Showing 2 results for Genetic Distance
F. Shokoohifar, A. Bagheri, M. Falahati Rastegar,
Volume 7, Issue 2 (7-2003)
Abstract
The poor information available on variation of Ascochyta blight fungus is the most important factor limiting chickpea breeding programs for resistance to blight disease. In this study, efforts were made to detect genetic variation of the pathogen in Iran. The RAPD marker was employed to evaluate 26 isolates collected from 16 provinces. Twelve random primers were used to analyze genomic DNA of the isolates. Only ten primers showed polymorphism among isolates. Primer OPK-01 defined the highest number of polymorphism and primer OPK-09 confirmed relatively low degree of polymorphism. On the basis of this molecular marker, the estimated genetic diversity index was 98% and the pair-wise genetic distance of the isolates varied from 0.16 to 0.61. The least genetic distance belonged to isolates 20 and 22 from Qazvin and Golestan while the highest distance belonged to isolates 26 and 12 from Mazandaran and Markazi. The phylogenic tree was constructed by cluster analysis and all the isolates grouped to 22 genetic clusters at the 90% similarity level. The genetic groups were named from A to V and their distribution in Iran was determined. The results revealed that genetic variation among Iranian population of the pathogen is very high, and further that RAPD is a vigorous tool for genomic analysis of Ascochyta rabiei.
M. Talebi Bedaf, B. E. Sayed-Tabatabaei, K. Razmjoo, B. Shiran,
Volume 10, Issue 2 (7-2006)
Abstract
Identification of grass species seems difficult due to the morphological similarities. However, selecting desirable parental genotypes of the crosses based on the genetic distances is considered as the most critical step in a breeding program. The aim of this study was to characterize grass species using AFLP techniques. Five species with five cultivars from each were selected and studied using AFLP reactions performed by PstI and MseI restriction enzymes. The obtained data was analyzed using NT SYS-pc Ver. 2.02 software and Jaccard’s method. Ten primer combinations amplified 1170 bands, all of which were polymorphic between cultivars and species. The maximum band (168) and the minimum number of band (81) were produced by P-AAG & M-CAG and P-ACT & M-CGC, respectively. The results also distinguished 5 species in 40% of genetic distances. Some of the markers were special to some special species that can be used in the identification of that species. Additionally, the results showed that AFLP techniques robust and efficient tools for the identification of genetic relationships of different genotypes within species. High levels of bands and polymorphism make AFLP one of the most powerful markers in the determination and classification of species and different cultivars of grass.
