جستجوی مقالات مرتبط با کلیدواژه « year » در نشریات گروه « زراعت »

Soybean has a lot of food and industerial uses. There is a growing demand for various soybean production, due to its nutritional value, wich included high protein and variety of vitamins and minerals. In order to evaluate and compare the yield of pure soybean lines in terms of important agronomic traits and grain yield, 20 top pure lines and two cultivars Sari and Caspian as control, were studied in a randomized complete block design with three replications, in four regions including Gorgan, Sari, Moghan and Dezful during two crop years 2017-18. It should be noted that the lines in this project were breeded and pured, through the hybridization between cultivars and selection in generations separated by pedigree and single-pod methods during the breeding programs. The results of the combined analysis showed that the response of genotypes varied during the two years and in different locations in terms of the grain yield. furthermore, the interaction between location and genotype on plant height and number of pods per plant was statistically significant. Mean comparison showed that G17 and Sari genotypes with average yield of 3215 and 3032 kg/ha had the highest grain yield in three regions of Sari, Gorgan and Moghan and were among the top cultivars in this study. G20 genotype with an average yield of 3093 kg/ha in two regions of Gorgan and Moghan, G14 with the yield of 3073 kg/ha in two regions of Gorgan and Dezful, also Caspian and G4 respectively with an average yieald of 2991 and 2944 Kg/ha in the two regions of Sari and Moghan were the superior cultivars with regard to the grain yield.

Rice (Oryza sativa L.) is the main staple food for more than half of the world’s population. In 2011, worldwide rice production exceeded 672 million mt. Iran ranked 20th in terms of rice production in the world. Plant spacing has an important role on growth and yield of rice. Optimum plant density ensures the plant to grow properly with their aerial and underground parts by utilizing more solar radiation and soil nutrients. Timing of nitrogen application had a significant role on reducing nitrogen losses, increasing nitrogen use efficiency and avoiding unnecessary vegetative growth.

In order to do this research, an experiment was conducted as split plot based on a randomized complete block design with three replications in a research farm located in Qaemshahr during the years 2013-14 and 2014-15. The experimental factors included three levels of plant density (16, 25 and 33.3 plants per m2) as the main factor and sub-factor was nitrogen splitting in 5 levels (S1: 100% at the beginning of planting, S2: 50% at the beginning of planting + 50% at the beginning of tillering, S3: 50% at the beginning of planting + 50% at the panicle formation, S4: 33.33% at the beginning of planting + 33.33% at the beginning of tillering + 33.33% at the panicle formation and S5: 33.33% at the beginning of planting + 33.33% at the panicle formation + 33.33% at the end of panicle emergence).

The results showed that grain yield of Hashemi and Koohsar cultivars in the second year decreased 9.21% and increased 23.74% respectively, than the first year. Also, the second year compared to the first year, showed a decrease of 11.62% and 30.36% of straw yield, respectively, in Hashemi and Koohsar cultivars. Grain yield and harvest index were increased and decreased with increasing density in Hashemi cultivar, respectively. Straw yield in both cultivars increased with increasing density. The lowest straw yield and the highest harvest index were obtained in both cultivars, with nitrogen application in equal proportions at the basic stages, initial cluster and complete clustering. The interaction between the factors in the cultivars showed that in each two years, the number of cluster per square meter increased with increasing plant density.

The results of this study showed that in the studied cultivars, the highest effect of plant density and nitrogen splitting on yield components was related to the number of panicles per square meter, because ultimately increasing the number of plants per unit area and nitrogen splitting equally in the basic stages, beginning tillering and primary cluster emergence resulted in the highest grain yield per hectare by increasing the number of panicles per square meter.

For recognizing exotic high performance genotypes, three new hybrid cotton genotypes (tbl180, Teskhi-9 and Cri108) were compared with control (Sahel) in a RCBD with four replicates at Khodafarin in 2012 and 2013. Genotypes were planted in six rows in 80×20 cm arrangement. Attributes like yield, homogeneity, boll number, plant weight and plant height were measured. Results showed that year×genotypes interaction for lint yield in both first and second cuts and total, and homogeneity were significant. Differences between two cuts were not significant in all genotypes. The results also revealed that Teskhi-9 having lowes TOL and highest STI values was recognized to be the most adaptable genotype as compared with other two genotypes.