IRANIAN JOURNAL OF AGRONOMY AND PLANT BREEDING
Year:2009 | Volume:5 | Issue:2|Papers Count:10

In order to study the effect of Plant density on Some Quantitative and Qualitative Grain Yield of three Cultivars of durum wheat (Triticum durum) under Irrigation Condition, a field experiment was conducted in Mehran Agriculture research station of Ilam province during 2007-2008 year. Experiment was split plot desigh based on RCB (Randomized complet block) with four replications. factors were cultivars (Yavaros, Karkheh and Saymareh) and plant densities (300, 350, 400, 450 and 500 seed m-2). Therefor, effect of Plant density and cultivars on Yield and Yield components, Bilogical yield and harvest Index and Grain Protein Content were evaluated. Results showed that Cultivar and Plant density effects were significant (P>0.01) for Grain yield and harvest Index. Karkheh cultivar with 5859.87 (kg ha-1) and 46.07 (%) were highest Grain Yield and Harvest Index respectively. Saymareh cultivar with 490.37 (kg ha-1) and 40.74 (%) were lowest Grain Yield and Harvest Index respectively. Density of 450 seed m-2 with 5649.05 (kg ha-1) and 300 seed m-2 with 5043.27 (kg ha-1) were highest and lowest Grain Yield, respectively. Density of 500 seed m-2 with 44.70 (%) and 300 seed m-2 with 41.67 (%) were highest and lowest (HI), respectively. Effect of cultivar on Bioligical Yield is not Significant. There is Significant difference (P>0.01) of density related to Biological yield. The plant densities giving the highest (HI) were at least 400 to 500 seed m-2 for most the varieties studied. There is Significant difference of cultivars related to all of Yield Components. Results Showed that Karkheh cultivar have highest Spike no. per m2, Kernal no. per Spike, Spiklet no. per Spike and Kernal no. per Spiklet whith 601.68, 62.42, 18.32 and 2.26, respectively and Saymareh cultivar have lovest Spike no. per m2, Kernal no. per Spike, Spiklet no. per Spike and Kernal no. per Spiklet whith 530.75, 51.85, 15.19 and 1.57, respectively. The highest and lowest 1000-Grain Weight were related to Yavaros with 46.01 (g) and Saymareh with 40.63 (g), respectively. Effect of density on Yield Components were Significant (P>0.01). The highest Spike no. per m2, Kernal no. per Spike and Spiklet no. per Spike were related to 450 and 500 seed m-2, respectively; and lowest of these relevant to 300 seed m-2. The cultivar ´ density interaction effect on Grain Yield, Harvest Index, Kernal no. per Spike and Spiklet no. per Spike was Significant. Results Showed that Karkheh Cultivar at 400 seed m-2 with 6048 (kg ha-1), 46.8 (%) and 19.6 were gave the highest Grain Yield Harvest Index and Spiklet no. per respectively, and also highest Kernal no. per Spike was gave Kharkheh cultivar with 65.1 at 450 seed m-2. Grain Protein Content was significantly affected by cultivar and density. The highest Grain Protein Content were related to saymareh cultivar and 300 seed m-2.

Drought is one of the most important environmental stresses that inhibit agricultural production. So, introducing new drought tolerant genotypes that grow well in these environments is important for researchers. In order to study the effect of drought stress on yield and yield components of nutty sunflower genotypes an experiment conducted in experimental farm of Islamic Azad University - Karaj Branch. Experimental design was split plot under randomized complete design with four replications. The main factor was irrigation and the sub plots were five nutty sunflowers (Pestehi, Ghalami, Yazidi, Doursefid, Shamshiri) genotypes. Leaf dry weight, petiole dry weight, stem dry weight, head dry weight, total dry weight, plant height, head diameter, seeds 1000 weight, kernel to coat rate, seed yield, harvest index and susceptibility index to drought were measured. Results showed significant differences between irrigation treatments for measured traits. According to our results, susceptibility index to drought can be used as an appropriate selection criteria for selecting drought tolerant nutty sunflower genotypes.

In order to evaluate the effects of different planting and harvesting dates on qualitative and quantitative characteristics of mono germ sugar beet seed bearing plants, this study carried out in Sugar Beet Elite Seed Production Station of Firozkouh at 2003. The experiment was based on Randomized Completely Blocks Design (RCBD) with four replications and split-plots. Planting date factor with three levels (including 19 March, 16 April and 30 April) and harvesting date factor with four levels (including 15, 30, 45 and 60 days after 50% flowering) composed main and sub-plots, respectively. After harvest and tresh pure seed yield, distribution pattern of seeds based on different diameter and thickness and laboratory seed viability were measured. According to the results, planting date had a significant effect on probability level of 1% on 50% emergency, bolting and flowering date based on days after planting and received growth-degree days (GDD), so that later planting date brought about a decrease in days until reaching 50% emergency, bolting and flowering. The main effects of planting and harvesting date and their interaction had a significant effect on the probability level of 1% on crude seed yield. The highest crude seed yield (1164 kg/ha) was obtain with sowing seed-bearing plants in 19 March and harvesting them at 45 days after 50% flowering. Late planting date caused a significant decrease in loss rate due to seed polish, while late harvesting date led to decrease in undersize seed portion because of its significant effect on undersize seed portion. According to the results, the studied factors did not have a significant effect on standard (with the diameter of 3.5-4.5 mm) and oversize (over 4.5 mm) seed percent. On the other hand, late harvesting date significantly led to the increase in germination rate of seeds, whilst planting date did not affect this characteristic.

The SWAP model was evaluated against a data set of four irrigation management. The study was laid out in RCBD with 3 replications for one popular traditional landrace Hashemi carried out in 2005 at Rice Research Institute of Iran, Rasht. The irrigation management were 11 with continuous irrigation while 12, 13 and 14 were irrigation 1, 3 and 5 days after water disappearance of pounded water. For evaluation model are compared simulated and measured leaf area index (LAI) and biomass of panicles, and total aboveground biomass by absolute and normalized root mean square errors (RMSE). On average, RMSE of model were 210, kg ha-1 for yield, 501-736, kg ha-1 for total biomass, 148-364 kg ha-1 for panicle biomass, and 0.47-0.62 cm2cm-2 for LAI. For these crop variables, normalized RMSE values were 5% for yield, 13-21% for total biomass, 6-18% for panicle biomass and 93-55%. for LAI. The model simulated LAI generally exceeded measured values. SWAP model simulate of water flow, to calculate soil water flow, SWAP employs Richard's equation for soil water movement in the soil matrix. The root mean square error (RMSE) range of soil water content was 0.016-0.062 and normalized root mean square error was 3-6 %.

Drought stress is one of the most important natural factors that caused reduction of grain yield in Bean cultivars. Optimum management's ways to plant support under drought condition and avoid of the yield loss is very important. Under drought condition, Selenium has important roles by means antioxidant activity enzyme can reduced cell damage. Therefore, this experiment conducted in research field of the Islamic Azad university of Karaj branch in 2005. Experiment carry out to shape of the split factorial in base of Randomize Complete Block with four replication. Main plot comprise to irrigation treatments in two levels (Normal and Stress) and sub plot treatments comprise to three Red bean cultivars and two levels Selenium density (0 and 18 g/ha). Result showed that traits mean grain yield, 100 grain weight, pod number per plant, and grain number per pod, in drought treatment was decreased significantly (p<0.5). Foliar application of Selenium avoided significant decrease of the grain yield to rate 1184.62 to 1118.6 kg/ha under drought stress. Foliar application of Selenium caused significant increase in rate of Super oxide dismutase enzyme activity. Rate of the Super oxide dismutase enzyme activity in stress condition in Goly cv. was higher than Akhtar and Sayad cv.

In order to compare of agronomical traits relations on safflower under drought stress and normal conditions, hundred genotype of safflower germplasm collections plant gene bank of Iran has been selected. They have growthed under two experimental conditions. One was normal 60-70mm water evaporation and other was stress condition with 170-180mm water evaporation from A class evaporation pan in 10x10 lattice design in two years. Genotypes showed genetic diversity for evaluated traits. Simple correlation coefficients showed that in drought stress condition 50% flowering, 50% maturity, plant height, head size, bract width and seed number on head have positive correlation with grain yield and in normal condition this traits with oil percentage (replace 50% maturity) showed positive correlation with it. Results of regression for grain yield in normal condition showed that head size, seed number, head number and kernel of thousand weight determined highest variance (50%) of grain yield. in drought stress condition seed number, head size and 50% maturity had highest role in variance of grain yield. Result of path analysis seed production with other traits in regression model analysis indicated that in normal humidity condition (0.52) head size and stress condition (0.48) seed number has most direct effect on production. According to direct relation between number of seed as most important seed production trait head size trait can be used as index of seed production improvement.

In order to evaluate responses of different corn hybrids to drought stress and to detect relations and correlations between different traits in studied genotypes, a study was conducted in northern west of Qom province, near to Shokohieh suburb during 2007. Twenty corn hybrids were evaluated using a complete randomized block design with four replications and in two distinct experiments under normal soil moisture and drought stress. (irrigation after depletion of 30 and 60 percent of soil moisture, respectively). Analysis of variance of studied traits in normal and drought conditions denoted existence of appreciable diversity in these traits among corn hybrids. The highest variation between two environments was belong to anthesis-silking interval (ASI) (-51.62%), and yield variation was 31.72%. In both conditions, heritability of kernel weight, hectoliter and grain yield were higher than other traits. Assessing correlations between traits in normal condition showed there is a positive, significant correlation between yield with hectoliter weight, kernel weight, kernel rows in ear, and kernels in row. Under drought stress, there was a high negative correlation between yield and ASI (-0.83), and also days to silking and tasseling, whereas grain yield showed positive correlation with kernels in row (0.82), kernel rows in ear (0.75), and also kernel depth and weight. Studying direct and indirect effects of traits effective in normal condition indicated that the highest direct effect on grain yield was related to kernels rows (0.868). In stress condition, however, direct effects of kernels in row (0.778) and kernels in ear were positive and higher than others, and direct effect of tassel peduncle length in inverse proportion on yield was more than other traits. ASI had a strong effect on yield reduction in stress condition, indirectly by reducing kernel number. According to results, the best way to selection toward yield enhancement is the direct selection in order to increase yield components, and in screening drought tolerant crops, a special attention should be paid to reducing ASI duration, and also days to silk and tassel appearance.

In order to investigate the effects of different irrigation regimes and methods on yield and yield components of SC704 corn hybrid, a field experiment was conducted similarly in 2006 and 2007, at agricultural research farm of Karaj Islamic Azad University (35o43’ N latitude, 50o56’ E longitude, 1160 m altitude). The studies were carried out in a factorial experiment based on a randomized complete block design with three replications. The factors were irrigation regimes at three level (plant irrigation after 40%, 60% and 75% available water loss) and irrigation methods at two levels (Irrigation of all furrows and irrigation furrows alternately). Results showed that irrigation regime had significant effect on biological and grain yield and yield components. Whereas irrigation method had significant effect on biological yield, grain number in cob and cob length. There was significant correlation between grain yield and grain number in cob, row number in cob, cob length, cob yield in m2, grain number in cob row, 1000 grain weight and cob yield and also inoculated part of cob negatively. Whereas there was significant correlation between biological yield and plant height, height of first cob and cob number in m2. Results of stepwise regression revealed that cob length, 1000 grain weight and row number in cob were important components in grain yield. But the most important components in biological yield were plant height. Results of path analysis showed that cob length had the most direct effect (0.761) on grain yield. Other components had the most indirect effects on grain yield by cob length. In general, cob height and 1000 grain weight were the most important components in grain yield and plant height was the most important component in biological yield.