Autumn sowing of sugar beet is a suitable way in sustainable agriculture. Bolting is an undesirable phenomenon which reduces sugar beet yield and it is the most important limiting factor in autumn sowing of sugar beet. Identification and comparison of the sequence of flowering genes in various genotypes can help to understand the molecular mechanisms controlling bolting. In the previous studies, it was revealed that expression level of FT1 and VIN3 genes in sugar beet is associated with bolting resistance. In this study, the sequence of FT1 gene promotor and three versions of VIN3 gene promoters of sugar beet were compared in three bolting resistant and three bolting susceptible genotypes. Primer design for each gene was carried out using the DNA sequences found at the NCBI database. DNA was extracted from leaf samples growing in pots and was used as template in PCR reactions. Similar length of amplified fragments for each promoter gene in bolting susceptible and bolting resistant genotypes were selected and sequenced for more accurate assessment. There was no mutation in the FT1 gene promoter, however 624 substitution and insertion/deletion mutations were observed in the promoter of three versions of VIN3 gene. A 228-bp ins/del region was detected in the VIN3-like1 promoter. This region contains promoter elements and seems to have a control function. Comparison of detected mutations between susceptible and resistant genotypes did not show a distinct pattern for bolting.

Mutagenesis has been one of the important sources of genetic diversity and Plant mutants can be important bio-resources for crop breeding and functional genomics studies. Breeding conventional methods for generating of genetic variability are of low efficiency. We showed that treatment of seeds of rice(Hashemi cultivar) with 0.8% EMS for 8 h caused visible phenotypic variations on M2 rice mutant genotypes including flowering date, plant height, number of fertile tiller, panicle length, number of filled and unfilled grains per panicle, grain width and length, 100 grain weight and grain yield. The phenotypic variation coefficients of most traits found to be more than the genetic variation coefficients. The number of filled grains per panicle and seed length had the highest and lowest general heritability, respectivly. The seed yield had also high heritability. Analysis of correlation between different characteristics in the mutant genotypes showed that the number of fertile tillers and the number of unfilled grains per panicle had positive correlation with yield. Also, grain yield exhibited positive and significant correlation with panicle length, number of tillers and number of filled grains at genotypic level. In multiple regression analysis by stepwise method, number of tillers, number of filled grains per panicle, 100-grain weight, and grain width entered into the model, respectively, that explained 96 percent of grain yield variations. Results of grain yield and its components path coefficient analysis showed that the number of tiller had the highest direct effect (0.77) through than other traits on grain yield and, therefore it can be considered as major trait in grain yield improvement in rice. Also, based on results of this research and by using optimal selection index, mutant genotypes EM 18-17-5 and EM 15-14-1 were selected as superior mutant genotypes. This mutant population is expected to be serves as a genetical resource for understanding rice biology as well as for use in genetic improvement of quantitative traits.