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An experiment was conducted to study the effects of some agro-technical factors (plant density, sowing date and cultivar) on qualitative and quantitative yield in two cultivars of Red bean (Phaseolus vulgar cv. Saiad, Naze) under the climatic conditions of Zanjan. The experiment was executed as split-plot factorial based on randomized complete block design with three replication. Sowing date was devoted to the main plots with three levels (5 May, 22 May and 10 June) and cultivar with two levels (Saiad and Naz) and plant density with three levels (15, 22 and 45 plant per m2) were factorially devoted to the sup plots. Analysis of variance showed that components of seed yield (number of pods per plant, number of branches per plant, number of seed per pod, number of seed per plant), biological yield, harvest index and percentage of seed protein were significantly affected by cultivar (P < 0.01). Cultivar did not have any significant effect on seed yield. The effect of sowing date was significant on seed yield, biological yield, harvest index and components of seed yield and weight of one hundred seeds (P < 0.01). The effect of plant density on percentage of seed protein and harvest index were non-significant, but other characteristics were significantly affected by density (P < 0.01). The highest number of pod per plant, number of branches, number of seed per pod, number of seed per plant, biological yield were related to cultivar Naz and the highest harvest index and percentage of seed protein were related to cultivar Saiad. Delayed planting increased seed and biological yield. The greatest percentage of seed protein was obtained from the third planting date. The density of 45 plant/m2 was significantly superior to the two other densities regarding seed and biological yield. There was not a significant difference between 15 plants/m2, 22 plant/m2 and 45 plant/m2 in percentage of seed protein. Cultivar Saiad at the density of 45 plant/m2 and sowing date of May 25th resulted in the highest seed yield. Cultivar Saiad at the density of 45 plant/m2 and sowing date of June 10th resulted in the highest percentage of seed protein.

Effect of different genestein concentrations on nitrogen content and nodulation in annual medics was studied; this research was done under controlled environmental condition at the 20/25 oC day/night air temperatures and 5 oC low root zone temperature. Three annual medics species (Medicago polymorpha, Medicago radiate, Medicago rigidula) adapted to cold and temperate zones and 5 genestein levels (0, 10, 20, 30 and 40 µM) were considered in this study. The experiment was conducted in complete randomize block design, factorially arranged, with 3 replications. M. rigidula and M. polymorpha were superior than M. radiata for all measured traits. The mentioned species produced more nodules than M. radiata at low root zone temperature. Genestein increased nodulation and nitrogen content of annual medics at low root zone temperature. Also 20 µ M genestein had the highest effect on nodulation and nitrogen content at low root zone temperature. Root dry matter, nodule number, nodulation and nitrogen content were increased in annual medics at 5 oC, by genestein application. Interaction between cultivars and genestein concentrations showed that M. polymorpha with 20 µ M genestein application was more efficient in most of measured traits than other species. So, using genestein could be helpful for increasing nodulation and size of nodules in regions with low air and soil temperature in the beginning of growing season.

To evaluate the resistance of promising chickpea ecotypes to freezing temperatures, an experiment with eight promising cold tolerant chickpea was performed. The ecotypes consisting of 4301, 4322, 4360, 4361, 4366, 4380, 4715, 4816 along with a sensitive one (304) were sown in pots at natural conditions. All the chickpea ecotypes were exposed to freezing temp eratures at controlled conditions during 4, 6 and 8 leaf growing stages. Experimental treatments were arranged factorially and were compared in a complete randomized block design with four replications. After 20 days, plant survival and leaf damage percentages were recorded. Stress at the eight-leaf stage caused the highest plant mortality and leaf damage while at the 4 leaf stage the least mortality and leaf damage was recorded. Ecotypes 4322 and 4715 indicated the highest resistance to freezing stress at the 4-leaf stage. A higher sensitivity to freezing damage for chickpea at more advanced vegetative stages was observed in this experiment.

To study the effects of plant density and species on forage and grain yield of Vicia sp., anexperiment was conducted in College of Agriculture, University of Lorestan, under dry farming conditions during 2007-2008 growing season. Three levels of plant density at 100, 150 and 200 seed per square meter along with three species of Vicia including Vicia narbonensis, Vicia sativa and Vicia dasycarpa were arranged factorially. The experiment was performed on the basis of a complete block design with three replications. The maximum dry forage yield of 3263 kg/ha belonging to broad leaf vetch at 150 seed/m2 was obtained. The highest stem dry weight of 1788 kg/ha was obtained from common vetch at 100 seed/m2. However, the maximum leaf dry weight of 1801 kg/ha was obtained from broad leaf vetch at 150 seed/m2. In some treatments the maximum seed yield, pod/plant, seed/pod and biological yield were obtained.

In order to study the genetic diversity among 49 genotypes of canola (Brassica napus L) a 7×7 Lattice square design on the basis of randomized complete block design (RCBD) with 3 replications was performed in Agriculture Research Station of Gorgan (Araghymohaleh) province during 2005-2006. Analysis of variance showed significant difference (at 1% level) in all studied traits. HYOLA 401, HYOLA 330 and Y3000 hybrids had the highest grain yield with 4053, 4032 and 3524 Kg/ha, respectively. Among the studied traits, pods per plant, had the highest correlation with grain yield (r =0.759**). According to the results of path analysis, pods per plant had the highest direct effect on grain yield. The result of genotypes clustering with UPGMA method classified genotypes into five clusters. According to Euclidean distance, highest distance (3.54) and lowest distance (0.121) were observed between PF60/89--308×401-B and HYLITE-B--HYOLA420, respectively. On the basis of principles component analysis, 93% of variation could be accounted for by the first and second principle components. Finally, height to first pod, pods per secondary stems as well as grain yield denoted the highest genetic diversity.

In order to reduce the herbicide rate, the combination of cultivation and eradicane herbicide application was tested under field conditions. Treatments including tillage practices of without cultivation, one cultivation and two cultivation and eradicane herbicide application levels of 0, 1.5, 3, 4.5, 6 Lha -1 were tested. Eradicane herbicide was used before plantation. Cultivation treatments were applied 25 and 38 days after planting. Corn cultivar was single cross 704 with 75000 plant per ha. Results showed that the two times cultivation with the high dose of herbicide was the most effective method for controlling weed resulting in the highest yield of 13841.5 kgha -1. There were significant differences among treatments for leaf area index, crop growth rate, leaf dry weight, total dry matter and grain dry matter. This research showed that the combination of cultivation plus herbicide was the most effective method for controlling weed in corn.

Striped rice stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae) is one of the key pests in north of Iran, which damages the rice fields and decreases yield, severely. With attention to the importance of population dynamics of pests in integrated pest management, the population dynamics of immature life stages (egg, larva, pupa) of C. suppressalis were analyzed on three dominant rice varieties including, Fajr, Khazar, and Nemat in Mazandaran. The results indicated that the population density of the pest on the Fajr variety was higher than the two other varieties; therefore Fajr is a susceptible variety to C. suppressalis. Means comparison of population density of immature stages in different dates (23 May until 15 August) indicated that the density was the lowest in early season (May) and then it was gradually increased and reached its highest rate in July and after that, the population density decreased again. With respect to the results of this research, application of controlling agents including, biological or chemical methods at maximum population density of pest and replacement of resistant varieties to the susceptible one (Fajr) are recommendable to the farmers of paddy fields.