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1.
Effects of temperature and soil moisture on the development of some plant and leaf traits and of freezing resistance were examined in 5 (6) European varieties of winter faba beans. After pre-growth at 15 °C for 1 week, temperature was kept either at this level or lowered to 8:2 °C (day might). Soil moisture was maintained at 70-90 % of or above field capacity, or was allowed to approach wilting point. At 15 °C, specific dry matter content (D.M. per unit area) and water/D.M. ratio were the only traits in the lower expanded leaves (1-3) that changed markedly with time. Several plant and leaf traits were affected by soil moisture and displayed varietal differences. However, freezing resistance remained unchanged with time and was hardly affected by soil moisture and varieties (Δ R < 0.2 °C). Interestingly freezing resistance and leaf traits were differently expressed in leaves 1-3 of plants and thus contributed to some low correlations between these items. Likewise at 8:2 °C, only low correlations between leaf traits and freezing resistance were established. They were mainly due to developmental effects and soil moisture, since (i) specific water and D. M. content increased in parallel with freezing resistance (rate - 0.45 °C/day), (ii) leaf traits and freezing resistance were differently expressed in leaves 1 and 2 (i.e. -12.5 and -13.5 °C) and (iii) low as well as high soil moisture raised freezing resistance (-0.7°C) and specific D.M. content, but lowered water/D.M. ratio. With the exception of the old French land race Cote ?Or, varietal differences in freezing resistance at 8:2 °C were small (<0.5 °C). Neither in the first nor in the second leaf varietal rank pattern of freezing resistance was consistent with that of other traits and hence no genotypic correlations could be established. On the basis of these data, the usefulness of leaf traits in breeding as indirect criteria for freezing resistance appeared doubtful.  相似文献   

2.
Combined effects of temperature and light quality on plants have received little attention. We investigated the single and interactive effects of temperature and light quality on growth and physiological characteristics of four canola (Brassica napus) cultivars – Clearfield 46A76 (cv1), Clearfield 45H72 (cv2), Roundup Ready 45H24 (cv3) and Roundup Ready 45H21 (cv4). Plants were grown under lower (24°/20 °C) and higher (30°/26 °C) temperature regimes at low red/far‐red (R/FR), normal R/FR and high R/FR light ratios in environment‐controlled growth chambers (16 h light/8 h dark). Higher temperature reduced stem height and diameter; leaf number and area; dry matter of all plant parts; and specific leaf weight, but increased leaf area ratio; and chlorophyll (Chl) fluorescence (Y). Low R/FR increased stem height; Y; and ethylene, but decreased stem diameter; Fv/Fm; Chl a; Chl b; and carotenoids. Among cultivars, plants from cv4 were tallest with thickest stems and greatest dry matter. None of the main factors affected gas exchange. Higher temperature at high R/FR caused cv3 to be shortest, whereas lower temperature at low R/FR caused cv4 to be tallest. We conclude that heat and other stress factors will adversely affect sensitive crops, but tolerant genotypes should perform well under future climate.  相似文献   

3.
Plants exposed to one stress factor may become more tolerant to another. Cold is the most often documented factor inducing plant resistance to pathogens. The aim of this work was to investigate whether resistance of spring barley and meadow fescue to Bipolaris sorokiniana and resistance of winter oilseed rape to Phoma lingam induced at 5 °C for 2, 4 or 6 weeks are associated with frost tolerance, water potential and soluble carbohydrate content. Cold‐acclimated plants of each species showed increased resistance to the studied pathogens. Barley, fescue and rape plants demonstrated higher frost tolerance after hardening, but only in the case of fescue a correlation between resistance to frost and resistance to B. sorokiniana was found. A significant decrease in the water potential of leaf cells was observed in cold‐acclimated barley and fescue. In these two species, water potential greatly affected resistance to B. sorokiniana. However, only in barley did accumulation of fructose, glucose and sucrose correlate as well with changes in water potential as with cold‐induced resistance to the pathogen. In the case of hardened rape, no correlation between the studied parameters was found. The results obtained indicated that the temperature of 5 °C used during cold acclimation was not favourable for hardening of this plant species.  相似文献   

4.
The physiological functions of epicuticular wax (EW) include reflectance of irradiation and the reduction of water loss. When a plant experiences stressful conditions, most notably, high irradiance and temperature, damage to the photosynthetic apparatus can occur and is signalled by a decrease in the Fv/Fmax ratio. In this study, we examined the influence of increased EW on physiological function in terms of chlorophyll fluorescence (ChFl), stomatal conductance (gs), leaf temperature and spectral reflectance indices (SRI) of bread wheat (Triticum aestivum L.) cultivars. The wheat cultivars were subjected to high temperature stress (HT) (38–40°C) under greenhouse conditions when the primary inflorescence was fully emerged to determine its effect on leaf EW deposition. Leaf temperature depression (LTD) was generally lower in control (2.3°C—2012, 0.94°C—2013) compared to HT stress (3.13°C—2012, 4.05°C—2013). Cultivars in control (0.69 to 0.74 Fv/Fmax) had significantly higher ChFl compared to HT (0.58 to 0.74 Fv/Fmax). HT treatment resulted in higher EW (1.28—2012, 4.59 mg dm?2—2013) compared to control treatment (1.04—2012 to 4.56 mg dm?2—2013). Leaves devoid of EW showed significant variation among cultivars at reproductive stages for water index (WI), normalized phaeophytinization index (NPQI) and simple ratio index (SRI). In HT stress conditions, significant correlations were observed between EWL and SRI only at 3DAFE (days after full emergence), suggesting that increased EWL induced by HT and irradiation in early development may provide relief and prevent grain loss. EWL significantly associated with the physiological traits ChFl, gs, LTD and spike temperature depression (SpTD). These observations suggest that EWL may lessen the effect of high irradiance, thereby, effectively adjusting stomatal conductance, ChFl and leaf temperature, limiting the risk of over excitation of photosystem II.  相似文献   

5.
不结球白菜单株产量与主要农艺性状的灰色关联度分析   总被引:2,自引:2,他引:0  
为揭示不结球白菜单株产量与主要农艺性状间的关系,利用灰色关联度分析法,对18个不结球白菜品系的单株产量和8个主要农艺性状间的关联度进行分析。结果表明,不结球白菜各农艺性状与单株产量性状间的关联度排序为株幅>最大叶叶宽>最大叶叶柄宽>最大叶叶柄厚>叶片数>最大叶叶长>株高>最大叶叶柄长。株幅、最大叶叶宽、最大叶叶柄宽对不结球白菜单株产量影响最大。在不结球白菜育种过程中,注重株幅、最大叶叶宽、最大叶叶柄宽性状的选择,同时兼顾其他性状的选择,可以获得单株产量较高的不结球白菜新品种。  相似文献   

6.
G. Galiba  J. Sutka 《Plant Breeding》1988,101(2):132-136
The genetic control of frost resistance was studied in callus cultures using some of the chromosome substitution lines of the variety ‘Cheyenne’ into ‘Chinese Spring’. The survival of the calli derived from immature embryos was studied with triphenyltet-razolium chloride (TTC) and fluorescein diacetate (5DA) methods after hardening and freezing at a temperatures of -7 °C, -9 °C, -11 °C, -13 °C, and –15 °C. The donor ‘Cheyenne’ and the substitution lines 5A and 5D proved to be more frost resistant than the recipient ‘Chinese Spring1. These results are well correlated with the previously published studies when seedlings were tested under controlled conditions. Based on these results the tissue culture technique seems to be useful for testing varieties and lines for different levels of frost resistance and even for mutant selection.  相似文献   

7.
8.
Recurrent selection programs can use several crossing arrangements to synthesize basic populations for breeding purposes. This study evaluated heritability and correlations among traits in forty-five populations of F2[4] and F2:3[4] generations obtained throughout four-way crosses [4] between two dialells among ten semi-late and ten late maturity soybean (Glycine max L. Merrill) genotypes. The generation advance was made by the TSHD (Thinned Single Hill Descent) method and all individual plants were evaluated for the following traits: number of days to flowering (NDF) and maturity (NDM), plant height at flowering (PHF) and maturity (PHM), agronomic value (AV) and seed yield (YLD). Four-way crosses associated with TSHD method provided high genetic variability in the populations with little or no reduction from F2[4] to F2:3[4]. The ‘narrow sense’ heritability estimated using correlations between F2[4] and F2:3[4] plants was lower than but closely related to broad-sense estimates. The populations 21(IAC-4 × IAC-9) × (GO79-1039 × Paranagoiana) and 23 (IAC-4 × Santa Rosa) × (GO79-1039 × Tropical) were the most productive with high variability in F2[4] and/or F2:3[4] generations. Genotypic correlations measured were generally high, positive and consistent for the two generations except for those related to AV and YLD. These results indicate that the use of four-way crosses can be an efficient method to increase the genetic base of populations for recurrent selection or cultivar development. Significant AV × YLD correlations indicated visual selection can be used as additional selection criteria for improving populations. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

9.
Two experiments were conducted in the Rift Valley, Ethiopia (8°N and 39°E) to determine associations between eight plant traits and seed yield, and to obtain estimates of narrow sense heritability for the traits. Experiment I evaluated seven dry edible bean cultivars/lines at two locations to simulate different soil moisture stress, including, Debre Zeit(non-stress) and Dera (moderate-stress). Experiment II evaluated 25 cultivars/lines in three environments including, Melkassa early planted (non-stress), Melkassa late planted (high-stress), and Dera (moderate-stress). A randomized-complete-block design with three replicates was used in both experiments. Plant traits evaluated were seed yield, pods plant-1, seeds pod-1, 100 seed weight, root dry weight, hypocotyl diameter, plant biomass, plant height and days to flowering. Plant traits that were significantly associated with seed yield were included in a stepwise-regression model to determine which trait or combination of traits provided the best model to estimate seed yield in each environment. An analysis of variance was conducted to test main effects and interactions between plant traits and environments. Significant variation among lines occurred for seed yield and all plant traits in both experiments. Strong positive correlations were observed between plant biomass and seed yield in all environments. Seed yield and pods plant-1 were also highly associated in four of the five environments. Stepwise regression models indicated that the combination of pods plant-1 and plant biomass consistently contributed to seed yield prediction, while other traits did not. Because both plant biomass and pods plant-1 had moderate to high narrow sense heritability estimates and low GE interactions, they should be useful as indirect selection criteria to improve and stabilize seed yield in a breeding program. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

10.
Embryo-derived calli of four rice varieties cultivated at high altitude in Burundi — Facagro 57, Facagro 76, Kirundo 3 and Kirundo 9 — were submitted to different temperature regimes. The percentage of regenerating calli greatly varied depending on variety, length of culture and callus temperature treatment. The reduction of regeneration percentages induced by low temperature was more pronounced in the more sensitive varieties. Regenerated plants (R0) and their progenies in R1, R2 and R3 were cold-screened together with control plants. In all varieties, significantly higher survival rates were obtained in R3 with in vitro plants than with control plants. Such chilling tolerance improvement was not obtained following a massal selection applied during 3 successive generations onto the control plants. In vitro plants regenerated from calli cultivated either at 25 °C, either at 4 °C, were cultivated at different altitudes in Burundi during two successive generations. For most observed traits, the in vitro plants were characterized by lower means, larger variation and higher maximum values than the control plants. The most chilling-tolerant somaclonal families were most usually characterized by extensive differences in fatty acid composition, chilling-induced electrolyte leakage and chlorophyll fluorescence, compared to the varieties they derived from. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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