg C ha^?1 yr^?1 larger for the prolonged rotation than for the base scenario, whereas the shortened rotation was 24 kg C ha^?1 yr^?1 smaller than the base scenario. The potential to substitute fossil fuel was 37 kg C ha^?1 yr^?1 larger for the shortened rotation and 17 kg C ha^?1 yr^?1 smaller for the prolonged rotation compared with the base scenario. The annual accumulation of carbon in biomass decreased in all scenarios, which resulted in a prolonged rotation scenario possibly being a poor long-term solution (> 100 yrs). The amount of forest residues that could substitute fossil fuel increased in all scenarios during the studied period.     

Digital mapping of soil carbon sequestration potential with enhanced vegetation cover over New South Wales,Australia

Digital soil maps of soil organic carbon (SOC) sequestration potential resulting from a hypothetical 10% relative increase in long-term vegetation cover are presented at 100-m resolution across the state of New South Wales (NSW) in southeast Australia. This land management outcome is considered realistically achievable for many land managers, using strategies such as revegetation, grazing management or crop residue management. A mean state-wide potential increase of 5.4 Mg ha⁻¹ over the 0- to 30-cm depth interval was derived. Assuming a 20-year period of re-equilibration, this equates to an average SOC increase of 0.27 Mg ha⁻¹ year⁻¹. Sequestration potential is systematically influenced by a combination of climate, soil parent material and current vegetation cover, for example only 1.6 Mg ha⁻¹ SOC under dry conditions in sandy, infertile soil material with sparse vegetation cover, compared with 15.9 Mg ha⁻¹ under wet conditions in clay-rich, fertile soil material with moderate–high vegetation cover. The outputs could be used to identify locations of highest sequestration potential and thereby help prioritize areas and inform decisions on sequestration programmes. Future application of the method at field scale with high levels of accuracy, together with strategic sampling, may provide statistically reliable estimates of carbon sequestration, for application in carbon trading schemes such as Australia's Emissions Reduction Fund. The modelling involved a conceptually transparent ‘space-for-time substitution’ process. Multiple linear regression (MLR) and random forest (RF) modelling techniques were applied, but only MLR gave consistently meaningful results. The apparent failing of RF in this application warrants further examination.     

Ability of chromosome 4H to compensate for 4D in response to drought stress in a newly developed and identified wheat–barley 4H(4D) disomic substitution line

A spontaneously developed wheat–barley 4H(4D) disomic substitution line was identified cytogenetically using genomic in situ hybridization (GISH), multicolour fluorescent in situ hybridization (FISH) and microsatellite markers. The ability of the barley 4H chromosome to compensate for wheat 4D in response to mild drought stress was also investigated. In the barley cv. 'Betzes' and the 4H(4D) substitution line, mild osmotic stress induced intensive stomatal closure, resulting in reduced water loss through transpiration and unchanged relative water content in the leaves. As the CO₂ assimilation rate remained relatively high, the water use efficiency, which is an important factor associated with drought tolerance, increased extensively under mild osmotic stress in these lines. In the case of the parental wheat genotypes, however, mild drought stress induced less intense stomatal closure and a greater decrease in the CO₂ assimilation rate than in barley or in the substitution line, resulting in unaugmented or reduced water use efficiency. The results demonstrate that genes localised on the 4H chromosome of barley were able to increase the water use efficiency of the wheat substitution line, which is suitable for improving wheat drought tolerance through intergeneric crossing.     

北京市高保护价值森林价值评估理论与方法初探

结合现行经济学理论界对森林价值的评估，针对高保护价值森林的特征，从生物多样性和生态服务功能两方面对北京市高保护价值森林的价值评估方法进行探讨。结合效用论、边际效益论等理论，根据实地情况，运用支付意愿法、补偿法、替代法等，从森林的实用价值和精神文化价值等方面作了评估方法概述。     

基于单片段代换系的水稻抽穗期QTL上位性研究

【目的】探索水稻抽穗期的遗传机制.【方法】以华粳籼74的8个单片段代换系为材料,构建了7个聚合了双QTL的次级F2作图群体,并通过分子标记的选择区分出每个群体的9种基因型以估算水稻抽穗期QTL的各类上位性分量.【结果和结论】除QTL HD3/HD8间的上位性互作不显著外,其他QTL对均存在显著的上位性效应,占85.7%;在检测的28个不同类型的上位性效应中,有60.7%的估计值达到5%或1%的显著水平,其中加加、加显或显加、显显上位性分别占71.3%、42.8%、85.6%.研究结果进一步证实了上位性作用在数量性状遗传体系中的普遍性和重要性,并为水稻抽穗期的分子聚合育种提供了依据和材料.     

Roles of Root Aerenchyma Development and Its Associated QTL in Dry Matter Production under Transient Moisture Stress in Rice

Abstract

Enhanced aerenchyma development in rice under transient drought-to-waterlogged (TD-W) stress promotes root system development by promoting lateral root production. This study analyzed the quantitative trait loci (QTLs) associated with the plasticity in aerenchyma development under TD-W stress. A mapping population of 60 F₂ genotypes of chromosome segment substituted lines (CSSL) derived from CSSL47 and Nipponbare crosses were grown in rootboxes and evaluated for shoot and root growth, and aerenchyma development (expressed as root porosity). The TD-W stress was imposed starting with water saturated soil condition at sowing and then to progressive drought from 0 to 21 days after sowing (DAS) prior to exposure to sudden waterlogging for another 17 days (21 to 38 DAS). We performed simple and composite interval mapping to identify QTLs for aerenchyma development. QTL associated with aerenchyma development was mapped on the short-arm of chromosome 12 and designated as qAER-12. The effect of qAER-12 on the plasticity in aerenchyma development under TD-W was significantly associated with the increase in lateral root elongation and branching. This resulted in greater root system development as expressed in total root length and consequently contributed to higher dry matter production. This qAER-12 is probably the first reported QTL associated with aerenchyma development in rice under TD-W and is a useful trait for the improvement of the adaptive capability under fluctuating soil moisture conditions.     

棉区有机肥替代化肥对棉花产量及其构成因子的影响

【目的】研究棉花合理的化肥减施量和有机肥替代量,筛选化肥减施与有机肥替代最佳模式,为新疆南部棉区棉花化肥减施增效技术提供理论依据。【方法】采用田间试验,以不施肥和无机复混肥为对照,分析化肥有机替代比例(20%、40%、100%)对棉花产量构成的影响。【结果】施肥可改善棉花产量构成,提高棉花产量。与无机肥处理(CF)比较,化肥减量20%下施用400 kg有机肥、化肥减量40%下施用800方有机肥处理,通过提高棉花单铃重和衣分,改善棉花产量构成,显著提高棉花产量。处理3、处理4处理棉花产量分别为423.50和403.76 kg/667m ²,比空白处理(CK)增产27.70%、21.75%,比CF处理增产5.81%、0.88%。【结论】新疆南部棉区棉花种植以化肥减量20%、化肥减量40%,即每667 m²基施有机肥400 kg,无机复混肥65.39 kg,追施尿素22.35 kg(每667 m²基肥施用有机肥800 kg,无机复混肥49.04 kg,追肥尿素16.76 kg)较为适宜。处理3、处理4模式(20%、40%的化肥减量)可以推广应用。     

Quality Effects of Rye (Secale cerealeL.) Chromosome Arm 1RL Transferred to Wheat (Triticum aestivumL.)

Quality effects of rye (Secale cerealeL.) chromosome arm 1RL transferred to wheat (Triticum aestivumL.) were characterised by comparison of a group 1R(1B) substitution lines and 1BL.1RS translocation lines. The experimental materials were sister lines derived from the mating Mironovskaya10/NE7060//NE80413. 1R(1B) substitution lines were identified by the presence of ryeomega- andgamma-secalins among 70% ethanol soluble proteins, combined with the presence of high molecular weight (HMW) secalin proteins in total grain protein extracts. Genes on 1RL reduced grain weight, grain hardness, Mixograph time, Mixograph tolerance and SDS sedimentation volumes. 1RL had no effect on flour yield or grain and flour protein concentrations. The HMW secalin proteins encoded by genes on 1RL most probably caused the decline in dough strength seen in 1R(1B) lines relative to that of 1BL.1RS sister lines. Reduced grain hardness might also be related to the presence of HMW secalins, although a role for additional, unidentified genes on 1RL could not be discounted.     

基于染色体单片段代换系的水稻粒形QTL定位

水稻的粒形是影响水稻产量和品质的重要因子之一, 是由多基因控制的数量性状。染色体单片段代换系由于减少了个体间遗传背景的干扰, 已经成为鉴定复杂性状QTL的新型遗传材料。本研究以广陆矮4号为受体,日本晴为供体的119个染色体单片段代换系群体为试验材料,通过单因素方差分析和Dunnett’s多重比较,测验单片段代换系与受体亲本之间粒形的差异,鉴定了代换片段上粒形相关的QTL。以P≤0.001为阈值, 共检测到39个粒形相关的QTL。其中,粒长相关的19个,其加性效应值为0.18~1.06 mm,加性效应百分率为2.40%~14.13%;粒宽相关的14个,其加性效应值为0.09~0.31 mm,加性效应百分率为2.71%~9.15%;粒厚相关的6个,其加性效应值为0.05~0.10 mm,加性效应百分率为2.14%~4.46%。这些QTL的鉴定,为进一步精细定位并克隆相应QTL和高产、优质水稻新品种的分子标记辅助选择奠定了基础。