Dissertation
Dissertation > Agricultural Sciences > Crop > Cereal crops > Wheat > Wheat

ISSR Marker-based Genetic Diversity in Wheat and Relationship between Regulation of Gibberellins Metabolism and Molecular Mechanism of Heterosis

Author DuJinKun
Tutor SunQiXin
School China Agricultural University
Course Crop Genetics and Breeding
Keywords Wheat Heterosis Gibberellin Gene Expression Molecular mechanism
CLC S512.1
Type PhD thesis
Year 2004
Downloads 321
Quotes 3
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ISSR molecular marker methods for the study of ordinary wheat Spelt wheat genetic differences between Spike wheat and progeny of recurrent selection, analysis of the relationship between genetic differences and heterosis, explore the expansion of hybrid wheat breeding parents genetic basis and build the kinds of subspecies of wheat heterosis group approach to raise the potential for heterosis for hybrid wheat. On this basis, use an ordinary wheat mutagenesis precocious spelled off wheat interspecific hybrids-depth study of the relationship between the tillering node of Hybrid and Its Parents hormone content differences tiller number heterosis analysis of gibberellin metabolism key enzyme GA20 Changes - oxidase gene expression in time and space between the hybrids and parents, while corn hybrids with the pro of the endogenous hormone content differences and maize GA20-oxidase gene system, in order to reveal hormone is gibberellin The relationship between metabolic regulation and heterosis performance provide valuable information. The main findings are as follows: 1) ISSR molecular marker studies show that there is greater genetic variation Spelt the wheat and compact panicle wheat groups, and with greater genetic differences between common wheat, another outside source wheat for main (outside the northern winter wheat region) also has a large genetic differences between the progeny materials and common wheat recurrent selection. Accordingly, we initially proposed to enrich the genetic basis of hybrid wheat parents can take advantage of the material to expand the genetic differences between the parental and is expected to further enhance the potential of wheat heterosis; 2) the heterosis in field test showed that different heterotic groups with hybrid F1 heterosis significantly between the groups, but the correlation analysis showed that only between common wheat and dense spike wheat in F1 plant height heterosis ISSR marker genetic distance was significantly correlated to other traits related not significant , using ISSR markers to genetic differences can not accurately predict wheat heterosis, but based on ISSR markers can help divide Wheat Heterotic Group and initially proposed to build a common wheat, Spelt wheat, the dense spike wheat and progeny of recurrent selection 4 large groups; 3) common wheat and spelled off wheat the precocious mutant lines interspecific hybrid species of the parent material, the relationship between the tiller and tiller Festival endogenous hormone content of the study. The results show that, the zeatin riboside tillering tillering node the ZR's content with the same period the number of tillers was significantly positively related to the ZR and IAA content heterosis tillering number of tillers heterosis also showed a significant positive correlation. 4) by RT-PCR method, cloned wheat GA 20 - oxidase gene, to study the genes expressed in the the hybrid varieties parent seed development situation. Found that higher than the of parent white cross seeds GA20-oxidase gene expression of the pros and cons of the hybridization contemporary seed, which is consistent with the GA content heterosis, GA 20 - oxidase gene may lead to hybridization and selfing Contemporary seeds GA content in the different key. The study also found that, in the interspecific hybrid and its parents, GA 20 - oxidase gene expressed in the jointing stage stems and leaves unexpanded mode mongrel enhanced; performance of high affinity expression in the roots and leaves of tillering; performance in the booting stage of panicle hybrid weakened, Spike in the first section, the parent expression levels consistent with hybrids; 5 of exogenous spraying GA) corn research material, the corn plant height, and endogenous hormone content affect the response of inbred lines and heterosis exogenous GA. The results indicate that exogenous spraying Ga significantly increase the corn plant height Daily growth amount, and the endogenous GA containing the most dramatic increase, while the other endogenous hormone levels did not change significantly; also been found that, compared with the hybrids selfing Department of parents exogenous spraying GA sensitivity is higher. We also cloned maize GA20-oxidase gene, and the identification of its expression between maize hybrids and inbred lines. RT-PCR results showed that the genes in the seedling root, stem, unexpanded leaves, as well as development in the Ear, embryo organs hybrid enhanced expression in mature tassel performance hybrid weakened. Exogenous GA 4 hours after treatment, the two parent GA 20 - oxidase gene transcription level increased, while the hybrid weakened rapidly; addition, through the GA content differences interspecific hybrids between parents and GA20-oxidase The differences in the expression of the gene in hybrids between the parents hormone formed the basis of heterosis.

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