نشریه علوم به زراعی گیاهی
سال ششم شماره 1 (بهار و تابستان 1395)

It is desirable to examine the possible attainment potential varieties of vetch crop in the region of Myanab (Shoushtar) in (2010-2011) as split plots based on randomized complete block design with four replications. In this experiment, the rows distance were (30, 45, 60 and 75 cm) as main plots and three cultivars (Parto, Gohar and India) were as sub polts. In this study, the density fixed on 133 thousand plants/ ha. Results showed that the effect of row distance was significant on grain yield and number of pods per plant at 1% level. The highest grain yield and pod number per plant achieved in row distance of 45 cm were 2932 kg/ha and 66.35, respectively. The Parto cultivar displayed significant differences in terms of yield, seed number per pod and pod number per plant in comporision to the other cultivars at 1% level. Interactions between the number of rows and number of pods per plant was significant at 5% level. Also highly significant positive correlation between the highest yield was obtained with the number of pods per plant. Based on this research, the 45 cm row distance and Parto cultivar were the best among the treatments.

In order to investigate the effect of sowing date on yield and yield components of soybean, an experiment was carried out at split-plot in a randomized complete block design with four replications under Sari region in 2009-2010. The main plot was sowing dates including on 5th June, 20th June and 5th July and sub plot was three cultivars including JK, 033 and Telar. Results showed the most of pod weight per plant, pod number per m2, stem weight per hectare, grain yield per hectare, straw yield per hectare and biological yield per plant were obtained on 20th June. Small pods were observed in 5th June and the lowest pod weight per plant, pod number per m2, straw yield per hectare and biological yield per plant were obtained on 5th July. Telar cultivar had been the most grain yield per hectare and biological yield per plant, but highest pod height were the most in JK cultivar. The maximum of pod weight per plant, stem weight per hectare, grain yield per hectare, straw yield per hectare and biological yield per plant were observed at the interaction of planting date on 20th June and JK cultivar. Becuase of the fact that yield and yield comonents increased in 20th june, this treatment was the best sowaing date.

In order to evaluate the effect of green gram (Vigna radiata) sowing date as a green manure in combination with different rates of nitrogen (N) and phosphorous (P) fertilizers on wheat grain yield and light extinction coefficient, a field experiment was conducted in Dezful during 2008-2009. The experiment was split-plot factorial based on RCBD with three replications. Main plot consisted of green gram sowing dates were 30th June and 10th August, besides to fallow and three rates of N (0, 60 and 120 kg ha-1) and P (0, 45 and 90 kg ha-1) were in sub-plots. Results indicated that the application of green manure increased soil organic matter and inorganic nutrients. The highest light extinction coefficient (K) found on 30th June. A significant increase in nitrogen rate led to more light extinction coefficient because of  higher LAI. In comparison to fallow treatment, the green manure sowing dates on 30th June and 10th August led to more grain yield by 15.3% and 3.1% respectively. Delaying in green gram sowing date reduced the benefit effects of the green manure in wheat grain yield. Generally, the results of this investigation showed that, sowing green gram as a green manure on 3th July has significantly increased wheat grain yield compared with fallow treatments. In green manure applied plots, wheat grain yield in 60 kg N ha-1 and 45 kg P ha-1 was higher than 120 kg N ha-1 and 90 kg P ha-1 under fallow conditions. The higher grain per unit area and biological yield in green gram residue incorporated plots influenced higher wheat grain yield than under fallow.

In order to study path analysis of grain yield with yield component in common bean genotypes and determine the traits that have most effective traitson grain yield, an experiment was conducted as a randomized complete block design with three replications in Research station of  agricultural and natural resources college of Tehran University in Karaj. Analysis of variance showed that there were significant differences among genotypes. Simple correlation coefficients between traits showed only the number of pods per plant and 100-grain weight had positive and significant correlation with grain yield. The results of stepwise regression analysis revealed that the most changing of grain yield concerned to the number of pod per plant, 100-grain weight and number of grain per pod. All intered traits to regression model studied by path analysis and this fact was found that the number of pods per plant and 100-grain weight had the highest positive direct effect on grain yield. Therefore, these traits can be used for the selection of high yield in breeding programs.

This expriment was carried out to evalute the effect of changing in sink- source relationship and grain yield of some wheat genotypes by path analyses. The exprimental arrangment was split plot in RCB design with three replication conducted in research field of agricultural and natural resources research of Khouzestan. Main plot were consists of six spring wheat genotypes and sub plot included flag leaf remove, flag leaf remove + spike covering, spike covering and control.  Significant differences were found between genotypes and treatments of grain yield, number of spike/m2 and number of spikelet per spike at 1% stataistics level. The interaction effect was significant for grain yield, biological yield, harvest index, 1000 grain weight, number of grain per spike, number of grain per m2, number of spike per m2 and number of spikelet per spike at 1% stataistics level.it should be noted that results showed the high genetic diversity existed among wheat genotypes and the number of grain per m2 was the most effective and most important trait that influenced the grain yield.

In order to study alfalfa genotypes from tolerance to salinity via multivative statistical methods, an experiment was conducted on 20 alfalfa genotypes in 5 salinity levels (0, 75, 150, 225 and 300 mM) with NaCl as factorial form under Completely Randomized Design (CRD) with 3 replications in green house located in Andimeshk city. The experiment was performed in pots containing 1:2 sand-agriculture soils and irrigated by water for 45 day after planting. Then salinity treatments was done and after 14 days characteristics were measured. The results of analysis of variance showed that salinity stress, genotypes and their interaction were significant for all of traits (P<0.01). By increasing salinity, all traits were decreased except root/shoot length ratio. Genotype KFA1 had the highest number of leaf per plant, shoot length and plant length, KFA2 had the highest dry/wet weight ratio, KFA10 had the highest root length and root/shoot length ratio and Yazdi Garmsiri also had the highest wet and dry weight. The most significent and positive correlation were obtained between shoot length and plant length. The principal component analysis, studied 8 traits to be divided in 2 components. With attention to results of biplot and cluster analysis KFA1, KFA11, KFA14 and KFA15 with origin Gareh Younjeh; KFA4, KFA6 and KFA16 with origin Hamedani and genotype Bami Garmsiri were considered as the most tolerant group, KFA3 with origin Gareh Yonjeh; KFA5 and KFA17, with origin Hamedani; KFA7 with origin Rahnani; genotypes Nikshahri Garmsiri and Yazdi Garmsiri were considered as the most sensitive group and the other genotypes as semi-tolerant to salinity stress.

In order to study the effect of late sowing date and nitrogen levels on seed yield and morphological characteristics of canola (Hayola 401 cv), a study was conducted in Ramin Agricultural and Natural Resources Research Farm in 2010-2011. Experimental design was split plot in Randomize complete block order with four replications. Main plot was application of 0, 90, 180, 270 Kg/ha nitrogen and sub plot was two sowing date including 10 November (optimum condition) and 26 December (late sowing condition). Result showed late sowing date decreased canola seed yield about 50 percentage. Increasing of nitrogen amounts in both optimal and late sowing date condition caused significant increase in canola yield. The highest canola seed yield in late sowing date condition obtained in used 180kg/ha nitrogen (1237kg/ha) but use of 270kg/ha nitrogen didn’t increase in seed yield compared to use of 180kg/ha nitrogen (1372kg/ha). Result of the study suggested that application of nitrogen, improve canola seed yield at late sowing date condition.