جستجوی مقالات مرتبط با کلیدواژه « فیزیولوژیکی » در نشریات گروه « زراعت »

Verticillium wilt disease is one of the most important damaging and limiting factors for cotton production worldwide. This pathogen causes leaf chlorosis, necrosis or wilt, leaf or pollen drop, and even plant death. It also reduces the quantity and quality of the product. Because of the economic importance of the cotton disease Verticillium wilt, the best way to control this disease is to use tolerant varieties. Therefore, breeding resistant varieties in a wide range is considered one of the most effective control methods. This experiment was conducted to determine the effect of the disease on the morphological and physiological characteristics of cotton cultivars in order to identify tolerant genotypes

The experiment was carried out during two years 2020-2021 and in a factorial form in a completely randomized design with three replications in the greenhouse of Khorasan Razavi Agricultural Education and Natural Resources Research Center (Plant Protection Department). In the first year, ten Iranian cotton cultivars belonging to Gossypium hirsutum were cultivated. In the first year experiment, cotton agronomic traits such as plant height, number of leaves, number of branches, crown diameter, leaf area size, disease severity, chlorophyll index, relative leaf water content and electrical conductivity were measured. In the second year, two tolerant cultivars (Bakhtegan) and sinsitive (Varamin) resulting from the first-year experiment were cultivated in the greenhouse along with the resistant cultivar of Thermous 14. At this stage, the amount of proline, soluble carbohydrates and total phenol was evaluated at different times after inoculation with the pathogenic fungus. All traits measured over two years using SAS statistical software were analysis of variance and the means were compared using Duncan's test.

In the first year, it was found that among the ten genotypes grown, all agronomic traits (except plant height) were higher in the Bakhtegan cultivar and lower in the Varamin cultivar than in the other cultivars. Under infection conditions, disease severity was highest in Varamin and Cocker100 cultivars. The lowest severity of the disease was in the variety Bakhtegan. Physiological traits such as chlorophyll index and relative water content were higher in Bakhtegan and lower in Varamin. The opposite was true for membrane electrolyte losses. In the second year, it was found that in the three cultivated genotypes Thermous14 (resistant), Bakhtegan (tolerant), and Varamin (sensitive), the amount of biochemical traits proline, carbohydrate, and total phenol was significantly increased in the infected plants compared to the control plants (no inoculation with pathogenic fungi).

Therefore, plants with more leaves, higher chlorophyll index and relative water content, lower electrolyte leakage, more proline, carbohydrates and phenols are more resistant to infection.

Temperature reduction since late December until late February is a dominate climate phenomena in Khuzestan which caused plant damage and subsequently yield reduction. In order to study the effect of chilling stress at heading stage on yield, yield component and some physiological traits of wheat genotypes, this research was carried-out with five genotypes (Chamran, Vee/Nac, Star, Kharkheh cv. and line M-83-17) and four environmental temperatures(non-stress, and+3,0 and -3°C) under greenhouse condition, in factorial experiment using CRD with three replications in Khuzestan Natural Resources and Agricultural Research Center in 2013. Date of physiological maturity, plant height and spike length, yield components including spikelet/spike, grain no./spike, 1000 grain weight and grain weight in main spike and Fo, Fm, andFv/Fm indices were evaluated. Results showed that the effect of chilling stress was significant for days from germination to physiological maturity, grain no. per spike, grain weight in main spike and Fv/Fm traits. The highest grain weight in main spike under non-stress and -3°C chilling stress was belonged to line M-83-17 and Chamran cultivar, respectively and under zero and 3°C chilling stress were obtained from Chamran cv. and Vee/Nac, respectively. The highest difference before and after chilling in Fv/Fm index was belonged to zero chilling stress. Differences in traits which were studied in this research indicated genetic variation in genotype response to chilling stress

In order to evaluate the effects of NaCl on some morpho- physiological traits in almond and alteration of photosynthetic parameters, an experiment was performed based on completely randomized design with five treatments included 0, 25, 50, 75 and 100 mM of sodium chloride in three replications. The results indicated that the contents of sodium and chloride were increased in almond seedlings but quantities of relative water content, chlorophyll index and dry weight of leaves were decreased in parallel with augmentation of salt levels significantly (p ≤ 0.05). In these conditions, alterations of leaf temperature were not significant but the seedlings percentage indicating marginal leaf scorch symptoms was increased up to 89% with relatively regular template. Applied salt in the lowest level enhanced the mean of internal CO2 and metabolic-stomatal limitation up to 35 μmol.mol-1 and 39.5% as well as decreased the mean of CO2 assimilation and stomatal conductance up to 6 mol.m-2.s-1 and 0.15 mol.m-2, respectively (p ≤ 0.05). In this probe, high efficiency of some measured traits such as relative water content, chlorophyll index and marginal leaf scorch symptoms was revealed in quick screen of the salt tolerant genotypes.

To evaluate terminal drought tolerance in barley genotypes and to study the relationship between morpho-physiological traits and grain yield in terminal drought stress conditions, 214 barley genotypes as well as two checks were examined at three locations; Varamin, Birjand and Esfahan Research Field Stations in 2002 -2003 growing season. Morpho-physiological traits including: days to anthesis, days to maturity, plant height, peduncle length, spike length, number of fertile tillers, grain.spike-1 and 1000-grain weight were measure and recorded in three locations. Results indicated significant differences between Six row and two row genotypes for grain yield components (number of fertile tillers, grain.spike-1 and 1000 grain weight), days to heading and spike length. Correlation, stepwise regression and path analyses studies indicated that days to anthesis, peduncle length and 1000 grain weight not only had the highest correlation with grain yield, but also had the highest direct effects on grain yield in both six row and two row barley genotypes. However, these correlations and effects were more pronounced in two row barley genotypes.