| Rice chilling injury is a worldwide problem, in northeast of China, chilling injury is one of the main factors in rice production. Buding stage Chilling cause seed to necrosis, low germination rate.seedling stage cause seed to chlorosis, growing weak, tillering blocked. booting stage and filling stage led to the shell and grain filling is not full, which led a serious impact on yield traits. Therefore, it is key that research rice cold tolerance and breed of cold tolerance in rice to solving the problem of cold damage. In recent years, studies of molecular markers in rice cold tolerance has made some progress in terms of indicating the use of molecular markers to identify cold tolerance gene. In this study, high-yielding rice varieties of high quality cold-sensitive Dong Nong 422 as female parent, Kongyu 131 as male parent that has cold tolerance, and Two parents constructed 190 F6 and F7 lines, which were use to research in germination stage、buding stage、seedling stage and booting stage, the result are as follows:(1)QTLIci Mapping V3.0 is used to analysis linkage of molecular markers, and using Map Chart 2.2 and genetic distance to draw genetic linkage map. Eventually, after polymorphism detection and partial separation of χ2 test identified 104 covering 12 chromosomes of rice SSR markers to construct full-length genome 2337.1c M, the mean distance of markers for genetic linkage map is 22.4c M.( 2) At low temperatures, germination stage and buding stage were cold tolerance identification, two parents in cold tolerance performance of the two periods are Kongyu 131 stronger than Dong Nong 422, progeny groups on each trait gave a continuous distribution, part phenotypic appear partial separation. Under normal and cold conditions on rice seedling and booting related traits were identified, the results show that Kongyu 131 is stronger than Dong Nong 422 in aspect of resistance to cold, under cold conditions, phenotypic values of all traits have declined compared to normal conditions, and Dong Nong 422 declines greater than Kongyu131, same individual appear partial separation and a bimodal distribution, the other characters are in line with the normal distribution, which meet the genetic typical characteristics of quantitative trait.(3)Correlation analysis showed that germination rate is positively correlated with Germination index, Mean daily germination,Peak value, Germination value, Coefficient of germination, which were positively correlated, while, it is a significant negative correlation between the Mean length of incubation time and other traits. In the seedling stage, under the room temperature, root dry weight is correlated with root length, root number, leaf dry weight, leaf fresh weight and root fresh weight. Under the cold stress, root dry weight and root fresh weight is highly significant positive correlation with other traits, indicating that the root of the low temperature can cause the growth of leaves, and determines the seedlings growing. At booting stage, in 2013, under the cold treatment, Seeding Setting rate is significant negative correlation with Grain density and Secondary branch number, under the cold water and natural conditions have shown the trend that the Panicle number is not correlation with other traits. In 2014, the same traits in two different irrigation environments, it is obviously that cold water treatment than the natural irrigation traits, which is an outstanding performance in Primary branch number and Secondary branch number, as well as Panicle number and Grain density, these traits is not obvious about correlations under the natural water irrigation with other traits, but in the cold water irrigation, the majority showed a significant correlation.(4)Detected addition QTL for germination was 17, distributed on 1, 2, 3, 6, 7, 9, 12 chromosomes, which 7d, 8d, 9d of the germination rate, coefficient of germination, the mean daily germination, germination index and peak value are detected 1 QTL, 10 d, 11 d and 15 d germination rate, mean length of incubation time and germination value are detected two QTL. Meanwhile,which nine QTL effect is negative, eight QTL effect is negative, explained phenotypic variation between 5.64% ~ 17.83%. Meanwhile,q GI12, q MLIT12, q MDG12, q LTG12-2 and q LTG12-3 in a range, q LTG7-3, q LTG7-1 and q LTG7-2 in a range, q LTG12-1 and q CG12 in a range. a total of 33 pairs epistatic QTL were detected, where the effect is negative performance of 12 pairs, 22 pairs showed positive, explained phenotypic variation between 0.41% ~ 13.54%, which 11 pairs additive QTL involved in interaction.(5)Buding was detected 1 Additive QTL, which is located on chromosome 4, named q CTP4, explained phenotypic variation 16.83%. Detected two pairs epistatic QTL, epistatic effect is positive, showed the parental interaction effect is greater than the recombinant, two pairs of QTL have occurred in the interaction between non- linkage locus.(6) Seedling was detected 12 additive QTL, which located on chromosome number 2, 3, 6, 7, 9, 10 and 11, explained phenotypic variation between 6.51% ~ 14.17%. Under normal temperature conditions,there are detected QTL associated with root dry weight, root fresh weightand leaf fresh weight each one separately. Under low temperature, there are detected QTL associated with two QTL about crimp ratio of leaves, one QTL about Relative conductivity of leaves, one QTL about leaf dry weightone, one QTL about leaves fresh weightand two QTL about root length. one QTL was detected about cold response index of RFW and RL. 13 pairs epistatic QTLabout seedling, under normal temperature conditions, one QTL was detected about root number, under the low-temperature treatment, there were same QTL from Root length、Crimp ratio of leaves、Relative conductivity of leaves. And same QTL about Cold water response index of Root dry weight、Root fresh weight 、Leaves dry weight and Root length were Detected,which number is seven. There are distributed on chromosome numbers 1, 2,3, 6, 7 and 9.(7)Booting stage is detected a total of 45 additive QTL, which controlling Panicle length, Grains per Panicle,Primary branch number Secondary branch number, Grain weight per plant, Panicle number, Plant height, Seeding Setting rate and Grain density, these QTLs were located on chromosome 1, 2, 3,6,7, 9, 11 and 12, under the natural water irrigation, the QTL was detected but Seeding Setting rate, under the cold water irrigation, the QTL was detected but PN, about CRI, same QTL associated with PBN, SBN, PN and PH was detected. Under natual and cold water stress condition,same QTL about GPP, PBN, SBN, PH and GD is detected. these traits is detected in both environments QTL, except in RM1331-RM283 interval is detected once, the other in between RM1306-RM70 mark is detected repeatedly. Booting epistatic QTL is detected a total of 69 pairs, these QTL include SBN, PN,PH, SSR and GD, and PL, GPP, PBN, SBN, PN,、PH and GD is detected in two different environments of two years is detected in the same marker interval of QTL.(8)Sametimes, QTL control germination stage and seedling stage about cold tolerance is detected in same marker intervals, there are q LTG7-2 and q CRL7-1, located on RM1335-RM182 from chromosome 7; q MLIT2 and qRL2-1, located on RM561-RM341 form chromosome 2; q LTG3 and q RFW3-1, located on RM517-RM1284 from chromosome 3; q GV9 and q RL9-1 located on RM215-RM245 from chromosome 9. About booting stage and seedling stage is detected QTL in same marker intervals, there are q GD2-1 and q RL2-2, located on RM13216-RM561 from chromosome 2. |
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