Of Xa and Xa which bracketed AQBT on chromosome . Some of them are regarded as as a single gene like AQBT designated as Xa around the Lemont x Teqing map (Li et al Immediately after interpolation around the Nipponbare CCF642 site physical map,AQBT was shown to become distinct to Xa positioned on chromosome . This interpolation around the reference Nipponbare physical map highlights common,specific and novel QTL genes for resistance to African and Asian Xoo strains. Indeed,xa(t) resistance gene to Chinese Xoo races V colocalize with qABB,the resistance QTL induced by the African Xoo strain MAI on rice chromosome . In the identical way,AQBT productive on Asian Xoo strains,colocalize with qABB,a resistance QTL induce by the African Xoo strain NAI on chromosome . xa (Ogawa and Yamamoto,qBB (QTL identified on chromosome ,Ramalingam et al. and qABB overlap on chromosome too as xa (Wu et al. a,b)Djedatin et al. Rice :Page ofand AQBT on chromosome . Lemont and Azucena,the donors’ parents of AQBT and qABB respectively,belong to the japonica subspecies. These resistance QTLs may be the identical. On chromosome ,xa,qBB and qBB colocalize perfectly. qBB and qBB may be underlined by the recessive xa gene,but the heredity of qBB and qBB has not been studied yet. On chromosome ,the QTL induced by African Xoo strains colocalized with Xa,Xa,Xa and xa(t),the identified single resistance genes to Asian Xoo strains. These Xa genes indicated that some significant R genes also contribute to quantitative resistance as reported in prevalent bean in which RGAs colocalized with anthracnosespecific QTL (Geffroy et al This was also the case of QTL connected with resistance to stripe rust and Barley yellow dwarf virus in barley (Toojinda et aland partial resistance to Cucumber mosaic virus in pepper (Pflieger et al Specifics and novels QTLs inducing resistance to African andor Asian Xoo strains are identified as qABB induced by the African Xoo strain NAI on chromosome ,qBB and qBB induced on chromosomes and by Asian Xoo strains PXO and PXO respectively,(Fig In addition to certain resistance QTLs to African Xoo trains,the recognized resistance genesQTLs to Asian Xoo strains which colocalized with QTL induced by African Xoo will probably be utilised in rice breeding programs to create bacterial blight resistant cultivars for Africa.MethodsPlant materialsThe reference mapping population consisted in recombinant inbred lines (RIL) obtained by single seed descent (SSD) in the cross among the tropical japonica landrace Azucena (susceptible parent) plus the indica cultivar IR (resistant parent) was utilized to identify and map the bacterial blight (BB) resistance QTLs. IR is an elite improved indica rice grown in tropical Asia. It carries the BB resistance gene Xa and features a big spectrum of resistance to Xoo. The Azucena landrace is susceptible to BB disease,and tolerant to drought along with other abiotic stresses. The IR x Azucena mapping population was employed to create genetic map for characterizing geneQTLs associated to drought,iron toxicity tolerance and resistance to the Rice yellow Mottle Virus (Boisnard A et alBacterial strains and plant inoculationsConclusion We mapped numerous resistance QTLs to bacterial blight in rice employing a reference recombinant inbred lines derived in the cross between Azucena and IR rice varieties. Some of them are distinct and novel to African or Asian strain of Xanthomonas oryzae pv. oryzae for example qABB induced by the African PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/24085265 Xoo strain NAI on chromosome ,qBB and qBB induced on chromosomes and by Asian Xoo strains PXO an.