Genetic Analysis And Gene Mapping Of A Short Growth Period Mutant

A extremely short growth period mutant,which is tentatively named short growth period(sgp(t)),was found in the progenies of transgenic plants of Minghui 86,an lateness indica rice restorer line.Linkage analysis of transgenic marker gene and sgp(t)gene indicated that sgp(t)mutation was not caused by T-DNA insertion.Days to heading of homologous sgp(t)was 40.9±2.1～62.4±5.2 d,which was 35～50 d earlier than that of wildtype Minghui 86 in different times and ecological regions.The subsequent analysis of the F2 populations from the crosses sgp(t)and wildtype Minghui 86,93-11,Minhui 3301 and Bobai B,respectively,showed that the early heading of sgp(t)is governed by a semi-dominant mutant gene.The extremely earliness plants and lateness plants in F2 segregation populations derived from the cross sgp(t)/93-11 were used for molecular mapping of the sgp(t)gene using molecular markers.First,the sgp(t)locus was preliminarily mapped between marker RM3628 and marker RM439 in the region of the long arm of chromosome 6.Subsequently,new SSR and Indel markers were developed using published rice genome sequence and the gene was further mapped between markers NSSR0699 and NSSR0692,within 75.8 kb region The mapping result suggested that the sgp(t)gene differed from the other earliness and lateness genes in rice.So,the sgp(t)gene was a new gene controlling rice growth period.