Journal of Plant Physiology and Breeding
Volume:2 Issue: 2, Summer-Autumn 2012

In order to investigate the effect of Cd and Zn on uptake, concentration and the translocation factor of the Cd and Zn in the rice plant, a factorial experiment was conducted with four factors including two rice cultivars of Vandana and Hashemi, two waterlogged and non-waterlogged conditions and three levels of Zn and Cd (0, 5 and 10 mg kg-1 soil). The experiment was carried out in a randomized complete blocks design with three replications in the greenhouse conditions. According to the results, by changing water regime from waterlogged to non-waterlogged condition, the Zn concentration of root and shoot and the Cd concentration of root were decreased in Vandana cultivar but Cd concentration of shoot was increased and exceeded from the critical level. Zn application caused an increase in Zn and Cd content of shoot, but caused a decrease in Cd concentration of shoot and root. Cd application caused an increase at the first concentration and then decreased the Zn concentration of shoot and root. With increasing the level of Cd, the Cd concentration of shoot and root and the Zn concentration of root increased at the first concentration of Cd and then at decreased at the second level. By application of Cd in each Zn level, the translocation factor of Zn and Cd were decreased.

Two different propagation procedures including aeroponics and soil systems were compared for the minitubers production in potato. The minitubers were evaluated for several quality characters. The plant materials were from three cultivars, Agria, Marfona and Savalan. The plantlets were grown in aeroponics and soil production systems at a plant density of 100 plants per m-2 and stem length, root length, stem diameter and yield were measured in both experiments. In the other experiment, germination, stem length and yield were measured for minitubers which were produced in aeroponics production system. Analysis of variance indicated that the main effects of cultivar and production system were significant for stem length, root length, stem diameter and yield. Also cultivar by production system interaction was highly significant at 0.01 probability level for stem length, root length and minituber yield of the plants. The aeroponics system led to increase in stem length, root length, stem diameter and yield. Cultivars Agria in terms of stem length and Marfona in terms of root length, stem diameter and minituber yield were the most favorable genotypes obtained from aeroponics production system. Minitubers of Marfona had more yield and better quality characters. It seems that cultivar Marfona could be considered as the most favorable genotype due to high performance in minituber production and having quality characters after planting.

Water stress effects on winter and spring leaves anatomy were investigated in experiments conducted at the experimental field of SB University of Kerman using five wheat cultivars.Xylem and phloem elements diameter and mesophyll, bundle sheath and epidermal cells area were measured in transverse sections prepared from middle parts of the leaves. Results showed that significant difference exists among genotypes in terms of anatomical characteristic.Results alsoshowed that water stress changes the diameter and the surface area of the cells. However, the changes were not the same in winter and spring leaves. The changes in some cases such as xylem vessels diameter were considerable.For example, in cultivars Azar2 and Azadi, winter leaves had bigger xylem vessels under water stress compared to the normal condition while in spring leaves the xylem diameter was smaller under the same condition.

In order to analyze general and specific combining abilities and gene effects in sunflower for some agronomic traits, five CMS lines and four restorer lines (tester) were crossed in a line × tester scheme. Hybrids were evaluated in a randomized complete block design with three replications in the Agriculture Research Station, University of Tabriz, in 2009 and 2010 growing seasons. Plant height, head diameter, empty seeds per head, days to beginning of flowering, days to maturity, stem diameter and 1000 seed weight were found to be controlled mainly by additive gene effects and over-dominance effect was important for days to end of flowering. Oil yield, oil percent, head dry weight, seed weight per head, seed yield and hulled seed yield were under the control of both additive and non-additive effects. CMS lines 52, 148 and testers R50, R25 were best general combiners for seed and oil yield. The hybrid combination of R50 × 222 showed high specific combining ability for seed and oil yield.

Genetic diversity of five improved varieties (Kaysari, Kadi, Ranger, Mesmir, Sea-River) and seven Iranian landraces (Gharayonje, Amozeynadin, Rahnani, Tazekand, Shazand, Hamedani, Yazdi) of alfalfa were assessed using Esterase (EST), Peroxidase (POX), Glutamate Oxaloacetate Transaminase (GOT) and Malate Dehydrogerase (MDH). GOT and MDH were monomorphic, whereas EST and POX showed polymorphic banding patterns. In total, four allozyme loci were detected for EST and POX. There were no significant differences between improved varieties and landraces for allelic frequency in the polymorphic markers. However, average heterozygosity in landraces (0.623) was higher than that of improved varieties (0.594). Genetic distance among populations was less than 0.02. FST of landraces versus improved varieties was 0.003 showing no differentiation based on the studied marker systems. The value of FIS was about 0.089, which indicated that inbreeding effect was larger than the genetic drift in alfalfa. Applying test showed that Hamedani was significantly different from nine varieties and Shazand from seven varieties. Based on cluster analysis, alfalfa landraces and improved varieties were not arranged in separate groups. This means that there were not appreciable differences between these groups for allozyme markers.

In order to study the inheritance of grain yield and its components in bread wheat, two cultivars, Karchyya(drought and salinity tolerant) and Gaspard (sensitive to drought and salinity stress) were crossed.Parents together with F1, F2, F3, BC1and BC2 generations were evaluated using a randomized complete block design with three replications in 2008-2009 growing season.Grain weight per spike, number of grains per spike, 1000 grain weight, number of spikes per plant and grain yield per plant were recorded. Analysis of variance indicated significant differencesamong generationsforall traits. Mid-parent heterosis for number of grains per spike and high-parent heterosisfor rest of the traits indicated the role of dominance gene action in governing the studied characters. Furthermore, estimates of degree of dominance was in the over-dominance range for all traits. Based onthe generation mean analysis and the subsequent joint scaling test,additive-dominance model wasinsufficient for explaining the inheritance of the agronomic characters under study. Therefore, different models consisting of four to six parameterswere fitted to the generation means.Considering all traits, at least one epistaticeffect was significant in the fitted models.These results suggest the importance of non-additive gene action in controlling the grain yield and its components in the terminal water stress condition. Therefore, breeding programs utilizing this type of gene action are recommended if hybridization problems could be solved in this important crop. The broad-sense and narrow-sense heritability of the traits were estimated from 0.31 to 0.42 and from 0.10 to 0.42, respectively. The narrow-sense heritability of 1000 grain weight and number of grains per spike were higher than that of grain yield per plant. This suggests that selection for grain yield in segregating generations would not be as effective as the yield components such as 1000 grain weight and number of grains per spike.