分子标记辅助育种在水稻育种中的应用

介绍了几种常用的分子标记辅助育种技术及其特点,对分子标记辅助技术在水稻主基因、抗病虫基因的转移和聚合、QTI．改良和杂交育种等方面的应用进行了综述。     

Strategy for Use of Rice Blast Resistance Genes in Rice Molecular Breeding

Rice blast is one of the most destructive diseases affecting rice production worldwide. The development and rational use of resistant varieties has been the most effective and economical measure to control blast. In this review, we summarized the cloning and utilization of rice blast resistance genes, such as Pi1, Pi2, Pi9, Pi54, Pigm and Piz-t. We concluded that three main problems in the current breeding of rice blast resistance are: availability of few R(resistance) genes that confer resistance to both seedling and panicle blast, the resistance effect of pyramided lines is not the result of a simple accumulation of resistance spectrum, and only a few R genes have been successfully used for molecular breeding. Therefore, novel utilization strategies for rice blast R genes in molecular breeding were proposed, such as accurately understanding the utilization of R genes in main modern rice varieties, creating a core resistant germplasm with excellent comprehensive traits, screening and utilizing broadspectrum and durable resistance gene combinations. Lastly, the trends and possible development direction of blast resistance improvement were also discussed, including new genes regulating resistance identified via GWAS(genome-wide association study) and improving rice blast resistance using genetic editing.     

水稻Pi9基因序列标记的开发及其抗瘟育种应用

利用广谱抗稻瘟病基因Pi9的3'UTR序列设计特异DNA标记pi9utr,通过分子标记辅助选择和连续回交育种实践,改良7份籼稻亲本(316B、金23B、R207、R228、R288、R389、明恢86)的稻瘟病抗性。结果表明:pi9utr是一个高效显性分子标记,除R207外,在其余6份受体亲本与Pi9供体亲本75-1-127间均存在明显而稳定的多态;在室内接种后的316B×75-1-127 BC4F1群体和R288×775-1-127 BC6F1群体中随机取样,进行稻瘟病抗性表型和基因型鉴定及Pi9基因表达分析,证明pi9utr对两个组合回交后代个体的抗病性辅助选择效率均为100%,且在所有抗病单株中均能检测到Pi9基因的高效表达,在所有感病单株中均没有检测到Pi9基因的表达。利用pi9utr在回交世代中的连续辅助选择,获得了3个组合的BC4F1及3个组合的BC6F2代群体,为选育抗稻瘟病新品种打下了基础。     

Understanding Brown Planthopper Resistance in Rice: Genetics,Biochemical and Molecular Breeding Approaches

Brown planthopper (BPH, Nilaparvata lugens Stål) is the most devastating pest of rice in Asia and causes significant yield loss annually. Around 37 BPH resistance genes have been identified so far in indica, African rice varieties along with wild germplasms such as Oryza officinalis, O. minuta, O. nivara, O. punctata, O. rufipogon and O. latifolia. Genes/QTLs involved in BPH resistance, including Bph1, bph2/BPH26, Bph3, Bph6, bph7, BPH9, Bph12, Bph14, Bph15, Bph17, BPH18, bph19, Bph20, Bph21(t), Bph27, Bph27(t), Bph28(t), BPH29, QBph3, QBph4, QBph4.2, Bph30, Bph32, Bph33, Bph35 and Bph36, have been fine-mapped by different researchers across the globe. The majority of genes/QTLs are located on rice chromosomes 1, 3, 4, 6, 11 and 12. Rice plants respond to BPH attack by releasing various endogenous metabolites like proteinase inhibitors, callose, secondary metabolites (terpenes, alkaloids, flavonoid, etc.) and volatile compounds. Besides that, hormonal signal pathways mediating (antagonistic/synergistic) resistance responses in rice have been well studied. Marker-assisted breeding and genome editing techniques can also be adopted for improving resistance to novel BPH biotypes.     

分子标记在水稻育种中的应用

分子标记技术的应用日趋广泛,对水稻育种研究有重要的价值。通过重点介绍近年来分子标记在水稻分子遗传图谱的构建、遗传资源保存和遗传多样性分析、基因的标记及克隆、分子标记辅助育种等方面研究的应用情况,探讨了分子标记的应用在水稻育种上的优势。     

Increasing Production of Rainfed Lowland Rice in Drought Prone Environments

Summary

Drought is a major production constraint of rainfed lowland rice grown in Thailand and Laos. Adverse soil conditions also reduce yield. In an attempt to increase rainfed lowland rice production in these countries, a major collaborative international project was conducted during a 6-year period in the region. The objectives of the project were to quantify production constraints, determine genotypic variation in yield, and identify an effective breeding strategy. A rice simulation model was developed also and used to investigate the potential impact of strategies for genetic improvement and agronomic management.

Four major physical or biological constraints to higher production levels of rainfed lowland rice were identified, (1) the lack of standing water at the appropriate time of transplanting, (2) severe water stress that often develops at the end of the growing season, (3) low yield potential of the present cultivars, particularly in Thailand, and (4) adverse soil conditions including low pH and low soil fertility. The results of the field experiments and simulation modelling exercises showed that the influence of these constraints can be reduced and yield increased by several methods : in particular, choice of appropriate cultivars and time of sowing to match crop phenology with water availability, application of appropriate fertilizer, adoption of high yielding cultivars, adoption of direct seeding in place of the traditional transplanting system, and reduction of percolation water loss from the paddies.

A technology package currendy being investigated for the rainfed lowland rice is direct seeding early in the season, using cultivars that flower by the end of the rainy season, with application of organic or chemical fertilizer. The appropriate cultivars are early flowering and short-intermediate statured, possess high yield potential and ability to maintain favourable plant water status at flowering, and have the ability to establish well and compete against weed under direct seeding.     

黑龙江省抗稻瘟病育种

综述了建国后黑龙江省在抗源搜集与鉴定、抗性基因分析、抗性鉴定方法、生理小种、抗病品种选育等方面的研究与实践。缺少品种抗性遗传基础研究是限制现阶段黑龙江省抗稻瘟病育种开展的重要因素;特异性分子标记可以在开展品种抗性遗传基础研究中发挥重要作用;根据黑龙江省水稻品种骨干亲本来源,在充分利用已开发的Pi-b、Pi-ta和Pi-t这3个基因特异性分子标记的同时,还需密切关注Pi-a、Pi-z和Pi-k等基因特异性分子标记的开发与利用,进而探讨了特异性分子标记开发过程中的难点和需要注意的问题。     

Four Decades of Breeding for Varietal Improvement of Irrigated Lowland Rice in the International Rice Research Institute

Abstract

Since the establishment of the International Rice Research Institute (IRRI) in 1960, IRRI’s breeding effort in varietal improvement for irrigated lowland has passed four decades. Breeding of semi-dwarf rice varieties such as IR8 at IRRI during first decade from 1960 to 1969 resulted in quantum leaps in yield potential, which marked the green revolution in Asia. During the second decade from 1970 to 1979, the primary emphasis of rice improvement has been directed towards incorporation of multiple disease and insect resistance and shortening of growth duration. Grain quality was the main target of crop improvement at IRRI during the third decade from 1980 to 1989. The fourth decade from 1990 to 1999 and beyond was focused again on the improvement of yield potential by developing hybrid rice and new plant type. Up to 1999, 46 indica inbred varieties and 2 indica/indica hybrid rice varieties were developed by IRRI and released in the Philippines for the irrigated lowland rice systems. Large-scale adoption of these improved varieties under modern crop management practices has resulted in a dramatic increase in rice production in major rice-growing countries. The hybrid varieties between indicas increased yield potential by 9% under the tropical conditions. New plant type (NPT) breeding has not yet resulted in an increase in yield potential. The second generation NPT developed by crossing tropical japonica with indica has demonstrated some promising results in terms of improvements in yield potential, disease and insect resistance, and grain quality.     

Estimating Percolation and Lateral Water Flow on Sloping Land in Rainfed Lowland Rice Ecosystem

Abstract

Quantifying water losses in paddy fields assists estimation of water availability in rainfed lowland rice ecosystem. Little information is available on water balance in different toposequence positions of sloped rainfed lowland. Therefore, the aim of this work was to quantify percolation and the lateral water flow with special reference to the toposequential variation. Data used for the analysis was collected in Laos and northeast Thailand. Percolation and water tables were measured on a daily basis using a steel cylindrical tube with a lid and perforated PVC tubes, respectively. Percolation rate was determined using linear regression analysis of cumulative percolation. Assuming that the total amount of evaporation and transpiration was equivalent to potential evapotranspiration, the lateral water flow was estimated using the water balance equation. Separate perched water and groundwater tables were observed in paddy fields on coarse-textured soils. The percolation rate varied between 0 and 3 mm/day across locations, and the maximum water loss by lateral movement was more than 20 mm/day. Our results are in agreement with the previously reported findings, and the methodology of estimating water balance components appears reasonably acceptable. With regard to the toposequential variation, the higher the position in the topoesquence, the greater potential for water loss because of higher percolation and lateral flow rates.     

花药培养育种在水稻育种上的应用

概括地介绍了花药培养育种技术的特点,总结了近年来花药培养育种在水稻育种上取得的成就。以籼稻和粳稻为例,分别阐述了一些学者从取材,处理材料,优化培养基成分等方面进行的试验研究。其共同的目的都是为了提高水稻花药培养诱导率,花粉植株成活率,辅助水稻常规育种工作,为实现水稻事业的新突破贡献力量。     

水稻超高产育种理论与方法的辩证分析

综述了水稻超高产育种的研究现状,并对水稻超高产育种的理论和方法进行了辩证的分析,阐述了超高产新株型创制、水稻杂种优势利用等水稻超高产育种的实践探索,提出未来水稻超高产育种研究的方向。冠层结构、光合作用、物质积累、分配与调运的综合作用是作物产量形成的基础,充分利用遗传资源和高光效育种以及传统育种和生物技术相结合,协调生物产量与收获指数的关系,协调穗数、穗粒数与粒重的关系,建立合理的产量结构,理想株型与杂种优势利用相结合,实现超高产育种。生态设计育种和分子育种是未来超高产育种的研究方向。     

分子标记与玉米遗传育种

建立在分子遗传学基础上的分子标记技术的快速发展,推动了玉米研究在各个领域的发展。本文从分子标记图谱的构建、自交系亲缘关系和遗传多样性评价、QTL分析及分子标记辅助选择等方面介绍了分子标记技术在玉米遗传育种中的应用。     

抗玉米丝黑穗病分子标记辅助育种研究

玉米丝黑穗病是春玉米生产中的主要病害之一,在世界范围内普遍发生。利用前期研究获得的主效QTL,采用分子标记辅助选择与常规育种技术相结合方法,成功地把抗病基因区段导入到10个玉米骨干自交系中,获得一批抗病自交系。利用这些抗病自交系组配的杂交种,使玉米丝黑穗病的抗性得到大幅度提高。     

Development of elite breeding lines conferring Bph18 gene-derived resistance to brown planthopper (BPH) by marker-assisted selection and genome-wide background analysis in japonica rice (Oryza sativa L.)

Brown planthopper (BPH) is a serious threat to rice production. In this study, we have used the novel resistance gene Bph18 derived from Oryza australiensis and incorporated it into an elite japonica cultivar, Junambyeo, which is highly susceptible to BPH. The Bph18 gene was introduced by marker-assisted backcross (MAB) breeding into Junambyeo. The backcrossed progenies were evaluated for desirable agronomic and grain quality traits and the selection of improved breeding lines while simultaneously evaluating BPH resistance by bioassays in the greenhouse and foreground selection. Of the 26 advanced backcross breeding lines (ABL), four lines showed agronomic traits similar to those of the recurrent parent, with strong resistance to BPH. Molecular genotyping of the four ABL revealed the conversion of genotypes closely resembling the genotype of Junambyeo. The percentage of donor chromosome segments in ABL decreased from 12.3% in the BC₂ to 9.4%, 8.4% and 5.3% in BC₃, BC₄ and BC₅ generations, respectively. ABL retained small sizes of the donor chromosome segments on chromosomes 1, 2, 10, 11 and 12 but the genomes of ABL2, ABL3 and ABL4 were homosequential to the recurrent parent on chromosomes 3, 4, 5, 6, 7 and 9 without donor chromosome segment introgression. The ABL1 and ABL2 retained only some small segments of the donor genome on chromosomes 9 and 8, respectively. Fine structure analysis of the Bph18 flanking region between RM511 and RM1584 markers on chromosome 12 showed a progressive elimination of donor-derived chromosome segments from BC₂ to BC₅ generations. The percentage of O. australiensis derived chromosome segment substitution in the recurrent parent background decreased from 28% of the donor parent to 6.7%, 3.9%, 3.4% and 3.4% in BC₂, BC₃, BC₄ and BC₅ generations, respectively. However, it was revealed that the O. australiensis-derived chromosome segment (1320 kb) in ABL containing the Bph18 gene was consistently maintained irrespective of advances in backcross generations. BPH resistant elite breeding lines with agronomic and grain quality traits similar to those of the recurrent parent were successfully developed by foreground and background analysis in japonica background without linkage drag.     

水稻群体育种的技术集成

论述了水稻群体育种法对效益型基因的累加作用、对高光效株型育种的实践过程,塑造了超高产水稻的植株模型。群体育种法育成品种遗传背景的厚重与复杂性,使品种对生态环境具有广谱适应性。论述品种内杂交的重要意义以及对未来品种提纯复壮和良种繁育体系的影响。     

大豆分子标记及辅助选择育种技术的发展

分子标记、QTL的研究和辅助选择应用已经得到很大的发展,一批与大豆形态性状、产量性状、品质性状、生态性状、抗生物胁迫性状相关的QTL在国内外均有报道.但近年来分子标记和QTL研究在比较发达的国家已经转向功能标记(FMs:EST-SSR、SNP和候选基因)的研究,相继肩动大豆EST计戈呼和大豆功能基因组计划,以期使功能基因和性状直接联系起来,目前已经取得了显著成效.而我国目前分子标记和QTL的研究还主要集中在利用随机标记(RMs:RAPD、SSR和AFLP)对性状进行研究.该文就国内外大豆分子标记和分子标记辅助育种及分子育种技术发展动态和发展中存在的主要问题做一概述.     

Genetic Improvement of Rice for Bacterial Blight Resistance: Present Status and Future Prospects

The production and productivity of rice has been challenged due to biotic and abiotic factors. Bacterial blight (BB) disease, caused by Xanthomonas oryzae pv. oryzae, is one of the important biotic stress factors, which reduces rice production by 20%–50%. The deployment of host plant resistance is the most preferred strategy for management of BB disease, and breeding disease resistant varieties remains a very economical and effective option. However, it is difficult to develop rice varieties with durable broad-spectrum resistance against BB using conventional approaches alone. Modern biotechnological tools, particularly the deployment of molecular markers, have facilitated the cloning, characterization and introgression of BB resistance genes into elite varieties. At least 46 BB resistance genes have been identified and mapped from diverse sources till date. Among these, 11 genes have been cloned and characterized. Marker-assisted breeding remains the most efficient approach to improve BB resistance by introducing two or more resistance genes into target varieties. Among the identified genes, xa5, xa13 and Xa21 are being widely used in marker-assisted breeding and more than 70 rice varieties or hybrid rice parental lines have been improved for their BB resistance alone or in combination with genes/QTLs conferring tolerance to other stress. We review the developments related to identification and utilization of various resistance genes to develop BB resistant rice varieties through marker-assisted breeding.     

水稻亚种间优质米组合的选育初报

对籼粳交组合及其亲本的稻米品质进行了分析，结果表明：在选育水稻亚种间优质米组合时，亲本中必须有１个优质米亲本，另一个为高产中等米质亲本；配制偏粳组合时，最好选用粳型不育系作母本；反之，配制偏籼组合时，应选用籼型不育系作母本；双亲垩白度都高的亲本不宜选用；另外，在选配偏粳组合时，不宜选用直链淀粉含量高（２４％以上）的籼稻作父本，最好直链淀粉含量在２０％以下。     

玉米转基因育种回顾

自从1990年首次获得可育的玉米转化体以来,转基因玉米研究与产业化取得飞速发展。应用转基因技术培育了一批抗除草剂、抗虫、抗病、抗逆、优质的转基因材料,转基因玉米生产已实现产业化。本文就近年来玉米转基因研究在转化技术体系、影响因素、筛选、鉴定等方面的进展做一概述,并就有关问题提出建议。