New Rice Germplasm Fu 8612-12 with Low Cadmium Accumulation Was Created by Radiation Mutagenesis of Huahui 8612
Cadmium pollution in paddy fields is serious in some areas of south China.Breeding new rice varieties with low accumulation of cadmium is the most effective way to solve the problem.In order to create a new rice germplasm with low cadmium accumulation,a chimeric mutant of OsNramp5 was obtained by molecular marker detection of the major cadmium absorption gene OsNramp5 in the M1 generation population through the gamma-ray radiation of the hybrid rice backbone restorer line Huahui 8612.In the M2 generation,a homozygous mutant plant with 12 bp deletion in exon 2 region of OsNramp5 was obtained,resulting in the deletion of leucine,alanine,histidine and valine at positions 45 to 48 of OsNramp5,while no other amino acids were changed.The Huahui 8612 mutant with this mutation type was named Fu 8612-12.The plant height,tiller number,panicle length,grain number per panicle,seed setting rate,1 000-grain weight and yield per plant of Fu 8612-12 were not significantly different from those of Huahui 8612.Using 48 SSR markers recommended by the Ministry standard(NY/T 1433-2014),Fu 8612-12 and Huahui 8612 were detected and showed a difference of one locus on chromosome 4.When planted in low and medium cadmium pollution environments,the cadmium content in grain of Fu 8612-12 was significantly lower than that of Huahui 8612,and was stably lower than the national limit of 0.20 mg/kg.The new rice germplasm Fu 8612-12 with low cadmium accumulation obtained in this study provides a material basis for the breeding of new rice varieties with low cadmium accumulation.