نشریه پژوهشهای زراعی ایران
سال دوازدهم شماره 3 (پیاپی 35، پاییز 1393)

Response surface models predict crop yield based on crop density and this is an important tool for evaluation competition at different density and hence selection of optimum density based on yield. In order to study intra and inter specific competition in intercropping bean (Phaseolus vulgaris) and sesame (Sesamum indicum)، an experiment was conducted at the Agricultural Research Station، Ferdowsi University of Mashhad during the growing season of 2010. For this purpose a complete randomized block design with 3 replications and 16 treatments based on different densities of sesame and bean intercropping was used. The model predicted the maximum yield of an isolated plant of bean and sesame approximately 33 and 17g per plant respectively. The area associated with the maximum yield per plant in bean and sesame were 0. 6 and 0. 1 m2، respectively. Bean was the dominant competitor with respect to both grain and biomass، and competition coefficient was 0. 35 and 0. 3 for bean grain yield and bean biomass respectively. Intra-specific competition was more important than inter-specific competition for bean. Competition coefficient was 2. 6 and 2. 9 for sesame grain yield and biomass respectively. Intra-specific competition was much less important than Interspecific competition in sesame. The highest grain yield in bean (300 g m-2) was obtained of sole crop with density of 20 plants، and the highest sesame grain yield (195 g m-2) was obtained of sole crop with density of 40 plants، the highest land equivalent ratio (1. 14) was obtained in intercropping of 20 plants of bean and 10 plants of sesame.

Twentieth century had faced considerable increase in crops yields. Nonetheless، it is postulated that world population will reach 10. 4 billion until 2050 which means the demand for agricultural crops production should be increased between 60 and 110 percent. In the present study، improvements in grain yields of wheat، maize and rice during the recent decades in Iran were studies through analyzing morphological and agronomic data relevant to these three crops between 1957 and 2012. Linear regression was used to analyze the trends of improvements in different traits. Results indicated that wheat and maize grain yields in the target period have significantly increased، while little increase in rice yield was observed. Results showed that breeding programs could significantly shorten plant height in wheat and maize، especially in spring wheat compared to winter wheat، but this was not the case in rice. Regarding one thousand-grain weight، little change was observed in wheat although the amount of increase in this trait was more in spring rather than winter wheat. The study showed that newer maize cultivars were more tolerant to higher plant density compared to older cultivars. In rice، it was revealed that crop growing period has considerably decreased during the studied period. Overall، it could be concluded that breeding could effectively increase spring and winter wheat and maize grain yields in Iran. However، regarding rice it seems that breeding was not successful toward grain yield improvement.

In other to evaluate the effects of Nitroxin biofertilizer and different levels of nitrogen fertilizer، on yield and yield components of winter wheat (Triticum aestivum)، a field experiment was conducted in Research Station، College of Agriculture، Ferdowsi University of Mashhad in 2009-2010. The experiment was conducted as a factorial arrangement based on completely randomized block design with three replications. The experimental treatments were all combination of nitroxin biofertilizer in two levels (inoculated with nitroxin and non inoculated)، and nitrogen fertilizer in six levels (0، 10، 20، 40، 80، 160 and 320 Kg ha-1 urea). Result showed that combination of biofertilizer with different levels of N fertilizer، had significant effect (p)

In order to study the intercropping arrangements of coriander (Coriandrum sativum L.) and fenugreek (Trigonella foenum-graecum L.)، a field experiment was conducted during growing season of 2010 at Agriculture Research Station، College of Agriculture، Ferdowsi University of Mashhad، Iran. A randomized complete block design with three replications was used. Treatments included: mono-crop of fenugreek (A)، %25 of optimum density of coriander + %175 of optimum density of fenugreek (B)، %50 of optimum density of coriander + %150 of optimum density of fenugreek (C)، %75 of optimum density of coriander + %125 of optimum density of fenugreek (D)، %100 of optimum density of coriander + %100 of optimum density of fenugreek (E)، mono-crop of coriander (F)، %125 of optimum density of coriander + %75 of optimum density of fenugreek (G)، %150 of optimum density of coriander + %50 of optimum density of fenugreek (H)، %175 of optimum density of coriander + %25 of optimum density of fenugreek (I). Biological yield harvested in coriander at %5 flowering stage and in fenugreek at %20 flowering stage. The result showed that B treatment had highest plant height and biological yield of fenugreek، highest total land equivalent ratio and also B treatment had lowest essential oil contents of leaf، essential oil yield and biological yield of coriander. I treatment had lowest biological yield of fenugreek and it had highest essential oil contents of leaf، essential oil yield and plant height in coriander. Also A and E treatments had highest percent of nitrogen of biomass in fenugreek and coriander، respectively.

Salinity of water and soil in arid and semi arid regions restricts the growth and yield of crops such as sesame. In order to evaluate yield and yield components of 43 lines and ecotypes of sesame (Sesamum indicum L.) under saline condition (EC of irrigation water، 5. 2 dS m-1) an experiment was carried out in randomize complete block design with three replications at salinity Research Station of Center of Special Crops، Agricultural College، Ferdowsi University of Mashhad in 2010. Results showed that 25 sesame accessions were capable to emerge and growth until maturity and others died in different growth stages. There were significant differences between sesame accessions for yield and yield components (number of capsule per plant، number of seed per capsule and 1000 seed weight). The maximum biomass was obtained from MSC3 (73. 2 g/plant)، and in 24 percent of accessions was further than 30 g plant-1 and the maximum grain yield was observed in MSC3 (24. 7 g m-2). There was considerable variation between accessions in number of capsule per plant، so that the range was from 2 to 57 capsules per plant. Results of correlation coefficients showed that there were significant and positive correlation between seed yield and number of capsules per plant (r=0. 46**) and biological yield (r= 0. 94 **). It seems that for selection of salt tolerant sesame accessions، screening of seed yield in field conditions is a reliable index. However، further study on growth and physiological processes is necessary for determination of salt tolerance in sesame.

Modeling is one of the best tools for quantitative analyzing of biological systems that is helpful for understanding physiological basis of crops growth and development especially under limited water. In this study، a model was developed based on FAO Penman-Monteith model to simulate soil water balance (SWB) components and linked with wheat growth and development model، which was developed based on basic models SUCROS and LINTUL. A field experiment was conducted in order to presented model validation in 2010-2011 at the Ferdowsi University of Mashhad Research Field. Experimental design was split plots with 5 irrigation treatments (main plot)، 2 cultivars (sub plot)، and 3 replications. Irrigation treatments included irrigation based on full water requirement (FI)، without irrigation during spring (NI)، irrigation at the rate of 75% of water requirement (75% FI)، irrigation at the rate of 50% of water requirement (50% FI) and irrigation at the rate of 25% of water requirement (25% FI) and subplots also included Pishgam (drought-resistant) and Gascogne (drought-susceptible) wheat cultivars. Then simulated results was validated with two

fitted linear regression between observed and simulated data and compare with 1:1 line and Root Mean Square Error in percent (RMSE %). The result of LAI-trend simulation was excellent for susceptible cultivar in non-stress condition (FI treatment) and medium for drastic stress condition (NI and 25%FI treatments). The simulation accuracy was good for other treatments. The LAI-trend simulation for resistant variety was good in all treatments. The model accuracy in maximum Leaf Area Index (LAImax) simulations and its day ripening was excellent for both varieties. Dry matter production of susceptible cultivar was simulated excellent only in FI treatment and good for other treatments. But the model accuracy was gained excellent for resistant variety in all treatments. The model accuracy in yield simulations also was excellent for both varieties. The simulated yield for NI، 25%FI، 50%FI، 75%FI and FI treatments was 1285، 3031، 4697، 6137 and 7649 kg. ha-1، respectively. The actual yield of Gascogne variety for the mentioned treatments was 1615، 2954، 4483، 5952 and 8132 kg. ha-1، and for Pishgam variety was 1758، 3652، 5071، 6064 and 7548 kg. ha-1، respectively. Overall، the results suggesting the effectiveness of presented model to predict wheat growth and development variation under different water supplies but should be revalidated with various experiments to reach better results.

Root depth and distribution have an important role in drought resistance and optimization of moisture content of soil. This research was carried out in order to consider of root response of triticale genotypes to water stress and recognition of root trait that can effective in resistance of water stress. This experiment was in a factorial experiment based on completely random design on the year 2009. The genotypes of triticale was included (i) ET-82-15 (ii) ET-82-8 (iii) ET-82-17 and commercial triticale genotype Juanillo-92. Two irrigation regimes included 100 and 50 % of field capacity، respectively. The result showed that water stress result in increased 9% of root depth in each plant. Differences between minimum root depth was observed in ET-82-15 rather than maximum root depth in Juanillo-92 was approximately 8. 2 centimeters. Late irrigation caused to diminish 25% of root length. Differences between maximum root length in ET-82-15 and minimum root length in ET-82-17 was not significant (p)

In order to study the effect of Ca، K، and Mn foliar spray on vegetative traits of safflower (Padideh cultivar) under salt stress، a factorial experiment was conducted based on randomized complete blocks design with three replications in Vali-asr university greenhouse. Factors included salinity with four levels representing 0، 500، 1000، and 1500 mg NaCl kg -1، and foliar spray with four level representing 10 mM spray of distilled water، CaNo3، K2HPO4 and MnSo4، 1 mM spray، respectively، sprayed two weeks after emergence، one application per 2 weeks. Results showed that increasing salinity level، reduced plant dry weight، leaf area، height، while salinity and foliar spray treatments has no effect on number of leaves. Highest leaf area was obtained after K2HPO4 and CaNo3 foliar spray، and lowest leaf area was obtained from MnSo4، K2HPO4 and CaNo3 foliar spray prevented somewhat early plant growth rate reduction treated with 500 and 1000 mg NaCl. Applying 1500 mg NaCl reduced SPAD value، and leaf chlorophyll fluorescence. MnSo4، K2HPO4 and CaNo3 foliar spray nutrients، also reduced SPAD value.

A pot experiment was designed to evaluate the effect of Trichoderma spp. on yield and yield components of wheat (cv. N81) under different levels of cadmium nitrate. Experiment was arranged in factorial based on completely randomized design with three replicates. Trichoderma harzianum at two levels (with and without inoculation) and four levels of cadmium nitrate (0، 50، 100، 150 mg l-1) were the treatment. Results of ANOVA and mean comparisons showed that inoculation of Trichoderma increased biological yield (46%) and straw yield (30%) as compared to control. Cadmium pollution has led to significant decrease in harvest index، grain number per spike and partitioning coefficient up to 5، 20، 24 and 38 percent compared to control، respectively. Furthermore، cadmium and fungus interaction were significant in terms of spike number، grain weight per spike، grain yield and tolerance index. Maximum grain yield and tolerance index were recorded in Trichoderma inoculation under cadmium-free plots which nearly increased 65 and 53 percent، respectively. In conclusion، using Trichoderma under cadmium pollution could improve wheat growth، yield and tolerance index

In order to investigate rice competition ability against weeds in direct-seeding and transplanting systems afield experiment was conducted at Mahmud Abad region of Mazandaran province on 2011 growing season. Experimental treatments were studied in a split plot factorial design based on randomized complete blocks with three replicates. Direct-seeding and transplanting of rice in wet seedbed were the main plots and three rice cultivars under two weed management systems (weed free and weed infested) were arranged in sub plots. Results showed there was no significant yield difference in both system of rice planting under weed free condition، but yield loss due to weed interference in direct-seeding and transplanting of rice were 66% and 14% respectively. Line 843 which showed high competition ability in transplanting of rice، encountered with low ability due to weed pressure derivedweek early vigor but our traditional cultivar (Tarom Deilamani) has acceptable competition ability and better yield sustainabilitythan improved cultivar (Khazar) and line 843 in direct seeding system. Cultivars competitiveness could be attributed to more height، higher growth rate in early season، panicle number and higher dry weight of rice. Also in direct seeding related traits to the early vigor was more important than others. Results revealed that direct seeding integrated with weed control could be a good strategy for reducing costs of rice production. In such a system seedling early growth has important role in weed suppression.

Broomrape would have irreversible effects on tomatoes in all growth stages and the damage would be unrecoverable. In order to chemically control Orobanche spp with consumption of bio-fertilizer in tomato cultivation، an experiment as factorial based on complete randomized blocks design in three replications and 12 plots was carried out at a farm which is located in Mahabad city (Iran). In this experiment، the experimental factors were including: A- sulfosulfuron 35 g/ha in three levels (application، at 40 days after transplanting of seedlings، application at 60 days and after sample transplanting without any chemical spraying)، B and C: bio- fertilizers، Barvar -2 and Nitrajin in two levels (application and non-application of bio-fertilizer)، were taken place. The results showed that Sulfosulfuron treatment at the rate of 35 gr/ha، with- twice application of 40 and 60 days after transplanting of seedlings decreased the biomass of Orobanche aegyptiaca in surface level and also it was possible to decrease the biomass per tomato bush and Orobanche aegyptiaca biomass to amount of 75%، 57% and 60% respectively compare to the main treatment without applying any kind of spray application. The applied bio-fertilizer-2 decreased the amount of fruit and economical function of tomato. The applying phosphate biofertilizer-2 resulted in a decrease in economical function of Lycopersicum esculentum and number of ripen fruits. However none of the applied treatment was influential on diameter and weight of ripen fruits.

Growth analysis is a valuable method in the study of quantitative of growth، development and crop production. In order to study the physiological growth indices of lentil plant under dry- farming conditions، an experiment was carried out as a randomized complete block design with three replications at the Agricultural Research Station of Lorestan University during 2010. In this experiment two cultivars were used including Gachsaran and Philip، that are appropriate and commonly in the area cultivating. In order to have more accurate study، Growing Degree Day (GDD) index was used for fitting growth curves، and then appropriate model was selected for each growth index using non-linear regression models. The results of the growth indices showed that Gachsaran cultivar has higher priority than Philip cultivar in leaf area index، but Philip cultivar had higher priority than Gachsaran cultivar in crop growth rate، net assimilation rate and dry matter production. Relative growth rate was similar in both cultivars. In total، growth characteristics of Gachsaran cultivar leading to higher seed yield and growth characteristics of Philip variety leading to produce more biological yield.

In order to investigate the effects of weeds interference on yield and yield components of different genotypes of common bean، an experiment was conducted as split plot based on randomized complete block design with three replications at Agricultural Research Station of Tabriz University، in 2011. The main plots were eight genotypes of different types of common bean including red bean، (cv. Gholi، Sayad، Derakhshan and Akhtar); pinto bean، (cv. Khomein and Sadri) and white bean (cv. Shokufa and Pak) and the sub-plots were two levels of weed including weed-free and weed-infested. Results indicated that the effect of bean genotype was significant on yield and yield components. The effect of weed treatment was significant on all traits of common bean، except 100-seeds weight. The pod number per plant of all common bean genotypes reduced significantly under weed-infested treatment. The interaction effect of weed treatment× genotype was significant on bean seed number per pod، grain and biological yield. Among the genotype، the cv. Gholi had the highest pod number per plant and the cultivars Gholi and Shokufa had the highest seed number per pod. The cultivars of Gholi and Khomein produced the highest and lowest seed yield، respectively in both weed-free and weed-infested treatment. The common bean genotype showed different competitive ability as the genotypes Gholi and Pak had the higher competitive ability against the weeds than other genotypes. Therefore by cultivating the bean genotypes with high competitive ability against the weeds، the yield loss of common bean could be reduced as well as the growth of weed species will be suppressed.

Considering importance of baby corn، the study was consisted of sowing date (14th June، 3th July and 24th July) as main Plots and plant densities (6. 5، 8. 5 and 10. 5. plant m-2) as sub Plots and two harvest methods (baby corn، as first harvest sweet corn and next ear as baby corn) on Growth parameter and yield of baby corn (Zea mays L. Var SC403su) in agricultural Research Center and Natural Resources of Khorasan Razavi Province، Mashhad on 2009. The experiment was carried out in a factorial split plot design based on randomized completely block design with 4 replications. The results showed the highest plant height on sowing date 3thJuly with average 168. 6 cm. Also the highest standard ear percentage that one of the important factors for food manufactory had on sowing date 24th July with plant density 10. 5 plants plant m-2، by harvesting method baby corn with 63. 9 percentages. Also The results showed the highest substandard ear percentage of baby corn was belonged to sowing date 24th July with 8. 5 plant m-2، by harvesting method (baby corn sweet corn) with 74. 6%. The highest harvest ear index was belonged to sowing date14thJune، by harvesting method (baby corn sweet corn) with 35. 29 percentages. Therefore، sowing date 3thJuly for forage production with average 4 kg m-2 by harvesting method baby corn are recommended for lateral produce production. Considering to Mashhad weather conditions، producing the highest and best standard ear percentage، density، 10. 5 plants per square meter and 24th July planting is recommended.