فهرست مطالب الهه برومند رضازاده

 Cumin is one of the most important medicinal plants in Iran and is widely used in food, health and beauty industries due to its antioxidant and antibacterial properties. Yield of some crops are higher in autumn planting compared to spring. However, low temperature and inappropriate distribution of precipitation are of factors affecting seedling emergence and establishment. So it seems that seeds with higher germination also have better emergence and establishment producing more vigorous seedlings in further growth stages. So, to success in autumn-planting of cumin, it is necessary to have ecotypes with appropriate and even emergence in low temperature and water restricted conditions. Since water is of high paramount importance in germination and lower water potentials lead to lower accessibility of water to seeds, the aim of this experiment was to study seed germination response of different cumin ecotypes to low water potentials.

This study was conducted to determine the germination of six cumin ecotypes under drought stress and low temperature conditions. Treatments comprised of six cumin ecotypes (Torbat-e-Heydarieh, Khaf, Sabzevar, Qaen, Quchan and RZ19) and seven water potentials (0, -1, -2, -3, -4, -5 and -6 bar) induced by  PEG6000 solution according to Michel B. E. and Kaufmann (1973). Distilled water was used for control. Seeds were disinfected by sodium hypochlorite (10%) and fungicide and were rinsed with distilled water. 25 seeds were placed in each petri dish and were incubated in 13°C after PEG solution or distilled water was added. Germinated seeds were recorded daily and germination percentage and rate, plumule and radicle length was determined at the end of the incubation. Ecotype ranking was also performed to determine the most tolerant ecotypes to drought stress. Statistical analysis was done using MSTAT-C and LSD test was used for mean comparison.

This study results indicated that water potentials was significantly affected all studied traits (p<0.05) in a way that germination percentage and rate and plumule and radicle length decreased as water potential decreased to -6 bar. Maximum germination percentages (61%) was obtained in control. Significant differences were also found among cumin ecotypes for all traits. Khaf and Torbat-e-Heydarieh had the highest germination percentage (25% and 23%, respectively). Decreasing water potential from 0 to the -2 bar, caused 69% decrease in germination percentage of Quchan ecotype whereas reduction of 43% and 57% was found in Qaen and Sabzevar ecotypes, respectively. Difference in germination percentage among genotypes may be due to the different water absorption by them. Ecotypes had different germination rate in water potentials (P≤0.01). Although germination rate was negatively affected by decreasing water potential, percentage of reduction was different among ecotypes in a way that Torbat-e-Heydarieh and Khaf showed the lowest (61 and 67%) and Quchan and RZ19 the highest reduction of germination rate (86%) in -4 bar compared to control (0 bar). Plumule and radical length were decreased as drought stress was increased . Decreasing water potential from 0 o -4 bar caused a 76% reduction in radical length. Significant difference was found among ecotypes according to radical length in a way that Khaf and Quchan had the highest and lowest radical length, respectively.

On the basis of ecotypes ranking for evaluated traits, Khaf and Torbat-e-Heydarieh indicated more tolerance to drought stress whereas Quchan was found as a sensitive ecotype.

In temperate climates, cool-season plants are usually grown in autumn. Due to the proper establishment of the plant in autumn, better use of rainfall, and avoidance of late-season heat and drought stresses, autumn planting leads to better plant stability and yield compared to spring planting. In chickpeas, autumn sowing increases plant height and nitrogen fixation. Scientists believe that autumn cultivation of chickpea leads to higher yields due to the longer vegetative growth period and coincides with the reproductive growth period with favorable humidity and temperature conditions. On the other hand, studies have shown that in severe freezing temperatures in cold regions, chickpea has a lower tolerance threshold than autumn cereals. This study aimed to evaluate the freezing tolerance of chickpea genotypes -desi type- in field conditions to select superior genotypes for autumn cultivation.

This study was conducted in the research farm station of the Faculty of Agriculture, the Ferdowsi University of Mashhad in 2018. In this study, 255 desi type genotypes and a Kabuli type genotype (Saral) as control were evaluated in a Randomized Complete Block Design with three replications. Seeds were provided from the Mashhad Chickpea Collection (Seed Bank of Research Center for Plant Sciences, Ferdowsi University of Mashhad). Planting was done in October with a density of 30 plants per square meter. Irrigation was done in three stages including immediately after planting, 14 days after the first irrigation, and at the flowering stage. To determine survival percentage, the number of plants for each genotype was counted 30 days after emergence and immediately after winter. Genotypes were classified into four groups (0-25, 26-50, 51-75 and 76-100% survival). Plant height, plant length, lowest pod height, number of branches, number of pods per plant, percentage of filled pods, plant dry weight, grain weight per plant, 100-seed weight, biological yield, grain yield, and harvest index were measured at the end of the growing season.

The lowest minimum temperature during the growing season was -12°C. Results showed that among 255 genotypes, 25 genotypes were lost before freezing stress and 20 genotypes were lost by freezing stress. Significant differences were observed among the genotypes in terms of plant height, plant length, lowest pod height, number of branches, number of pods per plant, percentage of filled pods, plant dry weight, seed weight per plant, 100-seed weight, biological yield, grain yield, and harvest index. The survival percentage of 39 genotypes was between 76 to 100%, 75 genotypes between 51 to 75%, 61 genotypes between 26 to 50%, and 55 genotypes less than 25%. Ten genotypes (MCC373, MCC658, MCC755, MCC212, MCC83, MCC864, MCC371, MCC756, MCC749 and MCC885) had a survival percentage higher than 90%. Plant height in 21 genotypes was higher than 50 cm and the lowest pod height in 47 genotypes was more than 15cm. The number of branches per plant increased as the survival range increased. Also, in different survival ranges, grain yield decreased as survival percentage decreased. The average grain yield in the survival range of 100-76% was 257 g.m-2, which was 24%, 2.5, and 8.6 times higher than the survival ranges of 51-75, 26-50, and 0-25%, respectively. No significant difference was found among survival ranges of 100-76, 75-51, and 50-26% according to the harvest index.

The results of cluster analysis of chickpea genotypes desi type under autumn cultivation showed that 230 studied genotypes were divided into four groups. The four groups included 106, 24, 43, and 57 genotypes, respectively. Standardized canonical coefficients of all traits except, the percentage of filled pods, seed weight per plant, 100-seed weight, and harvest index were significant in the first canonical diagnostic equation. These results show that these traits have the greatest impact on the diversity between genotypes. Based on the results of the analysis of the variance of groups, except for the percentage of filled pods and harvest index, a significant difference was observed between the groups in all studied traits. A comparison of the means of the groups showed that the genotypes of the second group had the highest mean survival percentage and then the fourth group was in the next rank. The difference between the means of these two groups with the total mean was 17.7 and 16.4%, respectively. The genotypes of the second group were superior to the genotypes of the other groups in terms of biomass yield and grain yield and produced 1252 and 606 g.m-2 more than the total average, respectively, then the genotypes of the fourth group were superior to the genotypes of the other groups. In general, due to the high yield in the cold-tolerant genotypes, autumn cultivation of desi-type chickpeas seems to be economical.

The agricultural sector needs to reduce the use of freshwaters and using low quality waters instead of increasing demand for domestic and industrial water uses, along with the reduction of groundwater level. Therefore, using saline water in the future for agricultural production is unavoidable. The soil fertility has been reduced due to decreasing the quality of water resources and increasing salinity in agriculture lands. Saline water and saline soil contain high concentrations of salts such as calcium sulfate and sodium carbonate, although sodium chloride is the dominant salt. Salt stress affects various physiological and metabolic processes in plant and may eventually impede crop production depending on the extent and severity of the stress. In the early stages, a high concentration of solutes present in the soil brings about osmotic stress which reduces the capacity of root systems to absorb water and, that start the loss of leaves water. This is accompanied by ion-specific effects that cause the accumulation of toxic concentration of Na+ and Cl− in the cells, which manifest in the form of chlorosis and necrosis. Planting legumes in saline soil is important for conservation of sustainability of production. However, legumes, including chickpea, show low-salinity tolerance and loss yield in saline conditions. To permit crop growth on natural saline soils considerable enhancement of salinity tolerance could be required for the chickpea which is a relatively salt sensitive legume. Therefore, identification and introduction of salt tolerated chickpea cultivars help sustainable crop production in moderate saline areas.

This study was carried out under hydroponic conditions in the greenhouse of Research Center for Plant Sciences, Ferdowsi University of Mashhad. The experiment was conducted as a completely randomized design with three replications to evaluate salinity tolerance of 140 Deci-type chickpea genotypes during seedling stage in a salinity level of 12 dSm-1 NaCl. Hoagland solution had been used in the sand culture method. Recirculating nutrient system was applied, nutrient solution was replaced weekly and salinity of nutrient solution was adjusted daily, but no acidity adjustments were made in the Hoagland solution. Four weeks after salinity application, growth stages, height plant, branch number, survival percentage, remained leaves, shed leaves, membrane stability index, sodium and potassium concentration were measured.

Results indicated that survival percentage of 21 genotypes was more than 76% among which, six genotypes of MCC18، MCC22، MCC29، MCC59، MCC136 and MCC430 showed 100% survival. In the survival range of 76-100, 51-75, 26-50 and 0-25%, 43, 57, 42 and 16 percent of genotypes were in the post-flowering stages, respectively. Plant height increased with increasing survival range, so that the genotypes in the survival range of 76-100% were 4, 5 and 12 cm higher than the survival range of 51-75, 26-50 and 0-25%, respectively. The highest plant was observed in MCC59 genotype with 100% survival range. The lowest number of branches per plant was observed in the 0-25% survival range. With increasing survival range percentage of shed leaves decreased and the percentage of remained leaves increased. The same percentage of shed leaves and the remained leaves were observed in the survival range of 76-100% and 51-75%. In three survival range 76-100%, 51-75%, and% 26-50, the shed leaves were about 50%. The highest percentage of remained leaves (73%) was observed in MCC177 genotype with 75% survival. The membrane stability index increased with raise up survival range. There were no difference in survival range of 26-50 and 51-75% in membrane stability index, but in the survival range of 76-100%, membrane stability 6% increased compared to the two previous survival ranges. The highest membrane stability index observed at MCC34 (53%) and MCC179 (52%) with 85%, 51% survival, respectively. However, among genotypes in 100% survival some genotypes, such as MCC29 and MCC136, had a relatively low membrane stability index. With rising up survival range, sodium concentration decreased and potassium increased. Sodium to potassium ratio was also decreased with increasing survival range. Dry matter productions per plant increased with improving survival range. Dry matter from 0-25% to 26-50%, 51-75% and 76-100% survival range, increased 16%, 24%, and 38%, respectively. MCC4, MCC43, MCC22, MCC49, MCC59 and MCC85 had the highest dry matter productions.

The correlation between traits showed the positive correlation between survivals and remained leaves which is depended on maintaining membrane stability and decreasing sodium uptake in plant. Based on this information, chickpea genotypes have salt tolerance mechanisms and it is possible to use these genotypes for breeding programs for moderate salinity stress conditions.

In Iran, clover is the second most important forage crop after alfalfa (Medicago sativa) and is cultivated on a surface of about 70,000 hectares. Yield improvement of this plant could be achieved through autumn cultivation. Iran is still one of the main centers for the diversity of clover species, there is not much information about freezing tolerance of native species of this important plant. Since freezing stress is one of the most important winter stresses which causes severe damage to the plant cells and tissues and ultimately plant death, evaluation of freezing tolerance of this crop could help to determination of the best planting date in order to achieve the highest yield. The aim of this study was to evaluate the freezing tolerance of four clover species through assessment of plant survival and re-growth after freezing stress.

In order to study growth criteria of four clover species after freezing stress in controlled conditions, an experiment was conducted in 2012-13 in Faculty of agriculture, Ferdowsi University of Mashhad. Treatments were arranged as factorial based on Completely Randomized Design with four replications. Factors were included of planting dates (late September and late October), clover species (red clover T. pratense, white clover T. repense, Persian clover T. resupinatum (autumn species) and crimson clover T. incarnatum (spring species) and freezing temperatures (0 (control), -3, -6, -9, -12, -15, -18, -21ºC). Survival percentage, LT50 according to Survival (LT50su), leaf area, Reduced 50% Leaf Area Temperature (RLAT50), dry weight and Reduced Dry Matter Temperature 50 (RDMT50) were measured after three weeks re-growth.

Results indicated that survival percentage was significantly affected by interaction of planting date, species and freezing temperatures. In both planting dates, crimson and white species showed a good survival till -15°C while they were killed as temperature was more decreased to -18°C. In first planting date, two species of red and Persian clover had 50 and 42% survival, but were killed in this temperature in the second planting date. The lowest LT50su in autumn (red, white and Persian) and spring (crimson) species was found in first and second planting dates, respectively indicating higher freezing tolerance in crimson species at second planting date and a better acclimation of autumn species at first planting date which led to a higher survival compared to spring species. Leaf area was significantly affected by planting date, species and freezing temperatures at the end of the recovery period. In first planting date, decreasing temperature from zero to -18°C caused reduction of 98 and 48% of leaf area in red and Persian species while no plant of white and crimson species was survived in this condition. In second planting date, leaf area was decreased about 6, 33 and 2% as temperature decreased from zero to -15°C while leaf area of Persian species, not only was not decreased, but also increased by about 12%. The lowest and highest RLAT50 were observed in Persian and red species. Interaction of planting date and species on RDMT50 was significant in a way that in delayed planting date, RDMT50 was increased in red, Persian and crimson species while it was decreased in white species.

Red and Persian species showed higher freezing tolerance according to indices of survival percentage and LT50su. The highest recovery ability of plants based on leaf area per plant, RLAT50, plant dry matter and RDMT50 was found for second planting date. Also annual species of Persian and crimson had lower RLAT50 and RDMT50 and higher freezing tolerance compared to perennial species of red and white clover.

Low yield and instability, is one of the most important issues in chickpea cultivation. In most regions of Iran, chickpea is mainly planted in spring. Consequently, the plant will be exposed to abiotic stresses such as heat and drought during growth season, especially during the final stages of growth. To increase the chickpea yield, Autumn planting can be used, but low tolerance of common chickpea genotypes to freezing stress is a problem. Therefore, according to the benefits of autumn planting of chickpea, identification of freezing tolerant genotypes of chickpea along with suitable yield is a necessity. In this way, the present study was conducted as a field experiment to assess winter tolerance of 29 deci- type chickpea genotype in Mashhad conditions.

Experiment was conducted as Complete Randomized Block Design with three replications and 29 deci-type chickpea genotypes in research station of Faculty of Agriculture, Ferdowsi University of Mashhad in 2016-2017. Genotypes were supplied from seed bank of Research Center for Plant Sciences, Ferdowsi University of Mashhad and seeds were planted in November 1st. The lowest minimum daily temperature during the growing season was -13ºC. To calculate survival percentage, number of plants werfor each genotype was recorded 30 days after emergence and on March 15th. At the end of the growth season, plant height, number of main and secondary branches, pod number per plant, 100-seed weight, seed weight per plant, seed yield per square meter, biomass, biological yield and harvest index were measured.

significant differences were found among genotypes according to all the studied traits. While only one genotype was entirely killed as a result of freezing stress, survival range differed between 8-100% for the other genotypes. Among all 29 deci chickpea genotypes, 11 genotypes were tolerant (76-100% survival) and five were relatively tolerant (51-75% survival). MCC890, MCC349 and MCC873 had the highest winter survival with 98.1, 95.7 and 95.2%, respectively. In total, 9 genotypes including MCC373, MCC884, MCC869, MCC916, MCC349, MCC386, MCC870, MCC291 and MCC876 produced high yield of 154g.m-2 (equivalent to 1540 kg.ha-1) and all of these genotypes had higher survival percentage than 66.7%, except MCC916. Significant positive correlation were found between seed yield and survival percentage (r=0.76**), number of secondary branches (r=0.23**), pod number per plant (r=0.52**), 100-seed weight (r=0.38**), biological yield (r=0.59**) and harvest index (r=0.58**).

According to the results of the present study, it seems possible to achieve cold tolerant deci chickpea genotypes for cultivation in cold regions. Based on cluster analysis, two groups of genotypes including 1) MCC10, MCC49, MCC207, MCC890 and 2) MCC868, MCC918, MCC884, MCC386, MCC291, MCC349, MCC916, MCC373 can be used in breeding programs due to their superior attributes such as early- season cold tolerance.

Carbon sequestration is defined as the permanent gain of carbon by soil, plant or water. Soil as the largest terrestrial carbon pool plays an important role in the global carbon cycle. Due to the role of agricultural systems in CO2 emission, attention to the carbon cycle in agricultural systems is of prime importance. So, the interest in agricultural soils and plant biomass as a carbon sink and an operational mechanism for reducing the atmospheric CO2 level, is increasing. It is estimated that world’s crop-based agriculture occupies 1.7 billion hectares, which can store up to 170 Pg carbon. Thus, the aims of this study were to simulate the relationship between crop residue decomposition rate with carbon to nitrogen ration (C:N) (an index of residue quality) as well as soil moisture regimes (the most important factors in residue decomposition) and also estimation of the attainable carbon sequestration in irrigated systems of five major crops in Iran based on the simulated model. Residue decomposition rate of wheat, maize, rapeseed, cotton and soybean (with C:N ratios of 131, 69.7, 87.1, 57.8 and 95.9 , respectively)  in different soil moisture regimes (100, 60 and 30 percentage of field capacity) was studied in a 390-day incubation experiment. Study data was used for simulation of residue decomposition and relative decomposition rate was defined as a function of moisture (fm), C:N (fC:N) and temperature (ftemp). The simulated model was used to evaluate attainable carbon sequestration of the studied crops in five years from 2002-2003 to 2006-2007 based on yield, harvest index and shoot to root ratio in three scenarios of residue retention (100, 50 and 0 percentage of total residue produced) as well as three scenarios of soil moisture regimes of 100, 60 and 30 percentage of field capacity for different provinces of Iran. In this step, residue decomposition during one year after harvest was calculated using fm, fC:N and ft. The difference between proportions of the residue returned to the soil and decomposed residues were considered as un-decomposed residue which was multiplied by 0.45 to gain attainable carbon sequestration. Data of attainable carbon sequestration was analyzed as factorial experiment based on completely randomized design. Results indicated that higher C:N and therefore lower residue quality caused lower residue decomposition rate. This parameter was also decreased in soils with lower moisture. Effects of soil moisture on reside decomposition was more pronounced than residue quality. comparison of attainable carbon sequestration in Iran’s provinces revealed that in wheat cropping systems: Kermanshah and Sistan and Balouchestan, in maize: Qazvin and Southern Khorasan, in rapeseed: Isfahan and Boushehr, in cotton: Eastern Azarbaijan and Hormozgan and in soybean cropping system: Ardebil and Eastern Azarbaijan provinces had the highest and lowest attainable carbon sequestration, respectively. Attainable carbon sequestration in all crops was decreased with increasing soil moisture from 30 to 60 and 100% of FC and decreasing residue retention from 100 to 50 and 0 % of total crop residue production. Maize and soybean showed the highest and lowest capability of carbon sequestration, respectively. Results of the present study highlight the effects of environmental factors such as soil moisture as well as inherent properties of plant residues on residue decomposition. Climate and residue quality are the main determining factors of soil microorganisms activity and residue decomposition and therefore soil attainable carbon sequestration. Better soil moisture condition and temperature, also higher residue quality increases microorganisms activity resulting in more residue decomposition. Furthermore, plant biomass and residue management affects attainable carbon sequestration. Resultant of the mentioned factors determines attainable carbon sequestration in soils of agroecosystems. Regarding to the total carbon sequestration of afore-mentioned crops, Ardebil and Sistan and Balouchestan provinces showed the highest and lowest carbon sequestration, respectively.

  Low precipitation, high temperature and high evaporation along with excessive consumption of water sources have led to reduced quantity and quality of water sources (e.g. water salinization) in arid and semi-arid regions which ultimately affect crop growth. Environmental stresses such as salinity, cause alterations in a wide range of physiological, biochemical, and molecular processes in plants. So, identification of plants which are less affected by salinity could be of great importance in breeding programs. Kochia (Bassia scoparia) is such a crop which its high tolerance to salinity has been reported in previous studies. Since photosynthesis is the most fundamental and intricate physiological process in all green plants determining plant yield under salinity stress, the aim of this study was evaluation of the effects of salinity on photosynthetic characteristics of kochia. In order to study photosynthetic characteristics of kochia under salinity conditions, an experiment was conducted as split-plot based on randomized complete block design with three replications. Three masses of kochia including Birjand, Borujerd and Sabzevar were considered in main plots and three levels of salinity (5.2, 10.5 and 23.1 dS.m-1) as sub-plots. Photosynthesis, evapotranspiration, stomatal conductance, Sub-stomatal CO2 concentration and quantum yield of PSII were measured in the youngest fully expanded leaf for seven weeks started from thirty days after imposing stress. Chlorophyll a, b and carotenoids and green area were measured at anthesis. Data were analyzed using Minitab 16 and means were compared by LSD test at a significance level of 0.05. Results indicated that photosynthesis and evapotranspiration was decreased over the time after salinity imposed. Photosynthesis and evapotranspiration in different masses and salinity levels was almost the same in the 8th week after imposing salinity stress. At the end of the growth season, photosynthesis and evapotranspiration indicated too much decrease in all salinity levels and reached to a same level. In the 4th week after salinity was imposed, the highest photosynthesis was observed in Birjand, Sabzevar and Borujerd, respectively. Reduction intensity of evapotranspiration in time was more in Birjand compared to Borujerd and Sabzevar masses. CO2 sub-stomatal CO2 showed a pronounced increase in all masses and a salinity levels in the 8th weeks after salinity imposed. Results of chlorophyll fluorescence indices in the salinity imposing period indicated an improvement of these indices and finally the increase in quantum yield of photosystem II. Stomatal conductance showed a decreasing trend during time and reached to the lowest level in the 11th week after imposing stress. The lowest mean of this parameter was belong to Sabzevar mass. Stomatal conductance did not vary much till tenth week after imposing salinity while it got a steep slope decreasing trend in the other two salinity levels in week seven. Decreasing trend of stomatal conductance was stronger in treatments of 10.5 and 23.1 dS.m-1 compared to 5.2dS.m-1. Leaf content of chlorophyll a, b, carotenoids and total pigments at anthesis were not affected by kochia masses and salinity levels. Interaction of salinity and mass indicated a lower green area in higher salinity levels. The highest and lowest green area was observed in Borujerd mass in salinity levels of 5.2 and 23.1 dS.m-1, respectively. Results of this experiment indicated that photosynthesis and quantum yield of PSII in kochia did not vary much as salinity intensity increased. Also, content of photosynthesis pigments was not affected by salinity stress. Generally, it could be concluded that photosynthesis system of kochia is capable to maintain its normal processes although being imposed to sever salinity stress and though could be used as a model crop in plant breeding programs

Providing light source for plantlet growth in potato tissue culture is expensive. So, an experiment was conducted in factorial arrangement based on completely randomized block design with nine replications under in vitro and four replications in greenhouse conditions to study plantlet production under natural light and comparing the morphological traits of these plantlets with the ones grown under fluorescent light conditions. Treatments consisted of two potato cultivars of Agria and Savalan and natural and fluorescent light. Results indicated that Savalan plantlets height was almost the same in both light conditions while a higher plantlet height was found in fluorescent light conditions in Agria. Root length, stem diameter, leaf area, number of nodes per plantlet, number of branches per plantlet and plantlet fresh weight was higher in natural light compared to fluorescent in both cultivars. An increase of 23 and 6 percent in leaf area, 2.2 and 22.5 percent in node number per plantlet and 18.9 and 17.2 percent in fresh weight was found in natural light compared to fluorescent light in Agria and Savalan, respectively. Longer internodes were observed in fluorescent light. Generally, according to the suitable morphological traits of plantlets grown under natural light and higher minituber production of these plants in greenhouse, reduction in minituber production costs could be achieved by using natural instead of fluorescent light in in vitro conditions.

IntroductionSoil salinity is one of the major abiotic stresses affecting plant growth and production. It is estimated that approximately half of the irrigated lands of Iran are affected by salinity and much of the agricultural lands of Iran especially in the central regions are susceptible to salinity. According to the development of saline soils and water resources, utilization of halophytes as alternatives for cultivation in saline conditions could be a suitable strategy to crop production. In addition to understanding the physiological salinity tolerance pathways, studying such crops could help to plant breeding and transferring these useful traits to crop species and also domestication of these plants.
Materials and methodsThis experiment was conducted in 2009-2010 in Salinity Research Station of faculty of agriculture, Ferdowsi University of Mashhad as split-plot based on Complete Randomized Block Design with three replications. Salinity as the main plot had two levels of 5.2 and 16.5 dSm-1 and five kochia ecotypes including Birjand, Urmia, Borujerd, Esfahan and Sabzevar were allocated as sub-plot. Seedlings were irrigated with saline water having electrical conductivity (EC) of 5.2 dSm-1 until the full establishment and thereafter salinity stress was imposed with saline water having EC=16.5 dSm-1. Physiological and biochemical traits were measured in the youngest fully expanded leaf at the beginning of the anthesis and shoot biomass at the end of the growth season. Data analysis was performed using Minitab 16 and means were compared by LSD test at a significance level of 0.05.
Results and DiscussionResults indicated that biomass was increased in Birjand, Isfahan and Urmia ecotypes as salinity level increased while it was decreased in Sabzevar and Boroujerd ecotypes. A reduction of 34, 31, 11 and 29 percentage and an increase of 4 percentage in seed yield was seen in Sabzevar, Birjand, Boroujerd, Urmia and Isfahan, respectively. Harvest index was also increased in Isfahan while it was decreased in the other ecotypes with the highest reduction in Birjand ecotype. An increasing trend of shoot Na content at anthesis was observed in all ecotypes showing the highest increase in Boroujerd and Isfahan and the lowest in Birjand ecotypes. A lower shoot K content at anthesis was observed in all ecotypes except Urmia in higher salinity levels. In contrast to Sabzevar soluble carbohydrates was decreased in Urmia, Isfahan, Boroujerd and Birjand in higher salinity levels. Increasing salinity intensity caused an increase in leaf proline content in Birjand and Isfahan ecotypes while it had no effect on Boroujerd and an additive effect on this parameter in Urmia and Sabzevar ecotypes. A higher osmotic potential was found in Boroujerd, Birjand and Sabzevar in higher EC levels. Phenol content was lower in Urmia, Boroujerd and Birjand in higher salinity levels while it was higher in Sabzevar. No significant difference was observed in Isfahan ecotype according to this parameter. DPPH radical scavenging activity was decreased in Birjand, Urmia and Boroujerd while it was increased in the other two ecotypes.
ConclusionRegarding higher biomass and lower physiological indices such as soluble carbyhydrates, total phenol, DPPH radical scavenging activities in Birjand and Urmia ecotypes, it may be cocluded that higher amounts of these parameters might not be suitable traits in salinity tolerant genotypes selection.

Conventional seed programmes take more than 10 years and diseases during each round of field multiplication become increasingly common and especially those transmitted through seed tubers. In contrast, the production of large volume of propagation material in protected environments requires only a few additional years of traditional seed multiplication in the field to produce the desired seed with an improved health status. This is useful especially in countries where there are no vector-free production areas for producing high quality potato seed tubers. In the last few decades, alternative seed production programmers have been developed in which the first multiplication steps are speeded up using in vitro plantlets, microtubers or minitubers. In the area of controlled environment agriculture (CEA), one of the most commonly discussed topics is lighting. The lighting system is generally the most expensive component of a controlled environment agriculture facility in terms of upfront costs as well as ongoing expenses (electricity use as well as replacement lamps). Naturally, advances in lighting technology are of great interest to the controlled environment agriculture community for these very reasons. Light emitting diodes (LEDs) are the most recent lighting technology to enter the controlled environment agriculture arena and have great potential to improve performance and reduce the overall cost of controlled environment lighting. Growth and morphogenetic effects of light (quality, intensity, and duration) and phytohormones are well documented, but their modes of action and mutual interactions are far from clear. One of the important questions is whether at least some of the morphogenetic effects of light are mediated by changes in phytohormone levels. This experiment was conducted in order to study the effect of different light sources on morphology and growth of potato plantlets under in-vitro conditions and their effect on minituber production in greenhouse to decrease energy consumption and production costs.
A factorial experiment was conducted based on completely randomized design with six replications under in-vitro conditions and four replications in greenhouse. Factors were consisted of cultivars (cv. Agria and Savalan) and light sources (LEDs emitting red, blue, white, combination of red and blue and also tubular fluorescent lamps as control). The experiment was carried out at the tissue culture laboratory of Yeka Seed Technology of Iran. Disease-free potato in vitro plantlets of Agria and Savalan cultivars were derived from the potato germplasm bank of Agricultural Biotechnology Research Institute of Iran. The plantlets were propagated using single-node cutting. Eight explants were cultured in sterilized culture vessels containing 30 ml of MS and pH was set to 5.8 before adding agar and autoclaving. Culture vessel were closed with polycarbonate caps and sealed with household plastic foil and were placed in a growth chamber at 24 °C and 16 h photoperiod for 4 weeks.
Results indicated that red spectrum caused an increase in plantlet height and Agria had a higher plantlet height under in-vitro conditions. Root length was higher in red-blue combination and no difference was observed between cultivars under in-vitro condition. The highest and lowest leaf area was obtained in white and red spectrum, respectively. Also, Savalan showed a higher leaf area in comparison with Agria. The lowest node number in plantlets was observed in red spectrum and the highest in white. The highest and lowest internode length was related to red and blue spectrum, respectively. Fluorescent light was resulted in the lowest plantlet fresh weight and no significant difference was observed among other treatments according to this parameter. Stem diameter and number of branches was not affected by different lights. Results of greenhouse study indicated that light conditions before transplanting of plantlets did not affected minituber number, while minituber weight was significantly affected by this factor and the lowest mean of this parameter was obtained in red spectrum compared to the other treatments.
Generally, results showed that less leaf area plantlet in vitro was also less leaf area in greenhouse (red light emitting diode). Leaf area is an important criteria for photosynthetic and biomass production. Therefore, in this experiment fresh and dry matter production was affected by this characteristics and red light showed the lowest dry matter production. LEDs could be considered as suitable light sources producing plantlets comparable with those grown under fluorescent light under in-vitro conditions along with saving energy and ultimately lower production cost.