مجله بیوتکنولوژی کشاورزی
سال هشتم شماره 4 (پیاپی 24، زمستان 1395)

In the physiological study of stem remobilization of assimilates during grain filling, mutant genetic materials are a valuable tool. Two advanced mutant lines of bread wheat (T-67-60 and T65-7-1) along with their wild type (Tabasi Cv.) were planted at two moisture conditions (normal and 30-40% of field capacity) as a factorial experiment based on a completely randomized design with three replications. Drought treatment initiated at full heading stage (Zadoks 60) and sampling done at 5 steps (0, 7, 14, 21 and 28 days after anthesis). Based on the results remobilization of stem and its efficiency in the mutant lines was significantly more than wild type, under terminal drought stress. The reasons for this were higher capability of the sink and early senescence in the mutant lines compared to the wild type. In consequence of changes in chlorophyll content and relative gene expression of key photosynthetic Rubisco (Rubisco large and small subunits and Rubisco activase), in the genotypes during grain filling seems degradation of chloroplasts and photosynthetic system occurred caused by senescence drought stress-induced in the mutant lines more strongly than in the wild type, and because of senescence is stimulating remobilization of assimilates from stem to grain, remobilization of stem and its efficiency in mutant lines were more than wild type. Also, wild type further with continuation of current photosynthesis in the leaves has acted for the grain filling.

Multiplication of pear cultivars using conventional vegetative propagation techniques such as soft or hard wood cuttings is difficult. Therefore, the possibility of micro-propagating 10 Iranian native pear cultivars and the establishment of their in vitro collection were studied. In vitro cultures of these cultivars, established using single node soft cuttings on MS Medium supplemented with BAP (1 mg/l) and NAA (0.1 mg/l), were evaluated for growth characteristics. At this stage, time to shoot induction in cvs Ghosi and Natanzi with the mean of 4.75 days was the shortest and in cv Khooj with 20.75 days was the longest, among all cultivars examined in this study. Cultivars Ghosi and Natanzi also produced the highest number of leaves ( 4.25 and 3.25, respectively) and the highest shoot height (9.25 and 6.5 cm, respectively). Micropropagation of in vitro grown plantlets were then studied by assessing 21 days old Micropropagated plantlets on the modified QL medium containing growth regulator combination of BAP (1mg/l), NAA (0.1 mg/l), Zeatin (1mg/l) and 2ip (1mg/l). Cultivar Ghosi produced plantlets with an average of 3.75 leaves and the average height of 4.27 cm, showing the highest growth rate. On the other hand, plantlets of cvs Beiruti and Shahmiveh with an average shoot height of 1 cm showed the lowest growth among the cultivars examined. Modified QL media supplemented with different concentrations of Auxin, IBA, were used for rooting of four selected pear cultivars. NO roots was observed on any of the four cultivars, cultured on media with IBA concentrations of 0.5 and 2.0 mg/l, while all selected cultivars rooted on the medium containing IBA with concentrations of 1mg/l. The highest mean number of roots (6.33) was produced in cv Ghosi and the lowest in cv Sardroodi (1.66). Root length was the highest in cv Shahmiveh and lowest in cv Sardroodi. The results of this research work showed that Iranian native pear cultivars can easily be micopropagated under in vitro conditions, but their growth and multiplication characteristics is genotypic specific. This research also successfully established the first Iranian in vitro collection of native pear genetic resources.

Barley is one of the world's grain is the most important corps after maize, wheat and rice.In order to spike and grain mapping in F3 and F4 families in Becher × Kavir cultivars cross in barly population of 103 families with parents in a randomized complete block design with three replications 2014-2016 during two growing seasons. Assessment transgressive segregation was observed that the existence of different allele combinations in their parents. Linkage map were prepared using SSR, iPBS, IRAP and ISSR marker that it covered 640 cM of barley genome. The distance between two markers 9.69 cM were estimated. Composite interval mapping identified fifteen QTLs in F3 and F4 families. QTLs for awn length, grain diameter and grain length was located in both F3 and F4 families. For grain length and number of spikelets in the F4 families was identified the major effect QTL by R2 12.2 and 15, with the percentage LOD 3.62 and 2.9 in 3.5 and 2.5 cM distance markers. Length grain and grain diameter were linked and co-location iPBS2076-5 markers in the F3 generation. co-location QTLs For awn length, number of spikelets, grain length and grain diameter identified. QTL identification characteristics of the controller can be effective in improving performance. It is expected to be followed by validation in various places and populations identified QTL in this study programs used in marker-assisted selection and accurate positioning.

Diacylglycerol acyltransferase 1 (DGAT1) is a microsomal enzyme that accelerates the final stage of the synthesis of triglycerides, means converting diacylglycerol to triacylglycerol. The aim of this study was to investigate polymorphism in exon 17 of the DGAT1 gene and their associations with milk fat percentage in Kurdi sheep breed in Hussein Abad breeding station of Shirvan. Hence, milk records of 100 ewes were randomly selected and milk fat percentage was measured by Total Eco milk device. Indeed, ewe DNA was extracted and amplified by specific primers for a 309 bp fragment of exon 17 of this gene. Genotypes were determined by PCR-RFLP digested with AluI endonuclease enzyme. Frequencies of C and T alleles were 0.65 and 0.35, respectively. Statistical analysis was conducted by GLM procedure of SAS 9.1 software and showed significant association of genotypes with milk fat percentage (P

Asymmetry is an indicator of genetic and environmental stressors in organisms and plays an important role in developmental instability. It is suggested that symmetrical individuals do generally have faster growth, higher fecundity, and better survival. To identify Quantitative trait loci affecting some asymmetric traits in Japanese quail, a three-generation resource population was developed by using two distinct Japanese quail strains, wild and white. Eight pairs of white (S) and wild (W) birds were crossed reciprocally and 34 F1 birds were produced. The F1 birds were intercrossed to generate 422 F2 offspring. All of the animals from three generations (453 birds) were genotyped for eight microsatellite markers on chromosome 1. Bone length measured by a digital caliper and bone weighed with an accuracy of 0.1 g. QTL analysis was conducted applying the line-cross model and the least-squares interval mapping approach. Among 12 examined traits, 6 QTL were identified in 59, 70, 134, 156, 164, and 184 cM on chromosome 1. Variance of detected QTL was ranged from 0.37 to 5.29%.

Plants require different defensive mechanisms for being survive and tolerance to environmental stresses. In present study, activity of defensive enzymes such as alternative oxidase (AOX), superoxide dismutase (SOD), catalase (CAT), electrolyte leakage index (ELI) and hydrogen peroxide (H2O2) amount as a cellular damage indices in two genotypes of chickpea, susceptible (ILC533) and tolerant (Sel96Th11439) under 4°C cold stress was evaluated. Statistical analyses results showed that there is a significant difference between genotypes under cold stress. Under cold stress, decrease in damage indices was accompanied with an increase in AOX activity. The maximum activity of AOX was seen in tolerant genotype on sixth day of cold stress, whereas under such conditions AOX activity in susceptible genotype significantly was lower compared to tolerant genotype. The increase in AOX activity which was accompanied with a decrease in cellular damage (ELI and H2O2 results) particularly on sixth day of cold stress showed the significance of AOX enzyme in tolerance of chickpea plants to cold stress. The simultaneous and significant increase in SOD and CAT activities along with confirmation the results of AOX activity increased degree of genetic tolerance of chickpea to cold stress or plant recovery after exposure to cold stress. These indices may be useful in assessment of chickpea genotypes under cold stress or utilization them in breeding programs.

When plants are exposed to stressful environmental conditions, the production of reactive oxygen species (ROS) increases and can cause significant damage to the cells. Antioxidant defense systems, which can detoxify ROS, are present in plants. In this study, the changes in expression profile and enzyme activity of superoxide dismutase and ascorbate peroxidase were analyzed in chickpea seedlings in response to different concentrations (0, 0.5, 2.5, 7.5, 12.5, 25 and 50 mM) of cadmium chloride. The results showed that in Chickpea plants, the SOD and APX were induced both at mRNA and enzyme activity levels in leaves of seedlings in response to cadmium overload. The enzyme activity of SOD and APX and mRNA transcript levels of Cu/ZnSOD and APX increased significantly at low and medium cadmium levels but decreased gradually throughout on increasing cadmium concentration from 12.5 to 50 mM. It was concluded that the enzymatic antioxidant defense system in chickpea played a major role in its response to cadmium tixicity.