Genetic Structure of Soybean Landraces (Glycin max (L.) Merr.) and its Changes During On-Farm Conservation

One of the main issues in plant breeding is the knowledge of situation of conservation in plant genetic resources. This research was conducted to study on on-farm conservation efficiency by using molecular markers and morpho-phenological traits in soybean landraces. The subjected plants had been collected in two times with 10 years intervals. Twenty-eight accessions were planted in a field and subsequently characterized their traits according to standard descriptors. Eighty samples of DNA were extracted by the CTAB method, then RAPDs fragments were produced using 24 10-mer(base) selected-primes. Data was used in the cluster analysis as well as to estimate genetic variability within accessions using NTSYS and SPSS softwares. These analyses showed the genetic relationships among accessions. In the dendrogram, only in one accession the individuals in the new and old accessions appeared in the different clusters. These two accessions were different in their morpho-phenological traits too. Genetic variability coefficients in the new landraces were higher than the old ones, exception to one landrace. As soybean is highly self-pollinated (99.9%) crop, high genetic variability in the new landraces could not due to allo-pollination by foreign pollen. But, it could be because of seed exchange by farmers. In this research was shown that the genetic variability coefficient within the improved line is too much less than landraces. Also, this research showed that on-farm conservation could not conserve genotypes, on the other hand this type of conservation will cause some changes in genetic structures of genetic resources during the times.