JOURNAL OF CROPS IMPROVEMENT (JOURNAL OF AGRICULTURE)
Year:2018 | Volume:20 | Issue:1 |Papers Count:20

In order to investigate the effects of irrigation intervals on pigments and biochemical components of fourgrapevine cultivars (Yaghooti-e-Ghermez, Askari, Sahebi and Keshmeshi-e-Sefid), an experiment wasconducted with five irrigation treatments (3, 6, 9, 12 and 15 days interval) in four replications ingreenhouse in 2012. The results of this experiment showed that irrigation intervals have effected onphysiological and biochemical factors of grapevine cultivars. The amount of chlorophyll a, b and totalchlorophyll in four cultivars were reduced with increasing irrigation intervals, and maximum reductionwas observed in 15 days interval irrigation in four cultivars. The maximum and the minimum ofchlorophyll a, b, total chlorophyll and carotenoids content were observed in ‘ Sahebi’ at 6 days intervalirrigation and ‘ Askari’ at 15 days, respectively. Total soluble sugars, phenolic compounds and prolinecontents of leaves in all cultivars increased and leaf relative water content decreased with increasingdiurnal irrigation. The maximum leaf relative water content and proline was observed in Sahebi cultivarand the minimum value was belonged to Yaghooti-e-Ghermez and Askari cultivars. Based on the resultsof this study, it seems that Sahebi cultivar had more tolerant in increasing irrigation intervals compared toYaghooti-e-Ghermez, Askari and Keshmeshi-e-Sefid cultivars.

This experiment was conducted to study the effects of sowing date and hydropriming on the yield of twocotton cultivars using a factorial experiment based on randomized complete block design in threereplications at the Research Farm of Islamic Azad University, Sanandaj Branch in 2013 growing season. The first factor was sowing date with three levels: April 29, May 13, and May 27. The second factor washydropriming in two levels of control (without priming) and hydro-priming application and the thirdfactor was cultivar with two levels of Paak and Varamin cultivars. Results showed that seed hydroprimingat the first sowing date (April 29) significantly increased seed cotton yield in comparison with control(without priming), however hydropriming had no effects on seed cotton at the second and the thirdsowing dates. Varamin cultivar responded well to early planting and its yield at the first sowing date wassignificantly higher than that of Paak cultivar whereas there was no difference between two cultivarsregarding seed cotton yield at the other sowing dates. Delay in sowing date and non-priming treatmentsresulted in a significant decrease in oil content of Paak cultivar, but had no significant effect on the oilcontent of Varamin cultivar.

To evaluate the effect of foliar application of nano iron and zinc chelated fertilizer on yield andagronomic characteristics of canola (Brassica napus L. ) cv Hyola 308 hybrid under drought stress, anexperiment was conducted in a randomized complete block design with three replications in Ramhormoz, Khuzestan province in 2012 growing season. Main plots consisted of three levels of irrigation: irrigationin the whole the growing season (control), irrigation cut at the green bud stage and irrigation cut at theseed formation stage and foliar application treatment at the beginning of stem elongation and flowering assubplots consisted of four levels: sprayed with water(control), foliar application with Nano-zinc, foliarapplication with nano-iron, foliar application composition with nano-zinc and nano-iron (each of themwas a concentration of two per thousand). The results showed that cut irrigation in reproductive growthstage decreased the grain yield (18%), biological yield (6%) and harvest index (14%). Plant height andthe weight of one thousand seeds were influenced by the interaction of irrigation and spray. Most of theseed oil content (45. 2%), the weight of one thousand seeds (4. 13 g) and plant height (106. 5 cm) wererelated to the irrigation treatment in whole growth stages and foliar application of nano iron and zincchelate combination. Spraying plants with nano chelate iron and zinc improved plant tolerance andincreased yield in drought stress condition in relation to spray by water (control).

The replacement of chemical inputs with ecological compatible inputs seems necessary for a step towardsin transition from common to sustainable agriculture. In this regard, an experiment was conducted at theresearch field, University of Zabol, as a split plot based on randomized complete block design with threereplications, during 2015. Four drought stress levels of 30, 50, 70 and 90 percent of available water wereconsidered as main plots and four levels of nano and nano bio-fertilizers were considered as sub plots. Main effects of fertilizer, drought stress and their interaction were significant for all studied traits. Maximum of photosynthetic pigments, fresh and dry weight of sepals were obtained under treatment of70% of available water irrigation and foliar application of nano-iron fertilizer. The highest amount ofanthocyanin, proline and carbohydrate osmolytes belonged to 30% of available water irrigation and thehighest relative water content of leaves belonged to 90% of available water irrigation and foliarapplication of nano-iron fertilizer. The result of principal component analysis showed that the beststudiedtreatment was 70% of available water irrigation including with foliar application of nano-ironfertilizer. Spraying nano-iron fertilizer mitigated the effects of drought stress and increased the quantityand quality of roselle sepals.

In order to study the effect of different levels of irrigation, nitrogen and zeolite on chlorophyll content, forage yield and quality of amaranth, a split plot factorial experiment was conducted as randomizedcomplete block design with three replications at the Research Farm of Tarbiat Modarres Universityduring 2013 and 2014 growing seasons. Main factor was three irrigation regimes, irrigation afterdepleting 40, 60 and 75 percent of soil available water and sub factor was the combination of the twofactors: nitrogen levels 0, 80, 160 and 240 kg. h-1 and zeolite levels 0 and 10 ton. h-1. Results showed thatincreasing irrigation intervals, especially irrigation after depleting 75% of available water, decreasedchlorophyll (37%), forage yield (40%), digestible dry matter (18%), crude protein (17%) and ash (16%)but increased neutral detergent fiber (16%) and acid detergent fiber (7%) compared to control irrigationtreatments. Zeolite application under water deficit stress conditions increased chlorophyll, forage yield, digestible dry matter, crude protein and ash, and reduced NDF and ADF. Nitrogen consumption morethan 80 kg. h-1 had no significant effect on forage dry yield and quality under soil water deficit conditionsand application of zeolite; Therefore, Nitrogen application (80 kg. h-1) was sufficient to obtain suitableforage yield and quality of the amaranth with zeolite application.

Information about the temperature requirements in fruit trees has an important effect on productivity anddetermining suitable regions for their growing. This research was carried out using single node cuttingstest in a randomized complete block design with three replications in Citrus and Subtropical ResearchCenter in 2015-16. This study was conducted to determine the chilling requirements of Hayward andTomuri cultivars and male and female golden genotypes using three chilling models (Chilling hours, Utah, Dynamic) and their heat requirements using growth degree hours (GHD) method. Results showedthat the chilling requirements of female and male golden genotype buds were 480 and 585 chilling hours, respectively, and for Hayward and Tomuri cultivars were 692 chilling hours. The amount of buds heatrequirements in the cultivar and genotype ranged from 2233 GHD in female golden genotype to 4066GHD in Hayward cultivar. Hayward cultivar required 966 hours of chilling requirement for maximumflowering, meanwhile Tomuri, male and female golden genotype had a similar chilling for bothvegetative bud break and flowering including 692, 585 and 480 hours, respectively. With continuedsampling, heat requirements reduced and significant negative correlation was found between chilling andheat requirements for bud break. From low chilling requirements of male and female golden genotypes, we can deduce that climatic conditions may be not limiting factor in the leading of them in growing area. It is thought that Utah and dynamic models may be more suitable than hour model to evaluate of chillingrequirements.

The limequat is a citrofortunella hybrid that is hybrid between the key lime and the kumquat. It hasconsiderable amount of vitamin C acids which tastes similar to limes. Regarding these traits and it'srelatively resistance to low temperatures. It can be a new commetrial citrus in thenorth of sour lemin treesin Mazandaran weather condition severely damaged by frost. Rootstocks had main affect on scion, suchas vegetative vigority, tolerance to biotic and abiotic stresses, yields and fruit quality. The objective ofthis experiment was to evaluate of citrage, citromelo and sour orange rootstocks on the vegetative growth, tree size and mineral absorption ability of limquate. The experiment was conducted in a compeletlyrandomized design with seven replications. The results showed that the rootstock had significant effect onall parameters except the leaves numbers. The highest amount of chlorophyll (4. 84 mg /100 gr) and plantstem diameter (7. 07 mm) were observed on the citrange rootstocks plant. Limequats plants on sourorange (91 cm) and citrange (90 cm) rootstocks had vertical growth with better height but lime quat scionproduced the most side branches on the citromello rootstock (5. 8). The highest and the lowest percentageof water relative content were observed on sour orange rootstock (62. 84%) and citrange rootstock(54. 60%). In terms of nutrient absorption (nitrogen, phosphorus, potassium, calcium, iron, magnesiumand manganese) significant effects were observerd between root stocks; the ability of citromello rootstockto absorb magnesium and manganese was less than other rootstock. In conclusion, citrange rootstock canbe a suitable rootstock for Limequat in Mazandaran weather conditions.

An experiment was conducted in a randomized complete block design in split-plot arrangement with threereplications to find the most suitable location and the planting density of Thymus vulgaris at dry farmingcondition in seven provinces of Iran. The experimental treatments consisted of plant density (4, 6 and 8plant/m2), year (1 and 2 years after planting) and location (Tehran, North Khorasan, Isfahan, Kurdistan, Kermanshah, Gilan and East Azerbaijan). The traits comprised of plant height, canopy diameter, drymatter of aerial parts, yield and content of essential oil in full flowering stage. The results revealed thatinteractions of density, location and year were significant on all studied traits. The highest dry matter(1734 kg/h) and essential oil yield (16. 84 kg/h) of aerial parts were obtained in 8 plant/m2 density inGilan. The maximum and minimum of essential oil content were observed in samples from Isfahan(1. 96%) and East Azerbaijan (0. 50%), respectively. Based on our findings, it seems that cultivation of T. vulgaris with higher density may cause a higher production of dry matter and essential oil yields underdry farming conditions in Iran.

Wheat (Triticum aestivum L. ) as one of the most important agronomic crops has a special status in Iran. Reducing the yield gap is one of the ways to raise the production. In order to, the production rate and thewheat yield gap in Golestan province were analyzed by using a simple simulation model SSM– Wheatand GIS software. For this purpose, the managerial information of wheat farming and cultivation werecollected based on the provincial level and with regards to the information of 25 weather station and theregion soil information, the potential yield was simulated in the irrigated and rainfed conditions at theprovincial level and then the potential yield zoning was performed in the GIS and then with regards to thefarmer's production rate and real yield at the provincial level, the yield gap and the production one werealso calculated in the irrigated and rainfed conditions. Results indicated that the yield average of irrigatedand rainfed potential with regards to the figures and current agricultural methods are respectively 8. 140and 4. 930 kg per hectare. Also, the potential production in the irrigated and rainfed conditions wasobtained equal to 1. 357 and 1. 112 million tons (total 2. 469 million tons). Results showed that in case ofstudying and removing the factors which may cause the yield gap in the said province, the wheatproduction can be increased from the current 926 thousand tons to 1. 975 million tons. Based on theresults of Golestan province, the most important factors causing wheat yield vacuum with currentcultivars and agronomic management, improper irrigation management, improper cultivation of cultivarsand inappropriate use of basic fertilizers, road and low fertilizer, and for eliminating yield vacuum, use of165 to 215 kg of seed per hectare, using certified seeds of suitable cultivars for water and dry farming, consuming at least 50 kg of phosphorus fertilizer (equivalent to P2O5) during cultivation, consuming atleast 95 kg of pure nitrogen per hectare and integrating farms are suggested.

In order to effect controlled ageing on parameters germination, membrane peroxidation and antioxidantactivity the stressed seeds of Balangu (Lallemantia sp), a four-factor factorial study in a completelyrandomized design with three replications was conducted in Laborartory Seed Science and TechnologyShahed University in 2015. Dragons’ head (Lallemantia iberica) and Lady’ s mantle (Lallemantiaroyleana ) were imposed three drought stress level (control, mild and severe) during seed developmentand the produced seeds were aged at different seed moisture content (5, 15 and 25% for 24 and 48 hoursduration). Analysis of variance showed that the interaction effect of species, moisture stress during seeddevelopment, duration of aging and seed moisture content on germination percentage, germination rate, mean germination time, membrane peroxidation and catalase activity was significant. It was observedincreasing germination percentage and rate germination, mean germination time and catalase activity inthe Lady’ s mantle stressed seeds and reduced membrane peroxidation and increasing membraneperoxidation and reduced germination percentage and rate germination, mean germination and catalaseactivity in the Dragons’ head stressed seeds. Impressed Dragons’ head stressed seed from maternal bymore aging were affected by negative effect of aging more than stressed seeds of Lady’ s mantle frommaternal.

This experiment was carried out on the effect of deficit irrigation and zinc foliar application on chase andchallenger sweet corn hybrids in Arak, Islamic Azad University, Agriculture Research Station as a splitplotfactorial experiment based on randomized complete block design with three replications during 2014and 2015. Different levels of water irrigation included full irrigation (control), every furrow irrigation andalternative furrow irrigation were measured assigned to main plot and foliar treatment included nonapplicationof zinc (water sprayed (control), application of drop zinc sulfate (2/1000 lit. ha-1) and fast zincsulfate (2/1000 lit. ha-1) and two sweet and super sweet corn hybrids by factors in sub plot. Resultsshowed that irrigation patterns, application of the zinc and hybrids and their interaction were significant at1% of probability in grain yield, grain protein, grain oil content, grain moisture content and prolinecontent in leaves. The highest leaf proline content was observed in every furrow irrigation by 30. 21 mg/gwhich it had 39. 86% significant difference with full irrgiation by 21. 60 mg/g. The highest grain contentwas observed in zinc fast foliar application by 28. 50 mg/g, while in none zinc spray (control), this amountwas reduced to 18. 09 mg/g by 57. 54% reducing. According to research, alternative irrigation and fast zincspray on Challenger hybrid is recommendable in deficit water conditions

To determine the best selection indices for facilitating the selection procedure in a reproductive stage of96 mutant lines (M2) of rice under different moisture conditions, an experiment was carried out in twoenvironments at the research farm of Gonbad Kavous University in 2016 base on randomized completeblock design with three replications. Evaluating the reduction percentage in the average values of traitsshowed that the most damages as affected by drought stress was due to decreases in numbers of filledgrains, numbers of tillers, and 1000-grain weight. Results of stepwise regression analysis indicated that1000-grain weight, plant height, numbers of filled grains, numbers of days to flowering, flag leaf rolling, numbers of tillers, and panicle length traits were respectively entered into the final multivariate regressionmodel as important traits affecting grain yield under a flooded condition, and 1000-grain weight, numbersof days to flowering, plant height, fertility percentage, panicle length, flag leaf frying, and numbers oftillers were respectively entered under drought stress. Evaluation of direct and indirect effects of studiedtraits on the grain yield using a path analysis showed that, 1000-grain weight, due to a positive and highdirect effect, and numbers of filled grains, due to an indirect effect via 1000-grain weight, can beconsidered as the most important traits for increasing the grain yield under flooded condition. However, 1000-grain weight and fertility percentage can be introduced as appropriate selection criteria for the grainyield under a drought condition.

Meta-analysisiscompressivescien ceandstatisticalanalysisofalar gecontentstatisticalresultsofdifferensttudiesinordetrotheorganizationofindin gsI. nthistudyt, h effectsosfomeagricultural operationws erestudiedongrainyieldb, iologicaylield andharvesitndexowf heatT. hetreatmentws ere includedsoiltillage, nitrogenfertilizer, saltstress , hydro-priming, osmopriming, hormopriming, and physicapl rimingwhichtestedusingHedgesmethodT. h ereforet, hestudiesthaht avecontrotlreatment andothertreatments, aftertheweightingofvalu eoftraits, effectsize, andreactionrelationand confidencreangestimatedM. eta-analysirsesultsshowed thantitrogenfertilizeirnrangeos5f0-250kg/ha causedincreasingingrainyield, biologicalyield, andharvestindex. Thehighestgrainyieldand biologicalyieldachievedin125-150kg/haandth emostharvestindexobtainedin230-250kg/ha. Secondaryt, illageinbothoffield(sirrigatedan dry farmingd) ecreasedgrainyieldb, iologicyielda, nd harvesitndexs, oareductionindryfarmingwase riousT. helowes(t21. 15%a)ndthehighes(t76. 41%) orfeductioninwheapt roduction(grainyieldo) btained in4-6and12-16ds/m. sr, espectivelyO. utcomes alsoshowedthathydro-priming, osmopriming, hormopriminghavepositiveeffectsongrainyield, biologicyielda, ndharvesitndexs, othaht ydroprim ingincreasedbiologicoperation(23%)g, rainyield (16%a)ndharvesitndex(19%)F. urthermoreo, smopriminghad 30%increasingeffecitnbiologicyield andiwt atso50%and59% inbiologiocperationandseedoperationwh iltehiesffechtacsausedthsemall amounot 1f %increaseinharvesitndexT. heinfl uenceopf hysicapl rimingoncharacteristicswasnot significanat ndijtusltedto3%increasegrainyiel dO. verallc, oncludesemphasisonconsuming125-150kg/haNn, oticetoresultosrfeplacingsecondarytillag ewithcurrenttillageindryfarminga, dviceto plantinginsoilasndirrigationwithsalinity<4 μ s/m. sp, ositiveffectoshformoh, ydroandosmopriming, aswelal sexpressingotfhegoodnessomf eta-analysismethodtodetecat ndfinalizethepositiveandnegativeffectostfhesdeifferenttr eatmentostnhperoductioonwf heat.

In order to study the effects of biofertilizers on the photosynthetic pigments, relative water content(RWC) and grain yield in medicinal pumpkin plants under drought stress condition, experiments wereperfumed across two years at research field station of Zanjan University. This experiment was conductedas a split plot based on randomized complete blocks design with three replications. The experimenttreatments consisted of drought stress as a main plot in four levels (i. e., control, mild stress, moderatestress and severe stress and biofertilizers as a sub-plot (i. e., no inoculation (control), nitroxin, mycorrhizha and thiobacillus)). Results of combined analysis of variance showed a significant associationbetween irrigation regimes and biofertilizers in terms of chlorophyll a, b and grain yield. Under severestress condition, nitroxin induced 15. 78% and 40% growth in terms of chl a and chl b contents andmycorrizha treatment induced 21% and 47% growth in terms of chl a and chl b contents in comparisonwith the control, respectively. Only mycorrizha treatment had a positive effect on the RWC andcarotenoid content (increased 19% and 5. 58% in comparison with no inoculation). Regarding positiveeffects of nitroxin treatment on increasing of grain yield (under moderate and severe stress condition, caused to 13% and 12. 6 % increases in grain yield in comparison with the control, respectively), low costand easy application, use of mentioned treatment can be recommended.

The current study was conducted to investigate the effects of different soil fertility treatments onqualitative and quantitative yield of sunflower (Helianthus annus L. ) under different irrigation regimes. The experiment was conducted in Tarbiat Modares University research field at 2012 and 2013 growingseason. Treatments were arranged as split plots based on a randomized complete block design with threereplicates. Irrigation regimes, (irrigation after consuming 30% (I1), irrigation after consuming 50% (I2)and irrigation after consuming 70% (I3) of available soil moisture) were randomly assigned to the mainplots and the subplots were eight different fertilizer types (providing 100% of plant nitrogen requirementfrom urea as chemical fertilizer (F1), combination of chemical fertilizer and cattle manure (F2), zeocompost (F3), vermicompost (F4), zeoponix (F5), combination of zeocompost and vermicompost (F6)combination of zeocompost and zeoponix (F7), combination of vermicompost and zeoponix (F8)). Theresults indicated that the maximum seed yield was obtained in normal irrigation treatment (irrigation afterconsuming 30% of available soil moisture). Under water deficit stress conditions (irrigation afterconsuming 50 and 70% of available soil moisture), organic treatments amended with more zeolite(zeocompost, zeoponix and zeocompost + zeoponix) improved seed yield. Under severe water deficitstress condition (I3), zeolite-amended organic treatments (zeocompost, zeoponix and zeocompost +zeoponix) increased seed oil percentage by 8, 9 and 13 percent in the first year and by 13, 10 and 12percent in the second year of the experiment in comparison with chemical treatment (F1). In addition, organic treatments improved oil quality through increasing linoleic and oleic acid percentage. Overall, theresults suggest that combined application of processed organic fertilizers such as vermicompost, zeocompost and zeoponix not only increases sunflower seed yield and oil quality but also reduceschemical fertilizers need in sunflower production.

In order to investigate the effect of a native plant growth promoting bacteria (Enterobacter sp. ) on somevegetative characteristics and paddy yield of rice (cv. ‘ Tarom Hashemi’ ), a field experiment was carriedout in Babol (Aghamalek village) at 2016. This experiment was arranged in split plots based on arandomized complete block design with three replications. Six levels of potassium sulfate fertilizer (PSF: 0, 25, 50, 75, 100 and 125 kg ha-1) were used as the main plots and four levels of inoculations (noninoculationas control, seed inoculation in the seedbed condition, seedling root inoculation beforetransplanting time and combined both previously methods) served as the sub-plots. The results indicatedthat various methods of inoculation increased plant height (1. 25-2. 54%), tillers number per hill (TNH; 11. 7-16. 5%), total leaves number per hill (TLN; 12. 5-14. 2%), leaf area index (LAI; 7. 16-17. 9%) andpaddy yield (PY; 14. 6-19. 8%) of rice and the occurring of anthesis stage were about one day sooner ascompared to the control condition. In this experiment, the studied traits significantly influenced by PSFand various methods of inoculation, but the interaction effect between them were not significant. Amonginoculation methods, the combined method was better than others. In addition, the values of all studiedtraits such as PH, TNH, TLN, LAI and PY (18. 2% more than the control) increased as PSF increasedfrom zero to 125 kg ha-1. Consequently, the application of Enterobacter sp. and PSF through improvedthe vegetative characteristics, particularly in LAI, TNH and TLN, resulted to increase in the radiationinterception capacity, photosynthetic efficiency and improved PY of rice.

The present experiment was performed to optimization of thorny and thornless blackberry propagation viafactorial in a CRD, the first factor included four cultivars (everthornless, thornless evergreen, early andmid-ripen thorny) from blackberry collection, the second factor root cutting's diameter (2-3 and 3-5 mm)and the third factor involves the root cuttings length (6, 8, 10 and 12 cm), with seven replications inMarch 2016. After three months rooting performed under shade and humid condition then the rooting andits related traits measured. Results of rooting in thorny and thornless cultivars showed root cuttings with2-3 mm diameter and 12 cm length produced the longest root in the proximal end of the mid-ripen thornycultivars with 123. 43 mm. In chimera and mid-ripen thornless cultivars the most rooting percent observedin the 12 cm length in all of the diameters with an average of 71. 42%. Thornless cultivars significantly, showed better survival percent (77. 33), inside of shorter roots length (51. 8cm) and shoot (46. 07cm), incompare to thorny cultivars. The highest percentage of survival (77. 33%) observed in normal thornless, among thornless cultivars, and early thorny (64. 58 %) in thorny cultivars. The results showed that rootcutting with 3-5 mm diameter and 10-12 cm length had significantly effect on increase of blackberry rootcutting rooting. The genetic difference between cultivars and amount of reserved material in cuttings mustbe considered in the propagation of blackberries by root cutting.

In order to evaluate the effects of chemical, biological and nano fertilizers on the yield and quality traits(oil and protein) of sesame seeds under different irrigation regimes an experiment was conducted as asplit-plot factorial based on completely randomized blocks design with three replications at ShahedUniversity during 2015-2016 growing seasons. Irrigation withholding levels (full irrigation (control) andirrigation withholding at 65 and 75 BBCH (codes of phonological stages that are equivalent to 50% offlowering and seed ripening respectively) were assigned as main plot and different nitrogen combinations(nitroxin, urea, and a mix of 50% nitroxin plus urea), various combinations of potassium (not used, nanopotassiumfoliar application (2 per thousand), irrigated use of potassium dioxide (2 L ha− 1) and soilapplication of nano-potassium (2 kg ha− 1) were allocated in the subplots. The highest number of per-plantcapsules (19. 26 numbers) was observed with irrigation up to 50% seed ripening and the use of ureatogether with the potassium nano chelate foliar application. The greatest grain yield and protein contentand yield were obtained in irrigation up to 50% seed ripening in the absence of potassium fertilizer andnitroxin usage (1340. 5, 276. 53 kg ha− 1 and 5-20%, respectively). The oil yield was utmost in irrigation upto 50% flowering and foliar application of potassium nano chelate together with the mixed system of 50%urea fertilizer plus nitroxin with average values of 47. 96% and 550. 46 kg ha− 1, respectively. The use ofnitroxin as a nano-bio-fertilizer and foliar application of chelated nano potassium in irrigationwithholding conditions up to 50% grain aggregation resulted in increased grain yield (approx. 15%compared to the control) as well as improved quality of sesame seeds.

To analyze the growth, it is necessary to access to accurate and well-arranged data obtained frommeasuring leaf area and dry matter accumulation. The purpose of this study was to evaluate differentnonlinear regression models to study the trend of changes in leaf area index and dry matter productionand to estimate the parameters related to the growth analysis. The experiment was conducted on faba bean"cv. Barkat" in a split-plot experiment based on randomized complete block design with three plantingdates and four densities in four replications. In this study, the beta and logistic models were fitted to theleaf surface data and the beta, Gompertz and logistic models to dry matter production. AICc benchmarkshowed that the beta model was fitted to the leaf surface data the better than the logistic model. LAImax indifferent densities varied between 2. 3 to 5. 3, tm between 131. 9 and 144. 2, and te between 158. 7 and 163. 5days after planting. AICc benchmark showed that the beta model was fitted to the dry matteraccumulation data the better than the Gompertz and logistic models. Wmax in different densities variedbetween 725. 1 and 1484. 3 g/m2, tm between 138. 3 and 146. 4 and te between 162. 60 and 179. 0 days afterplanting. Grain yield varied from 231 to 2744 g/m2, and with increasing density in each planting date, grain yield showed the increased trend. The results showed that yield changes were directly affected bymaximum leaf area index, maximum dry matter accumulation and crop growth rate.

The present study aimed to investigate the effect of silicon (Si) on alleviation of the drought-reverseeffects in two Althernanthera genotypes “ Entire leaf” and “ Undulated leaf” . Pot experiment, consists ofequal parts of soil, sand and manure, was carried out as factorial based on a completely randomizeddesign with six replications. After plants establishment, 0, 1 and 2 mM of silicon were weekly sprayed onplants grown under drought stress conditions (90% field capacity (FC), 75 and 55 percent FC). Sitreatment started one week before the beginning of drought stress. Samples were taken after 12 weeks oftreatment. The analysis of variation showed that increasing drought stress significantly affected allmorphological (plant height, stem diameter and root length), physiological (fresh and dry weight of stemand root, relative water content, electrolyte leakage) and biochemical (chlorophyll a, chlorophyll b, totalchlorophyll, proline and anthocyanin) characteristics. Whereas, silicon application (especially with 2 mMconcentration) alleviated the stress effects and improved growth parameters. Electrolyte leakage as anindicator of cell membrane integrity was decreased by application of silicon. Results of this study showedthat different varieties have the variable resistance to stress. In this study, “ Undulated leaf” genotype wasmore resistant compared to “ Entire leaf” . So, it can be cultivated in gardens in areas where the waterscarcity is prevalent.