دکتر محمد زمانیان

In order to evaluate the impact of different ratios of forage sorghum of espidfid cultivar and clover of berseem cultivar intercropping on forage yield and economic profitability, an experiment was conducted based on a randomized complete block design with eight treatments and three replications during 2016 and 2017 growing seasons at the Research Farm of Seed and Plant Improvement Institute (SPII), Karaj, Iran. The treatments consisted of eight different planting ratios: 75% sorghum + 25% clover, 50% sorghum + 50% clover, 25% sorghum + 75% clover as replacement intercropping; 100% sorghum + 50% clover, 50% sorghum + 100% clover, 100% sorghum + 100% clover as additive intercropping; and sorghum monoculture and clover monoculture as control. For economic analysis was used partial budgeting method and profitability indices including net income, the percentage of sale return and the percentage of cost recovery in production. The results showed that, the highest cost of production were achieved in 100% sorghum + 100% clover treatment with a average of 49.7 million rials ha-1 and the lowest cost were obtained in clover monoculture with an average of 40.6 million rials ha-1 . The treatment of 100% sorghum + 100% clover had the highest net income with an average of 99.6 million rials ha-1. In the treatment of 100% sorghum + 100% clover the sale return was calculated 66.7%. Also, the percentage of cost recovery was estimated 200%. According to the results, 100% sorghum + 100% clover was recommended as a superior treatment in Karaj.

Clover is considered as one of the most important forage crops of the leguminous family which is appropriate for temperate and humid areas. Insufficient water can severely affect the production of forage legumes leading to a reduction in yield based on the severity and duration of drought stress. Due to the relative sensitivity of clover to drought stress, the yield of this crop is affected by water scarcity, especially in arid and semi-arid regions. One of the effective solutions in the field of plant breeding for drought resistance is to identify stress-tolerant genotypes. This study aimed to compare the forage yield and water productivity of Persian clover genotypes under full irrigation and drought stress conditions, as well as evaluate their drought tolerance. The experiment was conducted as a split plot based on a randomized complete block design with three replications at the Seed and Plant Improvement Institute, Karaj, Iran, during the 2017-18 and 2018-19 cropping seasons. Irrigation regimes at two levels (full irrigation and deficit irrigation with supply 100% and 75% of clover water requirement, respectively) as the main factor and Persian clover genotypes at five levels (cultivar Pars, and ecotypes Zabol, Aleshtar, Eghlid, Harati) as sub-factor were evaluated. Each subplot consisted of four rows with a length of five meters and 50 cm between rows. The planting operation was carried out manually on September 11 of each year with 20 kg ha-1 seeding rate. The volume of irrigation water was determined by the Penman–Monteith method and the counter meter was used to accurately measure and control the amount of applied water. In the first and second cropping seasons, the total volume of irrigation water used were equal to 10125 and 11985 for full irrigation and 7594 and 8989 for deficit irrigation conditions, respectively. In this study, the fresh forage and dry matter yields, irrigation water efficiency for production of fresh forage and dry matter, the days to flowering, and drought tolerance indices were investigated. For all three cuts, clover cultivars were harvested at the 10% flowering stage. To determine the fresh forage yield, the middle four rows of each plot were harvested and weighed. To determine the dry matter yield, fresh samples (2 kg plot-1) were randomly selected and dried in a forced-air oven at 65 °C. Irrigation water-use efficiency was calculated from the ratio of yield to the amount of water consumed. The combined analysis of variance was performed using SAS9.1 and the means were compared by the LSD method at P < 0.05. The fresh forage and dry matter yields in the first, second and third cuttings, as well as their total and the irrigation water-use efficiency for forage and dry matter production were significantly affected by the year × irrigation × genotype interaction. Ecotype Harati had the highest total fresh forage and dry matter yields during three cuts (91.19 and 13.02 ton ha-1, respectively) in full irrigation conditions, whereas, under deficit irrigation conditions, the maximum total fresh forage and dry matter yields (68.07 and 10.79 ton ha-1, respectively) were obtained by ecotype Zabol. The maximum water-use efficiency (1.455 kg dry matter m-3) was obtained in the second year and by ecotype Zabul under deficit irrigation conditions, whereas the minimum efficiency (0.899 kg dry matter m-3) was recorded in the first year under full irrigation conditions and in the ecotype Zabol. Drought stress treatment in genotypes Pars, Aleshtar, Eghlid, Harati and Zabol compared to full irrigation caused a decrease in dry matter yield by 24.0, 21.7, 23.4, 23.8 and 11.9%, respectively. Among the drought tolerance indices, tolerance index (TOL), stress sensitivity index (SSI), yield stability index (YSI) and relative stress index (RSI) had the highest correlation with yield under full and defecit irrigation conditions. Based on the mentioned indices and principal components analysis (PCA), the ecotype Zabul, followed by ecotype Eleshtar were identified as the most tolerant genotypes to the defecit irrigation stress. Overall, the results of this experiment demonstrated that in the irrigation water availability conditions, the ecotype Harati and in the water limitation conditions, the ecotype Zabol are recommended for cultivation in the semi-arid regions of the country.

The present study is conducted to separate the effective and influential management factors in the production of clover forage in Iran and to identify its limiting factors. In this study, the data obtained from 68 research projects conducted by the Agricultural Research, Education, and Extension Organization (AREEO) throughout the country during the 2009-2020 years have been analyzed, using the meta-analysis method. The results show that planting date -3.31%, planting method -22.82%, species +40.14%, seeding rate (planting density) +1.53%, drought stress -16.16 %, and phenological stage of forage harvesting -15.42% justify the amount of forage clover variation. Thus, fall planting in the middle of September, basin planting method, choosing the Berseem clover species (Trifolium alexandrinum var. Karaj), the seeding rate of 15-20 kg ha-1 (for forage production), and forage harvesting at the phenological stage of 10-25% flowering, are the most important management and agronomic factors in increasing clover forage production in cold and temperate regions, and not complying with one or a set of these factors will reduce the clover production and will cause yield gap. Overall, the species, planting method, and drought stress are respectively recognized as the most important factors affecting clover forage yield in Iran.

Climate change drastically reduces the amount of water available to plants and increases the severity and frequency of droughts. By the end of this century, it is anticipated that droughts will continue to increase significantly. Drought stress, as one of the major climate events, induces physiological and morphological alterations, which can restrict crop growth, yield, and quality. In recent years, separate research projects and studies in the country have evaluated the effects of drought stress on grain maize, forage maize, grain sorghum, forage sorghum, grain millet, alfalfa, and clover yields, as well as the effects of drought stress on their yield gap. However, if the results of these separate studies were evaluated together, it would have been possible to compare the drought sensitivity and tolerance of various crops. Consequently, the optimal crop to plant under drought-stress conditions in the nation's agroecosystems would be determined. The meta-analysis is a statistical analysis that can assess the aggregate effects of numerous studies conducted under varying conditions. In other words, meta-analysis is a statistical technique for integrating the findings of multiple studies in order to comprehend a problem. The purpose of this meta-analysis was to determine the impact of different drought stress levels on the yields of grain maize, forage maize, grain sorghum, forage sorghum, grain millet, alfalfa, and clover.

In this study, the data obtained from 145 final reports of the Agricultural Research, Education, and Extension Organization (AREEO) and published articles over the past decade were analyzed using the meta-analysis method. This included grain sorghum (18 studies), forage sorghum (21 studies), grain maize (28 studies), forage maize (23 studies), grain millet (18 studies), alfalfa (17 studies), and clover (20 studies). In addition to the difference in quantitative results between studies, the effect size variance was utilized in this method. Consequently, the means, standard deviations, and sample sizes (replications in each study) for the control and evaluated treatments were determined. After classifying the data, the reaction ratio (R) and its natural logarithm were calculated. Subsequently, the method determined which treatments have additive or decreasing effects on yield under drought stress conditions, as well as which treatments had no positive or negative impact on yield. Utilizing the T-test, a group comparison was conducted between the mean yield under drought stress conditions and the mean yield under normal irrigation conditions in order to determine the significance level of yield changes caused by drought stress. The statistical analysis and preparation of the figures were performed by Excel.

According to the findings of the meta-analysis, the overall effect of drought stress on the yield of all seven crops was significant for grain sorghum (-16.30%) (P<0.05), forage sorghum (-18.27%) (P<0.05), grain maize (-31.75%) (P<0.01), forage maize (-33.24%) (P<0.01), grain millet (-25.66%) (P<0.01), alfalfa (-30.79%) (P<0.01), and clover (-32.14%) (P<0.01). The yield reductions in grain maize, forage maize, alfalfa, and clover were significant under all levels of drought stress, whereas grain sorghum, forage sorghum, and grain millet yield reductions were significant only under severe drought stress. The yields of grain sorghum, forage sorghum, grain maize, forage maize, grain millet, alfalfa, and clover decreased by 10.03, 11.84, 18.21, 20.27, 14.13, 19.74, and 20.37%, respectively, under moderate drought stress, and 21.98, 25.41, 39.09, 41.37, 32.55, 40.13, and 42.08%, respectively, under severe drought stress.

As a result, it is impossible to cultivate and develop grain maize, forage maize, alfalfa, and clover in areas with limited water resources without significantly reducing yield. According to the findings of this meta-analysis, grain sorghum, forage sorghum, and grain millet with a moderate drought stress tolerance threshold could be recommended for cultivation in regions where drought stress conditions are likely to occur.

To evaluate the quantitative and qualitative forage yield of clover cultivars under water deficit, a split plots experiment was conducted in randomized complete block design with three replications at the Seed and Plant Improvement Institute, Karaj, Iran, for two cropping years (2017-18 and 2018-19). Three irrigation regimes included full irrigation (supplying 100% of clover water requirement), moderate stress (supplying 75% of clover water supply) and severe stress (supplying 50% of clover water supply) as the main factor, and five clover cultivars (Karaj, Elite, Ekinaton, Win and Alex) were evaluated as the sub-factor. The results showed that the maximum yield of fresh forage and dry matter in all three irrigation levels were obtained from Win and Karaj cultivars and the minimum from Ekinaton cultivar. The highest water use efficiency for the production of lactation energy at the irrigation levels of 100%, 75%, and 50% was obtained from Win, Alex and Elite cultivars, respectively. In water deficit stress, dry matter yield, metabolizable protein yield, content and yield of net lactation energy decreased, whereas metabolizable protein content increased. In addition, water deficit stress increased water use efficiency for the production of dry matter, metabolizable protein, and net lactation energy. Overall, due to the both quantitative and qualitative traits, Elite and Karaj cultivars are recommended as the best genotypes for cultivation under water deficit stress conditions.

Advantage of native populations of Persian clover to increase quantity and quality of the forage yield, high diversity among the native clover populations of Iran and the lack of registered cultivars driven from these landraces are important reasons for introducing new clover cultivars with native origin in the country. Pars cultivar was selected by pure line selection method in 1999 from 22 native multi cuts clover populations. In 2000-2001, the seed of primary population were planted and superior single plants in each row were selected based on comparison with the native population of Baladeh Kazerun as check cultivar. Then, the selected single plants (top 150 lines) were compared in an alpha lattice design with two replications in 2002-2003. Selected top lines during 2004-2005 were compared in three regions of Karaj, Shahrekord and Broujerd in a semi-final performance trial. To determine the stability and value for cultivation and use (VCU) of the top 15 selected lines, these lines were compared in a completed randomized block design in five regions of Karaj, Boroujerd, Shahrekord, Arak and Sanandaj in 2006-2007. Evaluation of the reaction of selected Iranian clover lines to rust and black clover spot in 2007-2008 cropping year was performed in Boroujerd station under natural infection in the field. To determine the quality and nutritional value of selected lines, an experiment was conducted in Karaj in 2008-2009 cropping year. The results showed that promising Iranian clover lines KPC-EqlidFars-78-4 with 19.9% protein content was superior to the control. In the cropping year 2015- 2016, a research-extension experiment was conducted to compare the forage yield of promising Iranian clover lines KPC-EqlidFars-78-4 with a local control (Harati) in Boroujerd. The results showed that line KPC-EqlidFars-78-4 under farmers' conditions had 72.65 tons per hectare of wet forage yield and 11.56 tons per hectare of dry matter yield with 10.60 and 12.20% superiority to the local control, respectively, Its appropriate optimal use of spring rainfall due to its high growth rate and possibility of mechanized harvesting, due to standing form and high height, early maturity and shorter growing period can result in less irrigation in one growing season, high forage yield potential, especially in onset of the season and also its resistance to rust and black spot diseases that is common in the native population, were some important characteristics of Pars cultivar for release and cultivation in the cold and temperate regions.

To identify the limiting factors in forage maize production in Iran, this study has been carried out in order to separate the effective and influential management factors in forage maize production in the country with data. It is obtained from 43 final reports or their derived extracted articles in Agricultural Research, Education and Extension Organization (AREEO) with meta-analysis method. According to the results, plant density (5.65%), drought stress (-13.44%), cultivar (0.31%), planting date (2.54%), and nitrogen fertilizer (24%) justify the amount of forage maize variation. Based on the results of this study, forage yield has increased by about 9.49%, increasing plant density between 80 to 100 thousand plants per hectare. Maize forage yield has decreased significantly under mild stress, severe stress, and very severe drought stress by 25.30%, 14.38% and 8.99%, respectively. Also, for different cultivars and different groups of maturity, group-700 has had a significant increase of 3.83% compared to other groups. For the planting dates of forage maize compared to the control, which is the first half of June, a decrease in forage yield is observed. Finally, the highest percentage of increase in maize forage yield has been obtained from the use of 450 kg ha-1 of urea fertilizer. Overall, nitrogen fertilizer, drought stress, and planting density are recognized as the most important factors affecting corn forage yield in Iran, respectively.

Berseem clover (Trifolium alexandrinum), is one of the most important imported species of cultivated clover that cultivated for many years in the south and north of Iran. To increase the diversity of clover in agricultural systems, the genetic resources of annual wild clovers have been collected and evaluated over the past years in Iran. But, the reaction of these resources in semi-humid temperate regions of the north of Iran has not been investigated the forage production. For this purpose, 17 accessions of clover from eight species, including three cultivated species as: T. alexanderinum, T. resupinatum, and T. incarnatum; and five wild species of T. angostifolium, T. echinatum, T. diffusum, T. lappaceum, and T. purpureum along with the local cultivar of Berseem clover were cultivated and evaluated based on randomized complete block design with three replications, over two years (2018 and 2019) under rainfed conditions in Gorgan, Iran. The required moisture to the plant was provided by natural rainfall. After harvesting, the dry forage yield of each plot was calculated and the data of the two years were analyzed using nested ANOVA and mean comparisons were made using Duncan’s test. Results showed a significant difference among the species for forage yield. Forage dry matter yield ranged from 2063 kg/h in T. diffusum to 6120 kg in T. resupinatum, respectively. Based on coefficient of variation (CV) and fluctuation of forage production over two years, T. resupinutum and T. incarnatum had the highest and T. lappaceum and T. purpureum had the lowest forage production and CVs. This study showed that the genetic resources of Barseem clover available in the Iranian National Plant Gene Bank, as well as accessions of 50TN00250 (Persian clover), and 50TN00708 (T. echinatu) could be used as direct cultivation for forage production in the northern regions of Iran within the range of annual precipitation (212-425mm). But, the wild clovers 50TN00555 (T. purpureum), 50TN01238 (T. lappaceum), 50TN01548 (T. angostifolium), and 50TN01443 (T. diffusum) due to their low CV in different rainy conditions and their low yield, need further breeding researches for improve varieties in northern regions of Iran.

In order to investigate the effect of Paraquat herbicide on induced drying of plants and therefore, early harvest of crimson clover seeds in Alborz 1 cultivar a factorial experiment was conducted using a randomized complete block design with three replications, and 12 treatments for two cropping seasons 2012-2013 and 2013-2014. The first factor was different dosage of Paraquat consisted of four levels (a1= no herbicide, a2= 50% less than recommended dose (2 litreha-1), a3= recommended dose (4 literha-1) and a4= 50% more than recommended dose (6 litreha-1) and the second factor was phonological stage of the plants when Paraquat herbicide was applied consisted of three levels. (b1= Physiological maturation of seed, b2= 50% browning of the inflorescence, b3= complete inflorescence browning). Results showed that different amount of Paraquat in all three phenological stages had significant effects on seed yield, number of seeds per in florescence and 1000-seed weight compared to the control treatment with no use of herbicide. Result of the two-years study showed that a3b2 treatment with seed yield of 585.83 kgha-1 had the highest seed yield. However, there was no significant difference between application of 2 and 4 liters of Paraquat (Gramoxone herbicide) per hectare at the browning stage of 50% of inflorescences. Therefore, a2b2 treatment with seed yield of 585 kgha-1 and near 25% increase compared to the control is recommended for seed production of crimson clover Alborz 1 cultivar in Karaj region.

Intercropping or mixed culture is known as one of the oldest models of sustainable systems in agriculture. This method of cultivation provides the opportunity for farmers to benefit from biodiversity, reduces the potential damages caused by pests and diseases and maximize the use of water and soil resources. Alfalfa mixed culture with grasses is more common than their pure cultivation in many countries. For example, the direct use of alfalfa in pasture causes bloating of livestock, while its mixture with grasses eliminates this risk and it provides a balanced and complete diet. Several species of forage grasses such as orchard grass, lolium, festuca, canary grass and smooth brome grass are commonly used in mixed crops, especially with alfalfa. The results of studies conducted in Iran have indicated that land equivalent ratio (LER) and forage yield, as well as, quality are increased in alfalfa-grass mix cultures. Among studied forage grasses, mixed culture of alfalfa with festuca and canary grass provides more suitable forage yield and quality than other grasses.

To evaluate the compatibility and stability of Persian clover lines in different regions of Iran, an experiment was carried out with fifteen promising lines in a randomized complete block design with four replications in Karaj, Broujerd, Sanandaj and Share-e-Kord for two years. The results of combined analysis of variance for dry mather yield in different locations and years showed significant differences among lines, so that in Karaj line no. 13 (KPC/Eqlid-e-Fars/78-37) with 14.13, in Sanandaj line no. 11 (KPC/Eqlid-e-Fars/78-5) with 9.87, in Share-e-Kord line no. 8 (KPC/Lordegan-e-Char./78-17) with 9.93 and in Broujerd line no. 7 (KPC/2Chinene-e-Kord/78-30) with 13.59 tha-1 were superior lines. The slope of the regression line for dry matter yield was between 0.52 and 1.29 respectively, indicating that lines showed different responses to the environmental changes. Considering stability statistics, lines no. 10, 11, 8, 13 and 7 with the lowest deviation regression, highest coefficient of determination and highest yield were also superior.The results of stability analysis by graphical Biplot (GGE) showed that about 60% of dry matter total variations were explained by the first and second components. The results of stability analysis by Biplot (GGE) method showed that lines no. 6 (KPC/Eqlid-e-Fars/78-14) and no. 3 (KPC/Baladeh-e-Kaz./78-43) with 62 tha-1 fresh yield and 10.60 tha-1 dry matter yield were the most stable lines in different locations.

In order to evaluate the effect of planting date on forage quality and quantity yield in different cultivars of clover, an experiment was conducted in research farm in preparation of seed and plant improvement of Karaj in 2014-2015. This experiment was conducted in split plots in a randomized complete block with three replications and twelve treatments. Main factor includes planting date in three levels (22 July, 15 August and 10 September) and sub-factor contains four clover cultivars (mono cut persian clover, multi cut persian clover, berseem clover and laki clover). The studied characteristics include qualitative properties such as a dry matter percentage, crude protein percentage, acid detergent fiber, calcium, phosphorus content, fructose and glucose content. Results showed that multi cut persian clover had the most protein percentage (17.88) and dry matter percentage (48.30) and the minimum acid detergent fiber (29.86). Berseem clover and multi cut persian clover had the highest content of phosphorus in all planting dates. Multi cut persian clover had the most protein and the least fiber in all three dates.

In order to study the effects of planting date on quantitative and qualitative characteristics of different clover seed varieties, this research was conducted in a field during cropping year of 2012. The research facilities of Seed and Plant Improvement Institute of Karaj use at this study. This research in split plots including the major factor of planting date on 3 cultivation levels (conventional planting date 11 September and delayed planting date including 5 September and 20 October) and the sub-factor clover genotypes at 10 cultivation levels (Persian clover 7 cultivar, Berseem clover (production in Karaj). red clover, a variety called Nasim and Locki clover, a variety called Alborz 1). This research was conducted in a randomized complete block design (RBCD) with four replications. The results showed that the effect of planting date for traits such as grain yield, harvest index and seed quality traits is significant at one percent level. The results seed quality traits showed that the first planting date (11 September) with 86.4 germination percentage and 38.3 germination rate is the best treatment. Comparing the varieties showed that the Persian clover cultivars number 1 with 92.2% germination and 43.8-rate germination is the highest rate. Comparing the mean of varieties showed that the Crimson clover Alborz number 1 seed with 35 grams weight and the harvest index of 4.5 best among the studied varieties

In order to assessment of the relation among low temperature with (Fv/Fm, leaf chloropyll and caratenoied contents) of clover spp, an experiment was arranged as split plot in RCBD with four replications include plant date as main plot ( 15 and 29 Sep.) and clover spp as sub plot ( Persian spp with 7 cultivars, Berseem , Red and Crimson clover with 1 cultivar) at Seed and Plant Improvement Institute of Karaj in during 2010-2011. The measurement of physiological traits in clover spp recorded at rosset growth stage in days with temperature under zero centigrad. The results showed that low temperature stress cuased significant decrease clover spp that the decrease rate could be because of low temperature stress at field. At among clover spp, Red clover cv. Nassim had the least less chlorophyll content. The results also showed that chlorophyll (a) is more affected to low temperature than (a/b), (a/b) and (b). During stress ( S1, S2 and S3), Fv/Fm of clover cultivars was 0.734, 0.788 and 0.555 respectively, that represent the effect low temperature stress to Fv/Fm in all treatments especially S3. In addition, the results showed that in low temperature stress, Red clover cv Nassim had less yield Fv/Fm than to other cultivars. In general the using of Fv/Fm, chloropyll content and caratenoied leaf parameters is recommended for screening and evaluating of clover cultivars in under low temperature stress conditions at fields.

Intercropping is an example of a sustainable system in agriculture that has such purposes as creating ecological balance, higher utilization of resources, increase in the quantity and quality of the product and reducing pests, diseases and weeds (Koochaki and Zand, 1996). Persian clover (Trifolium resupinatum L.) is a plant native to Asia and Iran and contains both early (single cut) and late (multiple cut) ecotypes (Taylor, 1985). One new method in intercropping, namely the interspecies intercropping of different cultivars of Persian clover that causes an increase in the yield. However, little known about this method in the litreture (Prasad et al, 1990). The objective of this study was to investigate the effect of intercropping of early (single cut) and late (multiple cut) ecotypes Persian clover cultivars on quantitative and qualitative forage yield and determe the best seed rate and seed mix in the Karaj region
In order to evaluate the effect of interspecies intercropping with Persian clover cultivars on increased forage yield, an experiment was carried out at the Seed and Planting Improvement Institute as a factorial design (base on a randomized completely block design (RCBD) with two factors (mixed seed at 5 levels, including 0-100,100-0,50-50,40-60,and 60-40 and seed rate at 3 levels of 10,15 and 20 kg ha-1) over two years (2012-13).
The results of combined analysis of variance showed that the effect of year, seed rate and seed mix rate on the forage and dry matter yield and protein percentage, and the interaction of seed mixed × seed rate for just the protein percentage, were significant at 1% probability levels. Mean comparison of seed mixed × seed rate showed the highest forage and dry matter yield with 68.19 and 12.02 t ha-1 were obtained, respectively, from the treatment of 60% Persian clover (single harvest) and 40% multiple harvest Persian clover and seed rate 15 k ha-1. Also, the lowest forage and dry matter yields of 42.52 and 5.18 t ha-1 were obtained from the treatment of 100% multiple harvest Persian clover and the seed rate of 10 kg ha-1, respectively. The quality results showed that the highest crude protein at 24.77% was obtained from the treatment of 100% multiple cut harvest Persian clover and a seed rate of 10 kg ha-1. Evaluation of the land equivalent rate (LER) showed the highest evaluation efficiency at LER=2.85 was obtained from the treatment of 60% Persian clover (single cut) and 40% multiple cut harvest of Persian clover and a seed rate 10 kg ha-1, and for crude protein from the treatment of 40% Persian clover (single cut) and 60% multiple cut harvest Persian clover and a seed rate of 15 kg/ha with LER= 2.17, respectively.
The results of this study indicate that interspecies mixed cropping of early and lately cultivars of Persian clover resulted in inceased forage yield compared to pure cropping. Since early cultivars have high a growth rate and suitable water and soil resources for utilization and high biomass production, in intercropping with late cultivars resulted in increased forage production in time and place units. The highest forage of 68.19 and LER=2.68 for forage yield, 12.02 t ha-1 and LER=2.85 for dry matter yield were obtained from the treatment of 60% Persian clover single cut and 40% multiple cut Persian clover and a seed rate of15 k ha-1. This mixed cropping model could be an agro-ecological approach for high forage production in crop systems.

In order to identify genotypes with drought tolerance in one year clover, ten type Iranian clovers and Berseem were evaluated in Research Farm of Islamic Azad University, Karaj Branch in 2015. This experiment was conducted in split plots in a randomized complete block with three replications. In this research, drought stress was studied as the main factor in three levels (no stress, average stress and high stress) and also different cultivars of Berseem and Iranian clovers as sub factor in ten levels. Irrigation circles in treatments without stress, average stress and high stress were 7, 10 and 14 days. Cultivars were investigated included Berseem clover (Karaj, Elite, Ekinaton, Win and Alex genotypes) and Iranian clover (Aleshtar, Eghlid, Harati, Zabol and 13 Line). Traits in this experiment contained fresh and dried forage yield, In this study, in order to genotypes yield in without / with stress condition, tolerance indicators including mean productivity (MP), tolerance index (TOL), geometric mean productivity (GMP) and Stress susceptibility index (SSI), Stress tolerance index (STI) were evaluated. The result of correlations among drought indices and Yp and Ys showed that MP, GMP, and STI were highly correlated with Yp and Ys. Based on the values of indices and higher forage yield, in stress and non-stress conditions, ecotype Karaj, Elite, Win and Alex were recognized to be as the most tolerant ecotype against drought.

In order to increasing forage production in country, mix-cropping cropping of Persian clover cultivars (single and multi-cuts) is simple and cheap method. In this experiment, mixed seed with 5 level including 0-100,100-0,50-50,40-60, and 60-40 and seed density with 3 levels of 10,15 and 20 kg/ha has been carried out as a factorial design with the base of randomized completely block design (RCBD) in Seed and Plant Improvement Institute for two years (2012-13). The results of two years study showed that mix cropping of Persian clover (single and multi-cuts) cultivars caused 30% forage increase yield, 32% dry matter yield and 8% percentage crud protein with sole cultivation. In generally with increase seed rate of one cut cultivar in mix cropping caused higher forage quality and increasing of seed rate in multi-cut cultivar, created higher forage quantity. According to the obtained results, the highest dry matter yield with 5.24 t/ha was obtained from the treatment of 50% Persian clover (single cut) and 50% multiple cut Persian clover whit using 15 kg/ha seed rate. Computation of LER (Land Equivalent Ratio) showed that the treatment of 50% Persian clover (single cut) and 50% multiple cut Persian clover and seed rate 15 kg/ha with LER=2.18, 1.99 and 2.17 for forage yield, dry matter yield and percentage crud protein respectively and the best mix cropping model in clover agronomy recommended.

Study and comparison of potential forage yield and morphological traits of imported Berseem cultivars with current clover cultivars, will increase diversity among clover cultivars and increase forage production in the country. This experiment was conducted in a randomized complete block design with thirteen cultivars and four replications in Karaj. The two-year combined analysis of variance showed that the effects of year and cultivars were significant for the fresh and dry matter forage yield and morphological traits at 1% probability level. This implies to genetic variation among cultivars and differential effect of year on forage production and morphological characteristics of Berseem clover cultivars. Mean comparisons showed that Polycross cultivar with 70.25 and 16.65 tha-1 and Isoleh-e-Mesri cultivar with 48.84 and 10.70 tha-1 had the highest and lowest fresh and dry matter yield, respectively. The effects of cultivar and year on some morphological characteristics such as plant height was significant and there was a positive and significant correlation between these traits and forage yield. The imported cultivars Wiener, Elite 2 and Selected line, and the local cultivars Tolidi-e-Dezful, Polycross Karaj and Sacromont Mazandaran with 68-69 tha-1 fresh and 16-16.5 tha-1 dry matter yield were the best cultivars, and compared to the control cultivar (Tolidi-e-Karaj) showed 7% and 10% superiority for the fresh and dry matter forage yield, respectively. There fore, these cultivars can be recommended for cultivation in Karaj.

To evaluate forage yield and quality of Persian clover lines, a field experiment was carried out using randomized complete block desigh with 15 lines and four replications in filed station of Seed and Plant Improvement Institute and nutrion labarotory of Animal Science Research Instiute of Iran, for two growing seasons (2009-11), Karaj, Iran. Combined analysis of variance showed significant diffrences among Persian clover lines for crude protein, digestable dry matter, organic matter digestability, dry matter organic matter digestability, AFD and NFD. Results showed that clover lines of higher quality belonged to Eqlid-e-Fars, Kordestan, Local Zabol, Hafte-e-chin Shazand and Baladeh-e-Kazeroon clover populations. Line No. 1 with 31.8 t.ha-1 and 6.6 t.ha-1 had the highest fresh forage and dry forage yields, respectively. Mean comparison of cuts showed that the first cut with 47.6 t.ha-1 fresh forage and 9.6 t.ha-1 dry forage yield was superior to the second and third cuts. Mean comparison of years showed that forge production was higher in the first year by 9%. Overall results showed that lines No. 1, 2, 3, 5, 6 and 8 were promising lines that can be used for animal feed.

Considering the decreasing amount of livestock feeding supplies and the overgrazed rangelands in Iran, growing forage plants has gained a prominence. Clover, which is among the most important forage crops, not only produces high quality forage for animals, but also plays a special role in enhancing soil fertility through fixing the nitrogen of the air. Persian clover is one of the important subspecies of clover which is native of Iran and Mediterranean regions. In an attempt to determine the quantitative yield and morphological properties of 15 lines of Persian clover, a split-plot experiment was carried out in a completely randomized block design with 15 treatments and 4 replications in the 400-hectare research field of the Institute of Plant Breeding and Seed Preparation in Karaj. On the basis of the results, Lordegan cultivar with 62.63 t/ha in the first cut had the highest wet forage yield. From among the total cuts, Kurdistan, Lordegan, and Mahaliy-e Zabol second cut cultivars had the highest yields with 123.99, 121.98, and 119.58 t/ha, respectively. Regarding dry forage yield, the highest amount belonged to Mahaliy-e Zabol cultivar with 12.04 t/ha in the first cut and after all cuts, Eqlid-e Fars, Mahaliy-e Zabol, and Baladeh-e Kazeroun had the highest yields with 24.35, 24.25, 22.07 t/ha, respectively. With respect to morphological properties, the highest leaf to stem ratio in the first cut and the highest stem with 61.25 cm in the second cut belonged to Eqli-e Fars cultivar.