نشریه به زراعی نهال و بذر
سال بیست و هشتم شماره 3 (1391)

To evaluate variation in grain yield and its components and growth characteristics of wheat in different crop rotation systems a field experiment was carried out using randomized complete block design with three replications at Agricultural Research Station of Jolgeh Rokh، Khorasan-e-Razavi province، Iran، in 2005-10. Five crop rotation systems included; wheat monoculture for the whole period (WWWWW)، wheat-wheat-wheat-rape-wheat (WWWRW)، wheat-sugar beet-wheat-sugar beet-wheat (WSWSW)، wheat-potato-wheat-potato-wheat (WPWPW)، wheat-potato-wheat-rape-wheat (WPWRW)، wheat-sugar beet-wheat-potato-wheat (WSWPW)، wheat-maize-wheat-potato-wheat (WMWPW)، wheat-maize-wheat-sugar beet-wheat (WMWSW). The lowest economic yield in the final year belonged to wheat monoculture as compared to the other crop rotation systems. Increment of 21-37% in grain yield، rotation index and water productivity for wheat and decreasing of 51-90% in weed dry matter in crop rotation treatments compared to wheat monoculture showed the positive effects of appropriate crop rotation systems. The average water productivity on the basis of economic dry matter were 2. 33، 1. 60، 0. 78، and 0. 79 kg m-3 for corn، sugar beet، potato، and rapeseed، respectively. The average water productivity on the basis of wheat economic dry matter were 0. 87، 1. 09 and 1. 56 kg m-3 in the first، third and fifth year، respectively. Rapeseed and potato were more effective on the productivity of wheat as compared to the other field crops.

Efficient use of natural and biological cycles such as nitrogen fixation by legumes may stimulate yield of the non-legumes crops in an intercropped system. To evaluate spring barley and annual medic intercropping، an experiment was conducted in the research field of Tehran University in Karaj، Iran، in 2009-2010 growing season. Randomized complete block design (RCBD) with four replications and 14 treatments were used. Treatments included: B1:1M، B2:2M، B4:4M، B6:6M، B6:2M، B4:2M، B2:4M، B2:6M، B100%: 20%M، B100%: 40%M، B40%: 100%M، B20%: 100%M and two additional treatments of barley and annual medic sole crop were established. The highest dry matter yield for barely and annual medic was achieved from sole crop (2900 kg ha-1 for barely and 1773 kg ha-1 for annual medic، respectively). The highest forage water soluble carbohydrates (WSC = 15. 42%)، forage crude fiber (CF = 38. 40%)، silage neutral detergent fiber (NDs = 44. 72%)، silage pH (pH = 5. 31) belonged to sole crop of barley. Also، the highest silage acid detergent fiber (ADF = 26. 42%) and forage acid detergent fiber (ADF = 30. 88%) belonged to sole crop of annual medic. The highest seed yield for barely and annual medic was achieved from sole crop (1907 kg ha-1 for barely and 877 kg ha-1 for annual medic، respectively) and the maximum harvest index (HI) was for B2:6M for barley (34. 75%) and B2:2M for annual medic (28%). The highest land equivalent ratio for dry forage yield (LER = 1. 232) was obtained from H1:1M. The highest land equivalent ratio (LER = 1. 29)، monetary advantage index (MAI = 1329877. 5 toman) and relative crowding coefficient (RCC = 2. 79) for seed yield obtained for B6:2M mixture. Results suggested that the suitable mixture for dry matter yield was B1:1M. For achieving better silage and forage quality، higher ratio of annual medic in mixtures with barley is necessary. Results also suggested that the suitable mixture for seed yield was B6:2M.

Previous researches demonstrated contrast response of apple and pear to systemic acquired resistance trigger by salicylic acid (SA) against fire blight disease. This research was conducted to understand how SA causes these responses، considering bi-lateral role of SA on catalase activity and (SAR= System acquired resistance activation. First، effect of SA were studied on catalase activity of extracted enzyme as well as in the host tissues of one and seven days pre-treated in vitro shootlets of MM111 (tolerant) and MM106 (moderately-susceptible) apples; and Harrow Sweet (tolerant) and Spadona (moderately -susceptible) pear cultivars. Salicylic acid had similar inhibitory effect on extracted catalase of both species، but increased this activity on pre-treated hosts at different rates in the tissues. Considering similar catalase behavior of two species to SA induction، subsequently، this response was evaluated in low (0. 1 to 0. 001 mgl-1) and high (50 to 50000 mgl-1) SA concentrations in pears and apples، respectively. By doing this the disease susceptibilities were inversed in comparison to the normal SA concentrations (1 to 50 mgl-1)، in both host species. Also، catalase activity comparison in resembled concentrations of total protein extracts showed significantly higher activity in apples. The contrast responses of two hosts seemed to be derived from the balance between catalase inhibition and SAR activation by SA.

To study the effect of salinity and ammonium: nitrate ratio on growth of saplings of Zard and Arbiquina olive cultivars، an experiment was carried out in a greenhouse in Tarom field station in 2010- using factorial arrangement in completely randomized design with three repetitions. Four levels of salinity: 150، 100، 50، 0 mMl-1 NaCl and four solutions with different ammonium: nitrate ratio including: N0:14 meql-1 nitrate; N2:2 meql-1 ammonium + 12 meql-1 nitrate; N4:4 meql-1 ammonium + 10 meql-1 nitrate; N6:6 meql-1 Ammonium + 8 meql-1 nitrate، were used on one-year old olive saplings grown in perlite: sand (1:1) medium. Results showed that different levels of salinity had significant effect on reducing leaf area، dry matter، vegetative growth (plant height)، change in plant height and N content and K: Na ratio in the leaf as well as increasing the number of dropped leaves and Na uptake. Application of different nitrogen ratio showed that ammonium increased in nutrient solution with reducing current year growth parameters and increasing the K: Na ratio and N content in leaves reducing Na uptake and number of dropped leaves. Therefore، high concentrations of ammonium and salinity intensified negative effects of either treatments.

To assess agronomic and economical aspects of mixed cropping of alfalfa and annual forage crops a filed experiment was carried out using split plot arrangement in randomized complete block design with three replications، in research field of Seed and Plant Improvement Institute، Karaj، Iran in 2007 and 2008 growing seasons. Experimental treatments included mixed ratio of alfalfa seed with other forage crops (Pesian clover، Crimson clover and Forage rape). These ratios were 100:0، 75:25، 50:50 and 0:100 (alfalfa: forage crop). For agronomic traits، fresh and dry forage yield، analysis of variance and mean comparison were preformed. For economical assessment partial budgeting and breakeven analysis were used. Results showed that there were significant differences among mixed cropping treatments for fresh and dry forage yield. Substitution of 75% Alfalfa + 25% Crimson clover by other mixed cropping treatment was not profitable. Application of 75% Alfalfa + 25% Crimson clover had 14. 94 million Iranian rials per hectare net profil which was greater than the other treatments. Breakeven point for selected treatment (75% Alfalfa + 25% Crimson clover) in comparison with sole crop of alfalfa (Second priority treatment) and 75% Alfalfa + 25% Forage rape (Third priority treatment) were estimated 22. 8 and 24. 8 million Iranian Rials، respectively. Breakeven points of gross income of selected (75% Alfalfa + 25% Crimson clover) in comparison to sole crop of Alfalfa and 75% Alfalfa + 25% Forage rape were 34. 6 and 32. 7 million Iranian Rials، respectively.

To investigate the effect of drought stress on some physiological، morphological and grain yield in eleven new maize hybrids، an experiment was arranged as split plot in complete randomized block design with three replicates in Seed and Plant Improvment Institute، Karaj، Iran in 2010 growing season. The experimental factors included three irrigation regimes as main plots; (70، 100 and 130 mm evaporation from the surface of class A pan) and 14 maize hybrids as sub-plots (11 new maize hybrids and three commercial hybrids KSC700، KSC704 and KSC720 as control). Results showed that drought stress significantly reduced leaf area index (LAI)، ear number plant-1، 1000 kernel weight and grain yield. leaf proline content. However، anthesis-silking interval (ASI) was significantly increased with increasing drought stress. Hybrid No. 3 which is one of the new hybrids had the highest grain yield (6977. 8 kg ha-1) and hybrid No. 4 (KSC700 control) had the lowest grain yield (4653 kg ha-1). The highest grain weight: ear weight ratio (0. 81) observed in two control hybrids (KSC700 and KSC704) and the lowest grain weight: ear weight ratio (0. 72) was observed in hybrid No. 12. Hybrid No. 12 had the highest 1000 kernel weight (286. 3 g)، and the lowest 1000 kernel weight (236. 7 g) was observed for hybrid No. 3. Hybride No. 3 is suggested suitable for further studies in future.

To study the effect of nitrogen and phosphorous fertilizers on seed yield and essential oil of anise a field experiment was carried out in research field of Agricultural and Natural Resources Research Center of Yazd province in 2004-2005 growing season-using factorial arrangement in randomized complete block design with three replications. Nitrogen fertilizer as urea at five leves (0، 50، 100، 150، 200 kg ha-1) and phosphorous fertilizer as triple super phosphate at five levels (0، 100، 200، 300، 400 kg ha-1) were applied. Results showed that the effect of nitrogen fertilizer on seed yield was highly significant (P < 0. 01). Application of 100 kg ha-1 urea had the highest seed yield (848. 9 kg ha-1) and control treatment had the lowest (687. 7 kg ha-1). Phosphorus fertilizer also significantly (P < 0. 05) affected seed yield of anise. The highest seed yield (811. 1 kg ha-1) was obtained in 100 kg ha-1 of phosphorus fertilizer and the lowest seed yield (725. 9 kg ha-1) was achieved in control treatment. Nitrogen × phosphorus interaction effect on seed yield was significant (P < 0. 01). The most suitable fertilizer treatment for seed production was 100 kg ha-1 of nitrogen plus 100 kg ha-1 of phosphorus fertilizers with seed yield of 930 kg ha-1. Effect of nitrogen fertilizer on essential oil yield of anise was highly significant (P < 0. 01). The highest essential oil yield (19. 5 L ha-1) was obtained by application of 100 kg ha-1 of nitrogen fertilizer and the lowest (9. 5 L ha-1) in the control treatment. Phosphorous fertilizer had not significant effect on essential oil production. In general، for seed and essential oil production in anise، application of 100 kg ha-1 of nitrogen and 100 kg ha-1 of phosphorous fertilizers was suitable treatment.

Fruit yield efficiency and some vegetative characteristics of commercial and spur type apple. cultivars was evaluated in Dr. Nakhjavani field station، Orumieh، Iran، in 2008 and 2009 growing seasons. Apple cultivars included: Red Spur، Red Chief، Golden Spur، Yellow Spur، Fujii، Red Delicious، Cooper Spur، Red Cooper Spur، Jonathan، Golden Delicious، Oregon Spur، Jonagold. The experimental design was randomized complete block design with three replications. Scions of these cultivars were grafted on M111. Results showed that highest and lowest vegetative growth were observed for Red Delicious and Red Spur، respectively. Red Spur had the highest fruit yield efficiency with 0. 693 kg cm-2. Fujii and Jonathan had the highest (17. 96%) and the lowest (12. 05) of TSS، respectively. Considering fruit yield efficiency، spur type apple cultivars are suitable to be grown in climatic conditions similar to Orumieh.

Scince 1990 research on clover has been commenced in Karaj and other field stations of Seed and Plant Improvement Institute، Iran. One of the achievements of this initiative is selection، improvement and release of Alborz 1 Crimson clover cultivar. New Crimson clover cultivar، Alborz 1 was primarily selected from clover germplasm received from Food and Agriculture Organization (FAO)، The United Nations، in Seed and Plant Improvement Institute، Karaj، Iran. Agronomic and yield trials were carried out in Karaj، Dezfoul، Arak، Mazandaran and Esfahan. Demonstration plots and research-extension verifications were performed in Karaj، Golpayegan and Shahr-e-Kord. The important agronomic characteristics of Alborz 1 cultivar are: earliness، high fresh forage yield in early spring season، suitability for being grown as second and third crop in cropping systems as well as tolerant to diseases and pests. Alborz 1 is also tolerant to deficit irrigation and cold، therefore، it is also suitable to be grown in cold and foothills areas. This cultivar is a reliable substitute for Berseem clover in paddy cropping systems. Alborz 1 cultivar had very good performance in agronomy and yield trails with 30-35 t ha-1 fresh forage and 5-5. 5 t ha-1 dry forage yields of 16% protein content، 60% digestibility and 70-80% platability.

Red clover (Trifolium pretense) has wide adaptability to different soil and climatic conditions, and suitable digestibility of forage compared to the other clover species. New red clover cultivar, Nasim, was primarily selected from clover germplasm received from Food and Agriculture Organization (FAO), the United Nations, in Seed and Plant Improvement Institute, Karaj, Iran. Agronomic and yield trails were carried- out in Karaj, Shahr-e-kord, Arak, Gorgan, Sanandaj, Kermanshah. This clover cultivar has the potential to increase the productivity and production of forage in the country. Nasim cultivar is a prennial and late maturing clover (4-5 cuts season-1) which can produce forage during whole growing season and is also suitale component in short-term crop rotation systems. Nasim cultivar is tolerant to powdery mildew and other fungal diseases and pests as well as cold. Nasim performance was excellent in agronomy and yield trails with 60-90 t ha-1 fresh forage and 12-15 t ha-1 dry forage yields.