CROP PHYSIOLOGY
Year:2013 | Volume:5 | Issue:18|Papers Count:9

In order to investigate the phonological characteristics of new hybrids of corn in drought tension, this experiment as a complete randomized block design in a strip-plot arrangement was done at the research field of University of Agriculture and Natural Resources of Ramin Khouzestan in 2010-2011. It included three levels of irrigation regime (irrigation cut-off in 8-leaf stage, irrigation cut-off in stage of male flower appearance and optimum irrigation) in longitudinal plots and 11 hybrids (07-101, 07-103, 07-107, PL710, PL711, PL706, PL774, AS71, Mobin, Karoon and S.C 704) in transversal plots with three replications. The results showed that irrigation cut-off in 8-leaf stage (vegetative stage) caused duration of vegetative growth to last longer, whereas it postponed starting of generative growth, so that the longest duration of vegetative growth was obtained for hybrid 07-107 in tension conditions in 8-leaf stage and the shortest duration happened to hybrid PL706 and in non-tension conditions. Duration of generative growth of different hybrids was influenced by the amount of water received by plant; of course this change happened more intensely in drought tension treatment in stage of male flower appearance. The longest duration of generative growth was obtained for hybrid PL706 in optimum irrigation conditions and the shortest duration was obtained for hybrid AS71 in drought tension conditions in stage of male flower appearance. Duration of pollination of different hybrids was affected by the degree of plant access to water. The longest duration (11.17 days) of pollination was obtained for hybrid PL706 in non tension condition and the shortest duration was observed for 07-101, 07-103, AS71, PL710 and PL711 hybrids all the same in 3.67 days in irrigation cut-off conditions in stage of male flower appearance. The trend of the variations in duration of flowering indicated that this duration was longer for all hybrids in optimum irrigation conditions, whereas it was shorter in tension conditions in stage of male flower appearance and Interaction drought tension and hybrid on duration of flowering adaptation was significant.

In order to investigate the effect of irrigation interval, humic acid and plant growth promoting rhizobacteria on relative humidity content, the resistance amount of cell membrane, chlorophyll content and amount of wheat leaf proline; this experiment was done during 2010-2011 cropping year, as split factorial in the basis of completely randomized blocks design in four replications in Fashafuyeh Shahr-e-Rey. Main factor (irrigation) in 3 levels (irrigation after 80, 120 and 160 millimeter evaporation from evaporation pan surface class A) and humic acid and a mixture of Plant Growth Promoting Rhizobacteria (PGPR) each in 2 levels application and non-application as factorial considered as sub-factor. The results of the analysis of variance showed that the effect of irrigation interval on all traits was significant, excepting content of chlorophyll a at possibility level of one percent. While effect of humic acid demonstrated significant difference in all traits except for content of relative humidity content at the possibility level of one percent and effect of growth stimulus bacteria showed such significant difference only for content of chlorophyll a+b at the level of five percent and the leakage of cytoplasmic materials and proline amount at the possibility level of one percent. In humic acid applying treatment, the highest amount of chlorophyll a at two levels of irrigation after 80 and 120 millimeter evaporation was at the rate of 0.0212 and 0.0206 mg/cm and maximum leakage of cytoplasmic membrane due to the absence of applying humic acid, in severe moisture tension (after 160 mm evaporation) at the rate of 663.06 ms/cm. The rate of leaf proline in all irrigation levels increased after using humic acid and with increasing the tension intensity; equals 171.9250, 152.4875 and 107.6875 microgram on leaf fresh weight unit, respectively.

In order to investigate the effect of water deficit tension on yield and yield components of mung bean in different densities, a field experiment was conducted in Dezfoul area in summer 2010 as a split plot in a randomized complete block design with four replications. In this research, treatments of irrigation after 90, 120, 150 and 180 mm evaporation from class A pan evaporation in the main plots and the density as distances 6, 9, 12 and 15 cm between two plants on rows of planting in the subplots. The results of experiment showed that the effect of different irrigation levels was significant on number of pods per plant, 1000- grain weight, grain yield, biological yield and harvest index, but had no significant effect on number of grain per pod. It is inferred that the mung bean plant is very sensitive to water deficit tension and significantly yield loss is occurred due to increasing water tension. Treatment effect of density was significant on traits the number of pods per plant, grain yield, biological yield and harvest index. Based on these results, increase or decrease of density both were the limiting factors of yield. Also, the interaction of water deficit tension treatments and plant density except on the number of grain per pod had significant effect on all the traits. According to the evaluation results of this research, a distance of 12 cm between two plants on rows of planting as the best distance for optimum irrigation treatment (irrigation after 90 mm accumulative evaporation from evaporation pan class A) is recommended for maximum plant yield of mung bean in Dezfoul area.

In order to identify tolerant forage sorghum lines to salinity tension conditions, this research was conducted at Seed Technical Laboratory of Islamic Azad University, Shoushtar Branch in 2013, as factorial under Completely Randomized Design (CRD) with three replications. The First factor included fifteen promising forage sorghum lines and the second factor included salinity tension with NaCL in five levels (0, -3, -6, -9 and -12 bar) .The traits germination percentage (27.23%), germination rate (30.18%), length of rootlet (77.74%), length of plumule (73.24%), seed vigor index (82.73%) and wet weight of seedling (59.38%) were decreased by decreasing in osmotic potential (-12 bar). The mean germination time trait (68.83%) increased with decreasing in the osmotic potential (-12 bar). Line KFS10 showed the highest germination percentage, length of rootlet, seed vigor index and dry weight of seedling. With attention to lines ranking basis the studied traits, line KFS10 as the tolerant line to salinity specified the best score and line KFS1 was in the lowest rank regarding salinity tolerance.

The effect of drought of the end of season on grain yield and quantitative characteristics of eleven promising lines of spring rapeseed, with Hyola 401 cultivar as control, were investigated as a randomized complete block design with three replications at two normal and irrigation cut tension conditions from the beginning of flowering in two years (2008-2010) at Safiabad Agricultural Research Center. After the combined analysis in the main effects of drought tension and lines, and their interaction, significant statistical differences was observed in grain yield average and other quantitative traits. Irrigation cut at the beginning of flowering reduced seed yield 25%, number of capsules per plant 14.4%, 1000-seed weight 13.6%, seed number per capsules 10% and oil content 6.5% in comparison to control treatment. The highest seed yield obtained on no tension conditions in Hyola 401 and L4 with 2537 and 2511 kg/ha, respectively; and on tension conditions was in Hyola401 and L1 with 2025 and 1974 kg/ha, respectively. The comparison of means in two conditions of irrigation separately showed that the difference between lines in tension conditions was more than no tension conditions. Thus, the lines regarding the reaction of yield to tension have different genetic tolerance. So, using of lines with desirable genetic traits such as minimum reducing grain yield, yield components and oil percentage is appropriate in breeding programs. Totally, the lines L1, L4 and L11 are recommended as alternative to Hyola 401 cultivar.

In order to investigate the effect of phosphorus fertilizer on yield ,oil and canola protein Hyola 401 cultivar in dry farming in different groups of soil phosphorus fertility sixteen experiments in four areas and in each area four experiments in four groups of phosphorus usable for the soil (less than 3 ppm, 3-6 ppm, 6-10 ppm and more than 10 ppm) was conducted in the form of randomized complete blocks design in 4 phosphorus fertilizer treatments (0, 25, 50, 75, kgs of P2O5 in each hectare) from the triple super phosphorus source with four repetitions in the city of Behbahan in cropping years (2008-2010). The obtained results showed that phosphorus fertilizer treatments in all soil fertility groups had no significant effect on grain yield, number of capsules, number of grain in the capsule, 1000 -grain weight, percentage of oil and percentage of protein. Also, interaction (phosphorus fertilizer ´ fertility groups) in all soil phosphorus fertility groups had no significant effect on the measured factors.

Drought is one of the most important environmental tension that affect yield and yield components of crops severely. This experiment was carried out at a research field in Agricultural Research Center and Natural Resources of Yazd in 2010-2011, in a Randomized Complete Block Design with six genotypes of barley including Yousef, Nosrat, ED3, ED6, ED8 and ED14 and three replications. In order to apply irrigation tension, irrigation cut was done in 50% ear emergence and drought tension was applied. Results showed that effect of genotype was significant on the majority of morphological traits (except for ear length, morphological characteristics (except for RWC), grain yield and harvest index. Totally, the highest amount of 1000-grain weight (29.12 gr) and stem diameter (41.67mm) was produced by Yousef cultivar, the highest amount of plant height (71.67 cm), day to anthesis (79) and day to maturity (112) was obtained by Nosrat cultivar. The highest leaf water potential (48.6%) was produced by ED3 line, the highest amount of proline content (18.27%) and spikelet number (15.33) and in ED6 line. The highest leaf area (3904cm2) was produced by ED8 line. The highest of grain number per ear (53.3), chlorophyll (12.73), harvest index (43.8%) and grain yield (3369 kg/ha) was produced by ED14 line. Generally, regarding the high yield of ED14 line in drought tension conditions, this line is recommended.

This research in three independent experiments each as split plots using complete randomized block design with three replications was conducted in 2010-2011 cropping year under Ahvaz climate conditions. Each experiment consisted of three planting dates as main factor and six genotypes (Chamran cultivar as control and five selected lines and cultivars from different groups of early maturity) as sub factor. First planting date in the first ,second and third experiment; was Oct.27, Nov. 16 and Dec.16 and 10 days interval between the second and third plantings date with first planting date in first and third experiments and 15 days interval in the second experiment were assigned. Grain yield was determined and accumulative growing degree-day amount from planting to some phonological stages and heat unit efficiency index from equation for genotypes were calculated. Results showed that planting date, genotypes difference and interaction genotype x planting date were significant for duration of different phonological stages duration. The average of day and accumulative growing degree-days from planting through phonological stages were decreased in response to planting delaying in which reduction intensity was higher in mid maturity genotypes due to delaying in planting. Correlation among grain yield with accumulative growing degree-day was not significant, while grain yield was significantly correlated and positive with heat unit efficiency. In comparison with accumulative growing degree-day index and regarding to its high accessibility due to planting date, that may bring about misleading results, according to the results of this research it seems that heat efficiency index has higher efficiency for wheat genotypes responsiveness explanation.