| Maize is a kind of typical crop which prefers to live in warm climate,it is native to the tropical and the subtropical regions and generally shows weak tolerance under low temperature.Cold stress has great influence on the develop of maize at the initial seedling stage,the cold stress occurs in this period would disturb the seed germination,prolong the emerging time,affect the ratio of emergence and restrict the develop of seedling in root,stems and leaves.So far,although researchers made some breakthrough in the maize physiology and genetic mechanism,due to the complexity of maize cold-related mechanism,the genetic control of cold tolerance seems to be different in different genotypes at diverse grow stage,hence,it is essential to carry out further research and debate,find out useful cultivated varieties with high cold tolerance by applying efficient breeding theories and technical methods.By applying the MX population which was derived from a single F1 individual from a cross between Mo17 and a wild teosinte(Z.mays ssp.mexicana,566686),genetic linkage map is constructed to perform the QTL mapping that measure the maize seedling associated traits(plant height,primary root length and dry weight),our research aims to provide useful basic of theories for the research about maize cold tolerance in the future.Our results finally find 10 QTLs in the entire genome region.Under low temperature,4QTLs are find with LOD greater than 3,among them,1 QTL control plant height and two QTLs(qMXRL2-1,qMXRL6-1)dorminate primary root length,1 QTL(qMXDW5-1)that related to dry weight,with R~2 ranging from 5.8 to 8.8%on chromosome 2,5 and 8respectively.Under normal condition,6 QTL are located,2 QTLs(qMXPH4-2,qMXPHN4-1)control plant height,1 QTL(qMXRL3-1)regulate primary root length and 3 QTLs(qMXDW1-1,qMXDW1-1,qMXDW6-1)are related to dry weight,with R~2 ranging from 6.1to 7.4%on chromosome 1,3,4,6 and 10 respectively.Among these QTLs,qMXPH2-1and qMXRL2-1 has the the nearest distance with 236.8-236.8 and 213.2-216.2 Mb on chromosome2.The results we obtain will provide better understanding on the basic genetic of maize on cold tolerance,at the same time,will help breeders utilize SNPs mapping to select cold resistant varieties. |
