Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2007 | Volume:14 | Issue:4 (26)|Papers Count:10

The present research was carried out for evaluation of general combining ability of P. atlantica. Parental trees were selected, isolated, pollinated and finally the fruits were harvested, in 2002 and 2004. Some characteristics were measured in seed technology laboratory and remaining seeds were sown and some characters were measured in field. The highest cross abilities for fruitfulness (%) was obtained in crossed female 9 with male 3 and 11, in 2002. The most seed producer belonged to cross 9 female with 9 or 11 as males. The highest germination percentage was found in females 12, 13 and 8 when crossed with all of the males, in 2002. It is worth knowing that female 9 showed a good performance in the most measured characteristics. The highest seed weights were shown to be in crossing of males 8, 10 and 1, in 2004. Meanwhile, the best combiners among maternal trees were 22, 18 and 12. The most superior parents for seed weight production in 2004 were shown to belong to males 4, 8 and 1 and the best maternal combiner trees were 22, 21 According to the results, males number 10 and 11 and females 9 and 13 in 2002, and females 17, 18, 21 and 22 and male 1 and 8 in 2004, have shown to be the superior P. atlantica trees. Thus, in order to improve P. atlantica for achievement of successful seed and seedling production, a pilot plan could be beneficial.

Stipagrostis species are among grasses that are grown mainly in arid areas particularly on moving sand dunes. Several species of the genus are useful in sand dune fixation as well as pasture values. In order to investigate genetic variation by karyotypic characteristics, 4 populations of the genus were studied in this research. To achieve the goals, karyotypic characteristics such as short and long arm length and total length of the chromosomes of the populations were measured. Ratios of the short arms to long arm and long arm to short arm of the chromosomes were also calculated. Principal components analysis was performed on the data to classify the populations based on the first two components of the analysis. The first two principal components were plotted to get scatter plot of the populations. Results of the analysis were used to study the role of the chromosome traits on principal components. Studies showed that the role of chomosome total length, long arms length, and long arms to short arms length ratio with values of 2.20, 0.71 and 0.82 respectively, showed the most effective role in formation of the first principal component. All plot showed that Mashhad population is in a far distance to other populations.

Genetic potential and variation of Jujube (Zizyphus jujuba Mill) ecotypes were investigated. The plants were collected from 15 provinces ofIran with different ecological and geographical conditions and have been evaluated during 1999-2002. Experiments were carried out with 29 ecotypes, using three replicated complete block design in Badiei Station in western part of Qom. Branch angle, stem thorns number, length of longest thorn, length of annual branches, length of annual thorn, border and shape of leaf, length of petiole, length and width of leaf, length and width of new leaf and leaf color were measured. Ecotypes showed significant differences for leaf length and width. Correlation coefficient indicated that branch angle, number of thorn and leaf length together and with other characters had significant correlation. Factor analysis determined four factors that describe 64% of variance. Factor analysis with Varimax method, determined three factors, including leaf shape, new leaf and angle of branch and number of thorn in annual branches. Cluster analysis separated the ecotypes into three groups based on origin sites (Isfahan, Mazanderan and Khorasan). Fars ecotype is originated from Isfahan and Qom ecotype is originated from Isfahan and Mazanderan basis.

In order to study of genetic variation and relationships among yield and quality traits in alfalfa (Medicago sativa L.), seventy two accessions were studied for yield, morphological and quality traits using a lattice design with 4 replications in Alborz Research Center, Karaj, Iran during 2002 to 2004. For dry matter yield (DMY), the accessions Karaj74, Kurdestanl90, Kazakhistan 2198, Ahar 20253 and France 1008 had higher production. The accessions of Karaj 1003, France 1008, Tabriz 248 and Itlay320 had higher values for both yield and quality traits. The results of path analysis showed that plant height and tiller number had a direct and positive effects and flowering date had an indirect and negative effect on DMY production. Results of principal components analysis accounted for 68% of total variation for first four components. Crude protein, dry matter digestibility, water soluble carbohydrates, acid detergent fibers were recognized as the important traits in the first components. In the second component, plant stand, plant diameter, DMY were the most important traits. The accessions were classified into 7 groups based on Ward's clusters method. Accessions in cluster 1 had higher DMY production, lower quality and early flowering date. Accessions in cluster 2 had lower quality, higher stand and higher insect resistance. Accessions in cluster 3 had medium values for quality, but higher values for DMY, in cluster 4 had higher quality but medium production, in cluster 5 had lower production, higher quality and late flowering date and in cluster6 had early flowering date and medium values for both DMY and quality traits and finally accessions in cluster7 had lower values for both DMY and insect sensitivity.

In this research 7 accessions of 2 perennial Trigonella species (5 T. elliptica accessions and 3 T. tehranica accessions) evaluated for forage quality in Estahban Research Station, Fars, Iran. Amounts of crude protein, crude fiber, total ash, fat, calcium and phosphorous were determined. Accessions showed significant differences (P<0.01) for all of the traits The lowest protein content (10.7%) belonged to accessions 7271 of T. elliptica and 770 of T. elliptica. The highest protein content (14.87%) belonged to accession 5310 of T. elliptica. The highest Ca content (2.5%) belonged to accession 76 of T. tehranica. The highest phosphorous content (0.57%) belonged to accessions 7271 of T. elliptica and 103 of T. tehranica. The highest of crude lipid (21%) belonged to accession of 162 T. elliptica. Cluster analysis classified the accessions into 3 groups and the similarity between accessions was 27.66 percent. The results at this study showed that accession 460 of T. elliptica with the highest protein content and the lowest crude fiber may be introduced as the best accession for forage quality.

The research was carried out in a split plot experiment based on complete block design with 4 replications, Zahedan, Iran. Stress responses were evaluated in 4 Atriplex speciesgrown under 3 salinity levels. The crude protein (CP), ash, Na, K, Cl, Ca and Mg contents of the aboveground (plant shoot) biomass was determined. Dry matter yields of A. leucoclada, A. canescens, A. lentiformis and A. verrucifera were 126.29,75.71,60.70 and 4.18 g/plant respectively. The maximum CP content (3.82%) was achieved in A. canescens, while the highest ash content (29.172%) was obtained from A. verrucifera. The highest Na content (6.052%) was recorded in A. leucoclada. The highest K content (1.991%) was achieved in A. canescens. The highest Cl content (6.157%) was observed in A. verrucifera. Maximum Mg content (1.402%) was obtained in A. verrucifera. The highest Ca content (0.517%) was observed in A. lentiformis. The results showed that the average quantity of Atriplex forage was not affected by different salinity levels. However, there was significant difference between species. The highest ability for forage production and quality under salinity was obtained in A. leucoclada.

The experiment was conducted under laboratory and natural condition for evaluation of seed germination characteristics in 2 Bromus ecotypes and 5 Agropyron species collected from different parts of Iran. Seeds samples were treated with spores of Fusarium graminearum (114x104/ml and 57x104/ml) and F. avenaceum (152x104/ml and 76x104/ml). Germination percentage, and speed, root/shoot ratio, dry/fresh weight ratio and vigour index were determined in the inoculated seeds, as well as in control (non-inoculated seeds). Significant differences for the above characteristics were observed between plant genera, species and ecotypes and also between 2 Fusarium species. At both densities of F. avenaceum spores, all of triats were decreased in treated seeds at laboratory except for root/shoot ratio. At natural  condition, there were no significant differences among agents of infection compared to control. In general, the seed contamination was higher in laboratory. Percentage and speed of seed germination and vigour index were higher in A. intermedium and A. elongatum comparing to other Agropyrone species and both B. persicus ecotypes. The higher density (114x104/ml) of F graminearum spores showed the highest effect on percentage and speed of germination and vigour index in all of species and ecotypes.