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1.
ABSTRACT

The selection response of wheat (Triticum aestivum L.) under water-limited condition can be enhanced through breeding novel genotypes possessing drought-adaptive and yield-related agronomic and physiological traits. The objective of this study was to evaluate terminal drought tolerance among bread wheat genotypes and select superior parents for breeding. Agronomic and physiological responses of 28 wheat lines were assessed under well-watered (WW) and terminal drought (TD) treatments using a 7?×?4 alpha-lattice design under rainout shelter (RS) and glasshouse (GH) environments. Significant (p?≤?0.05) genotype?×?environment interaction effects were observed for number of days to heading (DTH), number of days to maturity (DTM), number of productive tillers per plant (TN), grain yield (GY), thousand kernel weight (TKW), stomatal conductance (SC), leaf canopy temperature (LCT) and chlorophyll content index (CCI) suggesting varied genotypic response under WW and TD treatments. Correlation analysis revealed significant associations TN and GY (r?=?0.67; p?≤?0.001), TKW and GY (r?=?0.72; p?≤?0.001), CCI and GY (r?=?0.39; p?≤?0.05) under TD treatment. Drought tolerant wheat genotypes such as LM100, LM72, LM22 and LM95 are useful for direct cultivation and for developing breeding populations with enhanced yield performance.  相似文献   

2.
ABSTRACT

Wheat genotypes with pre- and post-anthesis drought tolerance offer enhanced yield gains under water-limited environments. This study determined pre- and post-anthesis drought responses of selected bread wheat genotypes in order to identify and select candidate genotypes for breeding. Fifteen genetically differentiated wheat genotypes were evaluated under non-stressed (NS), pre-anthesis drought stress (PrADS) and post-anthesis drought stress (PoADS) in glasshouse (GH) and field (FLD) environments. Data were collected on agronomic and physiological traits including number of days to heading (DTH), days to maturity (DTM), plant height (PH), number of spikelet per spike (NSPS), number of kernels per spike (NKPS), thousand kernel weight (TKW), grain yield (GY) and canopy temperature (CT). Analysis of variance revealed significant effects of genotypes, environments and their interactions for studied traits. Weak and positive correlations were recorded between GY with PH (r?=?0.47 and 0.32), NSPS (r?=?0.37 and 0.52) and TKW (r?=?0.30 and r?=?0.20) under PrADS and PoADS conditions, respectively. Genotypes SMY-006, SMY-008, SMY-016, SMY-042 and SMY-044 were identified with pre- and post-anthesis drought tolerance and high yield potential and suitable yield-component traits. These are useful genetic stocks for breeding or cultivation in water-limited environments to improve yield gains.  相似文献   

3.
The recent drought in South Africa has reduced the production of both dryland and irrigated wheat. This study evaluated physiological traits of irrigated wheat genotypes in response to water stress (WS) imposed at different growth stages. A 8?×?2?×?3 [(genotypes)?×?(water treatmets; stresses and non-stressed)?×?(growth stages; tillering, flowering and grain filling)] factorial experiment based on a randomised complete block design with three replicates was conducetd. In general, the rate of photosynthesis was unaffected by WS except for genotypes LM43 at tillering and LM98 at grain filling. Stomatal conductance (SC) and transpiration rate (Tr) followed the same treand except for genotype LM35 which reduced its SC and Tr significantly at grain filling. Instantaneous waster use efficiency (IWUE) of genotype LM35 and LM57 was unaffected (p?>?0.05) by WS at tillering but at flowering stage it was affected. However, at grain filling IWUE was affected (p?<?0.05) in genotypes LM35, ML57, LM79 and LM 98. The relative water content was unaffected at tillering except for LM35 and LM47 genotypes whereas at flowering LM57, ML79, LM83 and LM98 were affected. These results indicate some degree of drought tolerance of these genotypes at different growth stages.  相似文献   

4.
ABSTRACT

The selection of relatively high and stable yielding genotypes is key in wheat breeding programs to improve yield performance under heat and drought-stressed environments. This study determined grain yield response and stability among elite heat and drought tolerant bread wheat genotypes under simulated drought-stressed (DS) and non-stressed (NS) environments to select promising parents for breeding. Twenty-four elite bread wheat genotypes selected from the International Maize and Wheat Improvement Centre (CIMMYT) drought and heat tolerant nursery were assessed under NS and DS conditions using a 7?×?4 alpha-lattice design under rainout shelter (RS) and glasshouse (GH) environments. Grain yield data was subjected to analysis of variance (ANOVA), the additive main effect and multiplicative interaction (AMMI) and genotype and genotype-by-environment (GGE) biplot analyses. ANOVA and AMMI revealed highly significant (p?≤?0.001) differences among test genotypes (G), environments (E) and G?×?E interaction effects suggesting differential responses for selection. The GGE biplot explained 83.76% of total variation and aided in selection of high-yielding and stable heat and drought tolerant wheat genotypes such as LM13, LM22, LM95 and LM100. These selections are recommended for breeding for yield gains under heat and drought-stressed environments.  相似文献   

5.
The objective of this study was to determine drought tolerance characteristics of dryland wheat genotypes based on leaf gas exchange and water-use efficiency in order to identify promising genotypes for drought tolerance breeding. Physiological responses of ten genetically diverse wheat genotypes were studied under non-stressed (NS) and water stressed (WS) conditions using a 2?×?10 factorial experiment replicated 3 times. A highly significant water condition?×?genotype interaction (P?<?0.001) was observed for photosynthetic rate (A), ratio of photosynthetic rate and internal CO2 concentration (A/Ci), ratio of internal and atmospheric CO2 (Ci/Ca), intrinsic (WUEi) and instantaneous (WUEinst) water-use efficiencies suggesting genotypic variability among wheat genotypes under both test conditions. Principal component analysis (PCA) identified three principal components (PC’s) under both test conditions accounting for 84% and 89% of total variation, respectively. Bi-plot analysis identified G339 and G344 as drought tolerant genotypes with higher values of A, T, gs, A/Ci, WUEi and WUEinst under WS condition. The current study detected significant genetic variation for drought tolerance among the tested wheat genotypes using physiological parameters. Genotypes G339 and G344 were identified to be drought tolerant with efficient A, T, gs, A/Ci and water-use under water stressed condition.  相似文献   

6.
Sorghum [Sorghum bicolor (L.) Moench] grown under rain-fed conditions is frequently affected by drought stress at different stages, resulting in reduced grain and biomass yield. The aim of this study was to characterise sorghum landraces and to select farmer-preferred medium-maturing genotypes under rainfed and irrigated conditions. Hundred and ninety-six sorghum accessions were evaluated at Kobo site of the Sirinka Agricultural Research Center in 2014/2015 in Ethiopia. Data collected from 14 traits were subjected to analysis of variance, cluster analysis, Pearson’s correlation coefficient analysis, path coefficient analysis and principal component analysis (PCA). Significant genotypic differences (p?<?0.05) were observed. Medium-maturing and drought tolerant sorghum genotypes including E-72457, E-72438, E-72435, E-206214, E-72449, E-75460 and E-75458 with superior agronomic performance were recommend for large-scale production or for further breeding. The genotypes evaluated under rain-fed and irrigated conditions were grouped into five and six clusters, respectively, representing varied different heterotic groups. Grain yield had significant and positive correlation with yield-related traits assessed under the two test conditions. Further, path coefficient analysis revealed that days to maturity under rainfed condition and harvest index under irrigated condition had the highest positive direct effects on grain yield, therefore can be targets for direct selection. Overall, there was marked genetic diversity among the tested genotypes. Suitable medium-maturing farmers-preferred accessions selected from the study will be useful for effective breeding for drought tolerance and medium-maturity.  相似文献   

7.
ABSTRACT

Assessing the genetic variation and relationships present in crop germplasm is a pre-requisite for parental selection and breeding. The objective of this study was to determine the genetic relationships present among selected heat and drought tolerant wheat genotypes using simple sequence repeat (SSR) markers, agronomic traits and grain quality parameters to select desirable parents for breeding. Twenty-four agronomically selected wheat genotypes sourced from the International Maize and Wheat Improvement Centre (CIMMYT)’s heat and drought tolerance nursery and four local check varieties were genotyped using 12 selected polymorphic SSR markers. The test genotypes were phenotyped using yield and yield-component traits, and grain protein content (GPC) under non-stressed (NS) and drought-stressed (DS) conditions. Expected heterozygosity mean value of 0.58 indicated moderate genetic diversity for breeding. The studied wheat genotypes were delineated into six genetic groups using cluster analysis. Significant genotypic differences were observed for agronomic traits and GPC under NS and DS conditions. Genetically unrelated breeding parents including LM02, LM13, LM23, LM41, LM44, LM71, LM73 and LM75 were selected for population development and breeding for enhanced grain yield and protein content under heat and drought-stressed environments.  相似文献   

8.
A field experiment was conducted to evaluate nine genotypes of sorghum grown for two consecutive cropping seasons in 2006 and 2007 under rain-fed conditions in a semiarid zone at the Research Farm of El Fasher Research Station, Sudan. The objective of the study was to assess genetic variability and heritability among sorghum genotypes using phenotypic morphological traits. A randomized complete block design with four replications was used for the experiment. The grain yield (kg ha?1), the number of heads/plant, followed by straw yield (kg ha?1) had the highest genotypic coefficients of variation in both seasons. High heritability (above 95%) was shown for plant height in both seasons. High genetic advance was reported in straw yield, 1000-grain weight and days to flowering in both seasons. Highly significant differences among genotypes were found for all characters. The high-yielding genotype was Adv-Edo-CWS (E-9) with grain yields of 2780.6 kg ha?1. Grain yield was significantly and positively correlated with straw yield (r = 0.91), number of heads/plant (r = 0.69), plant height (r = 0.53) and 1000-grain weight (r = 0.36). However, it was significantly and negatively correlated with days to 50% flowering (r = ?0.21). Based on their positive association with grain yield, the character’s straw weight, number of heads/plant, plant height and 1000-grain weight would be the preferable selection criteria for sorghum improvement program in the country.  相似文献   

9.
The relationship of solvent retention capacity (SRC) values with four solvents, alveograph and farinograph properties, and cookie‐baking performance was evaluated with 20 Chinese soft wheat genotypes, including four cultivars and 16 advanced lines grown in the 2009–2010 season. Significant positive correlations were observed between water SRC (WSRC), sodium carbonate SRC (SOSRC), lactic acid SRC, and sucrose SRC (SUSRC) values. WSRC, SUSRC, and SOSRC showed significant positive correlations with farinograph water absorption (WA), alveograph P (tenacity), and P/L (ratio of tenacity to extensibility). Cookie diameter was significantly correlated with wet gluten (r = –0.491, P < 0.05), WSRC (r = –0.882, P < 0.001), SUSRC (r = –0.620, P < 0.01), SOSRC (r = –0.712, P < 0.001), P (r = –0.787, P < 0.001), L (r = 0.616, P < 0.01), P/L (r = –0.766, P < 0.001) and WA (r = –0.620, P < 0.01), respectively. SRC values were effective predictors of cookie quality in Chinese soft wheat. Alveograph parameters were more closely correlated to cookie quality than were farinograph parameters.  相似文献   

10.
Because of the large number of cultivars that require examination in the development of spring wheat (Triticum aestivum L.) cultivars, breeding programs use predictive methods to test end use quality. The Mixograph is a widely used predictive test with which end use quality of many genotypes can be assessed in a short time. By comparison, the Mixolab is a relatively new device with additional capability that might be used for the same purpose. Our objective was to document variability of, and relationships among, 20 parameters obtained from Mixolab, Mixograph, and bake tests. Tests were performed on flour from 18 genotypes grown in 20 environments. Both genotype and environment had significant effects on quality parameter values. Several Mixograph and Mixolab parameters were highly significantly correlated, particularly when genotype mean values over environments were considered. Correlations between loaf volume and Mixolab parameters within environments were inconsistent and suggest that average genotype values over environments will be most useful. For example, the correlation between Mixolab stability and loaf volume (r = 0.25, P < 0.001) was much higher when genotype averages (r = 0.70, P < 0.001) were considered. Our results show that selection for Mixolab stability and water absorption should help delineate and improve the selection of genotypes with greater loaf volume.  相似文献   

11.
The role of cropping systems practices in agronomic biofortification programs with the aim of increasing micronutrient density in food plants has to be clarified. In these field experiments, the effect of four preceding crops, i.e., sunflower (Heliantus annus L. cv. Allstar), Sudan grass (Sorghum bicolor L. cv. Speed Feed), clover (Trifolium pratense L.), and safflower (Carthamus tinctorius L. cv. Koseh-e-Isfahan), on the total amino acids (AA) and dissolved organic carbon (DOC) concentration in rhizosphere soil solution and grain Zn content of successive wheat (Triticum aestivum cvs. Back Cross and Kavir) was investigated during 2009–2010 and 2010–2011 growing seasons. A fallow treatment was also considered as the control. In both growing seasons, preceding crops increased the concentrations of AA and DOC in the soil solution in comparison with the fallow control treatment; although the magnitude of this increase varied upon the preceding crop type and wheat cultivar. In general, clover and sunflower had greater effect on increasing soil solution DOC probably due to higher decomposability of their litter residues in soil. Preceding crops increased the total AA concentration, on average, by 45.9 % for the first year and 10.8 % for the second year. The preceding sorghum and clover had the highest and lowest influence on the concentration of AA in wheat rhizosphere soil solution, respectively. The preceding crops increased grain wheat Zn concentration and content over the fallow control treatment, although this effect was dependent on the crop type. For “Back Cross”, a positive and significant correlation was found between grain Zn concentration and soil solution DOC concentration (r?=?0.60, P?<?0.05) and particularly AA (r?=?0.76, P?<?0.001), while no such correlation was found for “Kavir”. At the second growing season, the concentration of AA in the rhizosphere of Back Cross was greater than that of Kavir, probably due to higher release of these compounds from the roots. According to the results, the preceding crop significantly affect grain Zn density of the successive wheat, that is, at least in part, by releasing soluble organic ligands into soil solution.  相似文献   

12.
Kernel hardness is not a well‐characterized food quality trait in barley. Unlike wheat, not much is known about the effect of barley kernel hardness on food processing. Ten barley genotypes differing in single kernel characterization system hardness index (SKCS‐HI) (30.1–91.2) of dehulled kernels were used to determine the association of barley HI with other physical grain traits and food processing parameters. Thousand kernel weight (TKW) values of 10 genotypes were 29.7–38.1 g. Values for bulk density of grains were 721.1–758.9 kg/m3. Crease width and depth values were 0.9–1.3 mm and 0.4–0.7 mm, respectively. Barley HI showed no significant association with TKW, bulk density, or kernel crease dimensions. Kernel loss due to pearling after 325 sec of abrasion was 28.8–38.4% and showed significant negative correlation with HI (r = –0.87, P < 0.01). Proportion of barley flour particles >106 μm had values of 34.5–42.0%, and starch damage values were 1.8–4.5% among those 10 barley genotypes. HI showed significant positive correlations with both proportion of barley flour particles >106 μm (r = 0.93, P < 0.01) and starch damage (r = 0.93, P < 0.01). Water imbibition of barley kernels and cooked kernel hardness did not show significant correlation with HI.  相似文献   

13.
ABSTRACT

Drought is a major constraint for agricultural productivity worldwide, and it is likely to further increase. Different strategies are required to mitigate drought stress in plants. In a two-year study that conducted at agronomic research area of the Islamia University of Bahawalpur, we investigated the role of rhizobacteria (RB) and cytokinins (Ck) on drought tolerance, nutrient uptake, yield, and physiological parameters in wheat under drought stress at different developmental stages (tillering, anthesis, and grain filling). Thirteen treatments used were well-watered control plants without RB or Ck, drought at tillering, anthesis, or grain filling without or with RB alone, Ck alone, or combination of both (RB+Ck). In both years, and at the different stages, measured parameters were highest in the well-watered plants but lowest in drought-stressed plants. Application of RB and Ck to drought-stressed plants increased these parameters in the order RB+Ck > RB > Ck. In some cases, under drought stress, there was no difference between inoculation with RB and application of Ck. It was concluded that the combined application of RB and Ck could play a significant role in improving wheat yield and also alleviation of stress under drought condition.  相似文献   

14.
Eleven rice genotypes with diverse Rapid Visco Analyzer (RVA) pasting characteristics were evaluated for their physicochemical and gel textural characteristics relative to their suitability for making rice noodles. Apparent amylose content (AC) was highly correlated with swelling power (r = -0.65, P < 0.05), flour swelling volume (FSV) (r = -0.67, P < 0.05), noodle hardness (r = 0.74, P < 0.01), gumminess (r = 0.82, P < 0.01), chewiness (r = 0.74, P < 0.01), and tensile strength (r = 0.72, P < 0.05). Solubility showed an inverse relationship with the pasting parameters and noodle rehydration, and a positive relationship with cooking loss, noodle hardness, and gumminess. FSV and most of the pasting parameters were negatively correlated with noodle hardness. RVA parameters and textural parameters of gels formed in the RVA canister were well correlated with actual noodle texture and may, therefore, be used for predicting rice noodle quality during early screening of genotypes in breeding programs.  相似文献   

15.
In an effort to characterise and select promising sweet stem sorghum genotypes with enhanced biofuel productivity, the present study investigated phenotypic variability present among diverse sweet stem sorghum genotypes based on ethanol production and related agronomic traits. One hundred and ninety genotypes were evaluated. Data were subjected to variance, cluster, correlation, path coefficient and principal component analyses. Significant differences (P?<?0.01) were detected among tested genotypes for all measured traits. Days to flowering varied from 62 to 152 with a mean of 93. Plant height varied from 90 to 420?cm with a mean of 236?cm. Stem diameter ranged from 7 to 31?mm with a mean of 16?mm. Biomass yield varied from 6.668 to 111.2?t?ha?1 with a mean of 30?t?ha?1. Stalk dry matter content ranged from 17.2% to 44.2% with a mean of 29.8%, while fibre content varied from 8.92% to 34.8% with a mean of 17.2%. The stalk brix yield varied from 3.3% to 18.9% with a mean of 12.1%. Ethanol productivity ranged from 240.9 to 5500?l?ha?1 with a mean of 1886?l?ha?1. The best ethanol producing genotypes were AS203, AS391, AS205, AS251 and AS448. Days to flowering, plant height, stalk brix and stem diameter exerted the greatest indirect effects on ethanol production through higher biomass production. Biomass yield had the greatest direct effect on ethanol production. Therefore, the above traits should be considered during breeding sorghum for bio-ethanol production. Also, the traits had high heritability values, hence selection should provide for good genetic gains. Overall, the above sweet stem sorghum genotypes are useful genetic resources for breeding of sorghum with enhanced bio-ethanol production.  相似文献   

16.
《Cereal Chemistry》2017,94(4):712-716
Free asparagine in wheat is known to be a precursor for the formation of acrylamide, which is unacceptable to consumers owing to its potential risks to human health. This research was performed to determine variation of free asparagine concentration (FAC) in hard red spring (HRS) wheat grown in North Dakota. Quality traits and FAC were analyzed for 75 HRS wheat genotypes grown at three locations. The ANOVA indicated that growing location had a strong effect on FAC. The main effect of genotype and interaction of genotype × location were also highly significant (P < 0.001). The genotype × location interaction was also explored graphically using a biplot of principal components calculated from the genotype and genotype × environment interaction model. The biplot analysis revealed that the pattern of interaction of genotype × location might be a noncrossover type. Certain HRS genotypes were identified to have consistently low FAC across growing locations. The FAC showed low genotypic correlations with quality traits, indicating low level of linkage between FAC and quality traits for HRS wheat genotypes.  相似文献   

17.
Micronutrient deficiency is one of the most common and widespread nutritional issues. Among the factors mitigating the bioavailability of Zn (zinc) and Fe (iron), phytic acid plays a key role; therefore, in order to scrutinize genetic alterations ?related to micronutrient and phytate contents, we examined the concentrations of zinc, iron, and phytic acid, as well as its mole ratio to ?zinc in various wheat species grown in two planting seasons. The concentrations of phytic acid and its mole ratio to zinc were 0.61?1.55 g kg?1 dry weight and 1.88?4.17 for autumn, and 0.97?2.02 g kg?1 dry weight and 2.10?4.05 for spring planting. There was a significant discrepancy among wheat species; tritipyrum had the highest concentration of iron, phytic acid and its mole ratio to zinc, and T. monococcum and T. aestivum recorded reasonable zinc bioavailability. Correlation studies between grain phytic acid concentrations and other measured traits revealed various relationships, denoting an irrefutable impact of planting season and wheat ploidy levels on modification of wheat genotypes. The characters contributing more positively with principal component (PC) 1 were Zn and Fe under spring planting and Fe under autumn planting. Spike number per square meter, biological yield and grain yield in spring cultivation, and grain zinc concentration in autumn cultivation were positively correlated to principal component (PC) 2. Given that the concentration of Fe and Zn in all the studied genotypes is relatively high and due to the existence of other desirable agronomic traits, this study believes that it could possibly enhance the applicability of some of these genotypes for breeding purposes.  相似文献   

18.
Little information exists on the phosphorus (P) use efficiency of Tithonia diversifolia under varying levels of soil P availability. This study evaluated biomass production, changes in tissue P concentration, P uptake, and P uptake and utilization efficiencies in a Costa Rican and Colombian T. diversifolia genotype when 0, 0.3, 5, and 30 mg P g?1 were available. Biomass, root length and tissue P concentration increased significantly (P < 0.05) with increasing levels of P availability and with time. Phosphorus uptake (mg plant?1) was significantly higher (P < 0.05) at 30 mg P g?1. Phosphorus uptake (mg P mg?1 Pf) and utilization (mg mg?1 P) efficiencies were greatest at 0.3 and 5 mg P g?1. Differences between genotypes showed that T. diversofilia from Colombia had a significantly higher (P < 0.05) biomass, tissue P concentration, root length, and a more effective uptake and utilization of P when availability of this nutrient was low.  相似文献   

19.

Purpose

In this study, we quantified soil organic carbon (SOC) stocks and analyzed their relationship with biophysical factors and soil properties.

Materials and methods

The study region was Veracruz State, located in the eastern part of Mexico, covering an area of 72,410 km2. A soil database that contains physicochemical analyses of soil horizons such as carbon concentration data was the source of information used in this study. The database consisted of 163 soil profiles representing 464 genetic horizons. Statistical analysis was used to investigate the effect of each factor (climate, altitude, slope) on SOC stock to 0.50 m depth and to assess differences in the distribution of SOC stock in terms of soil depth (0.0–0.20, 0.20–0.40, 0.40–0.60, 0.60–0.80, 0.80–1.0 m) and land use. In order to compute the spatial distribution of SOC stock to 0.50 m depth based on the soil sampling location, the kriging method was used.

Results and discussion

Results indicated that SOC stock (0.50 m depth) ranged between 0.44 and 41.2 kg C m?2. Regression analysis showed that SOC stocks (0.50 m depth) are negatively correlated with temperature (r?=??0.38; P?<?0.001) and positively correlated with altitude (r?=?0.40; P?<?0.001) and slope (r?=?0.40; P?<?0.001). In addition, by multiple regression, temperature combined with precipitation explained more SOC stock variations (r?=?0.43; P?<?0.001) than the regression model with precipitation (r?=?0.13; P?=?0.16) alone. Also, slope combined with temperature and precipitation explained more SOC stock variations (r?=?0.46; P?<?0.001) than the regression model with slope alone. Forest lands, grasslands, and croplands have higher SOC stocks in the 0.0–0.20-m soil layer than in deeper layers. On average, forest lands, grasslands, croplands, and other lands (wetland and dunes) had a SOC stock of 13.6, 14.6, 15.1, and 8.5 kg C m?2 at 1 m depth, respectively. Soil color correlated (?0.25 ≤ r ≤ ?0.89) with SOC content.

Conclusions

Overall, these results indicate the influence of major interactions between biophysical factors and SOC stocks. This research indicated that SOC stock decreased with soil depth, but with slight variations depending on land use. Thus, there remains a need for more SOC data that include an improved distribution of soil sampling points in order to entirely understand the contributions of biophysical factors to SOC stocks in Veracruz State.  相似文献   

20.
Abstract

Iron-deficiency chlorosis (IDC) and soybean cyst nematode (SCN) result in yield and income losses for soybean growers in the U.S. Breeding programs are identifying soybean genotypes with resistance to IDC using calcareous soils infested with SCN, where SCN might interfere with evaluation. Our first objective was to examine whether associations could be established for chlorosis symptoms with SCN infestation of soybean grown on SCN-infested calcareous soils. Two breeding populations, their parents, and five SCN-susceptible, IDC-control genotypes (IDC controls) were evaluated for IDC symptoms on SCN-infested calcareous soils in 2000 and 2001. In general, no significant correlations were detected between chlorosis expression and SCN infestation in either year, although a negative correlation (r = ?0.93, p ≤ 0.05) was observed for the IDC controls in 2001. For our second objective, we examined the relationship between genotype resistance to SCN and IDC. Although IDC controls were all equally susceptible to SCN and chlorosis observed in the field and nutrient solution was similar, SCN-resistant genotypes expressed resistance to IDC in the field, but severe susceptibility to IDC in nutrient solution. Our third objective was to investigate the value of calcareous soil properties to predict IDC in soybean grown on SCN-infested calcareous soils. For one breeding population in 2001, positive correlations (p ≤ 0.05) were detected for chlorosis with calcium carbonate (r = 0.62) and electrical conductivity (r = 0.59), and a negative correlation (r = –0.41) with soil Fe-DTPA-TEA. No significant correlations were observed for the remaining genotypes. Our study indicated that associations between IDC, SCN, and calcareous soil properties are dependent on genotype and environment. In addition, our study demonstrated a potential association between plant health and SCN reproduction in SCN-susceptible genotypes, the possibility that SCNresistant genotypes may be sensitive to iron availability, and the importance of genotype on the detection of associations between IDC expression and SCN infestation.  相似文献   

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