جستجوی مقالات مرتبط با کلیدواژه « Tuber yield » در نشریات گروه « زراعت »

In order to evaluate tuber yield and traits related to tuber quality, 30 potato genotypes were studied in a randomized complete block design with three replications at the Potato Research Station of the countrylocated in Ardabil city during 2021 year. During the growing season and after harvest traits of tuber yield, tuber soluble sugar amount, tuber proline amount, tuber starch percentage, tuber protein amount, tuber dry matter percentage, tuber polyphenol oxidase activities amount, tuber catalase amount, tuber superoxide dismutase amount, tuber fiber amount, tuber nitrogen amount, tuber fat amount, tuber vitamin c amount, tuber reducing sugar content, tuber eye depth, tuber shape, tuber skin and flesh color, tuber hollow heart, tuber inner ring, baking type, discolored of raw tuber flesh after 24 h and maturity were measured according to the National Guidelines for Determining the Field Value Tests. There was a significant difference between genotypes in terms of all measured traits. The highest tuber yield was related to genotypes 7009-3, Rona, Takta, 905675 and 8707-112. High-yield genotypes had higher tuber proline amount, tuber catalase amount, tuber fat amount, tuber superoxide dismutase amount and acceptable tuber reducing sugar content, tuber eye depth, tuber hollow heart very minor and the internal rust of the tuber was very low. The Rona, Takta, 905675 and 8707-112 genotypes belong to the moderately late maturity group and 7009-3 genotypes belong to the moderately early maturity group. Genotypes 7009-3 and 905675 with dry matter between 21 to 21.99% with round tuber shape, suitable for chips, 8707-112 genotype with more than 22% tuber dry matter percentage and long oval tuber shape, suitable for French-fries, Rona genotype with more than 22% tuber dry matter percentage and round oval tuber shape, suitable for chips, and and Takta genotype with a percentage of tuber dry matter between 18 to 20% with the oval round tuber shape, suitable for salads and canned were determined. Genotypes 7009-3 and Rona had the highest tuber protein and tuber vitamin c amount.

Autumn cultivation of potato plant is very important because of meeting domestic needs of the country in winter and reducing the price of this product in the market. Cold stress in the early stages of potato growth is the most important factor that limits potato production in these areas.The yield and chemical composition of potato tubers under winter planting date and salicylic acid foliar application in Khuzestan region are very importance because one of the problems in cultivation of potato under Khuzestan conditions is insufficient growth due to dealing with high temperature at the end of the growing season in the autumn cultivation. Because few studies have been done in this regard on new cultivars of potato plant. Therefore, this experiment was performed to investigate of the tuber yield and attributes of tuber yield in potato plant.

The current study was conducted in a split-split plot based on randomized complete block design with three replication in the experimental farm of the Department of Plant Genetics and Production Engineering, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran, during the crop year 2020-21. The experimental factors in this research include the date of cultivation as the main plot in three levels (25 November, 9 December, 26 December), salicylic acid foliar application as a sub-plot in two levels (0.5 mM and non-foliar application) and cultivars as sub-sub plot at three levels (including early and new cultivars Sifra, Challenger and Columba).

According to the results of this experiment, the three-way interaction effects of investigated factors on tuber yield and attributes of tuber yield, the number of tubers more than 100 g, number of tubers between 50-100 g and number of tubers less than 50 g was significant. The interaction effects of planting date × salicylic acid foliar application and planting date × cultivar on plant height trait was significant, also the interaction effect of salicylic acid foliar application × cultivar was significant for the starch percentage trait and the simple effect of planting date and cultivar on the SPAD value trait was significant. In the following, the results of three-way interaction effects of the studied factors showed that the highest number of tubers more than 100 g in Sifra cultivar under 0.5 mM salicylic acid foliar application in 9 December planting date (with an average of 4.33 tubers per 1 kg), the highest number of tubers between 50-100 g related to the Challenger cultivar with 0.5 mM salicylic acid foliar spraying under 9 December planting date (with an average of 8.33 tubers per 1 kg), the highest number of tubers less than 50 g related to the Challenger cultivar under 26 December planting date and non-foliar application of salicylic acid (with an average of 33.33 tubers per 1 kg) and the highest tuber yield (with an average of 2.368 kg /m2) was related to the Sifra cultivar with 0.5 mM salicylic acid foliar application in the 9 December planting date. In addition, the highest amount of SPAD value belonged to the 25 November planting date (with an average of 42.61) and the Challenger cultivar (with an average of 42.41). Sifra cultivar also showed the highest starch percentage of tubers under 0.5 mM salicylic acid foliar application (with an average of 46.16%).

Now, due to the lack of potato product in late winter, especially in the southern regions in the Iran, cultivation of early cultivars compatible with the region, such as Sifra on 9 December, in order to achieve optimal yield, and the use of salicylic acid foliar application is suggested in conditions similar to this study.

The use of biological fertilizers can be effective and beneficial in abiotic environmental stresses specially in drought stress, arid and semi-arid regions of the world.

An experiment was conducted to investigate the effect of deficit irrigation stress and Pseudomonas bacteria on some morpho-physiological traits of two potato cultivars at the research farm of Shahroud University of Technology located in Bastam region in 2010. Treatments included irrigation cycles as the main factor at three levels (7, 10, and 14-days), Pseudomonas bacteria (inoculation and non-inoculation) and cultivar at two levels (Savalan and Agria) as the sub-factor with three replications.

The results showed that the highest dry matter accumulation in the aerial part was observed in the 7-day irrigation cycle and inoculation with Pseudomonas bacteria. The number of tubers was increased about 12.66% because of inoculation with Pseudomonas fluorescens per square meter. Savalan cultivar interaction and 7-day irrigation cycle also obtained the highest number of tubers with an average of 166.39 per square meter. The application of inoculation with Pseudomonas fluorescens increased chlorophyll A by 9.3%. It compared with non-bacterial inoculation. Chlorophyll B had the highest chlorophyll content in the main treatments of the 7-day irrigation cycle and Agria cultivar. The highest amount of potassium content was obtained at the rate of 2.06% at the highest irrigation cycle (14-day). The application of inoculation and non-inoculation with Pseudomonas caused the highest amount of proline at 14-day irrigation cycle. Inoculation with Pseudomonas bacteria increased the final tuber yield about 22.85%. Furthermore, Savalan cultivar increased the final tuber yield about 110.09% in the 7-day irrigation cycle compared to the 14-day. Finally, the 7-day irrigation cycle was the best irrigation cycle to increase the morpho-physiological traits, chlorophyll, number of tubers, and the final tuber yield. Inoculation with Pseudomonas bacteria increased the effectiveness of these traits. Also, the production of compatible osmolytes (proline and potassium) improved drought stress tolerance in 14-day irrigation cycle. Growth-promoting bacteria improves seed germination, root propagation, shoot and root weight, leaf area, chlorophyll content, hydraulic conductivity, protein, nutrient absorption and plant yield (Batool et al., 2020). Growth-promoting bacteria of polysaccharides increases biomass production under drought stress conditions (Daffonchio et al., 2015). Potassium is one of the most important osmolytes under drought stress conditions and adverse conditions (Anschütz et al. 2014). Cellular and physiological responses are carried out through organic salts as proline to reduce cellular damage during drought stress. It is an osmotic regulator (Merwad et al., 2018)

The 7-day irrigation cycle was the best irrigation cycle to increase the morpho-physiological traits, chlorophyll, number of tubers, and the final tuber yield. Inoculation with Pseudomonas bacteria increased the effectiveness of these traits. Also, the production of compatible osmolytes (proline and potassium) improved drought stress tolerance in 14-day irrigation cycle.

Given the growing rate of population and its consequences, such as hungrier people and more demand for food, the Food and Agricultural Organization (FAO) has introduced potato (Solanum tubersum L.) as a food security plant. Thus, the need for expanding potato production is globally felt to manage the increase in food demands and food security (4, 10). The interaction between the genotype and the environment creates complexity in yield prediction and is a challenge for plant production and breeding programs. This study was conducted to achieve a stable high-yielding genotype that is adaptive to climatic conditions of potato-producing regions in Iran.

A total of 20 potato hybrides along with five commercial varieties (Savalan, Agria, Caesar, Luta and Satina) were evaluated in a randomized complete block design with three replicates in the agricultural research stations of five locations (Ardabil, Hamadan, Isfahan, Karaj, and Razavi Khorasan) in Iran, for two years (2016 and 2017). Each of the hybrids and control cultivars were planted in two rows with six meters long. The rows with inter row spacing of 75 cm and plant spacing of 25 cm was taken. The genotype yields were measured after the harvest. Combined analysis of variances was done and comparison of means was done by LSD at one percent probability level. The principal coordinate analysis was used to analyze yield stability.

The results of combined analysis of variance indicated that the effect of genotype, year, location and year – location, location – genotype, year – genotype and year - location – genotype interactions were significant at 1% level of probability. Therefore, the analysis of genotype - environment interaction was performed using multivariate analysis of principal coordinates. Compared to the grand mean, 10 environments under study were divided into two groups including three environments with higher performance than the total average and seven environments with lower performance than the total average. The most stable genotypes based on the MST (Minimum Spanning Tree) and distance from the center of plots were hybrids 1, 8 and Savalan cultivar in low cycles and hybrid 5 was identified in high cycles.

The hybrids 1 (35.57 ton/ha), 8 (35.05 ton/ha) and Savalan cultivar (33.52 ton/ha) which could be recommended for environments with the yield lower than the average mean of all studied environments. Also, hybrid 5 (41.21 ton/ha) was identified for environments with higher performance than the total average.

Potatoes are a plant sensitive to water stress and are a rich source of carbohydrates, essential nutrients such as fiber, vitamins, minerals, proteins and antioxidants. Drought is one of the most common tensions that has always threatened the production of agricultural products and has affected a large area of the world. Therefore, due to the scarcity of water resources, it is necessary to increase water consumption efficiency in the agricultural sector and to pay more attention to water control and storage methods, including irrigation. The present study was conducted to evaluate the effect of dehydration stress on yield, quantitative and qualitative traits of hybrids obtained from crosses of commercial potato cultivars in Ardabil province.

This study was conducted to investigate the effect of dehydration stress on yield, quantitative and qualitative traits of hybrids resulting from cross-breeding of commercial potato cultivars for two years (2017-97) in the greenhouse of Zare Gostar Arta Agricultural Company in Ardabil province. Split plot experiment Based on a completely randomized design with three replications. The main factor included three levels of irrigation (100, 85 and 70% of the plant's water requirement) and the sub-factor included 12 potato hybrids that were the result of crossing four cultivars Losta, Banba, Spirit and Agria as parents. Statistical calculations were performed using Sas 9.1 and Mini-tab 16 statistical software.

The results of analysis of variance showed that there was a significant difference in terms of all evaluated traits except main stem diameter, tuber dry matter percentage, tuber specific gravity and tuber starch percentage. In terms of bilateral effect of irrigation levels × cultivars, except for tuber dry matter percentage, tuber specific gravity and tuber starch percentage, significant differences were observed in other traits. Treatment of 100% water usable in the swamp (a Luca × Esprit♂) with an average of 53.56 tons per hectare maximum tuber yield and treatments of 85% water usable in the confluence (♀ Luca × Esprit×) and 65% water usable in the swamp (uc Luca × Esprit♂) with an average of 49.75 and 50.39 tons per hectare, respectively, had the lowest tuber yield. Crossing No. 10 (baBanba × Esprit♀) with an average of 21.52% had the highest percentage of dry matter and along with crosses No. 1, 7 and 9 were in the top group. The results of correlation between the evaluated traits in these three conditions separately showed that in all three water conditions the correlation between tuber yield and tuber weight per plant was positive and significant and at irrigation levels of 100, 85 and 65, respectively ( r= 0.98**, 0.99** and 0.99 **). Percentage of tuber dry matter, tuber specific gravity and percentage of tuber starch had a significant negative correlation with tuber yield and tuber weight per plant at 85% of usable water stress.

With this in mind, Cross No. 10 (baBanba × Esprit♀) is recommended among the crosses under evaluation for processing (chips).

To estimate general and specific combining abilities and heritability in potato genotypes diallel analysis based on Griffing method was used. Reciprocal crosses were made between four commercial potato cultivars; Savalan, Luca, Satina and Caeser parents. For crosses and preliminary tuber seed increase carried out at greenhouse, and main gentypic evaluation trial was performed in field at Alarouq research field station during 2016-2019. There were significant differences between genotypes for tuber yield, tuber number and weight plant-1, main stem number plant-1, plant height, mean of main stem diameter, and tuber dry matter content. General and specific combining ability of tuber yield, tuber weight per plant and plant height were significant. The highest positive and significant general combining abilities for tuber yield, tuber weight plant-1 and main stem number plant-1 belonged to cv. Luca and cv. Savalan. The highest positive and significant specific combining ability for tuber yield was observed for ♂Savalan×♀Luca, ♂Satina×♀Luca, ♂Caeser×♀Luca, ♂Caeser×♀Savalan, ♂Luca×♀Caeser and ♂Savalan×♀Caeser. Tuber yield, tuber weight plant-1, plant height, main stem number plant-1 and tuber dry matter content had higher general heritability.

Drought is the most important environmental stress that limit plant growth and crop production around the world. Long-term tension affects all metabolic processes of the plant and as a result, it often reduces plant production. On the other hand, potatoe is important for dry matter production and dietary intake and has been ranked as the fourth crop for volume of production after wheat, rice and corn. Due to water scarcity, population increase and necessity of more production of this crop, it is necessary to study the effects of water deficit on the yield and physiology and quality of potato. The purpose of this experiment was to investigate the effect of various irrigation regimes by subsoil irrigation at different depths on the potato yield and potassium effects as a damage reducer factor caused by irrigation reduction.

This experiment was conducted in 2014 at Research Farm of Faculty of Agriculture of Ferdowsi University of Mashhad. The experiment was split factorial in a randomized complete block design with three replications. In this experiment, the main plot consisted of irrigation at three levels of 100 percent irrigation (control), 80 percent and 60 percent of the required blueberries throughout the plant growth period and Sub plots consisted of two sub-surface drip irrigation systems in two levels, including drip tape in depth 7.5 cm soil layer and drip tape in depth 15 cm layer of soil and the factor of potassium fertilizer application in two levels, including 100 percent and 120 percent recommended soil test. In this research, Fontaneh, cultivar which has a better adaptability with Mashhad conditions than the other cultivars, were used for growing season and industrial market. Plant water requirement in Mashhad conditions was also determined using software (OPTIWAT). Irrigation volume during growth season to supply 100 percent water requirement was 6840 cubic meters per hectare, for 80 percent was 5742 cubic meters per hectare and for 60 percent was 4104 cubic meters per hectare. Weeding is carried out manually. The measured indexes included number of tubers per plant, tuber mean weight, tuber yield, relative water content of leaves (RWC), dry matter content, electrolyte leakage and chlorophyll content. The data were analyzed by SAS statistical program and the meanings were compared by Duncan test at 5 percent level.

The results of the experiment showed that irrigation have a significant effect on most traits. So that the highest number of tubers in the plant and the relative water content was obtained in the control treatment, namely 100 percent water requirement of potatoes, but percentage of dry matter, electrolyte leakage and chlorophyll were increased with irrigation reduction. There was a significant difference between the two drip irrigation systems in terms of gland performance, and the amount of this trait was higher in the treatment of the drip tape at 7.5 cm depth. The results of this experiment showed that there was no significant difference between two levels of potassium fertilizer in terms of most traits. In general, it can be concluded that although irrigation treatment has a significant effect on most of the studied traits, the trend of changes in the two types of drip irrigation systems used in this experiment is one.

The results of this experiment showed that reduction of irrigation water in the potato whole growth season can have a negative effect on morphological characteristics, yield and yield components compared to the full supply of water. The tuber yield decreases with decreasing irrigation volume, due to the sensitivity of the plant to soil moisture, especially at the time of tuber initiation and tuberization.

This study aims at investigating the morpho-physiological responses of potato superelite mini-tubers to different coating treatments factorial experiment, based on randomized complete block design with three replications in Research Farm of Mohaghegh Ardabili University between 2018 and 2019. Experimental factors at four levels include mini-tubers filler (zeolite and cocopeat), superphosphate (soil and pellet application), chitosan, and superabsorbent with control treatment (without pelleting). Application of cocopeat with superphosphate leads to the highest average number of tubers per plant (8.36), fresh and dry tuber yield (18.23 and 3.88 tons per hectare), and biological yield (21.69 tons per hectare). The use of chitosan in mini-tuber pelleting decrease the activity of catalase and peroxidase enzymes (19.67% and 16.37%, respectively), increasing the activity of polyphenol oxidase (37.80%). Zeolite increase and cocopeat decrease the tuber protein percentage, compared to the control. This increase in protein percentage with increasing tuber yield leads to a 32.23% increase in tuber protein yield in zeolite application, compared to control treatment. The use of superphosphate in mini-tuber pelleting also increase the protein percentage, thus leading to a 30.30% increase in protein yield, compared to control mini-tuber. In principal component analysis (PCA), the first component, with which 35% of the changes could be explained, include the yield of protein, lysine, and methionine, and the second component, with which 25% of the changes could be explained, include the protein, methionine, lysine, and total nitrogen. Finally, the results show that the mini-tuber pelleting by superphosphate, zeolite, and superabsorbent have had significant additive effects on yield and quality traits.

Potatoes play an important role in ensuring food security in Iran and many other countries due to their high yield potential.. There is a vast need for cultivars adapted and stable to Iran’s weather conditions so that evaluation of yield stability and adaptation experiments is vital. In this study, nine medium-late maturities imported genotypes along with one medium-late maturity control genotype, were cultivated in RCBD with three replications in three important cultivation sites (Khorasan Razavi, Zanjan, and Hamedan) in two years (2016, 2017). Then traits of tuber yield, marketable tuber yield, number of the main stem in a plant, plant height, number of seed tuber, total number of tuber, and finally dried matter percentage were assessed. Results showed significant differences between cultivars in different places. It was concluded by the analysis of variance (ANOVA)results that the effect of year × place × genotype has a significant difference for all evaluated traits except plant height and dried matter percentage. The Rodeo, Sifra, Fabula, Panamera, and Sagitta were selected for spring cultivation as best genotypes and Challenger genotype was suggested to be sowed by the aim of consumption in the industrial. In general, the most adapted genotypes with the highest yield tuber were Rodeo genotypes for Khorasan Razavi, Sifra, and Fabula genotypes for Zanjan, and Panamera, and Sagitta genotypes for Hamedan.

Potato (Solanum tuberosum L.) is one of the important crops in Iran with high nutritional value. Potato is grown on approximately 159.061 ha-1 in Iran during 2015-2016 (Sajedi et al., 2012). Even though potato plants have robust growing and quick spreading nature but it turns as a weak competitor with weeds. Potato yields and quality can be seriously affected by the presence of weeds. It was observed that the most critical period of crop-weed competition is first 4-6 weeks after planting when the crop must be kept free from weeds. The yield reduction due to weeds in potato is estimated to be as high as 10 to 80 percent (Auskarniene et al., 2010). The most important weeds in potato field are redroot pigweed (Amaranthus retroflexus L.) and common lambsquarters (Chenopodium album L.). Chemical techniques have been still preferred by growers due to less cost and easier implementation. Weed control with herbicides is limited to a few older compounds with the primary criterion for herbicide selection being previous weed problems, or standard routines not only in Iran but also in the North America (Ivany, 2010). Among herbicides registered (e.g. metribuzin, sulfosulfuron, paraquat and rimsulfuron) in Iran, pendimethalin (Prowl) is a new selective herbicide belong to dinitroaniline family used to control most annual grasses and certain broadleaf weeds in field potatoes.

In order to evaluation of the best herbicidal treatment to weeds control on potato field, an experiment carried out as randomized complete block design with eight treatments and three replication at Hamedan Agricultural and Natural Resources Research Station, during 2017. Experiment treatments included, the application of metribuzin at 0.75 Kg.ha-1, sulfosulfuron 30 gr.ha-1, paraquat 3 lit.ha-1, rimsulfuron 100 gr.ha-1 and pendimethalin in three levels of 2.5, 3 and 3.5 lit.ha-1 with Hand weeding and untreatment. 15, 30 and 45 days after spraying, sampling of weeds and potato carried out in middle of the plots with 0.5 × 0.5 quadrate, respectively. Then, samples were dried at oven-dried at 75 °C for 48 h and weighed. At the final harvest to determine yield, all treatments sampling performed from four lines of each plot by 1 × 1 quadrate. Based on final yield, tubers classified to three groups involved, small tuber (< 35 ml), middle (between 35-75 ml) and large tubers (> 75 ml), then weighted. Results

The results of analysis of variance showed the application different herbicidal treatments had significant effect on weeds density and dry matter and also potato yield. According results, In spite of significant reduce in all of herbicidal treatments on weeds, the lowest weeds density and dry matter were showed in metribuzin. Also, the different applied treatments had significant effect on potato tuber number and yield. The best treatments on increase potato plant dry weight at 15, 30 and 45 days after emergence were hand weeding with 70, 75.02 and 78.64 percent and then metribuzin with 65.09, 70.28 and 72.35 percent, respectively. The highest percentage of increase on potato tuber yield was shown in hand weeding with 22.2 percent and then in metribuzin with 19.8 and rimsulfuron with 16.9 percent.

In conclusion, metribuzin was the best of herbicidal treatment for weeds control and yield enhance in potato. In spite of being particular of paraquat in potato, this herbicide did not enough control of weed at 30 and 45 days after emergence, hence resulted a lower total yield compared to other treatments. Despite the favorable of weeds control by sulfosulfuron, yield reduce caused due to the negative effect of sulfosulfuron, necrosis and clouding of potato leaves and finally the degradation of photosynthesis in potato. Rimsulfuron was as the best treatment after metribuzin on weeds control and yield boost. But application of rimsulfuron not suggestion in potato with barley, rapeseed and alfalfa alternation because of the rate of low decomposition and long-term residues in the soil. The application of pendimethalin at the highest dose e.g. 3.5 l.ha-1 caused to 32.4 percent to promote in potato tuber yield compared to control treatment, whilst the same rate was achieved 49 percent for the metribuzin at 0.75 kg.ha-1. Hence, metribuzin at 0.75 kg.ha-1 is suggested as the best herbicidal treatment in Hamedan potato fields.

In order to achieve optimum quantitative and qualitative yield of potato in each region, new cultivars need to be compared. As such, this study has been carried out to compare 13 new potato cultivars along with two cultivars of Agria and Banba with each other to identify suitable cultivars for leaf area index, agronomic, and qualitative traits under climatic conditions of Razan. The statistical design, used in the present study, has been complete randomized block with three replications. Results show that Manito cultivar has reached the maximum leaf area index later than other cultivars, having 12 tubers per plant, which is 112% and 83% superior to Banba and Agria, respectively. Also, Natascha cultivar with a leaf area index of 3.65 has been 57% and 19% leafier than Agria and Banba, respectively. Tuber weight in Ottawa (157.8 g per tuber) has been 70.5% and 20.4% greater than Agria and Banba, respectively. Manito cultivar yields 71399 kg/ha, which is 123% more than Agria and 70% than Banba. Protein percentage of tubers in this study do not differ among the potato cultivars, while the difference is significant among the potato cultivars in tuber starch percentage and the highest values belong to Manito (18.09%) and Ottawa and Concordia cultivars, in the second and place. Generally, Manitou, Caruso, and Faluca cultivars are recommended for planting in the Razan on the basis of traits of maximum leaf area index, number of tubers per plant, and tuber yield.

In order to detect the reaction of different potato genotypes to different irrigation regimes and evaluate their water productivity, a research was carried out as a split plot experiment based on a randomized complete block design with three replications in Agricultural Research Center and Natural Resources of Ardabil, Iran in 2015-2016. Five potato genotypes (Agria, Caesar, Savalan, 397081-1 and 397082-10) and three irrigation regimes (normal irrigation, 15 and 30 days without irrigation after 75 days of normal irrigation) were considered as treatments. The results showed that the effect of irrigation cuttings on the genotypes was significant for the mean fresh weight of tuber, number of tubers per plant, tuber yield per unit area, total dry matter yield and harvest index, marketable yield, dry matter percentage of tuber and water use efficiency. Under water stress conditions, water use efficiency was increased on the basis of tuber yield per unit area and marketable yield in genotypes 397081- 1, Agria and 397082-10. The highest water use efficiency was observed based on harvest index in Caesar and Agria genotypes (54.29 and 49.29 percent, respectively), and also based on the percentage of dry matter of tubers in genotypes 397081- 1, Caesar and Agria (6, 9 and 26 percent, respectively). When producing the highest tuber yield and water use efficiency under drought stress is aimed at planting genotypes 1-397081, agria and 397082-10 may bring about an effective use of water and show better growth and yield.

In order to study the effect of planting methods and planting depth on qualitative and quantitative characteristics of potato cultivars a factorial experiment carried out based on randomized completely block design in three replications under Mahidasht Town in Kermanshah Province, 2014-15 season. Experimental factors in this research were planting methods includs conventional cultivation (Hill planting), planting in leveled soil surface (Flat planting) and planting in furrow. Planting depth were 7, 12 and 17 cm and three studied cultivars were Agria, Arinda and Banba. Results showed that planting methods had significant effect on all of studied parameters. Planting depth had not significant effect except of tuber PH. The interaction effect of planting method and planting depth on tuber mean weight and total tuber yield was significant. Triple effect interaction of examined factors showed that the Agria cultivar produced the highest tuber numbers (14.67) into furrow planting in the depth of 17 cm and the Banba cultivar produced the lowest tuber numbers (6.33) in hill planting in the depth of 7 cm. Mean comparison of parameters showed that the highest percentage of dry matter was observed into furrow planting with amount of 3.29% and the lowest in the hill cultivation method with amount of 4.6%. The highest tuber pH was obtained into furrow planting (5.81) because of better availability to nutrients. totally, the Arinda and Banba determined as the best cultivars to cultivation in this region.

This field experiment was conducted to study the effects of water limitation stress and planting dates on growth and yield of potato in 2014-15 and 2015-16 growing seasons at Faculty of Agriculture, Shiraz University, Shiraz, Iran. Experimental treatments included, four irrigation levels: 55%, 70%, 85% and 100% of water requirement of potato assigned to the main plots, and three planting dates: March 11, April 9 and May 10 randomized in the sup plots as split plot arrangement in randomized complete block design with three replications. The results showed that plant height and shoot dry weight had a slow growth until 48 days after planting (DAP), however, these two traits considerably increased between 48-104 DAP. At early growth stage, plant height and shoot dry weight was slightly less in March 11 planting as compared with other planting dates, while these two traits were greater in March 11 planting. Water limitation stress reduced plant height, leaf area index, tuber number m-2, tuber yield, biological yield and weight of seed and large tubers weight and increased small tuber weight. There was no significant difference between 100% and 85% of water requirement levels for most of measured traits. In water stress conditions planting date was more important. In 100% water requirement level there was no significant differences between planting dates. Whereas, in stressed conditions, growth and tuber yield of potato were greater in March 11 planting. In conclusion, the results indicated that potato performance was greater in March 11 planting date, particularly in water limited stress conditions, because of better use of precipitation, cooler temperature and lower evaporation in the early season as well as suitable temperature during tuber initation.

Introduction Potato is amongst the most important crops in the world, which is the third most consumed crop worldwide after rice and wheat and is followed by corn in this regard (Kazemi et al., 2016). Abiotic stresses like drought may cause adverse effects on growth and tuber yield of potato plants as they are very sensitive to soil moisture reduction (Deblond et al., 1999). Potassium is used as a cofactor of enzymes, osmotic activities and plant electrolyte regulation, and is an essential element for osmotic control that can reduce osmotic potential and improve plant acclimatization under drought conditions (Taiz & Zeiger, 1991). Given the importance of potato production and its high demand for water and because of scant research being conducted on the planting patterns of this crop, the present study aimed to investigate the effects of various planting patterns and different potassium levels on potato growth indices under water-limited conditions in Khorasan Razavi province. Materials and Methods This experiment was conducted in Jolge Rokh- agricultural research station over spring and summer of 2016 and 2017 cropping seasons. The experiment was set up as split split plot arrangement based on a randomized complete block design with three replications. The trial factors consisted of three planting patterns including common planting, common dense planting and zigzag planting designated as the main plots, and irrigation with three levels [control (without stress), irrigation based on 80% of the crop water requirement (as deficit irrigation treatment), and irrigation based on 60% of the crop water requirement (as stress treatment)] designated as the sub -plots, and three levels of potassium fertilizer (0 (control), 75 and 150 kg potassium sulfate per hectare) designated as sub-subplots The water needed for the plant was determined based on water requirement of the potato, which was determined using the software (OPTIWAT) and FAO Penman- Monteith method. The leaf area and leaf dry weight were measured during the growing period at two-week intervals. Results and Discussion The results showed that the greatest leaf area index (LAI), crop growth rate (CGR) and total dry matter (TDM) were observed with zigzag planting pattern at either year of the study. The maximum TDM under common, common dense and zigzag planting in the first year were 634.3, 671.9 and 870 g.m-2, respectively, while the corresponding values for the second year were 808.5, 919.2 and 1065 g.m-2, respectively. Irrigation treatments based on 80 % and 60% of the crop water requirement reduced the growth indices and yield of the tubers. The greatest tuber yield was observed with full irrigation treatment (100% of the crop water requirement (32 and 35.2 ton. ha-1 in the first and second year, respectively), while the lowest tuber yield was obtained with 60% of the crop water requirement (20.2 and 20.4 ton. ha-1 in the first and second year, respectively). The results showed that potassium sulfate increased TDM, LAI, CGR, NAR and tuber yield. The application of 150 kg of potassium sulfate produced the greatest TDM (850.2 and 1118.9 g.m-2 in the first and second year, respectively), whereas no fertilizer usage gave the lowest TDM (584.2 and 743 g.m-2 in the first and second year, respectively). In potato plants, sufficient quantities of potassium increase the number of tubers and dry matter production through strengthening potato stems, and at the same time, the plant can acclimatize to environmental stresses. Conclusion The results showed that the greatest LAI, TDM, CGR, NAR and tuber yield were observed with the zigzag planting. On the other hand, irrigation based on 60% the crop water requirement reduced the growth indices and tuber yield. It is worth noting that applying 80% of the crop water requirement also decreased the investigated the growth traits of the potato plants. Therefore, it is recommended that the exposure of potato plants to deficit irrigation conditions be avoided and the efforts should be made to provide them with adequate water. But the remarkable point was that the usage of potassium sulfate fertilizer could enhance and improve growth rates under low irrigation and water stress conditions.

This study was conducted during 2009 and 2010 to investigate the effect of green manure and nitrogen fertilizers on the yield, dry matter, starch, protein and reducing sugars content in potato. A split plot experiment based on a randomized complete block design with 3 replications was carried out. Green manures were applied at 5 levels (barley, canola, clover, vetch and without green manure) as main plot and nitrogen fertilizer were applied at 4 levels (100, 75, 50 and 25% of recommended) as sub-plot. The results for both years were statistically analyzed separately and also combined. Dry matter, starch, protein, reducing sugars percent and also potato tuber yield were affected by green manures and nitrogen manure levels. Also the interaction of treatments was significant on the yield, protein and reducing sugar percentage of potato tubers. The vetch green manure and 75% of recommended nitrogen was the best green manure. This treatment significantly increased dry matter and starch percentage of potato tuber by 22.3 and 12 percent, respectively. Also, the vetch green manure and 100% of recommended nitrogen increased protein percentage of tuber significantly; and the interaction of green manures and nitrogen fertilizer on the reducing sugars percentage was within the permissible limit. In terms of tuber yield per area unit, the interaction of clover with 75% of recommended nitrogen was the best treatment and resulted in a 33% increase in tuber yield. In addition, it decreased the amount of nitrogen consumption by 25%.

Terminal heat sterss considered as one of the major challenges of winter production of potato in warm areas of the country including the south of Kerman provience. To determine the suitable strategy for mitigating terminal heat stress injury, a split-split plot experiment based on randomized complete block design with three replications was conducted in South Kerman Agricultural Research and Education Center (Jiroft), Iran, for 2 years (2013 and 2014). The main factor was heat stress: normal (on time planting; Dec. 31) and terminal heat stress (late planting; Feb. 4) and three potato cultivars; Satina, Sante and Milva and four calcium applications; (without calcium nitrate application, foliar application of 2500 mg.l-1 calcium nitrate in two and three stages and soil application of 75 kg.ha-1 calcium nitrate in two stages) were in sub and sub-sub plots, respectively. Results showed that heat stress reduced marketable yield and the weight and number of marketable tubers per plant. Sante and Satina cultivars produced the highest marketable tuber yield in normal condition (47.15 and 44.9 ton.ha-1, respectively), but under heat stress conditions, the difference between marketable tuber yield of those cultivars was not significant. The application of calcium nitrate improved marketable, non-marketable and total tuber yield and its components in potato cultivars and soil application of 75 kg.ha-1 of calcium nitrate was significantly suprior than the other treatments. The interaction effect of terminal heat stress and calcium nitrate applications on marketable and total tuber yield, mean weight and number of marketable and non-marketable tuber was significant. Soil application of calcium nitrate (75 kg.ha-1) increased marketable tuber yield of potato cultivars under normal and terminal heat stress conditions (10.5 and 24.5%, respectively) that revealed the mitigating effect of calcium nitrate on terminal heat stress in potato cultivars. It concluded that soil application of calcium nitrate seems to be an appropriate method to reduce the adverse effects of terminal heat stress in winter potato production.