| Functional rice is a kind of rice with nutrition and regulating human physiological function that suitable for specific population, not to treat the disease. Compared with ordinary rice, it not only is more rich in protein, essential amino acids, minerals and other nutrient components, but also contains resistant starch, dietary fiber, unsaturated fatty acids, flavonoids, y-aminobutyric acid (GABA), sterols, alkaloids and other special physiological active substances. These physiological active substances have an effect on prevention of hypertension, hyperglycemia, cardiovascular diseases, obesity and other chronic diseases. The breeding of functional rice is of great significance to prevent chronic disease through daily diet, and also has a high practical value to solve global sub-health problem. Therefore, it is necessary to study on the genetic variation and gene mapping of functional components contents in the functional rice.This study was based on117lines of derect cross and101lines of back-cross from "gongmi3/Diantun502" F3population. The contents of four functional components, including resistant starch, alkaloids, flavonoids and GABA, in brown and polished rice were detected, then discussed the genetic variation of these four functional components contents and the correlation with agronomic traits, and also analyzed QTL mapping of resistant starch and other functional component which was associated with it. The results were as follows:1. The results from analysising genetic variation of the four functional components contents in brown and polished rice of F3population showed that:Resistant starch contents in brown rice were0.59%-7.82%, coefficient of variation were35.58%-55.24%; In polished rice, the contents were0.48%-6.22%, coefficient of variation were42.55%-45.16%. Alkaloids contents in brown rice were12.16-52.05mg/100g, coefficient of variation were21.1%-25.08%; In polished rice, the contents were5.66- 44.04mg/100g, coefficient of variation were24.15%-35.29%. Flavonoids contents in brown rice were70-194.66mg/100g, coefficient of variation were13.96%-20.72%; In polished rice, the contents were9.24-147.23mg/100g, coefficient of variation were36.79%-47.01%. GABA contents in brown rice were2.89-18.54mg/100g, coefficient of variation were37.45%-45.18%; In polished rice, the contents were2.04-13.9mg/100g, coefficient of variation were36.27%-46.8%. Four functional components in brown and polished rice showed a wide range of genetic variation, this indicated that they were quantitative traits controlled by multi-genes.2. Resistant starch and GABA contents in brown rice, alkaloids/flavonoids and GABA contents in polished rice were different at0.05or0.01level, indicated that cytoplasmic effects on the accumulation of functional components in rice.3. Functional components and agronomic traits correlation analysis showed that: For F3population, although four functional components contents in brown rice were higher than that in polished rice, no matter in derect cross or back-cross, the same functional component content showed extremely significant positive correlation between brown and polished rice. For brown rice in derect cross, resistant starch and flavonoids contents showed extremely significant positive correlation; Resistant starch/flavonoids contents and GABA contents showed extremely significant negative correlation; For polished rice in derect cross, alkaloids and flavonoids contents displayed extremely significant positive correlation, resistance starch and GABA contents showed extremely significant negative correlation; In back-cross, just flavonoids and GABA contents of polished rice displayed extremely significant positive correlation.In derect cross, plant height and flavonoids contents of brown rice, total panicles/panicle length and flavonoids contents of polished rice showed extremely significant correlation; In back-cross, filled grains per panicle and resistant starch contents of brown rice/flavonoids contents of polished rice, blighted grains per panicle/spikelet fertility and GABA contents of brown rice displayed extremely significant correlation. It was suggested that plant height, total panicles, panicle length, filled grains per panicle, blighted grains per panicle and spikelet fertility can be used as an agronomic indicator to identify functional component content.For agronomic traits, there were extremely significant positive correlation between plant height and panicle length/filled grains per panicle, between panicle length and filled grains per panicle, between filled grains per panicle and spikelet fertility; Blighted grains per panicle was extremely significant negative correlation with filled grains per panicle and spikelet fertility.4. Detected two QTLs by CTM(composite interval mapping) relating to resistant starch/alkaloids content of brown rice, resistant starch content of polished rice, respectively. They were located in interval RM7110-RM3211and RM3404-RM478on chromosome7. The interpretation of the phenotypic variation ranged from7.6%to19.3%, the positive alleles were all from gongmi3. |
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