| Rice is one of the most important food crops in the world,and in most countries in Asia and Africa,rice is the main food.However,the phenomenon of water shortage and uneven distribution has become an important factor restricting grain production and food security in China and many other countries.Researches showed that the yield formation of rice under different water conditions is a complex system,which is related to photosynthesis,transpiration,water metabolism and other physiological factors,and its also directly affects the evaluation of drought resistance of rice?It is important to resolve the genetic mechanism of rice drought tolerance and drought resistance in rice breeding by clarifying the relationship between physiological indexes and yield traits of rice under different water conditions,and to use the molecular marker technology to locate the QTL and analyze the interaction between genes and environment.In this study we used an F8,F9 recombinant inbred line contains 207 strains,which is derived from upland Xiaobaijingzi(male parent)and Kongyu 131(female parent).The materials were grown in four environments: E1 and E2 were drought stress and normal irrigation at Northeast Agricultural University's Harbin experimental base;E3 and E4 were drought stress and normal irrigation at Northeast Agricultural University's Harbin Acheng experimental base.Firstly,dissect the genetic basis of chlorophyll content(CC),plant height(PH)and panicle dry weight(PDW)by developmental dynamics QTL analysis combined with QTL×environment interactions.Secondly,mapping the additive and epistasis QTLs of canopy temperature(CT),leaf area(LA),relative water content(RWC),transpiration rate(TR),stomatal conductance(SC),net photosynthetic rate(PR),spike number(SN),spike lenth(SL),grain number(GN),thousand grain weight(TGW),seed setting rate(SSR)by single environment analysis and multi-environment analysis.The main results were as follows:1.The CC,PH,PDW of each stages under drought stress were lower than normal irrigation in phenotypic analysis of physiological and yield related traits in rice under normal irrigation and drought stress.PDW of Kongyu 131 in all stages and environments were higher than Xiaobaijingzi.CC of Xiaobaijingzi were higher than Kongyu131 under all environments and most growth stages.The PH of Kongyu131 were higher than Xiaobaijingzi before S4.The RWC,SC,PR,LA,CT,SN,SL,GN,TGW,SSR under normal irrigation were all higher than drought stress.SSR of Kongyu 131 under normal irrigation were higher than Xiaobaijingzi,but Xiaobaijingzi was higher under normal irrigation.The TR,SC,SN,TGW of Kongyu 131 under four environments were higher than Xiaobaijingzi,and the other is the opposite.2.Based on the correlation analysis of physiological and yield traits in rice,it was found that the correlation of several traits was not affected by the annual and water conditions.In four environments,TR showed very significant and positive correlation to SC,LA showed significant and positive correlation to SL.And for PH,SL,GN,The three have very significant positive correlation with each other.3.In developmental dynamic QTL mapping,26 additive QTLs and 23 epistasis of CC were detected.Unconditional QTL q Cc7-3 was detected in four stages,q Cc4-3 were detected in three stages,no conditional QTLs were detected in three or more stages.26 additive QTLs and 37 epistasis of PH were detected.Unconditional QTL q PH-7-5 was detected in four stages,qPH-2-3,q PH-4-3 and qPH-7-4 were detected in three stages.Conditional QTL q PH-4-3 was detected in four stages,qPH-3-5 ? qPH-6-1 were detected in three stages.27 additive QTLs and19 epistasis of PDW were detected.Conditional QTL q Pdw 3-5 was detected in three consecutive stages S3|S2,S4|S3,S5|S4 and all of the positive alleles were derived from Xiaobaijingzi.5.Stages that CC,PH and PDW QTL concentrated expressed were found by analyzing the distribution of dynamic QTL in different growth stages of rice,may be important period of phenotypic variation.There were seven additive and four epistaisis QTLs expressed in S5|S4 for CC and the contribution was the highest,it could be inferred that S5|S4 is an important period of CC gene expression.There were eight additive and four epistaisis QTLs expressed in S3|S2 for PH and the contribution was 66.59%,significantly higher than other periods,it could be inferred that S3|S2 is an important period of PH gene expression.There were nine and eight additive QTLs expressed in S1|S0 and S2|S1 for PDW and the contribution was also significantly higher than other periods,it could be inferred that S1|S0 and S2|S1,are important period of PDW gene expression.6.116 QTLs for CT,LA,RWC,TR,SC,PR,SN,SL,GN,TGW,SSR and DC for each trait were detected by mixed composite interval mapping under single environments.57 of them were only detected under drought stress(E1,E3)and 52 of them were only detected under normal irrigation(E2,E4).q Pr6-1,q La4,qLa7-3,qLa7-4,qCt5,qGn4-2,q Gn7-2 were detected both under drought stress and normal irrigation and could be drought resistance QTLs.qPr6-1 was detected in all four environments whose reliability is strong,worthy of further study.7.40 drought resistance coefficient QTLs for physiological indexes and yield traits of rice were detected that related to rice drought resistance.3 for CT,5 for LA,4 for RWC,2 for TR,6 for SC,3 for PR,4 for SN,4 for SL,4 for GN,3 for TGW,2 for SSR.qCtdc1-2,qScdc10,qScdc11-1,qPrdc6-1,q Sndc6-1,qSndc11-1,qSldc1-1,q Gndc4-2,q Gndc7-2 qTgwdc3-3,qTgwdc1-3,qTgwdc5,qSsr1-4 were detected in single environment analysis.8.42 additive QTLs and 51 epistaisis QTLs were detected in the joint analysis of multiple environments.29 and 30 among them has gene×environment interactions,account for 69% and58.8% of the total.In the joint analysis,30 additive QTL were detected by single environment,12 QTLs were firstly detected by joint analysis,account for 28.6% of the total.9.There are some QTLs detected by joint analysis of multiple environments whose environment effects in drought stress were all positive and could be drought resistance QTLs:(1)Unconditional additive QTLs for CC qCc3-1,q Cc7-2,conditional additive QTLs for CC qCc2-5,qCc11-2,unconditional epistasis QTLs for CC q Cc1-1/ qCc4-4,q Cc1-6/ qCc1-7,q Cc1-5/ q Cc1-7,conditional epistasis QTLs for CC qCc1-5/ qCc1-7,q Cc7-2 /q Cc10-2.(2)Unconditional additive QTLs for PH q PH-6-1,conditional additive QTLs for PH qPH-3-1,qPH-3-5 and qPH-6-1,unconditional epistasis QTLs for PH q PH-6-1/q PH-9-1 and q PH-7-4/q PH-11-1.(3)Unconditional additive QTLs for PDW q Pdw4-2,q Pdw10,qPdw8-2,conditional additive QTLs for PDW qPdw2-1,q Pdw6-2,unconditional epistasis QTLs for PDW q Pdw1-1/ q Pdw1-3,q Pdw6-2/qPdw9-4,qPdw7-2/ q Pdw9-1,conditional epistasis QTLs for PDW Pdw2-2/ qPdw8-2,Pdw3-2/qPdw12-1q,Pdw2-2/ q Pdw9-4.(4)Additive QTLs for LA,TR,SC,SL,GN,SSR qLa9,qPr11-1,qPr6-2,q Sc3-2,q Sl7-1,q Gn7-2,q Ssr1-1,q Ssr10;epistasis QTLs for PR,SN,TGW,SSR q Pr3-1/ qPr11-2,qPr1-1/ q Pr1-2,q Sn3-4/ q Sn11-2,q Tgw9/ q Tgw12,q Ssr1-2/ qSsr3.10.Genes for closely linked traits are clustered distributed.q Tr10-2 and q Sc10 were both located in RM1375-RM25741.qSl1-1 and q Gn1-1 were both located in RM1331-RM490.qSn4-1,q Sl4-2 and q Gn4-2,q Sl7-1,qGn7-2 were located in RM349-RM470 and RM180-RM1377 respectively.Further more,q Gn4-2 have been detected more than once in previous studies,it is suggested that there may be one or more major genes controlling panicle traits in RM349-RM470 interval.In this study,we detected CC,PH,PDW QTLs' dynamic expression in different growth stages and its interaction with environment.Meanwhile many drought resistant QTLs for physiology and yield traits of rice were detected.Compared with previous studies,the accuracy of QTLs detected in this study has been verified,and some of the results of this study is new,which provide an important reference for drought resistance and high yield of rice molecular breeding. |
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