Showing 3 results for Genetic Variation.
A. Dehdari, A. Rezai, M. Mobli,
Volume 5, Issue 2 (7-2001)
Abstract
In order to evaluate the morphological and agronomic characteristics of 19 land races of onions and one foreign cultivar (Yellow Sweet Spanish), an experiment was conducted in 1998 at the Research Farm of the College of Agriculture, Isfahan University of Technology.
Analysis of variance showed significant differences among genotypes for all of the morphological and agronomic traits. Dry weight and number of days to emergence had the highest and lowest coefficients of genetic variability, respectively. Plant fresh weight, yield of 30 plants and total yield also had high coefficients of variability. Broad sense heritability estimates were high for all of the traits, indicating low environmental affects them. Based on cluster analysis and plot of the first two canonical variables, the genotypes were classified in four groups with different agronomic traits. Canonical discriminant analysis based on nine agronomic traits introduced three canonical variables which justified 99.9 percent of the total variation among characters. Principal component analysis revealed four components while factor analysis showed three factors which explained 87.3 and 95.5 percent of the total variation among characters, respectively. The first and second factors were related to adaptation and assimilate translocation, respectively. Bulb diameter, bulb height and bulb weight in positive directions and sensitivity to Fusarium in negative direction had greater loads in the third factor.
T. Najafi Mirak, A. Zali, A. Hossainzadeh, Gh. R. Rasoulian, A. Saeidi,
Volume 7, Issue 4 (1-2004)
Abstract
Russian Wheat Aphid (RWA) is a serious pest of wheat, barely and other small grains in cereal-producing regions of the world. The use of resistant cultivars is an effective management strategy to control this pest. In this study, 15 lines and 13 cultivars of durum and bread wheats along with two resistant and susceptible controls were used to evaluate their reaction to RWA under greenhouse conditions, using completely randomized design with four replications. Three seedlings at each plot were considered as an experimental unit. Five aphid nymphs (4-5 ages) were placed on each plant at 1-2 leaf stage. Leaf rolling and leaf chlorosis percentages were measured 21 days after infesting and used to screen the genotypes. Despite the relatively high linear correlation between two resistance components, leaf rolling and leaf chlorosis, estimated as 80%, analysis of variance indicated significant differences among genotypes. Eight durum lines DW9, DW14, DW4, DW2, DW7, DW8, DW12 and DW3 and one bread wheat cultivar (Azadi) were significantly more resistant than the resistant control (Halt). One durum line (DW13) and two bread wheat cultivars (Shiroodi and M-75-7) had higher leaf rolling and leaf chlorosis than the susceptible control (Sholeh). So they were selected as the most susceptible to the biotype of D. noxia. under study. Orthogonal comparison showed that durum lines were more resistant than bread wheat cultivars. These results were confirmed by Cluster Analysis based on leaf rolling and leaf chlorosis.
A.r. Khanahmadi, Gh. Rahimi, A. Nejati-Javaremi, S. Esmaeilkhanian,
Volume 11, Issue 40 (7-2007)
Abstract
In order to detect genetic variation of native fowls in Mazandaran native Fowls breeding station, blood samples were collected from 100 male and female of birds (1:11). The DNA of the blood samples was extracted according to an optimized salting out protocol. The extracted DNA was amplified through polymerase chain reaction (PCR). Of the twenty random primers (10 mer) were used in this study, fourteen yielded satisfactory PCR. The total 63 polymorphic and 77 monomorphic bands were detected for the 14 primers. The number of bands displayed for each primer ranged from 4 to 16 with 200-2100 base pairs. The highest and lowest percentages of polymorphism band were observed for primer 9 (72%) and primer 14 (16%) respectively. The band sharing frequency was calculated for each primer, which ranged from 79 to 96. The genetic similarity within population and genetic variation were estimated as 89 and 11 percentage respectively. In conclusion, the existence of high level of polymorphism after ten generation of selection may indicate the accuracy of genetic evaluation program, suitable selection strategies and also large enough effective population size in this breeding flock.
