Approach To Physiological Base And QTL Analysis Of Seed Dormancy In Rice(Oryza Sativa L.)

Seed dormancy, a kind of adaptability for unfavorable environmental conditions, has been evolving during systematic development for years, and is an important physiological stage in the life of seeds-bearing plants, with universal ecological significance. Seed dormancy is controlled by many minor genes, and largely affected by environmental factors during growth, development and storage, making it comparatively difficult to perform investigation on it.In present study, the mechanism about dormancy-formation and dormancy- breaking was conducted from three aspects affecting seed dormancy significantly: temperature, hormone and husk; Furthermore, BILs(Backcross Inbred Lines ) population derived from Nipponbare(japomca)/ Kasalath(indica)// Nipponbare was use to detected QTL controlling seed dormancy on different developmental stages, during storage for different periods, after treatment with exogenous hormone GA3 and ABA and different temperature during storage.Combining the study above mentioned is to clarify the mechanism and genetic base about dormancy-formation. The results were as follows:1. The physiological studies on seed dormancy mechanismThe depth of seed dormancy was determined by the temperature during seed development, especially grain-fulfilling.The treatment of exogenous hormone during seed development plays an important role in determining seed donr.ancy, but the seed was more sensitive to GA3 than to ABA; During seed germination, the seed was more sensitive to exogenous hormone than that on developmental stage; Meanwhile, the content of endogenous ABA is critical in dormancy-maintaining or breaking.The reason that seed husk function primarily in seed dormancy lies in: inhibition effects existing in seed husk; controlling content of endogenous ABA; thickness of seed husk; numbers of seed stoma and compactness of seed husk.2. QTL analysis of seed dormancyOn different developmental stages, putative loci controlling seed dormancy betweenmarkers G132-C777, R2289-C1268, R2171-R2123, R1962-C191B, R1357-R1245, C1226-R1440, R2676-G187, R1877-C488, G1465-C50 on chromosome 2, 5, 6(2), 7(2), 8, 10, 11 respectively were detected, with variance explained 6.44%-15.82%.After treatment of exogenous ABA, putative loci controlling seed dormancy between markers C1455-C1221 , R19-G332 , C166-C905 , R1751-G385 , R1877-C488 on chromosome 2, 3, 8, 9, 10 respectively, were detected to be insensitive to exogenous ABA during development, with the variance explained 8.18%-19.87%; After treatment of exogenousGAs, putative loci between markers C747-R480A , R1687-C1454 on chromosome 2, 9 respectively, were detected to be insensitive to exogenous GA3 during development, with the variance explained 14.48%, 10.58% each.Meanwhile, after treatment of high temperature immediately harvest, putative loci controlling seed dormancy between markers C955-C885, R19-G332, C734-R288. R2171-R2123, R1687-C1454, R1465-C50 on chromosome 1,3,4. 6, 9, 11 respectively, were detected to be insensitive to high temperature during storage, with the variance explained 7.2%-19.67%.After storage for half year under different temperature, putative loci controlling seed dormancy between markers R1613-C970, C747-R480A. C734-R288, R2171-R2123, C1226-R1440,R1877-C488,C1465-C50 on chromosome 1,2,4.6*7, 10,11 respectively, were detected to function steadily, with the variance explained 6.81%-19.44%.