Crop Production
Year:2012 | Volume:5 | Issue:2|Papers Count:10

In order to evaluate the effects of drought stress and plant density on yield, yield components and morphological characters of pinto bean (Phaseolus vulgaris L.) C.O.S16 cultivar, a field experiment was conducted in split plot arrangement based on a randomized complete block design with three replications in research field of Yasouj University during 2010. Experimental treatments were pinto bean plant density at four levels (15, 25, 35 and 45 plants per square meter) as subplots and drought stress at three levels (in growth stage, reproductive stage after 90 mm evaporation from class A, evaporation basin and common irrigation) as main plots. Result showed that there were significant interaction between drought stress and plant density on characters such as 100 grain weight, plant height, number of branches per plant, harvest index, biological and grain yield. Maximum biological and grain yield recorded at 35 plant.m2 treatments in normal irrigation (11235 and 3368 kg.ha-1 respectively), that was not significant difference in 45 plant.m2 treatment. 15 and 35 plant.m2 density had the maximum and minimum of grain yield and water use efficiency respectively, under drought stress in growth and reproductive stages. In general, 35 plants per square meter in without stress and 25 plant/m2 densities in all water stress levels, had maximum yield for this pinto bean cultivar.

Organic fertilizers such as vermicompost (VC) are an undeniable source of required nutrients of plants. This field experiment performed as split plot arrangement based a randomized complete block design withthree replications in 2008. The main factors (vermicompost treatments) added to soil atsix levels including 20 and 40 ton.ha-1, 20 and 40 ton.ha-1plus (1/2) chemical fertilizer, chemical fertilizer (consists of 100 kg.ha-1 urea, 150 kg.ha-1 triple superphosphate and 100 kg.ha-1 potassium sulphatebased on soil testing analysis) and control. Also, sub plots considered VC application periods (1, 2 and 3 years). Results showed that usingVC and also fertilization year's factor significantly affected studied traits of rice. So, 40 ton.ha-1 VC plus 50% chemical fertilizer determined as the best fertilizer level, because the maximum content of biomass (12.43 ton.ha-1), tiller number, height, total number of grains in panicle (124.3), harvest index (41.41%) and yield (681.1 g.m2) and also the lowest percent of unfilled grain in panicle (15.52%) recorded in this treatment. Meanwhile, 40 ton vermicompost per hectare treatment had the highest panicle fertility percentage (94.08%). Increasing application periods regularly enhanced the content of studied traits. In addition, the maximum positive and significant correlation coefficient (r= +0.91**) existed between paddy yield and harvest index.

In order to study the effect of different levels of nitrogen and sulfur fertilizers on yield, yield components, content of some elements, qualitative and quantitative traits of spring safflower (Serin cv.) an experiment was conducted at agriculture and natural resource research station of Ardabil in 2008. This experiment was carried out in factorial experiment in completely randomized block design with three replications. Nitrogen fertilizer levels included 0, 50 and 100 kg ha-1 and sulfur was 0, 25 and 50 kg ha-1. Results showed that application of nitrogen and sulfur fertilizers has significant effect on yield, yield components, so that nitrogen fertilizer application caused to increasing the number of lateral branches, number of capsule, 100-seed weight, seed yield, and biomass and harvest index. Some of traits had no significantly differences in 25 and 50 kg per hectare sulfur fertilizer. Also, using of sulfur did not affect harvest index, but the plant height and distance of the first branch from the ground level were significantly different by nitrogen and sulfur application so that, the highest plant height was observed in combination of highest amounts both of nitrogen and sulfur fertilizers. The Leaf relative water content increased with increasing nitrogen and sulfur fertilizer. The highest leaf area index obtained with 100 kg N ha-1, but application of 25 and 50 kg ha-1 nitrogen had no significantly effect on LAI. Light extinction coefficient was decreased by applying both N and S fertilizers but light use efficiency was increased.

This study was carried out to evaluate the association between laboratory seed characteristics and seedling emergence of canola cultivars that it’s produced under different irrigation regime and planting date. The treatments were included two planting date and two levels of irrigation (main factors) and seeds of five canola cultivars (sub factor) which in first year (2006-2007) had been cultivated in a factorial split plot design based on RCBD at experimental field of Seed and Plant Improvement Institute. In second year, the experiment was conducted in research field and laboratory of agronomy and plant breeding department at college of Aboureyhan -university of Tehran- during spring 2008. The analysis of variance results indicated that planting date and irrigation regime had no significant effect on measured traits under field experiment, whereas, in laboratory experiment, the effect of planting date and irrigation regime were significant on radical length (RL) and shoot length (SL), alone. Based on the laboratory results, the Sarigol cultivar due to higher mean daily germination (MDG), radical length (RL), lower mean time to germination (MTG) and daily germination speed (DGS) had the highest vigor seed. The results of correlation showed that there is the positive and significant correlation (0.59**) between final emergence percentage and RL in laboratory experiment (accelerated ageing test), therefore, accelerated ageing test can be used for predication of percentage of emerging plants in the field.

Management practices can affect the yield, maturity, and fiber quality of cotton. One practice used to increase yield has been to adjust the spacing between cotton rows. Typically cotton is planted in row spaced 70-100 cm apart. Ultra narrow row cotton production has been proposed as an economical means to increase yields and reduce production costs. A field study was conducted to assess the effects of ultra-narrow row (20 cm-UNR) and conventional row (80 cm-CR) production systems on canopy closure, yield, and fiber quality at three commercial cotton cultivars (Golestan, Sahel, and Sepid) at Gorgan in 2011. Results showed that cotton canopy closure more occurred rapidly in 20 cm rows compared to 80 cm rows (about 18 to 36 days earlier). Cotton in 20 cm rows was produced more yield than cotton in 80 cm rows. The yield increase in 20 cm rows was a result of increase in the number of boll production per unit area and increase radiation interception by canopy. No conclusive differences for fiber quality could be ascertained between in 20 cm and 80 cm rows. A higher yield in UNR compared to CR indicated that UNR system is an agronomic feasible option for farmers.

To investigate the effect of deficit irrigation on quantitative and qualitative yield of soybean cultivars, an experiment was conducted as split plots based on randomized complete block design with three replications at agricultural research farm, university of Guilan, during 2009. Main factors were included four irrigation levels based on potential moisture 30-35 (I1), 50-55 (I2), 70-75 (I3) Centibar (irrigation time was determined by tensiometer) and without irrigation (I4), and sub plot factors were included seven soybean cultivars: 033, 032, Sahar (group maturity 4), L.17, Zan, Clark and Madari (group maturity 3). Results showed that seed yield of soybean had decreased in I2 I3 and I4 treatments (15%, 20% and 65% respectively). Among the studied traits, just oil and protein content have increased by drought stress. Highest (1379 Kg) and lowest (478 Kg) seed yield per unit area obtain from I1 and I4, respectively. 033 in I3 treatment had the highest and Zan in I4 had the lowest oil and protein yield. Also irrigation water productivity increased significantly with application of deficit irrigation treatments (13% and 33% increment in I2 and I3, respectively). Results of the present experiment showed that in soybean production in Rasht region, irrigation based on potential moisture 70-75 Centibar, moreover in economize of water use and increase in water productivity, can improve of soybean seed oil and protein percentage.

Use poor quality resources of water and soil for food production in developing countries must be considered. Therefore, three experiments were conduct in complete randomize design with four replications, to study effects of gradually application of different salinity levels (0, 10, 20, 30, 40, 50 and 60 dS.m-1) at different growth stages (planting and early seedling) and gradually application salinity at the end of growth stage on kochia. The results showed that increasing salinity at gradually in planting and early seedling and the end of growth, plant height, branches number, shoot fresh and dry weight, digestible dry matter, digestive value, and crude protein yield were increased. On the other hand with increasing salinity digestibility of dry matter, organic matter digestibility, crude protein and ash percentage in applying salinity, gradually at planting and early seedling, and gradually at the end of growth were increased. Generally, kochia be able to tolerate salinity up to 128 dS.m-1 gradually with increase salinity.

In order to study of drought tolerance in bread wheat genotypes, this study was conducted in Maragheh dryland agricultural research station. The study included two experiments and the statistical design of each experiment was a RCBD with four replications, and 20 bread wheat genotypes that were compared under drought stress (rainfed) and supplementary irrigation. Analysis of simple variance supplemental irrigation showed that there were significant differences among lines in grain yield, biological yield, harvest index, spike number in square meter, number of grain per spike and thousand kernel weight. Also, in drought stress experiment, there were significant differences among wheat genotypes in agronomic traits such as harvest index, spike number in square meter, grain number per spike and thousand kernel weight, but there were non-significant differences in grain yield and biological yield. Combined analysis of variance or two experiments showed that, drought stress significantly reduced harvest index, grain respect to number per spike and thousand kernel weights but it had non-significant effect on grain and biological yield. Under drought condition lines No. 3 (ARG/R16// BEZ* 2/3/AGRI/KSK/5/TRK13/6/M) and11(M-70-4/5/ Alborz/ 4/ K6290914/ Cno// K58/ Tob/3/Wa) had the highest grain yield by an average of 2.2 and 2.19 t.ha-1 respectively, and under supplemental irrigation experiment, lines No.3 and 17 (DARI98-MA-39CIT98/99(F4)-1MA-0MA) produced the highest grain yield with an average of 3.84 and 4.19 t/ha grain yield. Results indicated that genotypes No. 3 and 17 had the highest amounts of GMP, MP and STI, therefore were selected as the most tolerant lines. Finally, under supplementary irrigation, genotypes No. 3 and 17 and in rainfed condition No. 3 and 11 could be recommended.

In order to evaluate the effect of salinity on water relation, ion accumulation, solute sugar, proline content, chlorophyll florescence and seed yield of Isabgul (Plantago ovata), French psyllium (P. psyllium) and Great plantain (P. major), an experiment was conducted at Vali-e-Asr University of Rafsanjan in 2010. This study was carried out as factorial experiment based on randomized complete block design with four replications. Treatments were included four salinity levels (9, 15 and 21 dS/m and control with distilled water) and three plantago species (Plantago ovata, P. psyllium and P. major). Results showed significant effect of salinity, species and interaction between them on relative water content (RWC) which was decreased in response of higher salinity in all species with different trend in species. Higher concentrations of salt led to higher leaf Na+content and lower K+, Ca++and Mg++content. Despite of species, Proline content and solute sugar were not significantly affected by salinity in all species. The highest and the lowest seed yield of great plantain were observed in control and 21 dS/m, respectively. No seed harvested from French psyllim in 21 dS/m. In general, among three species, great plantain had higher stability in ion balances, RWC and seed yield in salinity condition.

In order to evaluate the influence of different sowing dates on quantitative and qualitative yield in four winter rapeseed cultivars (Brassica napus L.), two field experiments were carried out as split plot arrangement in complete block design with four replications. This research was performed in agricultural experimental station of agricultural and natural resources research center of Markazi province, Arak (Iran) during growth seasons 2007-2008 and 2008-2009. Four planting dates (September 11, 21 and October 1 and 11) and four canola cultivars (Licord, Opera, Okapi and Modena) were randomized in main plot and sub-plot, respectively. Results showed that at the second sowing date, plants produced the most grain yield (4518 kg ha-1). The least grain yield (3786 kg ha-1) was obcained the fourth sowing date. The delayed sowing dates decreased grain yield due to decrease of pod number per plant. In this research, Modena cultivar had more seed yield in comparison with other cultivars due to genetic diversity and high using of sources such as nutrient elements, soil moisture and solar radiation. The best sowing date for Arak region was September 11 to October 1.