| In this study, a doubled haploid population, derived from anther culture of FI hybrid between a typical indica and a japonica (ZYQ8 / JX17) has been used as genetic material. Systematical genetics anslysis of physiological triats, such as low temperature germinability, photosynthesis and related traits, photooxidation tolerance, root vitality, drought tolerance, and anatomical (peducle vascular), resistant traits (sheath blight resistance) was undertaken. The results summarized as follows:1. QTL analysis of rice low temperature germinabilityThe low temperature germinability (15℃) of two parents was significantly different. In 6-lid, the germination percentage of ZYQ8 was higher than that of JX17. In 12-16 d, the germination percentage of JX17 was higher than that of ZYQ8. The quantitative trait loci (QTLs) of every day for low temperature germinability have been mapped based on a molecular linkage map constructed from this population. In 8-11 d, qLTG-9 was identified in C397B-RZ617B on chromosome 9, the additive effect was positive showing allele from JX17 increase low temperature germinability. In 12-16d, qLTG-4 was mapped between RG908 and CT563 on chromosome 4, the additive effect was negative showing allele from ZYQ8 increase low temperature germinability. These two QTLs were detected at different stages showing the complexity of the mechanism of low temperature germinability.2. QTL analysis of leaf photosynthesis and related physiological traitsNet photosynthetic rate, chlorophyll content, stomatal resistance and transpriation rate of the parents and DH lines were investigated in flourishing tillering period. The quantitative trait loci (QTLs) for each trait were analyzed based on the constructed molecular linkage map of this population. Total 8 QTLs for photosynthesis and related physiological characters were detected. Two putative QTLs for net photosynthetic rate (qNPR-4 and qNPR-6) were mapped on chromosome 4 and 6, respectively. Three QTLs (qCC-1 > qCC-3 and qCC-8) for chlorophyll content were detected on chromosome 1, 3 and 8, respectively. One QTL for stomatal resistance (qSR-4) was identified on chromosome 4. Two QTLs for transpriation rate (qTR-4 and qTR-7) were detected on chromosome 4 and 7, respectively.3. QTL analysis of photooxidation toleranceThe photooxidation tolerance of DH population in flourishing tillering period wasinvestigated by using a facilitated screening technique. The quantitative trait loci (QTLs) for photooxidation tolerance were analyzed based on the constructed molecular linkage map of this population. Four QTLs (qPOT-1, qPOT-3a, qPOT-3b, qPOT-12) were identified on chromosome 1, 3 (two QTLs), and 12 Their total variation expressed was 39.4%. On the loci of qPOT-1, qPOT-3a, and qPOT-12, alleles from JX17 increased the photooxidation tolerance. On qPOT-4, tolerance allele was contributed by ZYQ8.4. Genetic analysis of root vitality in riceThe vitality of root of DH population was detected by using TTC method in heading period. Based on the constructed molecular linkage map, a QTL for root vitality was detected between RG449 and RG809 on chromosome 4 by using Mapmaker/QTL. Single gene effect and interaction between QTLs were identified and tested by Epistat software. A single gene near RG809, two conditional interactions and four coadaptive interactions were identified for root vitality. These loci were on chromosome 1.2,4, 7, 8, 9 and 11.5. Analysis of gene loci and epistasis for drought tolerance in seedling stageThe drought tolerance of the DH population and their parents were investigated after water supply was stopped in seedling period for 15 days. Mapping_quantitative trait loci (QTLs) was undertaken base on the constructed molecular linkage map of this population. Two QTLs (qDR-5 and qDR-12) for drought tolerance were identified, they were in the region of GA41-GA257 on chromosome 5 and RG457-Y12817R on chromosome 12, respectively. The tolerance alleles of both QTLs were from the indica parent. ZYQ8. In the meantime two genes for droug...
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