Iranian Journal of Crop Sciences
Year:2013 | Volume:14 | Issue:4 (56)|Papers Count:8

To evaluate the seed vigor in six advanced wheat genotypes (Sardari-39, Sardari-101, Sar/Sak//Arufen, 914-Genbank, Rasad and Azar-2) and to determine the correlations of qualitative traits of seed vigor with wheat field performance, this research was carried out in two laboratory and field experiments in 2009- 2010 at Dryland Agriculture Research Institute (DARI), Maragheh, Iran. Laboratory tests were performed as completely randomized design with four replications, and field experiment was carried out as randomized complete block design with three replications.Results of laboratory experiment showed significant differences among wheat varieties for all traits including germination rate, mean time of germination, electrical conductivity, number of normal seedlings, primary root, shoot and seedling dry weights. Rasad variety had greatest primary root, shoot and seedling dry weights, and was superior in seed vigor. Results of field experiment showed significant differences in spike.m-2, harvest index, biologic and grain yield among wheat genotypes. The highest biological and grain yield belonged to Rasad and Sardari-101, respectively.The highest negative and positive correlations were observed between electrical conductivity and umber of normal seedlings with grain yield, respectively. Therefore, these traits can be used as criteria in primary screening for seed vigor in rainfed wheat.

This experiment was conducted to assess the effect of drought stress on yield and yield components of canola (cv. Talayeh) during 2008-2009 growing season, in Bajgah Research Station, College of Agriculture, Shiraz University, Shiraz, Iran. The experimental design was randomized complete block design and treatments included; full irrigation during the growing period, water stress in the spring re-growth stage, water stress in the flowering and silique formation stage, water stress in the grain filling stage and rainfed with the supplemental irrigation at the beginning of the season (sowing and germination stage). Results indicated that rainfed treatment and irrigation in flowering and grain formation stage were highly and least affected with grain yield of 750 and 2980 kg.ha-1, respectively. Water stress in flowering and silique formation stages had the least effect on plant dry weight. The highest harvest index was obtained in water stress in spring re-growth stage (51%) while the lowest harvest index (41% and 31%) was obtained in flowering and rainfed conditions, respectively. Calculated crop sensitivity coefficients showed that rapeseed is more sensitive to water stress in the period between the spring regrowth and the beginning of flowering stages. It is concluded that using the calculated crop sensitivity coefficients, an appropriate estimation of rapeseed yield could be achieved for being used in crop yield models under similar conditions.

To determine the effect of intercropping of maize with potato on yield, yield components of two crops and land equivalent ratio (LER), a field experiment was conducted in Shahid Moghabeli Agricultural Research Center of Jiroft and Kahnooj, Iran, in 2010 and 2011 cropping seasons. The experiment was grown as early planting in spring. The experimental treatments included; maize sole cropping (T1), potato sole cropping (T2) and intercropping of potato: maize with planting row ratios: 1: 2 (T3), 2: 2 (T4), 1: 1 (T5), 2: 1 (T6), 2: 2 (T7, in which 100% plant density was used for maize and 100% was used for potato), 1: 3 (T8), 3: 1 (T9), 2: 3 (T10), 3: 2 (T11), 4: 2 (T12), 2: 4 (T13), 2: 2 (T14 in which 100% plant density was used for corn and 50% was used for potato). The experimental design was randomized complete block design with three replications. Results showed that the highest maize yield (11690 kg ha-1) was obtained in treatment T8 (1 row of potato and 3 rows of maize) which was higher than that in maize sole cropping. The highest potato tuber yield (16010 kg ha-1) was produced in potato sole cropping. The highest LER was obtained in T8 (1.61). It is concluded that potato: maize intercropping with planting row ratios of 1: 3 was more suitable in early spring planting in Jiroft region in Iran.

To evaluate yield and productivity indices of chickpea and canola intercropping with different planting ratios, a field experiment was conducted in randomized complete block design with four replications at Agricultural Research Station of Mazandran province in Ghaem-Shahr, in 2010. The planting ratios were 0: 100, 25: 75, 50: 50, 75: 25 and 100: 0 (chickpea: canola) using replacement method. Results showed that intercropping had significant effect on yield and some yield components of both crops. The number of branch and silique.plant-1, 1000-seed weight and grain yield of canola as well as shoot height, number of pod.plant-1 and kernel yield of chickpea were significantly affected by different planting ratios. Calculation of land equivalent ratio (LER) revealed that planting ratio of 50: 50 (LER=1.26) and 25: 75 (canola- chickpea) (LER=1.18) had the highest efficiency by 26% and 18%, respectively. Canola in the planting ratio of 50: 50 had the highest relative crowding coefficient (KB=2.36) as dominant crop and chickpea had the least RCC (KC=0.72) in the ratio of 75: 25 (canola- chickpea) as the in dominant crop. Results also indicated that the interference type was positive and complementary and the observed yield of canola and chickpea were not different from their expected yields in all planting ratios. It is concluded that increased number of branches and siliques.plant-1 in canola, in intercropping with chickpea, were the main reasons of yield benefit.

In order to study the competitive performance of spring bread wheat (Triticum aestivum) cultivars with wild oat (Avena lodoviciana), a field experiment was conducted in research farm of Ramin University of Agricultural and Natural Resources, Khouzestan in 2010-2011 cropping season. The experimental design was strip blocks with three replications. Four wild oat densities (0, 40, 80 and 120 plant.m-2) were assigned to horizontal plots and spring bread wheat cultivars (Chamran, Baz, Atrak, Arvand, Maroon, Shoeleh, Chenab, Vee/Nac and Falat) were randomized in vertical plots. Competition indices calculated and analyzed for each cultivar. The highest competition index was obtained for 40 and lowest at 80 and 120 plants.m-2. Results showed that new index was better than older by many aspects, as there is 8 category scales including; highly susceptible, susceptible, semi susceptible, moderate, semi-tolerant, tolerant, high tolerant, and immune. Newly cultivars Chamran, Daz, Virinak Vee/Nac and Falat with 1.3, 1.4, 1.6 and 1.8 competition indices, respectively, were identified as semi susceptible and Maroon with 7.0 as tolerant, but there is no immune, high tolerant, susceptible, or high susceptible among these 10 cultivars. According to the results of the present experiment, tolerance of Maroon cultivar implies that low tillering cultivars with more than 400 plants.m-2 density may decrease weed damage by earlier wheat canopy closure.

Two separated field experiments were carried out in Iranian Research Institute of Plant Protection, Karaj Field Station, in 2008 and 2009 to assess cover crops affect on sugar beet weed suppression. In the first experiment, rye, wheat, barley and triticale were sown as cover crops in autumn. In the second experiment, cover crops (rye, wheat, barley and triticale for the first year and barley, wild radish, and berseem clover for the second year) were sown in spring and compared with three controls (including: weed free, weedy and chemical weed control). Experiments were arranged as randomized complete block design with four replications. Barley was recorded as the best treatment for weed suppression, in the first experiment in 2008 and 2009 with 22 and 78 g.m-2 weed dry matters, respectively. Root yield of sugar beet (29.3 and 48.7 ton.ha-1, respectively) did not differ significantly from control (weed free) in 2008 and 2009. In 2008, planting of cover crops in spring had no satisfactory results and their effects on weed dry matter were similar. In the second year, barley was compared with wild radish and berseem clover, and results showed that barley was more suitable as cover crop, with 21.7 g.m-2 weed dry matter, sugar beet yield, however, was similar in different cover crop treatments.

For evaluation and grouping of 45 genotypes of white bean using different phonological and agronomic traits as; emergence (%), emergence index, days to 50% flowering, days to 50% pudding, days to 90% maturity, number of pods.plant-1, number of seeds.pod-1, 100 seed weight, pod length, biomass per plant and grain yield per plant, a field experiment was conducted in randomized complete block design with three replications in 2009. Genotypes were divided into three groups by cluster analysis based on phonological and agronomic traits.The groups were: early maturing with high yield and yield components, late maturing with high yield and yield components, and early maturing with low yield and yield components. In principal component analysis, the first three principal components explained 82.29% of the total variance. Grouping genotypes using biplots showed a high agreement with the results of cluster analysis. In general, early maturing white bean genotypes in the first cluster that had highest grain yield were identified as superior lines for further evaluation as well as also to be used in white bean breeding programs.