Relationship between GRAIN FILLING rate, GRAIN FILLING DURATION, yield components and other physiological traits of rice was investigated in 93 genotypes of rice at Rice Research Institute of Iran (Rasht, Iran) during the growing season of 2001-2002. The experiment was performed without any statistical design. Panicles of main stem were tagged and taken at 3- day intervals during the GRAIN FILLING period. A cubic polynomial model was used to fit the GRAIN dry weight data (mean of R2= 0.98 for all genotypes) and the GRAIN FILLING rate and DURATION estimated for the genotypes. Traits related to sink capacity such as GRAIN weight, GRAIN size and GRAIN number per panicle correlated with GRAIN FILLING rate but source capacity- related traits except chlorophyll content of flag leaf and secondary leaf did not correlate with GRAIN FILLING rate. Stepwise regression showed that final GRAIN weight, GRAIN FILLING DURATION and flag leaf angle contributed to GRAIN FILLING rate, however, path analysis showed that only final GRAIN weight and GRAIN FILLING DURATION had the greatest effect on GRAIN FILLING rate. The results of stepwise regression irrespective of final GRAIN weight showed that chlorophyll content of flag leaf, GRAIN width, GRAIN FILLING DURATION and GRAIN length contributed to GRAIN FILLING rate. Path analysis results showed that the final GRAIN weight had the greatest direct positive effect on GRAIN FILLING rate, while GRAIN FILLING DURATION had negative effect on GRAIN FILLING rate.

Final GRAIN weight is a component of GRAIN yield in Wheat (Triticum aestivum L), that is dependent on the rate and a DURATION of the GRAIN FILLING period. A thorough understanding of the GRAIN FILLING process my be helpful in attempts to breed for increased yield and early maturity in Wheat. This study was conducted to evaluated ten wheat cultivars, at Research Farm, College of Agriculture, Islamic Azad University Shoushtar Unit, in 2009-10. A randomized complete block design With for replication was conducted. The logistic curve provided a good fit to the GRAIN FILLING data obtained in this study. Rate and DURATION of GRAIN FILLING were obtained from the fitted curve. Cultivars differed significantly in rate GRAIN FILLING, DURATION of GRAIN FILLING and final GRAIN weight. Correlation coefficient between final GRAIN weight and rate GRAIN FILLING was high positive. But the phenotypic correlation between the rate GRAIN FILLING and DURATION of GRAIN FILLING was not significant and suggested that there was no genetic association between these characteristics. Results suggested that it should be possible to simultaneously improve rate of GRAIN FILLING and final GRAIN weight without lengthening DURATION of GRAIN FILLING.

Final GRAIN weight a component of GRAIN yield in wheat (Triticum sativa L), is dependent on the rate and DURATION of the GRAIN FILLING process. A thorough understanding of the GRAIN FILLING process maybe helpful in attempts to breed for increased yield and early maturity in wheat. This study was conducted to evaluated ten wheat cultivars, at Research Farm, College of Agriculture, Islamic Azad University Shushtar Unit, in 2004-5. A randomized complete block design with four replications was conducted. The logistic curve provided a good fit to the GRAIN FILLING data obtained in this study. Rate and DURATION of GRAIN FILLING were obtained from the fitted curve. Cultivars differed significantly in GRAIN FILLING rate, GRAIN FILLING DURATION and final GRAIN weight. Correlation coefficient between final GRAIN weight and GRAIN FILLING rate was highly positive. But the phenotypic correlation between the GRAIN FILLING rate and GRAIN FILLING DURATION was not significant and suggested that there was no genetic association between these characteristics. Results suggested that it should be possible to simultaneously improve GRAIN FILLING rate and final GRAIN weight without lengthening DURATION of GRAIN FILLING. Since the result of linear and logistic models justified more meaningfully the physiological processes of the plant, it was recommended to use these equations in estimation of rate and DURATION of GRAIN FILLING.

In order to evaluation of the process of genetic improvement rate and DURATION of GRAIN FILLING among wheat cultivars, the field experiments were conducted at the Agricultural and Natural Resource Research Center of Golestan province. in the growing seasons of 2007-2008 and 2008-2009. The 16 cultivars were sown in a randomized complete blocks design with three replications. The results showed that wheat cultivars had not changed during breeding activities in order to improve yield in GRAIN weight and DURATION of GRAIN FILLING while rate of GRAIN FILLING was increased. Also rate of GRAIN FILLING was improved %26.19, in 38 years of the release, was observed %0.7 and it improvement. This increase was due to increasing GRAIN number per unit area. In order to positive and significant correlation between GRAIN FILLING rate and GRAIN yield it seems that selection for high yield and GRAIN FILLING rate is possible without the need to increase of GRAIN FILLING DURATION.

In order to investigate the effects of temperature and radiation on rate and DURATION of GRAIN FILLING and final GRAIN weight in rice cultivars, a split plot experiment based on randomized complete block design with three replications was conducted at different transplanting times at the research field of University of Guilan, Rasht, Iran in 2013. Factors were: transplanting dates in main plots (5 May, 20 May and 5 June) and rice cultivars (Hashemi, Ali Kazemi, Sangejo, Khazar, Dorfak and Gouhar) in sub plots. The greatest GRAIN weight (31.9 mg) was obtained in Gouhar at 20 May and the smallest GRAIN weight (20.4 mg) was observed in Sangejo at 5 June transplanting dates. The longest effective FILLING period (32.9 days) was achieved in Gouhar at 5 May transplanting date and the shortest GRAIN FILLING DURATION (13.9 days) was obtained in Hashemi. The greatest GRAIN FILLING rate (1.62 mg day-1) was obtained in the Hashemi and the smallest rate (0.92 mg day-1) was observed in Gouhar. Significant correlations were observed between cumulative temperature and radiation with final GRAIN weight (R = 0.689). There were significant and positive correlations between the cumulative temperature and irradiance with GRAIN FILLING DURATION, in contrary to negative correlations with GRAIN FILLING rate and GRAIN FILLING period. The results of this experiment showed that the GRAIN FILLING DURATION plays a greater role, than GRAIN FILLING rate, in determination of the GRAIN weight. It could be concluded that an early transplanting (5 May) brings about favorable temperature and radiation conditions for an appropriate GRAIN FILLING period and a greater final GRAIN weight.

Eleven wheat cultivars were evaluated at 10-day intervals, beginning from anthesis, under irrigated and drought stress conditions during 2006-2007. The effects of irrigation, genotype and date of harvest were significant for most of the studied characters. Water deficit decreased pre-and post-anthesis assimilation rate, GRAIN weight per spike, GRAIN number per spike and 1000 GRAIN weight about 5.7, 24.5, 21.2, 15.7 and 6.4 %, respectively. Mobilization, mobilization efficiency and contribution of pre-anthesis assimilates to kernels were considerably increased under drought stress condition. GRAIN weight, GRAIN growth rate and contribution of current assimilates to GRAIN FILLING decreased under drought stress about 7.18, 22.1 and 29.6 %, respectively. However, the effective GRAIN FILLING period was considerably increased in the stressed plants. GRAIN FILLING rate was correlated with the accumulation of dry matter at maturity, GRAIN weight per spike and GRAIN number per spike in the irrigated and drought stressed environments (r=0.87** and 0.53, r=0.87** and r=0.62*, r=0.75* and r=0.63*, respectively). A negative correlation was found between effective GRAIN FILLING period and GRAIN yield/spike under irrigation (r =-0.65*) and drought stress (r =-0.76**) conditions. Furthermore, positive correlations between GRAIN FILLING rate and GRAIN yield were obtained in the irrigated and drought stressed environments (r = 0.87** and r = 0.62*, respectively). It seems that accumulation of pre-anthesis assimilates (mainly under drought stress), short effective GRAIN FILLING period and high GRAIN FILLING rate are major factors for producing higher GRAIN yield in wheat under both irrigated and drought  stress conditions.

Two field experiments were conducted at the Research Farm of Tabriz University in 2002 and 2003, to evaluate effects of shading on rate and DURATION of GRAIN FILLING and yield of faba bean cultivars. Seeds of three faba bean cultivars including Barakat, Saraziri and HBP-B were sown by hand on 28 April 2002 and 7 May 2003. Both experiments were split- plot, based on randomizedcomplete block design with three replications. Shading levels and cultivars were allocated to the main and sub-plots, respectively. Shading treatments consisted of no shade (control), 18%, 48% and 70% shade. GRAIN FILLING DURATION was similar for faba bean cultivars. However GRAIN FILLING rate and maximum GRAIN weight of Barakat and Saraziri were higher than HBP-B. Although, mean GRAIN weight of barakat and saraziri were significantly higher than HBP-B, but HBP-B was clearly superior in production of the number of GRAIN per plant and GRAIN yield per unit area. GRAIN FILLING DURATION under shade was 3-4 days longer than under control, which resulted in producing comparatively larger GRAINs under shade. Consequently, mean GRAIN yield of faba bean per unit area for shaded plants was higher than that for unshaded plants. Therefore, faba bean can be successfully used in intercropping and agro forestry, where shadind is a limiting factor.

The objective of this study was to evaluate the effects of limit irrigation on effective traits on GRAIN weight in two cultivars of wheat. The study was conducted using a split plot design in completely randomized blocks with four replication and 16 treatments. All farm experiments were conducted in agriculture research field of Azad University of Karaj in 2007 cropping season. The main plot treatments consisted of 8 irrigation regimes as control treatment (T1), irrigation in 60 and 80 depletion of soil moisture (T2 and T3), stop irrigation in stem elongation stage (T4), stop irrigation during stem elongation to ripening (T5), stop irrigation in flowering stage (T6), stop of irrigation during flowering to ripening (T7), stop irrigation in GRAIN FILLING stage (T8) as first factor. The second plot as secondary factor consisted of two wheat cultivars (Chamran and Marvdasht). AsT1 and T2 treatments had the greatest GRAIN FILLING DURATION and T5 had the greatest GRAIN FILLING DURATION and GRAIN growth rate. Drought stress condition decreased GRAIN FILLING DURATION and 1000 weight GRAIN that leads lower GRAIN yields. Results of correlation showed that seed yield is no significantly correlated with GRAIN growth rate. Also seed yield has a positive and significant correlation with GRAIN FILLING DURATION (r=0.57) and GRAIN growth rate showed a negative significant correlation with GRAIN FILLING DURATION(r=-0.51).

This experiment was conducted to evaluate rate and DURATION of GRAIN FILLING among old, modern and promising rice cultivars under different nitrogen levels in fields of Sari Agricultural Sciences and Natural Resources University, during 2008. Two factors consisted of different urea fertilizer (0, 100 and 200 Kg ha-1) as main plot and four promising lines (Jelodar, Partou, Danesh and Jahesh), 2 old cultivars (Tarom Mahalli and Tarom Deilamani) and improved cultivar (Ghaem1) as sub plot were examined using a split plot design based on randomized complete block design with 3 replications. Among all mentioned traits, in nitrogen levels, flag leaf area, chlorophyll content (a + b), days to 50 percent of flowering, paddy yield and cultivars except for effective GRAIN FILLING DURATION showed significant differences. GRAIN FILLING in different fertilizer treatment had nearly similar pattern (third degree equation). GRAIN FILLING and maximum individual GRAIN weight respond differently to different nitrogen fertilizer rates. The highest and lowest GRAIN FILLING rates were belonged to Partou and Jelodar with no fertilizer application. Among genotypes, Danesh with 6.72 Kg ha-1 had the maximum paddy yield.Orthogonal contrast for three groups of genotypes indicated that in terms of chlorophyll content (a + b) and GRAIN FILLING rate, old cultivars showed higher rate compared to modern cultivars used in this experiment (Ghaem1).