فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 25 (بهار 1392)

Study the relationships of some agronomic traits with grain yield of 14 late maturing corn hybrids, an experiment based in RCBD with four replications was carried out at Miyandoab Agricultural and Natural Resources Research Station in 2009. Results showed that there were significant differences among corn hybrids for plant and ear height, number of kernel row and kernel numbers per ear, 1000 kernel weight, biological yield and grain yield. Hybrid KLM76005 × MO17 produced highest grain yield. Grain yield had high positive significant correlations with biological yield and harvest index. Stepwise regression analysis showed that traits like harvest index, biological yield and 1000 kernel weight justified the grain yield variation. Path analysis indicated that these traits had the highest positive direct and significant effect on grain yield. Based on the cluster analysis results, corn hybrids under study divided into 5 groups. Groups number 2 and 3 in cluster analysis did have higher mean values for effective traits on grain yield (harvest index, biological yield and 1000 kernel weight) as compared to the others. Grain yield had negative significant correlation with GDD at tasseling time and total GDD during growing season. Based on principle components analysis basic vector values two factors explained data total variation by 80.3 %. Based on results obtained it can be concluded that Hybrid KLM76005 × MO17 due to its higher biological yield and harvest index would be the best option to be recommended.

To investigate the effects of methanol on relative water content (RWC) and leaf chlorophyll content of common bean an experiment was carried out at the Research Field of the Faculty of Agricultural and Natural Resources of Islamic Azad University, Karaj Branch in 2009. A factorial experiment with randomized complete block design with three replications was used. First factor consisted of 8 levels of aqueous spraying on plants [0 (control), 10, 15, 20, 25, 30, 35 and 40% (v/v) methanol] by 3 times during growing season at 12 days intervals. Traits measured were grain yield, RWC, chlorophyll content and dry weight of the plants. These traits measured before and after methanol spraying. Results showed that were significant differences between methanol spraying solution on leaf chlorophyll content and RWC after second and third stages at 1% and on grain yield at 5% probability levels. Methanol using affected to dry weight accumulation. Means comparison showed that increasing levels of methanol foliar application increase chlorophyll content and relative water content. Effect of M3, M4 and M5 methanol levels on measured traits was greater than other treatments. Application of methanol increased grain yield, chlorophyll content, relative water content and leaf area.

To evaluate the effect of different levels of diaminozied on the potato cultivars mini-tubers produced by tissue culture under greenhouse condition a factorial an experiment on the base of completely randomized design in three replications was performed at the Ardabil Villkige Company Greenhouse in 2010. The first factor consisted of four levels of diaminozied, as plant growth regulator, (0, 40, 80 and 120 mg.L-1) and the second factor of five cultivars of virus-free potato (Satina, Savalan, Marfona, Agria and Cesear). Virus-free plantlets were transferred to isolated greenhouse and planted in 20×20×15 cm in plastic pots beds made by 1:1 volume of Biolan peat moss and perlite. During growth period traits like plant height, leaf and stem number per plant, mini-tuber weight and number per plant and square meter, and mini-tuber size were average measured. The analysis of variance showed significant differences among different levels of diaminozied for leaf number per plant, mini-tuber weight and its number per square meter, tuber average size in all cultivars under study. The interaction of diaminozied by cultivars showed significant difference as to leaf number per plant, mini-tuber weight, its number per square meter and average tuber size. Cesear and Marfona cultivars produced higher mini-tuber weight and tuber number per square meter by applying 40 mg.L-1 diaminozied. The correlation was significant and positive between mini-tuber number per square meter with mini-tuber weight per square meter and root length. It was also significant and positive between mini-tuber weight per square meter with plant height and average mini-tuber size. The results of multi regression analysis indicated that mini-tuber weight per square meter, average tuber size, plant height and root length were effective on changes of the mini-tuber number. The highest positive direct effect on number of mini-tuber per square meter was due to the plant height and the less negative direct effect to the mini-tuber weight per square meter.

The effects some traits on seed yield of recombinant inbred lines of wheat under water deficit stress was studied. This research was done at the Agricultural Research Stations, Islamic Azad University, Tabriz Branch in 2010- 2011. 28 recombinant inbred lines of wheat bread with two parents (Norstar and Zagros) in split plot experiment based on a randomized complete block design with three replications at two irrigation levels (70 and 140 mm evaporation from pan class A) were studied. Analysis of variance indicated a significant genetic differences in all traits under study among the lines. Lines No. 32, 163 and 182 produced highest yield under both irrigation levels. Number of spikes, grains per spike and harvest index had the highest positive correlation with grain yield. Path analysis based on stepwise regression showed that under the normal irrigation conditions, number spike (0.556), number of grains per spike (0.278), weight of 1000 grain (0.259) and the drought stress number spike (0.430), straw yield (0.276) and peduncle length (0.323) had the most direct and positive effect on yield respectively.

To study the effect of different irrigation regimes on morphological and physiological characteristics of soybean cultivars, this experiment was conducted at Moghan Agricultural Research Center during 2009-2010 in Iran. The experiment was split plot based on randomized complete block design, with 3 replications. The main plots consisted of four irrigation regimes: I1, I2, I3 and I4 indicating irrigation after 60, 100, 140 and 180 mm evaporation from class A pan respectively and 3 soybean cultivars named Linford, L17 and Williams assigned in the sub plots. Results of combined analysis showed that with increasing irrigation intervals from I1 to I4 reduced growth period, plant height and leaf area index (LAI), number of nodes, branches and internodes significantly. Physiologic characteristics such as chlorophyll contain of leaves and relative water content (RWC) were also affected by irrigation regimes. LAI in I1 was 4.94 reduced inI4to 3.70.Plant height of soybean cultivars were declined by 21% in I4 (irrigation after 180 mm evaporation) as compared to I1 (irrigation after 60 mm evaporation). Soluble proline content of the leaves and electric conduction (EC) on the other hand increases significantly. There was significant differences among cultivars concerning the vegetative and physiological characteristics. Willams and L17 cultivars produced the highest numbers of nodes (15.5) and internode length (4.95cm) receptivity. The maximum proline content (65.6 µmol/F.W) and relative water content (67.65%) belonged to Linford cultivar. Interaction of irrigation regimes and cultivars was significant on plant hieght, LAI and proline content. Linford cultivar had more soluble proline under water limited condition and maintained higher LAI and plant height in I4 treatment as compared other treatments.

To evaluate the effect of bio-fertilize on yield and its components in maize cultivars, an split plot experiment based on randomized complete bock design with three replications in was conducted in Payam-noor University of Ilam, Iran, in 2009-2010. Treatments were cultivar (SC604, SC704 and SC807) assigned to main plots and bio-fertilizer (non- inoculation, inoculation with Azetobacter, Azospirillum and dual inoculation ofAzotobacterand Azospirillum) to subplots. The effect of cultivar on days to maturity, plant height, dry matter, ear length, stem diameter, number of grain per ear row, 1000-grain weight, grain yield, biological yield and protein content was significant cultivar. SC 704 had the highest dry matter (259.5 g.m-2), plant height (201.1 cm), number of grain per ear row (42.8 grain), grain yield (10850 kg.m-2), and biological yield (22040 kg.m-2). The effect of plant growth promoting rhizobacteria on all traits expect harvest index was significant. Dual inoculation ofAzotobacterand Azospirillum had the longest days to ear initiation (71.2 days), days to maturity (115.4 day), number of leaves above ear (5.6 ear), dry matter (240.4 g.m-2), ear length (24.3 cm), plant height (212.4 cm), seed number of rows per ear (14.5 row), number of grains per row (44.2 grain), grain yield (10190 kg.m-2), biological yield (21320 kg.m-2) and protein content (10.7%). Interaction effect of cultivar× plant growth promoting rhizobacteria on grain yield was significant. The highest and lowest grain yield was obtained from SC 704 and application of dual inoculation ofAzotobacterand Azospirillum (12320 kg.ha-1) and lowest from SC 604 when inoculation treatments were not used 7570 kg.ha-1 respectively.

To study the response of barley genotypes to terminal drought stress, 20 promising barley genotypes were compared under two stress and non-stress conditions, in a split plot experiment based on randomized complete block design with three replications at the Agricultural Research Center of Southern Khorasan during 2007-2008 growing season. Drought stress levels consist of control (complete irrigation) and irrigation up to the 50% heading stage. Results showed that skipping irrigation at 50% heading stage resulted in 14.64 reduction in seed yield and 8.12 percent in biological yield compared to control condition. Spike length, plant height and flag leaf area in drought condition decreased by 12.4, 7.65 and 24 percent against complete irrigation treatment. Also, irrigation up to the 50% heading caused increasing of chlorophyll index and cell membrane permeability and declining of relative water content of flag leaf. There weren’t any significant differences among barley genotypes in terms of biological yield but the highest and lowest grain yield achieved from genotype number 18 (5997.2 kg.ha-1) and genotype number 16 (3420.8 kg.ha-1) respectively. Cultivar number 5 and 13 had the highest rate of chlorophyll index, and also number 8 had the highest relative water content (80.7%) in flag leaf. Based on the results of this study, genotypes number 18 and 20 had higher yields in both normal and drought stress conditions.

Biofertilizers are inputs that naturally supplement replace chemical fertilizers and they are recommended in sustainable agriculture. To study the effects of biological fertilizers on yield and yield components of corn, a factorial experiment in randomized complete block design with three replications were conducted at Dareh-shahr, Iran in 2010. Biological factors were 4 levels of nitrogen biofertilizers (nitroxin, nitrokara, supernitroplus and control) and 4 levels of phosphorus biofertilizers (biophosphore, phosphate fertilized 2, MC1 and control). Results showed that biological nitrogen and phosphorus fertilizers had significant effects on all traits under study. Interaction of nitrogen biological fertilizer × phosphate biological fertilizer was significant on 100 seed weight (P