RFLP characterization of Indian Musa germplasm for clonal identification and classification

Summary Nineteen single-copy clones isolated from a PstI genomic library (cv. Maiden Plantain), and eight Vigna chloroplast DNA clones were used to probe total genomic DNA digests of 57 genotypes of Musa from India. The 19 genomic clones detected a total of 107 polymorphisms among the 57 genotypes. Principal coordinates and phenetic analyses of these data placed cultivars and species into distinct groups that were in general agreement with a previously published RAPD-based classification of these same plant materials. The 107 polymorphisms were sufficient to differentiate each clone from every other clone. Heterologous Vigna chloroplast DNA probes were used to characterize the cytoplasm of Musa cultivars and species. PCO analysis of these RFLPs were detected both within and between the generally recognized genome groups, indicating multiple hybridization pathways in the origin of hybrid clones. Data presented demonstrate that RFLPs are sufficiently abundant to classify Musa germplasm and that genetic relationships among Musa cultivars, based upon RFLP data, are in general agreement with relationships determined by analysis of morphology and RAPDs.     

Cryptic improvement for fertility by continuous selfing of diploid potatoes using Sli gene

While a diploid potato was continuously selfed by a function of Sli gene, the level of heterozygosity reduced, and the fertility also reduced (inbreeding depression), which might be improved because continuous selfing could eliminate undesirable recessive alleles. To explore what was occurring as advancing self-generations in terms of fertility, 51 plants of an S₃ diploid potato family were evaluated for fertility-related traits and analyzed by RFLP markers. The level of heterozygosity was positively correlated with any of fertility-related traits (r = 0.108−0.333). At least six loci on six chromosome sections were associated with fertility-related quantitative trait loci (QTLs), of which three performed better in the heterozygotes and three in the homozygotes. By further continued selfing, QTLs performing better in heterozygotes were likely fixed to homozygotes with secondly better performance, and those performing better in homozygotes were fixed to the best genotypes. Thus, the selfed progenies were cryptically being improved for fertility by genetic fixation to the best or better genotypes in fertility-related QTLs.     

Use of multiparental inbred populations to determine allelic relationships of molecular markers

The assessment of polymorphism exhibited by molecular markers is an arduous but essential task that facilitates the use of molecular tools by breeders and geneticists. For that purpose, the value of a wheat composite population was assessed for characterizing the diversity of restriction fragment length polymorphism (RFLP) markers developed by INRA-Génoblé. The polymorphism of 13 genomic probes was measured over a set of 80 inbred lines randomly extracted by single-seed descent from a composite-cross of 16 wheat lines. The 13 probéenzyme combinations revealed 27 loci with codominant polymorphism. As many bands were so far unmapped, the segregational analysis of the progenies appeared very suitable for complex patterns, both in determining allelic relationships and in revealing linkage between loci. Allelic diversity, band sizes and chromosomal location assessed from nullisomic-tetrasomic lines are given for the 27 loci.     

Characterization of the A4 cytoplasmic male-sterile lines of sorghum using RFLP of mtDNA

Three sorghum cytoplasmic male sterile lines CSV4 A(V), CSV4 A(G₁) and CSV4 A(M), grouped as A₄, were compared with a milo (A₁) and two other non-milo (A₂ and A₃) cytoplasms for their RFLP patterns of mitochondrial DNA (mtDNA). A 9.7 kb clone from pearl millet mtDNA discriminated each of the three A₄ entries whereas other maize and pearl millet mtDNA clones used could not distinguish this group completely. The molecular differences within the A₄ cytoplasmic group offer some explanation for the inconsistency in the fertility restoration behaviour of these A₄ lines obtained with a definite set of testers in the field. This revised version was published online in July 2006 with corrections to the Cover Date.     

Detection of linkage between RFLP markers and genes affecting anthocyanin pigmentation in maize (Zea mays L.)

Summary Linkages between molecular markers and genes involved in the expression of agronomical traits have already been described in all of the major crops. In most cases, the genetic model underlying the Quantitative Traits Loci (QTL) is discussed. Here, Restriction Fragment Length Polymorphisms (RFLPs) and Mapmaker-QTL have been used to pinpoint seven regions of the genome significantly correlated with four pigmentation qualitative traits of maize (Zea mays L.). Two of these, located on chromosomes 2 and 10, explain most of the variation of these traits. The R and B gene loci known to be involved in the regulation of the anthocyanin pathway map to the same regions and we suggest that these loci could be the candidate genes involved in the correlations detected with RFLPs. This type of result is in accordance with the hypothesis of the candidate gene which supposes that, if we have a very high density map of randomly-selected cDNA clones, it should theoretically be possible to associate a cloned genic sequence with a phenotypic trait where correlations are found.     

Mitochondrial DNA RFLP in genus Oryza and cultivated rice

Summary Ninety-three accessions representing 23 species from the genus Oryza were surveyed for restriction fragment length polymorphism (RFLP) in mitochondrial (mt) DNA by probing total DNA with 15 known mt sequences cloned in plasmids from higher plants, and five mt genomic cosmid clones from maize. Very low levels of intra-specific and even intra-cytologically-defined nuclear genome mt DNA RFLP were found. High between-genome differentiation appeared, suggesting phylogenetic relationships consistent with data from previous nuclear and chloroplast (cp) DNA studies. Parallel inheritance of cp and mt DNA was found. There was one major exception: the mt DNA of the allotetraploid CD genome is apparently equally related to two putative diploid progenitors, which is suggestive of an interspecific recombination.RRLP in mt DNA was also probed in 82 cultivars, with four plasmid probes. Some bands not seen in the wild species appeared in O. sativa, with intra-specific polymorphism relatively higher than in the wild species. The pattern of variation paralleled that at the cp DNA level between the indica and japonica subspecies.     

生物技术在玉米育种上的应用

系统介绍了RFLP、RAPD概念、原理及特点以及国内外RFLP、RAPD在玉米育种应用上研究现状，同时概述了转基因技术发展现状。     

重庆地区柑桔衰退病毒组群分析

柑桔衰退病毒(CTV)存在着许多生物学特性不同的株系。通过铲除感染强毒株植株或利用弱毒株交叉保护的方式来防治柑桔衰退病都需要对CTV株系进行准确、可靠的鉴定。根据对CTV衣壳蛋白基因(CPGs)的限制性片段长度多态性(RFLP)和单链构象多态性(SSCP)分析,发现在重庆地区CTV主要以CP/HinfⅠRFLP第1,3和6组群为主,并且在田间以多株系混合感染为主?     

辽宁营口地区锦鸡儿与树锦鸡儿根瘤菌遗传多样性研究

对锦鸡儿与树锦鸡儿根瘤菌进行研究,以了解其系统发育地位及遗传多样性。通过分离、纯化、回接结瘤测定共获得了31株待测菌,并采用16S rDNA PCR RFLP及BOX-PCR等方法对这些菌进行了研究。结果表明,31株待测菌的系统发育地位全部源于中间根瘤菌属（Mesorhizobium spp.）,并产生5种不同的rDNA图谱组合。BOX-PCR研究中,待测菌株呈现出较高的多样性,在80%相似性水平上,将待测菌归于17个不同的类型当中。     

RFLP在植物遗传育种研究中的应用

RFLP作为一种主要的分子标记手段,在植物遗传育种研究中占有重要的地位.它较传统的形态学标记、细胞学标记和生化标记有明显的优点,现已广泛运用于遗传图谱构建、基因定位、数量性状位点(QTL)分析、外源染色体鉴定、遗传多态性分析、进化和分类研究、细胞质遗传研究等领域.