杂交水稻茎秆形态学优势性状与抗倒伏能力研究

以茎杆粗壮型海南野生稻S和安仁籼稻、R199、武育粳、R215及其配制组合F1为材料，研究杂交水稻茎秆形态学优势性状与抗倒伏能力的关系，结果表明：海南野生稻s的茎秆基部抗折断能力较强，基部节间结构较优，株高和茎杆长度合理，基部伸长节间较短、充实度高，是一个茎秆物理性状良好、抗倒伏能力强的光温敏核不育系材料；以海南野生稻S为母本与安仁籼稻、武育粳、R199和R215所配制的组合F1茎秆基部抗折断能力和充实度、基部伸长节间粗度、横切面面积和茎壁厚度等性状明显优于其父本并袁现出一定的平均优势或超亲优势，株高较父本明显增加，但基部伸长节间长度较父本短，具备抗倒伏性较强的生物学基础。     

重穗型水稻植株抗倒伏能力的研究

以18个不同穗重型水稻品种为材料，研究了重穗型水稻植株的抗倒伏能力及其与茎秆的物理性状、机械组织特性的关系。结果表明：重穗型品种单穗重大、产量高与其株高的适当增加密切相关。重穗型品种由于单穗重和株高的增加，弯曲力矩加大，但抗折力也明显提高，故而其茎秆抗倒伏能力并未降低。重穗型品种茎秆抗折力强的主要原因     

甜菜M14品系BvM14-UNG基因克隆及生物信息学分析

为研究Bv-UNG蛋白在植物碱基切除修复(base-excision repair,BER)途径中的功能,以甜菜M14品系为材料,根据NCBI上二倍体栽培甜菜UDG编码基因Bv-UNG序列,利用同源序列克隆法获得甜菜M14品系BvM14-UNG基因cDNA全长,并对其进行生物信息学分析.结果 表明,该基因编码374个氨...     

不同水直播方式水稻植株抗倒特性研究

为研究不同水直播方式水稻植株倒伏的差异,在稻麦两熟制下,以2个常规粳稻(常农粳7号、超级稻南粳44)和2个杂交粳稻品种(甬优2638、甬优7号)为试材,设置水直播点播和条播2种方式,于齐穗后30 d,研究了不同直播方式高产水稻植株地上部分各节间抗倒伏能力的差异,并对倒伏指数、抗折力与茎秆主要物理性状进行相关分析。结果表明,条播方式水稻倒伏比例较大,水稻植株基部第2,3节间抗折力和弯曲力矩,点播方式显著高于条播方式;条播方式倒伏指数显著较高。点播方式水稻株高、重心高度高于条播方式,但相对重心高度低于条播方式。点播方式水稻基部第1,2节间长度显著小于条播方式,基部3个节间的茎秆内径长均显著高于条播方式,除基部第1节间外,基部第2,3节间外径长和茎壁厚度点播方式显著高于条播方式。点播方式基部第1,2节间单位节间干质量显著高于条播方式。上述茎秆性状在不同类型品种间有较大差异。直播水稻茎秆的抗折力和倒伏指数与水稻茎秆基部节间长、茎壁厚、节间充实度等性状密切相关。点播方式水稻具有基部节间短而粗、茎壁较厚,且充实度好的特点,是其抗倒伏能力强的直接原因。     

甜菜M14品系BvM14-Tpx基因克隆及原核表达体系下应答氧化胁迫功能的初步研究

为了研究甜菜M14品系BvM14-Tpx基因的抗氧化功能,本试验以带有野生白花甜菜第9号染色体的单体附加系M14品系为试验材料,利用RACE技术获得甜菜M14品系硫氧还蛋白过氧化物酶基因(BvM14-Tpx) cDNA全长,对其进行生物信息学分析,利用Real-time PCR和半定量RT-PCR技术对该基因进行组织特异性表达分析,在原核表达体系下进行BvM14-Tpx基因应答氧化胁迫研究。生物信息学分析结果表明,BvM14-Tpx基因cDNA全长为1044 bp,包含最大的ORF为489 bp,编码162个氨基酸;含有过氧化物酶Ⅱ(PrxⅡ)型的保守结构域;BvM14-Tpx蛋白与豌豆(Pisum sativum L.)和苜蓿(Medicago truncatula L.)中Tpx蛋白的亲缘性较高。组织特异性表达分析结果表明,BvM14-Tpx基因在甜菜M14品系各组织表达量从高到低的顺序是根、茎、叶、花。通过原核表达体系下BvM14-Tpx基因应答氧化胁迫的研究,表明BvM14-Tpx基因能够提高大肠杆菌对于环境中氧化胁迫的适应能力,减轻H₂O₂对细菌生长的抑制。本研究对挖掘甜菜M14品系优质基因,提高甜菜对于非生物胁迫的抗性以及开展甜菜遗传改良工作具有重要意义。     

寒地早粳稻秆部性状与产量关系的研究

针对寒地特殊的生态环境,以180份不同基因型早粳稻为材料,较系统地探讨了秆部性状与产量及产量构成因素之间的相互关系。研究表明:在节间长度配置上,在一定范围之内,控制倒3节间长度、增加倒1、倒2节间的长度有利于提高产量,并且对倒1、倒3节间长的选择是最为有效的。在节间粗度配置上,在保证倒1节间粗的基础上,增加其下部节间的粗度有利于高产。增加基因型的基部节间重、单位茎鞘长干重、单株干重是有利于高产的。适当增加株高和秆长来提高生物产量可能是今后水稻超高产育种的发展方向。在进行茎部性状综合评价时,基部节间重、倒2节间粗、单位秆长干重和穗颈节长4个因子就足以代表12个茎部性状的全部信息量。     

杂交粳稻不同穗位垩白性状的差异与遗传率分析

以辽宁省近年审定的2个杂交粳稻组合9946与1052及其对应亲本为材料,对稻米垩白品质性状在穗上不同部位和不同枝梗上的分布特点和遗传差异进行研究。结果表明:垩白米率、垩白面积和垩白度表现了下部穗位最大,中部和上部穗位次之,二级枝梗大于一级枝梗。差异大的组合(9946)遗传率大,一级枝梗的遗传率大于二级枝梗的遗传率。垩白性状受遗传、栽培条件以及穗位与遗传互作的影响。因此,选择垩白性状差异小,而其他性状优良的亲本进行组配,结合合理的株型育种,有可能育出低垩白的优质组合。     

杂交粳稻及其亲本抗倒伏的材料学特性研究

对11个杂交粳稻的品系或组合与其相应的12个亲本测定了茎秆的材料学特性，并用DPS分析软件对其相关性进行了分析。结果表明：杂交粳稻品种间和其亲本品种间在材料学特性方面的差异很大。基节弯矩M都对倒伏指数有负向的影响，但是提高M值的途径并不相同。杂交粳稻品种中，增加茎秆的硬度比增加茎秆构成材料更有效；而在亲本品种中则相反。相关性上分析，杂交粳稻中，株高与倒伏指数间存在着显著的正相关关系，但在亲本中并不显著。而秆型指数与其相关性在亲本中达到了显著水平。本试验进一步说明，在杂交粳稻和其亲本中，通过提高茎秆构成材料的质量和数量因素来保持甚至提高植株的抗倒伏能力是可能的。     

甜菜M14品系BvM14-RIN4基因的克隆及应答盐胁迫分析

为了研究甜菜单体附加系M14品系RIN4基因耐盐功能,本研究以甜菜M14品系为实验材料,通过PCR技术获得BvM14-RIN4基因cDNA全长序列,对BvM14-RIN4基因进行了生物信息学分析、组织特异性和应答盐胁迫分析.BvM14-RIN4基因ORF长度为264 bp,编码87个氨基酸,蛋白分子量为9.67 kDa...     

甜菜M14品系BvM14-Dof3.4基因的克隆及响应盐胁迫表达分析

为进一步研究BvM14-Dof3.4基因响应盐胁迫的功能,以甜菜M14品系根为材料,通过PCR技术获得BvM14-Dof3.4基因cDNA全长序列并进行生物信息学以及盐胁迫应答分析。结果表明：该基因最大ORF为408 bp,编码135个氨基酸,蛋白分子量为12646.63 Da,理论等电点为4.68,为亲水性蛋白;BvM14-Dof3.4蛋白质二级结构和三级结构主要由延伸链和无规卷曲组成;BvM14-Dof3.4蛋白氨基酸序列与NCBI数据库中甜菜(Beta vulgaris)的氨基酸序列相似度为99.26%;系统进化分析表明BvM14-Dof3.4蛋白与菠菜(Spinacia oleracea)Dof3.4蛋白亲缘性较高。结合实验室前期盐胁迫下甜菜M14品系根的转录组数据分析,BvM14-Dof3.4基因参与甜菜M14品系应答盐胁迫过程,在200 mmol/L NaCl处理下上调2.05倍,在400 mmol/L NaCl处理下上调1.41倍。实验成功获得BvM14-Dof3.4基因cDNA全长,并确定该基因响应盐胁迫,该结果对挖掘甜菜M14品系优质基因和提高栽培甜菜抗逆性等方面具有重要意义,为后续进一步开展BvM14-Dof3.4基因响应盐胁迫功能研究提供参考。     

Evaluation of field resistance of Daucus carota cultivars to Cercospora carotae (carrot leaf spot)

Summary A world collection of 142 cultivars of carrot was tested for resistance to Cercospora carotae in the field. C. carotae infection was observed in all the cultivars. Field resistance was observed in only about 30% of the cultivars, the remainder being highly susceptible.     

高抗褐斑病性和含糖率甜菜品种田间鉴定

为选择抗褐斑病性高、含糖率高的优良甜菜品种用于生产,提高经济效益。2015—2016 年,采用田间试验自然发病鉴定方法,15 个品种为处理,随机区组排列,4 次重复,对商用甜菜品种的褐斑病病情指数、含糖率进行调查测定。统计分析结果表明：不同甜菜品种间抗褐斑病性差异极显著,甜菜品种的抗褐斑病性不稳定,不同年份间差异较大。品种间含糖率差异极显著。同一品种不同年份含糖率存在差异,抗褐斑病性高并相对稳定、含糖率高的甜菜品种为‘KWS1197’,2 年的平均病情指数为18.34,平均含糖率为14.01%。     

SSR analysis of cultivated groundnut (Arachis hypogaea L.) germplasm resistant to rust and late leaf spot diseases

Cultivated groundnut (Arachis hypogaea L.) is an agronomically and economically important oilseed crop grown extensively throughout the semi-arid tropics of Asia, Africa and Latin America. Rust (Puccinia arachidis) and late leaf spot (LLS, Phaseoisariopsis personata) are among the major diseases causing significant yield loss in groundnut. The development of varieties with high levels of resistance has been constrained by adaptation of disease isolates to resistance sources and incomplete resistance in resistant sources. Despite the wide range of morphological diversity observed in the cultivated groundnut gene pool, molecular marker analyses have thus far been unable to detect a parallel level of genetic diversity. However, the recent development of simple sequence repeat (SSR) markers presents new opportunities for molecular diversity analysis of cultivate groundnut. The current study was conducted to identify diverse disease resistant germplasm for the development of mapping populations and for their introduction into breeding programs. Twenty-three SSRs were screened across 22 groundnut genotypes with differing levels of resistance to rust and LLS. Overall, 135 alleles across 23 loci were observed in the 22 genotypes screened. Twelve of the 23 SSRs (52%) showed a high level of polymorphism, with PIC values ≥0.5. This is the first report detecting such high levels of genetic polymorphism in cultivated groundnut. Multi-dimensional scaling and cluster analyses revealed three well-separated groups of genotypes. Locus by locus AMOVA and Kruskal–Wallis one-way ANOVA identified candidate SSR loci that may be valuable for mapping rust and LLS resistance. The molecular diversity analysis presented here provides valuable information for groundnut breeders designing strategies for incorporating and pyramiding rust and late leaf spot resistances and for molecular biologists wishing to create recombinant inbred line populations to map these traits.E.S. Mace and D.T. Phong contributed equally to this work.     

Characterization of resistance to angular leaf spot of common bean (Phaseolus vulgaris L.) breeding line SPS50HB

The common bean (Phaseolus vulgaris L.) makes an important contribution to the human diet, particularly in Africa and Latin America. Because angular leaf spot (ALS), caused by the fungal pathogen Pseudocercospora griseola, is one of the most severe foliar diseases of the bean plant, an important priority is to identify genes encoding resistance. The present study focused on the resistance shown by the Mesoamerican common bean breeding line SPS50HB. From the pattern of segregation for resistance displayed in an F₂ population bred from a cross between SPS50HB and the ALS-susceptible Ethiopian variety Red Wolaita, it was concluded that the resistance of SPS50HB is controlled by two unlinked dominant genes. An allelism test indicated that one of these genes was either identical with, allelic to, or closely linked to the major gene Phg-2 carried by variety Mexico 54. The sequence-characterized amplified region assays OPEO4 and PF13, which are diagnostic for an ALS resistance gene carried by the germplasm accession G10909, both tracked a possible second gene present in SPS50HB.     

Inheritance of resistance to angular leaf spot (Isariopsis griseola Sacc.) in french bean (Phaseolus vulgaris L.)

Summary Angular leaf spot (Isariopsis griseola Sacc.) is a serious disease of French bean in the hills of India and 40 to 70 per cent of the green pods are damaged and rendered unmarketable. Crosses were made between PLB 257, (Phaseolus coccineus L.), a red flowering pole tope, resistant to angular leaf spot, and Contender (Phaseolus vulgaris L.), a highly susceptible commercial cultivar. Studies of the F₁, F₂, and F₃ progenies indicated that PLB 257, carries a recessive gene imparting resistance to angular leaf spot.     

Molecular marker-assisted selection for development of common bean lines resistant to angular leaf spot

The objective of this work was to develop homozygous common bean lines carrying angular leaf spot resistance genes derived from the cultivars ‘Mexico 54’, ‘MAR 2’ and ‘BAT 332’ through marker‐assisted selection. Molecular markers SCAR OPN02₈₉₀, RAPD OPE04₅₀₀ and OPAO12₉₅₀ linked to the resistance genes of ‘Mexico 54’, ‘MAR 2’ and ‘BAT 332’, respectively, were used in segregating backcross‐derived populations to selection. DNA fingerprinting was used to select homozygous BC₂F₃ and BC₁F₃ resistant plants genetically closer to the recurrent parent. Two homozygous BC₂F_2:3 and two and five BC₁F_2:3 families derived from ‘Ruda’ vs. ‘Mexico 54’ (RM), ‘MAR 2’ (RMA) and ‘BAT 332’ (RB) crosses were selected, respectively. After only one (RMA, RB) or two backcrosses (RM), five and eight BC₁F₃ lines derived from RMA and RB, respectively, and seven BC₂F₃ lines derived from RM, with 14.9–16.6, 16.9–18.6 and 9.3–11.1% of relative genetic distances to the recurrent parent were selected. This is the first report of lines resistant to angular leaf spot carrying genes of the cultivars ‘Mexico 54’, ‘MAR 2’ and ‘BAT 332’ developed with the aid of molecular markers.     

Molecular mapping of a new gene for resistance to frogeye leaf spot of soya bean in 'Peking'

Amplified fragment length polymorphism (AFLP) and microsatellite (simple sequence repeat, SSR) techniques were used to map the _RGSp_eking gene, which is resistant to most isolates of Cercospora sojina in the soya bean cultivar ‘Peking’. The mapping was conducted using a defined F₂ population derived from the cross of ‘Peking’(resistant) בLee’(susceptible). Of 64 EcoRI and MseI primer combinations, 30 produced polymorphisms between the two parents. The F₂ population, consisting of 116 individuals, was screened with the 30 AFLP primer pairs and three mapped SSR markers to detect markers possibly linked to Rcs_Peking. One AFLP marker amplified by primer pair E‐AAC/M‐CTA and one SSR marker Satt244 were identified to be linked to Res_Peking. The gene was located within a 2.1‐cM interval between markers AACCTA178 and Satt244, 1.1 cM from Satt244 and 1.0 cM from AACCTA178. Since the SSR markers Satt244 and Satt431 have been mapped to molecular linkage group (LG) J of soya bean, the Res_Peking resistance gene was putatively located on the LG J. This will provide soya bean breeders an opportunity to use these markers for marker‐assisted selection for frogeye leaf spot resistance in soya bean.     

Inheritance of angular leaf spot resistance in common bean line BAT 332 and identification of RAPD markers linked to the resistance gene

The existence of genetic variability for angular leaf spot (ALS) resistance in the common bean germplasm allows the development of breeding lines resistant to this disease. The BAT 332 line is an important resistance source to common bean ALS. In this work we determined the inheritance pattern and identified RAPD markers linked to a resistance gene present in BAT 332. Populations F₁, F₂,BCs and BCr derived from crosses between BAT 332 and cultivar Rudá were used. Rudá is a commercial cultivar with carioca type grains and susceptible to ALS. The resistance of BAT 332 to race 61.41 of the pathogen was confirmed. Segregation analysis of the plants indicated that a single dominant gene confers resistance. For identification of RAPD markers linked to the resistance gene, bulk segregant analysis (BSA) was used. Two RAPD markers,OPAA07₉₅₀ and OPAO12₉₅₀, linked in coupling phase at 5.10 and 5.83 cM of this gene, respectively, were identified. These molecular markers are important for common bean breeders and geneticists as source of genetic information and for marker assisted selection in breeding programs. This revised version was published online in July 2006 with corrections to the Cover Date.     

Pathogenic variation in, sources of, and breeding for resistance to Phaeoisariopsis griseola causing angular leaf spot in common bean

If we are to breed common bean (Phaseolus vulgaris L.) for durable resistance to diseases, we must understand pathogenic variation and find sources of resistance. Our first objective was to determine the patterns of pathogenic variation found among isolates of Phaeoisariopsis griseola (PG), the fungus that causes angular leaf spot (ALS) in common bean. We characterized 433 PG isolates from 11 Latin American and 10 African countries, using differential cultivars, isozymes, and/or random amplified polymorphic DNA (RAPD) markers. We also systematically screened, for ALS resistance, common bean accessions from the world collection held at CIAT, and assessed the progress so far made in breeding for resistance to ALS. Despite their great diversity within and between countries on both continents, the PG isolates were classified into two major groups: Andean, and Middle American. Although each group had internal differences for virulence, and biochemical and molecular characteristics, the ‘Andean’ PG isolates were more virulent on common beans of Andean origin, than on those of Middle American origin, thus, suggesting a host-pathogen co-evolution. The ‘Middle American’ PG isolates, although more virulent on common beans from Middle America, also attacked Andean beans, thus, exhibiting a much broader virulence spectrum. To find sources of resistance, we tested 22,832 common bean accessions against naturally occurring PG isolates in the field at CIAT's Experiment Station, Quilichao, Colombia, between 1985 and 1992. The resulting 123 intermediate (scores of 4 to 6) and resistant (scores of 1 to 3) accessions were then tested in the greenhouse against selected 14 PG isolates of diverse origins. Nineteen accessions were intermediate or resistant to at least 13 of 14 PG isolates. Similarly, of 13,219 bred lines tested in the field between 1978 and 1996, 89 were intermediate or resistant. Of these, 33 bred lines proved intermediate or resistant to at least eight of nine PG isolates to which they were challenged in the greenhouse. We suggest that, to breed for durable resistance to ALS, common bean populations should be developed from crosses between Andean and Middle American gene pools. The populations should then be systematically evaluated and selected against the broadest range of the most virulent PG isolates of diverse evolutionary origins. This revised version was published online in August 2006 with corrections to the Cover Date.