Dissertation > Excellent graduate degree dissertation topics show

Studied on Genetic Variability if Amylose Contein in Rice Grain and Its Selection Efficiency in the Early Generations of Rice Crosses

Author: LiuHaiYing
Tutor: JinZhengXun
School: Northeast Agricultural University
Course: Crop Genetics and Breeding
Keywords: Rice Early generation of hybrid Amylose content Genetic variation Select an effect SSR markers
CLC: S511
Type: Master's thesis
Year: 2007
Downloads: 71
Quote: 1
Read: Download Dissertation

Abstract

Cooking and eating quality of rice quality traits amylose content is one of the main underlying factors that affect the cooking and eating quality, and early generation hybrids traits separation and selected generation. Therefore, the study RICE HYBRID amylose content of genetic variation and selection effect of high yield and quality of rice breeding has important theoretical and practical significance. Used in this experiment with different amylose content of four rice varieties formulated two crosses, that is selected from 1 × through 769 and DongNong, 423 × vine train 180, to study the hybrid F ₂ ~ F ₅ progeny amylose content of genetic variation in the early generation of directional selection effect. The results show that: rice grain amylose content in the hybrid offspring of a wide range of genetic variation, the two combinations F ₂-generation plants amylose content separation showed a unimodal distribution, which combination I was normal points, combination II was positive skewed distribution, and tend to the low amylose content, have more super pro variability, provides a wide range of variation of material for high and low amylose content of directional selection. No major gene differences between the parents, the amylose content by multiple genes control early generation hybrid additive gene effects-based, but there are some dominant effect. The heritability of the early generations of straight-chain starch content of 64.48% to 95.34%, with the generational promote incremented. Inter-generational amylose content significantly, and a higher degree of correlation between adjacent generations. Amylose content for future generations the choice of indicators, to the high, low amylose content by generations of directional selection from the generation of the hybrid F ₂ offspring amylose content can be significantly increase or decrease the directional selection through the traditional method of selecting the Hybrids amylose content to the high and low two different directions, and select the direction of the low amylose content obtained by selection efficiency is greater than the choice of the high amylose content, to elect ultra-high affinity and ultra-low pro offspring. Selection intensity of the early generations of straight-chain starch content should not be too large, F ₂-generation plant selection rate of 15% is appropriate, and the the F ₃, the F _{4 < / sub> and F ₅-generation plant selection rate of 10% is appropriate. Select amylose content cooking and eating quality and yield of hybrids of various degrees, the extent of its impact on different crosses and traits. The viscous peak setback and fall viscosity variability in the cooking and eating quality traits, heading in the agronomic traits variability. Amylose content and cooking and eating quality of the relationship and the relationship between cooking and eating quality traits with amylose content relevance and related changes in the nature. The relationship between the amylose content and cooking and eating quality is not a simple linear relationship between the amylose content is too high or too low, eating quality are varying degrees of deterioration. Amylose content of moderate levels of offspring has good eating quality. Amylose and protein content is the main component of rice, the main factors to affect the cooking and eating quality, there is a shift in the relationship between the two, so coordination of amylose and protein content of the relationship is to improve the quality of rice an important way. SSR markers of genetic similarity coefficient, in combination in I, a single genetic hybrids similar to the average coefficient ranged from 0.468 to 0.624, the overall average of 0.556, paired hybrid offspring genetic similarity coefficient maximum value of 0.929, the minimum value of 0.143; combination II, a single genetic hybrids like coefficient average value ranged from 0.500 to 0.595, and the overall average of 0.560, paired hybrid offspring genetic similarity coefficient maximum value of 0.938, a minimum value of 0.125. Parents and hybrids cluster analysis showed that most of the offspring strains with high amylose content together with high affinity, and most of the offspring strains with low amylose content together with low affinity. Continuous directional selection of the hybrid offspring of a trait, their offspring genetic background easily biased in favor of one of the parents, the selected the offspring genetic relationship with one of the parents is very tight, is not conducive to good genes polymerization parents and offspring genetic diversity.}

Studied on Genetic Variability if Amylose Contein in Rice Grain and Its Selection Efficiency in the Early Generations of Rice Crosses

Abstract

Related Dissertations