Crop Production
Year:2014 | Volume:7 | Issue:3|Papers Count:13

Hydrotime analysis of seed lots allows them to be ranked them according to their potential for successful emergence. An experiment was done on 10 wheat seed lots (N-80-19 cv) to evaluate water potential for determining seed vigor by hydrotime analysis in research field and seed research laboratory on the Gorgan University of Agricultural Sciences and Natural Resources. Seed lots were planted in complete block design whit three replications in field. Water potential was created with PEG6000 at seven levels (0, -0.3, -0.6, -0.9, -1.2, -1.5, and -1.8 MPa). Maximum germination percent for all seed lots were same. Because there were significant differences in maximum emergence percent in field for seed lots it was demonstrated that seed lots vigor were significantly different. According to hydrotime model's parameters, the seed lots that had more emergence their hydrotime constant (qH) were lower, but their base water potential (yb(50)) were higher. Uniformity constant (syb) for all seed lots were same. Unlike the maximum germination percent result, the hydrotime model output results showed that there is difference in terms of seed lots vigor among this study's seed lots. This study results demonstrate that hydrotime model has a great ability in determining wheat seed lots vigor. This model can predict emergence percentage in stressful situations.

In order to study the variation of nitrogen use efficiency (NUE) and associated traits with it, the field experiments were conducted at the Gorgan University of Agricultural Sciences Research Farm, Gorgan, Iran in the growing seasons of 2007-2008 and 2008-2009. The 16 cultivars which are released between 1968 and 2006 were sown in a randomized complete block design with three replications. The results showed that during breeding activities to improve wheat yield, NUE and nitrogen utilization efficiency (NUtE) increased 0.28% and 0.31% per year, respectively; while nitrogen uptake efficiency (NUpE) was not changed. Since NUE divided into two components: NUtE and NUpE, most of the breeding effects on NUE were associated with change in nitrogen utilization efficiency (NUtE). Also grain protein concentration (GPC) have been decreased 0.05 %. It appear that in studied cultivars, grain harvest index increased more rapidly than nitrogen harvest index. This problem can explain the decline of grain protein.

In order to study of yield, yield components and tolerance to drought stress, 15 safflower genotypes, and two separate experiments were conducted with a Randomized Complete Block Design with three replications in cropping season 2010-2011 in agriculture research station of Zahak. In non stress experiment, irrigation was applied from planting to physiologic ripening and in stress experiment, from appearance 50% head to growth terminal, irrigation interrupted. Results showed that under non stressed condition, the highest grain yield obtained from variety Goldasht, TN79-582/2, TN79-634.2, TN79-562 and TN79-5325 genotypes with average yield of 4987, 4940, 4648, 4427 and 4413 kg ha-1, respectively. Under stressed condition the highest seed yield obtained from TN79-5325, TN79-581 genotypes, Goldasht variety, TN79-678 and 2811 Arak variety with average yield of 2623, 2572, 2550, 2510 and 2433 kg ha-1, respectively. Goldasht, 5-TN79-5325 and 1-TN79-678 genotypes had higher grain yield in both conditions and showed the highest rates of STI, GMP and MP indices. Biplot graph, according to principle component analysis (PCA), indicated that tolerant genotypes had high yields, and located near to tolerant indices, therefore these genotypes and indices can be suitable sources and criteria for breeding and assessment drought tolerance in safflower.

In order to evaluate the effect of row spacing and weed density on growth indices of canola (Brassica napus) in competition with wild mustard (Sinapis arvensis( a field experiment was conducted based on randomized complete block design with factorial arrangement and three replications at Agricultural Research Station of Agricultural Sciences and Natural Resources of Gorgan University, during 2009-2010 growing season. The factors included canola row spacings at 3 levels (12, 24 and 36 cm) and wild mustard densities at 4 levels (0, 4, 8 and 16 plant per m2). Results showed that growth indices of canola (leaf area index (LAI), crop growth rate, relative growth rate and total dry matter) decreased in competition with wild mustard in all row spacings of canola. The most leaf area of canola distributed at higher height of canola in row spacing of 12 cm as compared to 24 and 36 cm. According to the results, it seems that LAI and vertical distribution of canola’s leaf area in canopy are the effective indices in reducing wild mustard biomass and increasing competitive ability of canola in competition with wild mustard.

In order to compare the seed yield of 15 winter rapeseed (Brassics napus L.) genotypes, a field experiment were performed in 2006-7 and 2007-8 cropping seasons in Agricultural and Natural Resources Research Center of Markazi Province, Arak, Iran. Rapeseed genotypes were compared in a randomized complete block design with three replications. Means comparison showed that Licord (3795 kg ha-1), Modena (3655 kg ha-1) and Okapi (3277 kg ha-1) genotypes had the highest seed yield, respectively. In the second phase of this research, in order to evaluate the effects of sulphur (S) rates on seed yield and accumulation of macro nutrient in seeds of high yielding rapeseed genotypes, a field experiment carried out as factorial arrangement based on randomized complete block design with three replications, during 2008-9 and 2009-10 cropping seasons at the same site. Treatments were three rapeseed varieties (Okapi, Modena and Licord) and three rates of sulphur (0, 40 and 80 kg ha-1). The interaction effect between sulphur*variety was significant for seed yield and other measured traits. The combination of 40 kg ha-1 Sulphur*Okapi showed the highest seed yield and seed nitrogen content. Greatest seed phosphorus and potassium content was observed in Modena cultivar and S2 treatment (40 kg S ha-1). Licord cultivar showed the highest ratio of seed sulphur content at control and different rates of sulphur utilization in comparison with other vareties. In general, it is presumed that utilization of 40 kg S ha-1 can enhance seed yield and seed macro nutrient content, related to rapeseed genotype.

In order to study the effect of different intercropping patterns of maize with vetch, common bean, bitter vetch and berseem clover on some maize qualitative traits, an experiment was conducted as randomized complete block design with three replications in Agricultural Research Station, Faculty of Agriculture, University of Tabriz, during two years. Treatments were two maize hybrids (704, 301), vetch (Vicia villosa), bitter vetch (Vicia ervilia), berseem clover (Trifolium alexandrinum L.) and common bean (Phaseolus vulgaris cv. Cos 16) sole crops as well as intercrops of maize hybrids with each of the legumes in additive series. The results showed that forage yield of maize in intercropping with vetch and bitter vetch decreased. Digestible dry matter of forage maize in intercropping with legumes was increased. The highest digestible dry matter was achieved from 301 hybrid with bitter vetch, vetch and bean intercrops. Forage nutritive value, as indicated by Relative feed value (RFV), was improved in all legume-maize intercrops in relation to the sole maize crop. The RFV value was higher than 151 in the intercrops of maize hybrid 301 with bitter vetch and vetch. So, it can be stated that forage crop from intercropping of maize hybrid 301 with the mentioned legumes is considered as prime forage. The highest metabolisable energy (ME/D) of forage belonged to maize hybrid 301-bitter vetch and maize hybrid 301-vetch intercrops. In conclusion’s intercropping of maize hybrids with legumes improved the maize forage quality in terms of DDM, RFV and ME/D as compared with the sole cropping of maize.

In order to improve the salinity tolerance of barley through hybridization, two spring barley cultivars namely Reyhan (susceptible) and Afzal (tolerant) and their F1 hybrid were planted at three salinity levels (0, 10 and 20 dsm-1) in greenhouse under a Factorial experiment with randomized complete block design with three replications. Proline content, quantitative activity of proxidase and catalase enzymes, sodium, potassium and sodium to potassium ratio and vice versa were measured for all of the treatments. Heterobeltiosis (superior parent heterosis) was observed for sodium content, potassium content and potassium to sodium ratio, and for catalase enzyme there was an average of parents-based heterosis. For sodium to potassium ratio, proline and proxidase no heterosis was detected. Ultimately, the third salinity level was the most desirable level for heterosis status assessment of hybrid plants derived from the crossing between the susceptible and resistant cultivars. Given the observed heterosis, it is expected that the improvement of plants for salinity tolerance is possible through targeted crosses.

In order to create different environmental conditions and to estimate the required growth degree days (GDD) and heat units (CHU), fourteen foreign and Iranian potato genotypes in three different maturity groups were evaluated in two regions, Shako Mountain, and plain region for three cropping seasons (2007-2010). The results revealed that both systems, i.e. GDD and CHU changed maturity group of some of the genotypes based on heat requirement during emergence and flowering. Some genotypes such as 397007-11 and Sante were grouped as the late matured compared to the previous grouping based on IBPGR. Year and year by genotype interaction effect were significant in both locations. Years with higher air average temperature increased the heat index 1200 (GDD) and 4000 (CHU) in the mountain region of Shahkooh whereas in the plain region of Gorgan GDD and CHU increased 1000 and 2000, respectively. Genotypes 397009-3 could be considered as the best genotype because of producing the highest tuber yield (27003 kg ha-1) in autumn and spring cropping (28446 kg ha-1), with production of 12.5 and 11.9 tuber plant-1 in autumn and spring cropping, respectively. Based on the information available about the maturing groups according to IBPGR and the time of the phonological stages during evaluation of these genotypes, the grouping based on GDD seemed more logical.

In order to study the effects of microelement fertilizer and phosphate biofertilizer on some morphological, physiological characteristics, yield and essence content of Purple coneflower under water stress conditions, an experiment was carried out as split factorial layout based on a randomized complete block design with three replications in the agricultural research station, Islamic Azad University, Tabriz Branch during growing season 2009-2010. Factors included water stress as the main factor on three levels (irrigation after, 120 and 170 mm evaporation from class A), application of micro elements in three levels (control, application of zinc sulphate and Iron sulphate) and phosphate biofertilizer in two levels (C1: not application and C2: application of biofertilizer). The results showed that the highest essence yield with 20.19 lit h-1 was obtained with foliar application of zinc sulphate under irrigation after 120 mm evaporation from class A basin. Application of phosphate biofertilizer increased essence yield under different irrigation regimes so that this increase was 15.1%, 16.57% and 14.64% under full irrigation, irrigation after 120 mm and under irrigation after 170 mm evaporation from class A basin, respectively. Also, the highest essence percentage obtained in irrigation after 120 mm evaporation from class A basin with foliar application of zinc sulphate and iron sulphate, it was equal to 0.7822 and 0.7775%, respectively.

In order to evaluation of plant density, rate and split application method of nitrogen fertilizer on yield and yield components of safflower (Sofeh variety) under weed competition a field experiment was carried out as a factorial based on randomized complete block design with three replications in Yasouj university field research in summer 2013. First factor was plant density with two levels (20 and 40 plants m-2) and second factor was nitrogen application rate on nine levels that included; non nitrogen application and 75 and 150 kg N ha-1 nitrogen application with four split methods. Split methods were included; S1(50% in preplanning stage - 50% in stem elongation stage), S2 (25% in preplanting stage - 75% in stem elongation stage), S3(25% in pre planting stage - 50% in stem elongation stage -25% in flowering stage) and S4 (25% in pre planting stage - 25% in stem elongation stage - 25% in flowering stage). Results showed that the most fertile heads number (296 head m-2) and highest grain yield (2314.17 Kg ha-1) was obtained from highest plant density (40 plant m-2) and highest level of nitrogen application (150 Kg N ha-1) with split level S4. In addition, that low plant density and high nitrogen level application caused higher weed dry weight. However, in high nitrogen level application, the lowest weed dry weight was achieved from S4 method of nitrogen application.

In order to evaluate interaction effect of saline and fresh water application with organic and chemical fertilizers on some organic and quality characters of cumin, a split-plot experiment in randomized complete blocks design with three replications was conducted at the Research Farm of agricultural research of Zabol University during 2011 and 2012. Main factor was irrigation levels including normal and salt water with EC 4.180 dS m-1 and the subplots were different type of fertilizers. The highest grain yield (213.5 kg ha-1) was obtained at the second year in Zahak from integrated fertilizer treatment in comparison to Bonjar, at the second year plant height (31.3 cm) significantly improved in comparison to the first year in the same treatment. Consumption of NPK-fertilizer in the first year related to low-quality of irrigation water produced the highest amount of essence (2.2%). Control and a separate NPK-fertilizer application, lead to significant sodium content in both years, while potassium, phosphorus, calcium and magnesium weren’t affected by the interaction of three factors (years, water and fertilizer). Application of manure to compose with NPK-fertilizer was more effective on plant height, seed weight and sodium content, and it was due to synergist-effects of two types of fertilizers. In general, plants will grow better in normal condition. For providing nutrient availability and increasing soil organic matter, NPK fertilizer with 40:20:15 kg ha-1 ratio with 20 ton ha-1 manure in area is recommended.

Each year, many studies carried out on various aspects of crops. Results of these studies were not similar and sometimes were inconsistent, due to different effects of environment. For example, results of studies on the effect of seed size on seedling emergence rate were varied: some of them were reported a positive impact, some negative impacts and some no impact. In such cases, the final conclusion is difficult. Meta-analysis is created for such cases. Using this method, various studies on a specific topic can be analyzed statistically and reliable conclusions can be obtained from several studies that were fragmented and even contradictory. This method is recently gained attention by the field crops researchers and most published articles are new on meta-analysis in agronomy sciences. There is no published study in field crops researches and agronomy in Iran and it is necessary to use this methods. Whit this method, it could be possible to summaries many studies on a specific topic (i.e. density, planting date, application of water and fertilizers, and application of various treatments) and to find a final conclusion about the topic. The statistical basis of meta-analysis method is described in this article, the advantages and limitations of its application are discussed with some examples (from national and international studies).

In order to investigate the effects of planting date and seed size on phenology, yield and yield components of Barakat cultivar of broad bean, an experiment was carried out on farm research of Gonbad Kavous University during 2011-2012. Two factors was planting dates in four levels of 5 and 19 November and 6 and 19 December and seed size (one seed weight) in four levels of 1-1.25, 1.25-1.5, 1.5-1.75 and 1.75-2 gr. The results showed that seed size only affected days from planting to 50% emergence, but all traits were affected by planting date. Number of days from planting to 50% flowering and pod setting, plant height in 50% flowering and green pod harvesting time, fresh weight of plant, number of pods/plant, number of seeds/pod and plant, fresh seed weight in plant, pod length, fresh weight of one seed, and pod fresh yield was the highest in the first planting date (6th Nov.). The maximum days from planting to 50% emergence and harvest index was belonged to last planting date (20th Dec). On the first planting date (6th Nov.) pod green yield was 22.85 ton ha-1. The minimum green pod yield belonged to fourth planting date (20th Dec.) with 14.57 ton ha-1. Harvest index on planting date of 6th November was 42.97% and on 20th December was 55.7%.