Evaluation of some physiological traits of winter canola varieties in drought stress conditions.
Drought stress significantly limits plant growth and crop productivity. However, in certain tolerant adaptable crop plants, such as rape seed, morphological and metabolic changes occur in response to drought, which contribute towards adaptation to such unavoidable environmental constraints . The fact that water stress effects on growth and yield are genotype-dependent is well known . In Iran, water is a scarce resource, due to the high variability of rainfall. The effects of water stress depend on timing, duration, and magnitude of water deficiency . Identification of the critical irrigation timing and scheduling of irrigation, based on a timely and accurate basis to the crop, is the key for conserving water and improving irrigation performance and sustainability of irrigated agriculture .
In arid and semi-arid environments, both efficient use of available water and a higher yield and quality of safflower are in demand [7,4,8]. Efficient management of soil moisture is important for agricultural production in the light of scarce water resources. Soil conditioners, both natural and synthetic, contribute significantly to provide a reservoir of soil water to plants on demand in the upper layers of the soil, where the root systems normally develop.
These polymeric organic materials and hydrogels, apart from improving the soil physical properties, also serve as buffers against temporary drought stress and reduce the risk of plant failure, during establishment [3,5].
This is achieved by means of reduction of evaporation through restricted movement of water from the sub-surface to the surface layer.
Brassica oilseed species now hold the third position among the oilseed crops and are an important source of vegetable oil . The reaction of plants to water stress differs significantly, at various organizational levels, depending upon intensity and duration of stress, as well as plant species and its stage of development. Environmental stresses, including drought and temperature, affect nearly every aspect of the physiology and biochemistry of plants and significantly diminish yield . Therefore, the primary objective of the present investigation was to examine the effect of water stress on the agronomic characters and physiological exchanges in leaves of rape seed. The work was also aimed at verifying whether a super absorbent polymer supply to plant might be a strategy for increasing the drought tolerance.
The effect of water stress on crop is a function of genotype, intensity and duration of stress, weather elongation conditions and developmental stages of rapeseed.
Material and methods
For appoint of resistance to drought stress two kinds of autumnal Rapeseed and survey of component of their function in conditions of treatment for examination drought stress and regular irrigation (witness), examination in case of split plot in form of complete basis project block in three repetitions that which the irrigation was the main factor in seven levels: consist of regular irrigation (witness), cutting irrigation in stage of tillering, cutting irrigation in stage of flowering, cutting irrigation in stage of fructify, cutting irrigation in stage of tillering and flowering, cutting irrigation in stage of tillering and fructify, and cutting irrigation in stage of flowering and fructify and also the accessory factor in two levels consist of Zarfam & Opera varieties. The experiment was carried out at the Seed and Plant Improvement Institute (35[degrees]59'N, 50[degrees]75'E, and altitude of 151 m above the sea level), in Karaj, Iran, in 2006-2007. This region has a semiarid climate (230 mm annual rainfall). The soil of the experimental site is a clay loam, with montmorillionite clay mineral, low in nitrogen (0.06-0.07%), low in organic matter (0.56-0.60%), and alkaline in reaction, with a pH of 7.9 and Ec = 0.66 dS m-1. The soil texture is sandy loam, with 10% of neutralizing substances.
In this survey all the stages of plant's phonology and various attributes such as length of the bush, number of the secondry branches in the bush, the sickness of the stem, the length of silique's main stem, secondry branch, the length of the silique, the number of the silique in the main stem and the secondary stem, number of the silique in the bush, the number of seed in the silique in main stem and secondary stem, the number of the seed in the silique, the weight of the thousand of seeds, function of the seed, biologic function of harvest's coefficient and the percentage of oil of the seed and the function of the seed's oil measured.
The experiment was organized in a randomized complete block design, with split plot arrangement, with three replications.
In order to better evaluate and determine the growth characteristics of canola growth in different treatments, growth analysis was performed. This requires accurate sampling is done. To measure and calculate indices of growth, from about 4 to 6 leaf stage of plant physiological interval of once every 14 days, all experimental plots, sampling was destructive, and leaf dry weight, total plant dry weight and speed plant growth was determined. In this study, instead of single days growing degree days (GDD) was used. Data matching statistical models split plot design in randomized complete block design was simple variance analysis and comparison of means using multiple range tests Duncan 5% level was performed. The simple correlation between test characteristics was calculated.
Results and discussion
The results of analysis of variance showed that cultivar traits such as yield, oil yield, seed oil (1 percent probability level) and seed weight (5 percent probability level) were significant. The interaction of irrigation and variety on grain number pod trait significant effect is exhibited.
The results of this study showed that a simple figure of 1% probability level on grain yield was significant. Mean levels Zarfam figures show that figure with the average 4192.2 kg ha maximum and average number Opera 3448.8 kg ha had the lowest yield.
Comparing different levels of irrigation also showed that grain yield with irrigation conditions in forming stems and flowering stages with mean 4769 kg/ ha respectively (Table 1).
Water shortages could affect deleterious effects on canola yield, but the effect of genotype and developmental stage of plant adaptation to drought depends. Canola ability to absorb water from the depths of the earth and need to be rain water in arid regions are among an advantage .
Simple interaction effects of irrigation and irrigation and variety on grain weight was not significant.
While the simple traits of 5 % probability level was significant. a simple comparison of traits revealed the highest seed weight associated with a mean traits Zarfam 3/85 g respectively.
In comparing the interaction of irrigation and genotype was found in drought stress conditions the highest seed weight traits Zarfam (4 g) cutting off the water in step stems forming and flowering found to have the least amount of this trait to traits Opera (4.3 g) and stress at flowering stage and was forming stem (Table 1). In the study of physiological drought tolerance in canola, expressed under drought conditions, significant differences in grain weight showed . It seems that in this study, pod number per plant with the loss of drought stress, the remaining pod seeds maintain their weights have.
Analysis of variance of seed oil percent was shown in the traits of 1 per cent level of this trait were significant. Also compare the interaction of cultivar and irrigation control irrigation was found that the highest percentage of oil to average figure Zarfam 40.5 percent, and the highest oil content under drought stress conditions Zarfam figure (42.5) with a water cut conditions Flowering stage and pod forming is obtained (Table 1). Drought stress on seed oil content has no significant effect (Munoz and Fernandez, 1998).
Seeds per pod is an important traits in rapeseed yield is a very important role. Analysis of variance in seed number pod showed that the interaction of cultivar and irrigation at 5% this trait were significant. Comparison of means of irrigation and cultivar interactions in drought conditions, the highest number of seeds per pod about opera traits mean 20.6 is that the amount of irrigation in the forming stage is derived stem (Table 1).
Drought pollination stage and grain filling decrease in canola seeds per pod is (Niknam and Turner, 1999). In the present study observed that the number of seeds per pod of drought (Opera) has a low above results with the results of such research [11,16]. All of which reduce the number of seeds per pod of stress reported is in accordance.
Table of simple correlation between traits indicated that the number of seed oil seed pod and seed oil yield positive and significant correlation in the 5 percent level, and positively correlated with grain yield and level of significance has had a percentage, the performance Seed, a significant positive correlation in the 1 percent level seed oil and seed oil yield has had (Table 2).
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Young Researchers Club, Chaloos Branch, Islamic Azad University, Chaloos, Iran.
Hossein Bagheri, Young Researchers Club, Chaloos Branch, Islamic Azad University, Chaloos, Iran. Email: Bagheri_hm2000@yahoo.com
Table 1: Mean comparison the interaction of irrigation and varity effect on some traits of colza. Irrigation Grain Yield 1000 SW Varity Varit Varity Varit Opera Zarfam Opera Zarfam Regular 3996 abcd 5021 a 3.82ab 3.77 abc Irrigation Cutting 2971 bcde 3758 abcd 3.77 abc 3.8 abc Irrigation in Stage of Tillering Cutting 2167 e 4108 abcd 3.61 bc 3.84 ab Irrigation in Stage of flowering Cutting 2838 cde 4204 abcd 3.69 abc 3.78 abc Irrigation in Stage of fructify Cut.Ir in 4404 abc 5133 a 3.45 c 4 a Stage of tellering and flowering Cut.Ir in 3638 abcde 2625 de 3.66 abc 3.83 ab Stage of tellering and flowering Cut.Ir in 4129 abcd 4496 ab 3.84 ab 3.92 ab Stage of tellering and flowering Irrigation Oil % N. Of grain in fructify Varity Varit Varity Varit Opera Zarfam Opera Zarfam Regular 39.49 cd 40.57 bcd 19.5 c 16.2 abc Irrigation Cutting 39.63 bcd 40.5 bcd 20.6 a 13.3 c Irrigation in Stage of Tillering Cutting 40.5 bcd 41.49 ab 13.6 c 17.6 abc Irrigation in Stage of flowering Cutting 39.19 d 41.26 abc 15.3 abc 15.3 abc Irrigation in Stage of fructify Cut.Ir in 39.85 bcd 42.52 a 14 bc 18.3 abc Stage of tellering and flowering Cut.Ir in 38.75 bcd 41.23 abc 15 abc 19.6 ab Stage of tellering and flowering Cut.Ir in 40.32 bcd 42.56 a 15 abc 16.3 abc Stage of tellering and flowering Irrigation Oil Yield Varity Varit Opera Zarfam Regular 1582 abcd 2040 ab Irrigation Cutting 1173 cde 1509 bcde Irrigation in Stage of Tillering Cutting 879.5 e 1716 abcd Irrigation in Stage of flowering Cutting 1116 cde 1729 abc Irrigation in Stage of fructify Cut.Ir in 1760 abc 2175 a Stage of tellering and flowering Cut.Ir in 1409 bcd 1080 de Stage of tellering and flowering Cut.Ir in 1666 abcd 1913 ab Stage of tellering and flowering Means in each column having similar leter (S), are not significantly different at the 5% leve (DMR-Test). Table 2: Simple correlation cofficients among different traits of rapessed cultivars. Grain 1000 SW Oil % N. of Oil grain in yield fructify yield Grain yield 1 0.137 ns 0.202 ** 0.163 ns 0.993 ** 1000 Seed weight 1 0.446 ** 0.104 ns 0.169 ns Oil Percent 1 0.356 * 0.308 * N. of grain 1 0.203 ns in fructify Oil yield 1 ns, * and ** :Non significant at the 5 and 1% levels probability respectively.
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|Title Annotation:||Original Article|
|Publication:||Advances in Environmental Biology|
|Date:||Jun 1, 2011|
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