جستجوی مقالات مرتبط با کلیدواژه « هم بستگی » در نشریات گروه « کشاورزی »

Drought refers to the lack of rainfall in the long trun, which is one of the most important natural disasters due to its spatial extent and short-term and long-term economic, social and environmental consequences (Nikbakht and Moradi, 2019). Factors affecting the physical, chemical and microbial properties of surface waters: precipitation, geographical location, climate, geology, industrial activities, domestic wastewater, agriculture, mineral pollutants, etc. can be mentioned (Mishra et al., 2017). In addition to drought, land use changes change the hydrological cycle of the basin and upset the balance between rainfall, evaporation, soil permeability and runoff (Farokhzadeh et al., 2016). Land use is one of the most important factors affecting the quality of surface water resources, especially rivers, as land population changes, land use patterns change. Therefore, runoff from rainfall as well as urban wastewater discharge leads to an increase in the amount of nutrients and other pollutants into rivers and surface water sources (Moradi et al., 2012). Tahiru et al. (2020) investigated the impact of land use change and land cover on water quality in a catchment area in the northern region of Ghana. Their results showed that there is a positive relationship between land use change and land cover and water quality parameters. Soltani-Gerdefaramarzi et al., (2021) investigated the effect of land use on surface water quality under both wet and dry periods in the Godarkhosh watershed. The results showed that barren and residential lands had the greatest impact on surface water quality and rangeland and forest land use showed a negative correlation with water quality parameters. Also, a strong significant relationship was found between water quality parameters and land use in dry years. Lei et al. (2021) investigated the effects of land cover, topography, and soil on water flow quality at multiple and seasonal spatial scales in a German lowland catchment. Overall changes in water quality on larger scales were estimated better in the summer. Due to the location of Iran in the dry land belt, most of its area will experience drought during most days of the year, which will cause changes in water and environmental resources. Biology, economic growth and development, agricultural activities, etc. are essential; on the other hands, land use changes have a significant impact on surface water quality. This effect can improve or reduce the quality of surface water. These changes have a great adverse effect on the environment and water resources, so the control and monitoring of surface water for various uses is necessary to make water of good quality available to the public. One of the main sources of drinking water, agriculture and industry in Isfahan province is the Eskandari watershed and the Plasjan river. Therefore, paying attention to water resources is one of the appropriate and necessary management measures at the level of the entire basin. Therefore, in the current research, land use changes during two periods of drought and drought have been investigated on the quantitative and qualitative parameters of the Plasjan River.

Water shortages in a defined area and in a certain period are called drought. This phenomenon is time dependent rather than aridity, and it is quitely temporary. drought in various regions of Iran in arid, semi-arid and even humid areas shows different forms and causes great damage. Drought is calculated using indices such as precipitation and evapotranspiration. The teleconnection is also a new branch of synoptic climatology, which recognizes the relationships between phenomena and climatic elements such as rainfall, drought, and temperature in remote locations. In other words, teleconnection patterns are the occurrence and continuation of large scale models of circulation abnormalities and air pressure that extend over a wide geographical range. These patterns are also oscillatory behavior of low frequencies. Teleconnection mechanisms are one of the important issues in justifying the behavior of the climate, and its effects do not always appear in the same form everywhere (Khosravi, 2004). In worldwide, many studies have been done on climate signals in variety ways. Iran is also affected by rainfall systems, which affects the pattern of rainfall and drought in it.

The purpose of this study was to investigate the relationship between NINO4 and NAO indices with meteorological droughts in synoptic stations in the southern part of the Caspian Sea. For this purpose, data of rainfall were obtained monthly from the Meteorological Organization of Iran. Then, SPI was calculated for different time scales of months including 1, 3, 6, 9, 12, 15, 18, 24, 48. The next step was to obtain the values of the Ocean Atmospheric indices, including NINO4 and NAO, at the monthly scale from the Australian Meteorological Organization. For analysis, the MINITAB16, SPSS16 was used. In this case, the simultaneous and asynchronous relationship between the time series of SPI and the NAO and NINO4 indices was determined. In this stage, Spearman's correlation test and cross-correlation function were determined. In the next step, regression modeling was done. In this way, regression models for the time series of SPI were calculated taking into the simultaneous and asynchronous state of the NAO and NINO4 indices. The lag times were 1-6, 12, 24, 48 months. Finally, errors for regression models were determined at all stations to select the best model.

The results showed relationships between NAO with SPI different series at Ardabil and Babolsar stations in January, April, August and December; the NINO4 with SPI at Ardebil station in all months except October and December. Also, the results of regression equations showed that in SPI time series of NINO4 with the highest coefficient, the highest and NAO with lowest coefficient, had the lowest effect on drought in studied areas. In this case, the Ardabil has the highest coefficient in SPI24 months. At the end, the error statistics including RMSE, R, R2, CE were calculated for model reliability and calculation of errors.

In this case, the best model was found at the Gorgan station by calculating the error statistics. The result suggests that these stations are neighbor to the Caspian Sea, which has affected the rainfall and drought pattern of the regions. This can also be the result of the universality of the Enso phenomenon that affects the world's climate. In order to obtain better results, it is recommended to study the precipitation and temperature pattern of these areas with other Ocean Atmospheric indices such as SOI and AO. Regarding the fact that the distant teleconnection indices do not occur in all directions in one way, it is suggested to study rainfall and temperature pattern of other parts of Iran in relation to climate signals. This study is also in line with another study by researchers who through statistical and synoptic methods have investigated the relationship between climatic factors such as rainfall and temperature with climatic signals. Study of other researchers determine that there is a significant relationship between the annual rainfall of Iran and the South Oscillation Index. temperature pattern of these areas with other Ocean Atmospheric indices such as SOI and AO. Regarding the fact that the distant teleconnection indices do not occur in all directions in one way, it is suggested to study rainfall and temperature pattern of other parts of Iran in relation to climate signals. This study is also in line with another study by researchers who through statistical and synoptic methods have investigated the relationship between climatic factors such as rainfall and temperature with climatic signals. Study of other researchers determine that there is a significant relationship between the annual rainfall of Iran and the South Oscillation Index.

This study examines the trend of ET0 changes using the Mann-Kendall nonparametric test and predicts it using time series analysis. To calculate FAO-Penman-Monteith ET0, Tmin and Tmax, RHmin and RHmax, sun-hours and wind-speedy of synoptic station Khorramabad during the 1991-2017 were used. The results showed that the trend of annual change in reference evapotranspiration with the Mann-Kendall statistics 0.2, was not statistically significant. The trend of monthly changes showed that the trend in September and July was decreasing by Mann-Kendall statistics -0.2 and -0.7, and in the rest of the months, it was increasing. In the stagnation time series check, the trend and ACF graph, showed an increasing trend in the series. for staging the series, the method of differentiation was used and the data were stagnant withfirstfirst-ordered differentiation. For modeling with SARIMA model, from period 1991-2015 for the modeling and from period ‎‎2016-2017 model verification was used, and condition of normality, accidentally and independent ‎of residual of the fitted model was examined. The results showed that the SARIMA‎(0,1,1)(1,0,1) for ET0 modeling, has the best accuracy. The RMSE and R2 ‎values for prediction with this model were 0.674 and 0.97 mm/month, which indicates that the ‎model is accurate.‎

Drought occurs due to lack of humidity and deficiency in precipitation amount. Therefore, it is important to recognize and investigate the effective factors on precipitation deficiency and consequently drought occurrence. Enso is a phenomenon of climatic teleconnection that can affect weather in different regions of the world. Enso is one of the important large-scale phenomena affecting the temporal and spatial distribution of rainfall and consequently the drought that occurs in the tropical Pacific. The objective of this research was to investigate the effect of Enso on meteorological drought in the midwest of Iran.

First, precipitation data of synoptic stations in 14 locations were obtained in the west of Iran. Then, SPI values was calculated at different time scales of 1, 3, 6, 9, 12, 15, 18, 24, and 48 month using the spi-sl-6.exe software package. In the next step, using the data of Enso including Nino1+2, Nino3, Nino3.4, and Nino4, the Spearman correlation test was simultaneously performed in the Minitab16 program. Then, the asynchronous relationship was investigated with the cross-correlation function between Enso and SPI in time series of months 1 to 48 in SPSS16. Finally, linear regression modeling was performed. Multivariate regression test with simultaneous and delayed states of 1-6, 12, 24, and 48 months was used based on the stepwise method.

Results are presented in three sections: simultaneous, asynchronous relations, and regression equations. Results showed a high correlation between seasons of autumn and spring with indices of Nino4, Nino3.4, Nino3, and Nino1+2. In addition, the asynchronous relationship was better than the simultaneous mode. Better significance in the asynchronous mode is due to the effect of Enso on weather and drought in Iran. Considering the p-value <0.05, it was shown that the highest significance was observed between Enso indices and drought index in Bushehr station. In addition, in a number of stations, including Arak, Urmia, Shiraz and Hamedan, no significant relationship was observed in their simultaneous state. The regression analysis showed that Nino4, Nino3.4, Nino3 and Nino1+2 indices had the highest effect in different time series of SPI with the highest positive and negative coefficients of atmospheric oceanic index in all stations. The results showed that high correlation between Enso and SPI can affect predicting climatic conditions, drought, floods, planning, and crisis management in watershed scale.

Enso can be used as predictors of long-term climatic factors such as precipitation and temperature. Enso phenomenon in Nino1 + 2, Nino3, Nino3.4 and Nino4 regions can be used as predictors of climatic factors such as rainfall for long-term forecast of precipitation and finally drought and wet season in different parts due to the universal Enso phenomenon. It seems that due to the mechanism of the Enso phenomenon and its relationship with natural disasters, further studies can be effective in predicting climatic conditions, drought and floods in Iran which ultimately can be used in predicting hydro-climatic events.

This experiment was conducted to investigate the identify traits explaining yield variation, recognize relationships between traits and classify accessions in spring rapeseed, at Dezful, Khozestan Province Iran,  in the agricultural year in 2015–2016. A randomized complete block design with four replications was used. The results of stepwise regression analysis revealed that 1000-grain weight, number of pods per plant, HI and days to maturity significantly had more important effects respectively on seed yield. The results of path analysis indicated that the number of grain per pod and 1000-grain weight had the largest direct effects on the grain yield. According to the results of the principal component analysis, PC1 was moderately correlated with number of seeds per pod, 1000-seed weight and seed yield. PC2 was moderately correlated with days to flowering, days to maturity and plant height. The results of factor analysis exhibited two factors including sink factor (number of seeds per pod, 1000-seed weight and seed yield) and fixed capital factor (phonological traits). It seems that its seams possible to use their traits as a selection criteria in breeding programs for improve seed yield of spring rapeseed cultivars. using WARD method cluster analysis revealed five groups and there was highest genetic distance between 1 and 5 groups, thus predict that hybridization of between 1 and 5 groups could provide best hybrids and supply a desirable genetic diversity in segregated generations for breeding programs.

In order to identify the yield related traits and to compare the yield and yield components twelve imported faba bean genotypes were evaluated in a randomized complete block design with three replications in a greenhouse experiment at Shahrekord University. The analysis of variance showed highly significant variation among the genotypes for all of the traits including plant height, dry straw weight, seed number per plant and biological yield. Correlation analysis revealed that there were positive and significant correlation between grain yield and harvest index and biological yield. Stepwise regression analysis indicated number of seeds per plant entered into model and explained about 91% of the total variation. Mean comparisons between genotypes indicated that among the 12 faba bean genotypes, genotype 114870 had the highest mean value for seed yield.

The experiment was arranged based on a completely randomized block design, with two replicates in hydroponic conditions at The University of Zabol in 2013.In present study, 7 barley double haploid lines along with two parents were experimented. The measured traits including: fresh and dry weight of root and shoot and their ratio, length of root and shoot and their ratio, length of the largest leaf, length of total plant, the concentration of chlorophyll and relative water content. Statistical analysis was conducted for phenotypic surveys such as analysis of variance, mean comparison, correlation between traits; cluster analysis, principal component analysis and factor analysis. Variations among lines were signification for all traits (except Relative water content). Based on mean comparison 9 lines (4, 5, 30, 33, 36, , 49, 67 and 72) were superior, to other. Using cluster analysis grouped lines 7 were identified. Maximum correlation was seen between length of root and length of total plant (r 0/925). In PCA (principal components analysis) analysis, four principal components explained 62% of the total variability and Factors analysis extracted several invisible factors that explained over 71 percent of total variance.

This research was conducted to study relationships among yield and yield components in Orchard grass (Dactylis glomerata). For this purpose 25 half sib families derived from poly cross of 25 parental genotypes were evaluated under two moisture environments (normal and drought conditions) according to a randomized complete block design at the research farm of Isfahan University of Technology. The results indicated that seed yield had positive correlation with most of the studied traits. The highest correlations were observed between seed yield and seed weight in panicle (0.96**) and seed number in plant (0.89**) in non-stress and drought stress conditions, respectively. The correlations of seed yield with flag leaf width and flag leaf length were 0.41 and 0.39 in non-stress conditions. The results of factor analysis indicated that flag leaf is an important trait for improving seed yield. According to regression analysis seed weight in panicle, seed number in panicle and seed number in plant accounted for 98 and 96% of seed yield variation under normal and drought conditions, respectively. Path analysis for seed yield showed that under normal condition, seed weight per panicle and seed number per plant and under drought stress condition, seed number and thousand seed weight had the highest direct effect on seed yield. Genetic information on association among seed related traits can be used for increasing efficiency of indirect selection of seed yield in this crop.

In order to study the effect of drought stress and determination of effective traits on grain yield of wheat in normal and terminal drought stress conditions, 82 wheat genotypes were studied in two separate experiments using randomized complete block design with three replications during cropping season 2011-2012. Drought stress was applied in heading stage by limited irrigation. Set of 22 traits including yield and yield components were measured. Results of analysis of variance showed that in both conditions there are significant different between all genotypes for all traits. Drought stress decreased all traits except number of leaves on the main stem and the number of tillers. The highest genetic diversity in two conditions were for awn length, grain yield and number of fertile tiller. Pearson simple correlation, stepwise regression analysis and path analysis in both conditions on all traits took over. In stress condition amount of correlation between grain yield with biological yield, straw yield, harvest index, Fertile spikes per square meter and total number of tillers per square meter equal to or greater than 50% was achieved. In both environments, the highest correlation was found between biological yield and grain yield. The results indicate the importance of peduncle length in becoming greater amount of grain yield under drought condition. Based on stepwise regression analysis in normal irrigation 6 variables and in stress conditions 5 variables entered the model and in total more than 80% of the changes were justified. To determine the direct and indirect effects of traits on yield, path coefficient analysis was done, the most direct effect on grain yield in both conditions belonged to biological yield. Based on this study the most important traits that are introduced as an indicator for selection high yielding varieties of wheat in both conditions, are biological yield, spike weight, number of fertile spike and 1000 kernel weight. Also the effective role of height plant in stress condition, selection of higher plants in addition to more spikes in increasing grain yield be important.

In addition to seed quantity, study of seed quality of crop in conditions of competition could be profitable for seed procurement from field. For this purpose, produced seeds of four wheat cultivars (Sayson, Alvand, Chamran and Sepahan) in interference with deferent densities of feral rye (0, 20, 40, 60 and 80 plants m-2) were harvested. In laboratory, of each field unit, 50 number of wheat seeds separated and placed in petridish for germination test. Results showed that by increasing feral rye densities, reduced grain yield, 1000-seed weight, percent and coefficient of uniformity germination, plumule length, radical length, radical dry weight, radical volume and density of seeds from wheat cultivars. In contrary, increased mean germination time. At each level of weed density, minimum and maximum amount of studied traits obtained from Alvand and Sayson, respectively. Obtained correlation coefficient was indicated of robust relation between 1000-seed weight and mean germination time. Also Mean germination time showed robust relation with seedling traits. Generally, results of this study showed that seed weight from interference with weed, had significant effect on seed quality and related traits.

In this research, we estimated soil shallow depths temperatures using regression methods (Linear and Polynomial). The soil temperatures at soil depths (5, 10, 20, 30, 50 and 100 cm) were correlated with meteorological parameters. For this purpose, temperature data of Hamedan station (in the period 1992-2005) were employed. Soil temperature data were measured on a daily basis at 3 PM, 9 PM and 3 AM. MS Excel was used for deriving the regressions between soil temperature and meteorological parameters (air temperature, relative humidity and sunshine hours). The results showed that the highest coefficient of determination (R2) of the linear regression was between soil temperature in 20 cm soil depth and air temperature at 3 AM (R2= 98.15%) and the lowest value in 100 cm soil depth at 3PM (R2= 83.96%). Also, the highest R2 of non-linear regression was observed between soil temperature in 10 cm soil depth and air temperature at 3 AM (R2= 98.45%) and lowest value in 100 cm soil depth at 3PM (R2= 84.11%). The results showed that the highest and lowest values of R2 of linear relations between meteorological parameters (relative humidity and sunshine hours) and soil temperature were observed in 10 cm soil depth (at 3 AM) and in 100 cm soil depth, respectively. Correlations of soil temperature with air temperature were greater than those with the other two parameters. Moreover, R2 values of non- linear relation were higher than linear relation.

Sediment yield estimation for small basins is essential in watershed management planning projects. However، almost all of these basins are ungauged. In this study، in order to determine a range for specific sediment yield and to develop a regression model for estimating annual sediment yield، sedimentation behind small dams within 25 basins in Western Azerbaijan province، were measured. The selected basins with an area ranged 29 to 1200 ha، cover a range of lithology، land uses and climates and all of the sediments had been trapped behind the check dams. The specific sediment yields showed a two digit differences ranged 0. 12 and 12. However، the weighted average of specific sediment yield for all basins was calculated a low value of 1. 3. Study of relationship between annual sediment yield and 18 characteristics of watersheds using correlation matrix showed that the sediment yield is significantly affected by geologic erodibility، basin area and land use factors. From several regression models which were developed، an equation including two independent variables، geologic erodibility and basin area، with a high determination coefficient (R2=0. 899) was chosen.

Homogeneity of soil particles is the potent factor which affects soil spectral signatures and known as the Geometric Standard Deviation of soil particles (σg). This study presents the influence of σg on spectral studying of soil texture using four spectral data sets of LISSIII-P6 and was coincident sampling operations. Subsequent to satellite data preprocessing، some operations were done such as: Normalized Difference Vegetation Index، Principal Component Analysis، Soil Line Euclidean Distance and Unsupervised Classification on acquired data. By stratified randomized sampling method and according to the false color composite and photomorphic units of the main image of the study area، 95 sample points were eventually selected and gathered from 0-5cm of soil surface. Afterwards، geometric standard deviation (σg) and texture fragments were determined for each sample point in the soil lab. Samples were accordingly divided into two parts، on the basis of the computed geometric standard deviation: the first، σg <10 (homogeneous soil) and the second، σg ≥10 (heterogeneous soil). Subsequently via correlation operations for both group، it was expressly displayed which in the first group (σg <10)، clay and sand had about 0. 7-0. 8 correlations with the remotely sensed data، whereas the second group (σg ≥10) had about 0-3-0. 4. Hence، the geometric standard deviation (σg) of the study region can powerfully impress soil spectral reflectance.

This study was conducted to analyze the correlation among grain yield and a number of important traits in twelve spring rapeseed (Brassica napus L.) cultivars at Dezful research station in Safi Abad, from 2009 to 2010. A randomized complete block design with four replications was used. Results analysis of variance showed that significant difference between cultivares for all parameters in expriment, indicated a geneticaly difference between cultivares.The correlation coefficients among the grain yield and 1000-grain weight and grain number/pod were positiveand significant(0.74** and 0.72**, respectively). Grain yield and days to maturity, days to flowering, plant height and oil percent were correlated negatively. According to stepwise regression grain yield trait is considered by dependent variables and other traits by independent variables. Model determination coefficient is R2=0.934. The highest level of determination coefficients were for 1000-grain weight and the number of grain per pod(0.547and 0.177, respectively). The results of path analysis indicated that the number of grain per pod and 1000-grain weight had the largest direct effect on the grain yield(1.10**and 0.41*, respectively) its seems possible to use the traits as a selection criteria in breeding programs for improving grain yield of spring rapeseedcultivars.

In order to study agronomic and morphological traits in maize hybrids in Hammedan, two early (108 and 301), three medium (604, 647 and TWC647) and two late maturing (704 and 711) hybrids were evaluated in a randomized complete block design with three replications in Agricultural and Natural Resources Research Station in Hammedan in 2005. 33 morphological and phonological traits were recorded from 10 plants randomly selected from two central rows of each plot. The maximum and minimum grain yield was obtained from SC647 and SC301, respectively. The grain yield had the highest correlation with dehusked ear weight. Factor analysis of data after varimax rotation identified four factors that accounted for 98.03% of total variance. The scatter plot of hybrids based on the two first factors (the seed yield factor and phenological structure factor) showed that SC704 had the maximum forage yield and the best physiological characteristics and SC647 had the maximum grain yield, cob diameter and number of seed in row.

In order to evaluate relationship between Different traits in lentils (lens culinaris Medik), a field study was conducted as an RCBD based design with 3 replications on Zanjan University Research Farm during spring of the year 2004. ANOVA analysis revealed significant differences for all characters except for the number of primery branches. Correlation analysis indicated positive and significant correlation between seed yield and harvest index, number of primery branches, pods/plant and biological yield, and grian yield. The result of the factor analysis also showed that the second factor including number of primery branches, pods/plant, grian yield, canopy width and seeds/plant was an important trait involved in the grian yield in lentil. In addition, cluster analysis helped divide the genotypes into four distance groups of large, medium, semi medium and low yields.

In this study external fat-tail dimensions (upper, middle and lower width, length, length of gap, depth and upper circumference) and fat-tail weights collected on 724 Lori-Bakhtiari sheep were used to study external fat-tail dimensions and their relationships with fat-tail weights. Sheep were 3 months to 6 years old and slaughtered at the industrial slaughter house of Joneghan in Chaharmohal and Bakhtiari province in 2003. The mean of fat-tail dimensions were estimated as 15.83, 23.85, 24.73, 26.52, 14.96, 14.12 and 52.59 cm for upper width, middle width, lower width, length, length of gap, depth and upper circumference, respectively. Fat-tail weight varied from 0.10 to 20.60 with overall mean of 2.71 kg. Fat-tail percentage varied from 1.18 to 37.18 with overall mean of 11.87 percent. The effects of fixed factors of age, sex and body condition of sheep on all of traits were highly significant (p<0.0001). The least square means of all traits except fat-tail percentage were increased with increasing age of sheep. Lowest least square mean (± s.e) of 2.12 ± 0.25 kg fat-tail weight and 7.91 ± 0.72% fat-tail were observed for sheep having body condition score of 1 and the highest least square mean with fat-tail weight of 9.84 ± 0.56 kg and fat-tail percentage of 20.59 ± 1.63 were observed for sheep having body condition score of 5. Estimation of correlation coefficients among external fat-tail dimensions and fat-tail weight were positive and varied from 0.60 between upper fat-tail width and fat-tail weight to 0.83 between upper circomference of fat-tail and fat-tail weight. Upper circumference of fat-tail accounted for %69.5 of variation of fat-tail weight. This study showed that fat-tail weight in live sheep of Lori-Bakhtiari could be estimated using external fat-tail dimensions with very high accuracy (r = 0.904).

In order to investigate path analysis and study correlations among 16 agronomic traits, 49 Iranian and foreign rice entries were evaluated in a simple lattice square as experimental design with 2 replications at research farm of Tonekabon agricultural college in 2001. Analysis of variance showed significant difference among genotypes for all the studied traits (p<0.05). Phenotypic and genotypic correlation analysis showed positive and significant correlation between grain yield and the number of productive tiller, total tillers and number of grain per panicle. Based on path analysis of the traits, the number of productive tillers had the highest direct effect on the grain yield. Furthermore, the number of grain per panicle and 100-grain weight had a high direct effect on the yield. Overall, the results are suggestive of the direct selection for grain yield in these genotypes through above - mentioned traits.

This study was conducted to analyze the correlation among grain yield, yield components, duration of vegetative and grain filling periods in twelve oat (Avena sativa L.) cultivars at the Research Farm of the College of Agriculture, Isfahan University of Technology, from 2001 to 2003. A randomized complete block design with three replications was used. The correlation coefficients among the grain yield/m2, fertile tiller/m2, grain number/panicle and the duration of grain filling period were positive and significant. Among yield components, the number of panicle/m2 and the number of grain/panicle had the largest direct effects on grain yield (0.68 and 0.30, respectively). Furthermore, the duration of the grain filling period had the highest direct effect on the number of grain/panicle and the grain weight (0.82 and 0.80, respectively), which were greater than its correlations with the number of grain per panicle (0.42) and 1000-grain weight (0.35). However, its negative indirect effects through other traits reduced the correlation coefficients. The results of path analysis indicated that the number of panicle/m2 and the number of grain/panicle had the largest direct effects on the grain yield. Considering the direct effects of grain filling duration on the number of grain/panicle and the 1000-grain weight, and also the fact that most of the dry matter in oat is produced in this period, it seems plausible to use these traits as a selection criterion in breeding programs for higher yields of cultivars of oat.