Phenotype Investigation And Genetic Analysis Of Photosynthesis-associated Traits Of Oryza Rufipogon Using Advanced Backcrossing Inbred Lines(BILs)

Photosynthesis is the main source of grain yield in rice(Oryza sativa L.).It is important that genetic analysis of morphological and physiological characteristics in leaves function,especially flags,to rice improvement.In this study,a recombinant hybrid population originated from an interference between index 9311(O.Sativa L.)cultivar and a wild rice(Oryza rufpogon)was estimated.Using the SPAD value variations as rule to identified leaf senescence in top three leaves.In three stages during grain filling,leaf senescence of top three leaf weren?t the same.The third leaf from top had the most senescence quickly.Correlation analysis about some traits has also conducted.There was a small negative correlation between high plan with ChlA,ChlB and ChlA+B.For the morphological traits,strong positive correlations were found between plant height and flag leaf length,and a negative correlation between carotenoid with ChlA and ChlB.The genetic linkage map generated for this population consisted of 127 InDel markers,the each InDel was chosen as approximately 20 bp,while the PCR products would be approximately 200 bp.Those markers were distributed randomly on the 12 chromosomes in rice,with an average interval of 2.39 Mb,ranging from 0.4 to 5.0 Mb.Eight traits were examined which were measured in multiple environments.A total of 44 QTLs for morphological traits and 44 QTLs for physiological have identified on chromosome from 1-12 except chromosome 8 and 9 that have an experiment-wise significance threshold of P < 0.01(corresponding to an interval mapping LOD > 3.6 or a composite interval mapping LOD > 3.9)were identified.20 QTLs for chlorophyll a and b contents,carotenoid of the flag leaf were identified and mapped to chromosomes 1,3,4,10,11 and 12 that have the environmental interactions for chlorophyll and carotenoid.Two pairs of epistasis QTLs for chlorophyll A content accounted for similar and higher phenotypic contributions,whereas seven pairs of epistasis QTLs for chlorophyll b content contributed 3.46-5.86% to phenotypic variations.These chromosome regions could simultaneously affect chlorophyll and photosynthesis component traits and showed tight linkages or pleiotropisms.QTLs for Chlb,Chla/b of the flag leaf and QTLs for PH,FFL located in interval r186-195 on chromosome1,had the same direction of additive effect,and the maternal parent 9311 allele increased the trait values.Thus,the results in this study may help in the selection of the rice variety with delayed leaf,on comparison with QTLs for photosynthesis traits detected in the same population.it was found in many cases that the QTLs for chlorophyll a and b,contents,carotenoid and those for agronomical traits were located in the same chromosome intervals.