The Sensitivity Of Identification And Gene Mapping To Nicosulfuron In Maize

. Maize (Zea mays L.) is an important food, forage and energy crop as well as a modelplant for genetics in the world. In China, the maize yield has exceeded rice and plays animportant role in the national economy. Weed management effects can greatly influence themaize yield. The use of herbicides plays a very important role in maize production. Thesulfonylurea herbicides, nicosulfuron, have been widely and rapidly used for weed controlbecause of the advantages such as low application rates, low toxicity, broad-spectrum andflexible application. This paper summarized the general situation of application, the mode ofaction, selective basis and nicosulfuron sensitive research to maize of sulfonylurea herbicides.Some maize (Zea mays L.) hybrids and inbreds can be severely injured by applications ofpostemergence herbicide nicosulfuron. Sensitivity of different maize was identified, somesensitive inbred lines and resistant inbred lines were hybridized and sensitive gene waslocated in order to clarify responses of different maize to nicosulfuron, study the genetic basisof sensitivity differences, locate the gene, solve the problem of sensitive maize phytotoxicityin production and lay the foundation for resistance marker-assisted selective breeding. Themain results are as follows:(1) Five maize hybrids and five maize inbred lines were sprayed of6doses, eighteenmaize inbred lines were sprayed of2doses, and the maize all will suffer serious injury withthe amount of spraying dose increase. Of5hybrids and93inbreds were evaluated,5hybridswere resistant,84inbreds were resistant and9inbreds were susceptible when spraying dosewas48g/hm2. Sensitive inbred lines and resistant inbred lines are both consist of waxy maizeand normal maize. Therefore, combined with previous studies, the following conclusions areobtained: maize sensitive gene existence of different maize subspecies, tolerant genotypecould be found among different maize subspecies. The injury phenomenon caused by therecommended spraying dose can be avoided by way of marker-assisted selection andcross-breeding. The study results are of practical significance to resistance hybrid breedingand promote the use of nicosulfuron.(2) There were no differences between reciprocal F1generations, so the gene is not acytoplasmic gene. Segregation of BC1families derived from a cross between Wny-1(tolerantinbred) and yn-6(sensitive inbred) for response to nicosulfuron was1:1(sensitive: tolerant)which was not significantly different from an expected1:1ratio (χ2=0.038<3.84=χ20.05)， indicating that susceptibility to nicosulfuron was conditioned by a single recessive gene. Thegene affecting sensitivity in yn-6was mapped to the5.01region, physical distance is76kb.This work supports that a single recessive gene or closely linked genes on the5.01, wherealleles previously designated nsf1and ben1, determine sensitivity to the herbicidenicosulfuron in maize inbred yn-6.