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1.
The relationship between biomass production and N2 fixation under drought‐stress conditions in peanut genotypes with different levels of drought resistance is not well understood. The objective of this study was to determine the effect of drought on biomass production and N2 fixation by evaluating the relative values of these two traits under well watered and water‐stress conditions. Twelve peanut genotypes were tested under field conditions in the dry seasons of 2003/2004 and 2004/2005 in north‐east Thailand. A split‐plot design with four replications was used. Main‐plot treatments were three water regimes [field capacity (FC), 2/3 available soil water (AW) and 1/3 AW], and sub‐plot treatments were 12 peanut lines. Data were recorded on biomass production and N2 fixation under well watered and water‐stress conditions. Genotypic variations in biomass production and N2 fixation were found at all water regimes. Biomass production and N2 fixation decreased with increasing levels of drought stress. Genotypes did not significantly differ in reductions for biomass production, but did differ for reductions in N2 fixation. High biomass production under both mild and severe drought‐stress conditions was due largely to high potential biomass production under well‐watered conditions and, to a lesser extent, the ability to maintain high biomass production under drought‐stress conditions. High N2 fixation under drought stress also was due largely to high N2 fixation under well‐watered conditions with significant but lower contributions from the ability to maintain high nitrogen fixation under drought stress. N2 fixation at FC was not correlated with the reduction in N2 fixation at 2/3 AW and 1/3 AW. Positive relationships between N2 fixed and biomass production of the tested peanut genotypes were found at both levels of drought stress, and the relationship was stronger the more severe the drought stress. These results suggested that the ability to maintain high N2 fixation under drought stress could aid peanut genotypes in maintaining high yield under water‐limited conditions.  相似文献   

2.
Mid‐season drought is a factor frequently limiting crop production in the moist to dry savannah zones of the tropical and subtropical regions of the world. Ten cowpea genotypes were subjected to a cycle of drought at flowering followed by re‐watering to study variation in drought performance and recovery. Drought caused a reduction in leaf assimilation rate, transpiration rate and stomatal conductance with genotypic variances of 75.4, 57.9, and 83.3 %, respectively. Only genotypic variance in stomatal conductance increased appreciably under drought. Reductions in leaf water potential as a consequence of drought positively correlated with a decline in assimilation rate, which was associated with stomatal closure. One week after re‐watering, the three gas exchange parameters of stressed plants recovered fully and attained values 10–30 % higher than the well‐watered plants with increased genotypic variability. Reductions in the total dry matter during the drought interval varied from 11 to 50 % among genotypes, but were of minor importance for the total dry matter at maturity. After stress, the gain in dry matter varied considerably among the stressed genotypes, with stressed plants showing higher gain than the unstressed plants during this interval. This was associated with increased availability of assimilates due to enhanced green leaf area duration after stress release. Variability in drought recovery among genotypes was found, and appears to be more important for final yield than responses during drought.  相似文献   

3.
Five cowpea genotypes, Gorom local (Go), KVX61‐1 (KV), Mouride (Mo), Bambey 21 (B21) and TN88‐63 (TN), differing in their susceptibility to water stress, were studied under glasshouse and field conditions, to determine their physiological, biochemical and agronomic responses to water deficit at flowering stage. Effect of water deficit on leaf water potential (ψl), canopy temperature, gaseous exchange, leaf proline content, total protein and starch contents, maximal quantum yield (ϕp0) and yield components was examined. Water deficit significantly increased the canopy temperature and the proline content of the five genotypes while ψl, gaseous exchanges, ϕp0 and starch content decreased significantly. Yield components, with the exception of seed number per pod, of the five genotypes, were also significantly affected. Under glasshouse and field conditions, the results showed that stomatal closure is the common strategy used by the five genotypes to avoid dehydration. Go, Mo and TN tolerated water stress better than B21 and KV. Furthermore, Go and Mo recovered more rapidly after rewatering than B21 and KV. These latter genotypes are revealed to be sensitive with low recovery capacity. The results suggest that the maintenance of net photosynthesis and solute accumulation seem to be traits conferring water stress tolerance in Go, Mo and TN. These traits and recovery capacity could be valuable selection criteria for higher yields under water deficit conditions.  相似文献   

4.
The phenotypic expression and heritability of quantitative traits vary due to genotypic differences, environmental influences and genotype by environment interactions. The objective of this study was to determine variance components and heritabilities of seed yield and its components in cowpea. Field experiments were conducted at three locations, three planting dates using ten diverse cowpea genotypes during 2004/2005. The experiments were laid out in the randomized complete block design with three replications. Results indicated significant interactions (P ≤ 0.01) among genotypes, locations and planting dates. The genotypic variance contributed ≥50% of the total phenotypic variance for the numbers of days to 50% flowering, seeds per pod, productive branches per plant and seed yield. The heritabilities of the numbers of days to 50% flowering were estimated at 50%, pods per plant (23%), days to maturity (66%), productive branches per plant (53%), 100 seed weight (11%) and seed yield (55%). The presence of considerable degree of genotypic variance among tested genotypes under various environments suggests that success in cowpea breeding could possibly be achieved through direct phenotypic selection.  相似文献   

5.
Increasing atmospheric carbon dioxide concentration (Ca) is one aspect of global change that will have a significant impact on the productivity of agricultural crops. Crop yields have been shown to increase with increasing Ca. The magnitude of yield response to increased Ca could vary depending on genotypic and environmental factors. The objective of this study was to determine the genotypic variation of yield response and its physiological basis in rice (Oryza sativa L.) through an initial varietal screening using 16 genotypes. The genotypes were grown under two concentrations of Ca, i.e. 370 ± 28 (ambient) and 570 ± 42 (elevated) μmol mol−1, in open top chambers under lowland field conditions at the Rice Research and Development Institute in Sri Lanka (7°50′N, 80°50′E) from May to August 2001 (yala season) and from November 2001 to March 2002 (maha). Ca within chambers was maintained around target concentrations by a computer‐based real‐time data acquisition and control system. There was significant variation between genotypes in the response of yield to elevated Ca, with absolute increases up to 530 g m−2 in yala and 347 g m−2 in maha. In relative terms, percentage yield increases from ambient to elevated Ca ranged from 4 % to 175 % in yala and from 3 % to 64 % in maha. Genotypic variation in yield showed significant positive correlations with light‐saturated net photosynthetic rate of the flag leaf during the grain‐filling stage. This indicated that increased assimilate supply and its genotypic variation contributed to the observed genotypic variation in yield response to elevated Ca. Furthermore, the capacity to develop a larger reproductive sink through increased panicle number per m2 and increased number of grains per panicle contributed to greater yield at elevated Ca. There was a significant genotype × season interaction with genotypes responding differentially to increased Ca in the two seasons. This was mainly due to inter‐seasonal variation in incident radiation during the grain‐filling stage. Our results demonstrate the significant genotypic variation that exists within the rice germplasm, in the response to increased Ca of yield and its correlated physiological parameters. A subset of genotypes from screening trials such as the present study can be used for more in‐depth analysis of the influence of elevated Ca on processes responsible for yield determination in rice and for molecular studies to elucidate the genetic basis of the response to increased Ca. This could pave the way for breeding genotypes which are more productive in a future high CO2 environment, provided that genotypes with greater flexibility in their physiology are selected to counter the genotype × environmental interaction.  相似文献   

6.
Peanut (Arachis hypogaea L.) is known to be sensitive to genotype-by-environment interaction (GEI) effects. While previous studies have reported strong GEI effects on peanut yield, most of those studies involved a relatively small number of unrelated genotypes. We examined the extent of GEI effects in elite Virginia-type peanut using a large population of recombinant inbreed lines (RILs). Two-hundred-sixty-six F7 RILs derived from different cultivars were grown in three environments. Net pod yield (NPY) was evaluated along with 11 other traits. ANOVA revealed that genotype and environment affected all of the examined traits, except for the triplet trait. The substantial influence of the environment was also demonstrated in a genetic-parameter analysis, in which the phenotypic variation coefficients were almost double those for genotypic variation. Still, relatively high heritability and genetic gain values were found for pod weight and NPY. Since NPY is the main target for selection, it was analyzed further. Path analysis showed that NPY is most directly influenced by pod weight and the shelling ratio. A significant GEI effect on NPY was identified using an AMMI model that described 42.7% of the total variation. This GEI component was subjected to a principal components analysis, which confirmed that the variability due to the different environments was greater than the variability that could be attributed to the different genotypes. Yet, several lines had stable yields across environments. These results demonstrate the importance of multi-location phenotyping for QTL analyses and crop improvement in peanut.  相似文献   

7.
Twenty-two genotypes of grain sorghum were grown under drought conditions by omitting one irrigation during stages of before flowering period, kernel filling period, and physiological maturity period at Assiut Univ. Farm in 1987 and 1988 seasons. The results obtained revealed that considerable variation existed among genotypes for all the studied traits. The most effective moisture stress treatment in reducing grain yield, panicle weight and plant height was during flowering stage. While 1000-kernel weight was much affected by moisture stress during grain filling period. The genotype x year interaction (σ2gy) was large compared to genotype x irrigation treatment (σ2gl) indicated that genotypes responded differently when they were grown from year to year. The genotypic variance (σ2g) for all traits were large reflecting the importance of genetic variability. Both phenotypic and genotypic correlations among traits showed that plant height and 1000-kernel weight were highly correlated with grain yield, while leaf area index was low associated with plant height.  相似文献   

8.
G. Oettler  G. Wahle   《Plant Breeding》2001,120(4):297-300
Fusarium head blight (FHB) is a widespread disease of small‐grain cereals and can cause substantial losses in grain yield. To assess quantitative genetic parameters as a basis for an efficient breeding programme for resistance, 100 triticale (×Triticosecale Wittm.) genotypes were tested in various environments and artificially inoculated at anthesis with an aggressive isolate of Fusarium culmorum. A visual rating (1–9 scale) was used to assess head blight infection. Five grain yield traits relative to an uninoculated control were also measured. The mean value of the average rating, calculated from four or five readings, was 4.4. It ranged from 3.0 to 5.9 and showed continuous variation. Infection caused a 48% reduction of mean kernel weight per spike, which was the result of 26% fewer kernels per spike and a 32% lower 1000‐kernel weight. The 50‐ml kernel weight was affected by only 20%. The range and genotypic variation was highest for relative kernel weight per spike. For all relative grain yield traits, the most important source of variation was the environment, followed by genotype‐environment interaction, with genotype generally coming last. In contrast, genotypic variation was the most important factor for the disease rating, which also had the highest heritability (h2= 0.89). Phenotypic correlations between the average head blight rating and relative grain yield traits were moderate (r = 0.42–0.57). In conclusion, an average disease rating provides a quantitative assessment of resistance and is suitable for screening large numbers of genotypes. Relative kernel weight per spike gives a ranking of the genotypes that is very similar to the visual score.  相似文献   

9.
A. Zougari    S. Guy  C. Planchon 《Plant Breeding》1995,114(4):313-316
Decreasing the lipoxygenase content of soybean (Glycine max (L.) Merr.) seed is a prerequisite for its increased use in human foods. These investigations aim to analyse the variation of lipoxygenase contents in relation to the genotype or the nitrogen nutrition of the plant. Four genotypes from a divergent selection for N2 fixation and the recurrent parent, Weber, were grown in pots, and two Bradyrhizobium japonicum strains (G.49 and SMGS1) were used. Dinitrogen fixation was estimated in situ using the acetylene–reduction assay. The lipoxygenase activity was determined polarographically on seeds taken from plants grown under controlled conditions in the presence or absence of symbiotic N2 fixation. The large genotypic variation observed for the lipoxygenase contents was enhanced by high N2 fixation. The variation range of lipoxygenase contents, which was obtained through the combination of the genotypic variation and the N2 fixation activity, was relatively large with a ratio of 2 on a seed dry–weight basis and a ratio of 2.6 when the total proteins were considered. Decreased lipoxygenase content and increased total protein content can thus be considered in parallel in a genetic context, together with more efficient N2 fixation.  相似文献   

10.
Low soil nitrogen limits maize (Zea mays L.) production in the West and Central African subregion. Levels of residual genetic variability were determined in two low‐N populations using selfed progeny evaluations, and results obtained indicate large genotypic and phenotypic variances for grain yield under both low‐ and high‐N environments for effective selection, while heritability estimates were generally low. Ear aspect and stay green were the most important traits contributing to grain yield for both populations. Selection reduced days to flowering, ASI and ear aspect, but increased plant height and yield. Yield gains of more than 25% occurred for the two populations under both low and high N with the most significant change of 42% occurring in one population under high N.  相似文献   

11.
This research was conducted to study the genetic diversity in safflower (Carthamus tinctorius L.) using agro-morphological traits and RAPD markers. Sixteen selected lines derived from landraces growing in various agro-climatic regions of Iran along with four exotic genotypes were evaluated in a randomized complete block design with three replications under field conditions. Days to emergence, days to initial flowering, days to flowering, days to maturity, plant height, branches per plant, capitula per plant, seeds per capitulum, 1,000-seed weight, seed yield per plant, seed yield, and reaction to powdery mildew (Leveillula taurica Arnaud) were evaluated in this study. Genetic diversity of the genotypes was assessed by RAPD markers. The results indicated significant differences among genotypes for the agro-morphological traits and clustering based on these traits classified the genotypes into five groups. Analysis of the RAPD markers revealed 15 polymorphic primers out of 50 used primers. Based on RAPD data, the highest genetic similarity was observed between the cultivars of “AC Sunset,” “AC Sterling” from Canada and the lowest relatedness observed between a local breeding line “E2428” and genotype “GE62923” from Germany. Cluster analysis based on RAPD markers and 54% coefficient of similarity divided the genotypes into five distinct groups. Comparing the clusters based on agro-morphological traits with those from molecular markers showed slight similarities. The finding of high genetic variation for agro-morphological traits and polymorphism at DNA level reveal that agronomic traits can be improved by selection programs.  相似文献   

12.
Finger millet [Eleusine coracana (L.) Gaertn.] is an important coarse cereal crop grown in the arid and semi‐arid regions and often experiences high temperature (HT) stress. The objectives of this research were (i) to quantify effects of season‐long HT stress on physiological and yield traits, (ii) to identify the developmental stages most sensitive to HT stress and (iii) to quantify the genetic variability for HT stress tolerance in finger millet. Research was conducted in controlled environment conditions. HT stress decreased the chlorophyll index, photosystem II activity, grain yield and harvest index. Maximum decrease in number of seeds per panicle and grain yield per plant was observed when stress was imposed during booting, panicle emergence or flowering stages. Maximum genotypic variation was explained by panicle width and number of seeds per panicle at optimum temperature (OT) and grain yield per plant at HT and number of seeds at HT. Based on the stress response and grain yield, tolerant or susceptible genotypes were identified. Finger millet is sensitive to HT stress during reproductive stages, and there was genotypic variability among the finger millet genotypes for number of seeds per panicle and grain yield under HT, which can be exploited to enhance stress tolerance.  相似文献   

13.
Fusarium culmorum is one of the most important Fusarium species causing head blight infections in wheat, rye, and triticale. It is known as a potent mycotoxin producer with deoxynivalenol (DON), 3‐acetyl deoxynivalenol (3‐ADON), and nivalenol (NIV) being the most prevalent toxins. In this study, the effect of winter cereal species, host genotype, and environment on DON accumulation and Fusarium head blight (FHB) was analysed by inoculating 12 rye, eight wheat, and six triticale genotypes of different resistance levels with a DON‐producing isolate at three locations in 2 years (six environments). Seven resistance traits were assessed, including head blight rating and relative plot yield. In addition, ergosterol, DON and 3‐ADON contents in the grain were determined. A growth‐chamber experiment with an artificially synchronized flowering date was also conducted with a subset of two rye, wheat and triticale genotypes. Although rye genotypes were, on average, affected by Fusarium infections much the same as wheat genotypes, wheat accumulated twice as much DON as rye. Triticale was least affected and the grain contained slightly more DON than rye. In the growth‐chamber experiment, wheat and rye again showed similar head blight ratings, but rye had a somewhat lower relative head weight and a DON content nine times lower than wheat (3.9 vs. 35.3 mg/kg). Triticale was least susceptible with a five times lower DON content than wheat. Significant (P = 0.01) genotypic variation for DON accumulation existed in wheat and rye. The differences between and within cereal species in the field experiments were highly influenced by environment for resistance traits and mycotoxin contents. Nevertheless, mean mycotoxin content of the grain could not be associated with general weather conditions in the individual environments. Strong genotype‐environment interactions were found for all cereal species. This was mainly due to three wheat varieties and one rye genotype being environmentally extremely unstable. The more resistant entries, however, showed a higher environmental stability of FHB resistance and tolerance to DON accumulation. Correlations between resistance traits and DON content were high in wheat (P = 0.01), with the most resistant varieties also accumulating less DON, but with variability in rye. In conclusion, the medium to large genotypic variation in wheat and rye offers good possibilities for reducing DON content in the grains by resistance selection. Large confounding effects caused by the environment will require multiple locations and/or years to evaluate FHB resistance and mycotoxin accumulation.  相似文献   

14.
为了明确花针期灌水后不同品种花生植株生长发育、 产量及构成因素的影响, 以不同花生品种为材料, 在花针期灌水后对不同器官的干物质积累进行了研究。结果表明, 花针期灌水处理对不同花生品种不同农艺性状及产量影响不同, 灌水处理下 ‘花育 25号’ 的主茎高、 侧枝长与其对照间差异不明显,但产量上差异明显; 即 ‘花育 25号’ 各性状和产量对灌水处理的适应性较好,‘花育 20号’ 表现较差。各品种主茎高和侧枝长的生长发育状况可用 Logistic方程很好的拟合, 花针期灌水可使主茎高和侧枝长最大生长速率出现时间(Tm)均提前, 主茎高Tm提前 2~5天, 侧枝长Tm提前 3~7天; 花针期灌水使 ‘花育22号’ 和 ‘花育 25号’ 两品种主茎高的最大生长速率(Vm)分别提高 21.29%、 5.67%, 侧枝长最大生长速率分别升高 3.61%和 5.42%, 却使 ‘花育 20号’ 主茎高和侧枝生长的最大生长速率(Vm)分别降低 15.48%和21.81%。花针期灌水处理下各品种基部茎长和茎粗均于开花后 20天的结荚期达峰值,‘花育 25号’ 、‘花育 20号’ 和 ‘花育 22号’ 三品种基部茎长较对照分别提高 0.30 cm、 0.57 cm和 0.46 cm, 其基部茎粗分别提高 18.33%、 11.11%、 10.34%。花针期灌水使各品种灌水生产效率明显提高,‘花育 22号’ 和 ‘花育 25号’ 灌水生产效率分别为 25.26 kg/mm和 22.6 kg/mm。无论是田间自然条件下还是花针期灌水处理, 均以 ‘花育 25 号’ 产量最高, 分别达 4794.3 kg/hm2和 5030.25 kg/hm2,‘花育 25 号’ 抗性和广适性能力均较强。  相似文献   

15.
Francis Kwame Padi 《Euphytica》2007,158(1-2):11-25
Twenty-four cowpea genotypes were evaluated under sole cropping or additive series intercropping with sorghum from 2004 to 2005 at four sites representative of the Guinea and Sudan savannah ecologies in Ghana. The aim was to determine whether cowpea breeding programs that emphasize selection under sole-crop conditions have the potential to produce cultivars that are effective under additive series intercropping. Genotype × cropping systems interaction was significant for days to 50% flowering but not for grain yield, biomass and other studied traits. Genotypic yield reaction to cropping systems indicated that bridging the yield gap between sole cropping and intercropping systems is best addressed by agronomic interventions that reduce stress on intercrop cowpea rather than by selecting for specifically adapted genotypes for intercropping. Significant genotype × environment interactions were observed for all traits when data was pooled over cropping systems. Partitioning of the genotype × environment interaction variance indicated that days to 50% flowering was dominated by heterogeneity of genotypic variance, whereas genotype × environment interactions for grain yield and biomass was mainly due to imperfect correlations. Large differences in genotypic yield stability were observed as estimated by the among-environment variance, regression of yield on the environmental index, Kataoka’s index, and by partitioning of genotype × environment interaction sum of squares into components attributable to each genotype. The results suggest that in regions where genotype × environment interaction for yield frequently causes re-ranking across environments, genotypes with the least contribution to the interaction sum of squares are likely to be most productive. On the whole, the results support the contention that breeding under sole-crop conditions has the potential to produce cultivars effective under intercropping conditions.  相似文献   

16.
This study was conducted to evaluate drought tolerance and persistence in a germplasm of smooth bromegrass and association of forage productivity with different traits. Thirty‐six genotypes of smooth bromegrass were clonally propagated and evaluated under two soil moisture environments for three years (2013–2015). High genotypic variation was observed among genotypes for all the measured traits. Drought stress decreased mean values for traits related to productivity. Also, the long‐term stress for three years reduced the persistence of plants. Results indicated that indirect selection based on components of forage yield, which had high heritability and high correlation with yield, would be more effective to improve drought tolerance in this germplasm. The results of principal component analysis showed that there was a negative relationship between phenological traits with the persistence‐related traits and yield production. This suggests that selection for earliness may indirectly promote persistent genotypes. The results showed that some Hungarian genotypes are valuable gene sources for persistence. The most persistent genotypes from both groups (Iranian and foreign) were identified using the biplot method. These genotypes may be useful for the development of populations for future studies.  相似文献   

17.
G. Oettler  T. Schmid 《Plant Breeding》2000,119(6):487-490
Septoria nodorum leaf and glume blotch is an important disease of triticale (×_Triticosecale Wittm.) and can cause severe losses of grain yield in some regions. Quantitative genetic parameters for resistance were estimated for 2 years in two locations in triticale genotypes artificially inoculated with S. nodorum. The effect of infection was assessed by a visual symptom rating of flag leaves and spikes and by grain yield traits relative to an uninoculated control. The mean ratings of flag leaves and spikes, calculated from two to four ratings, were 2.6 and 3.9, respectively, with a range of six ratings for spikes and over five for flag leaves. Infection caused an 11.5% mean reduction in kernel weight per spike, which was the result of 13.2% lower 1000‐kernel weight. The number of kernels per spike and 50‐ml weight were little affected. For all relative grain yield traits, genotypic variation was small with high genotype‐environment interaction effects and thus moderate to low heritabilities. In contrast, for visual ratings genotypic variation was high, with low interaction effects leading to high heritabilities. Phenotypic correlation between flag leaf and spike ratings was low, indicating independent disease resistance mechanisms. The best association, although still moderate, was obtained between flag leaf rating and relative 1000‐kernel weight. Therefore, visual disease ratings do not satisfactorily assess the effect of Septoria infection on grain yield traits. The reduction in 1000‐kernel and possibly 50‐ml weight are good indicators, provided that multi‐environment tests are conducted.  相似文献   

18.
Pre-flowering photoperiod effects on floral initiation, flowering time and yield components of various crops have been well studied, but the post-flowering photoperiod effects on major field crops are not clearly understood. A controlled environment study was carried out using six long-day (LD) crops, flax, sugar beet, broad bean, triticale, wheat, and rapeseed, and seven short-day (SD) crops including Adzuki bean, potato, rice, peanut, mungbean, cotton and corn with a major objective of evaluating the post-flowering photoperiod effects on their reproductive development and yield components. There were significant inter- and intra-specific differences in their response to post-flowering photoperiod treatments. The effects of short days on LD crops were similar to LD effects on SD crops. The post-flowering duration was prolonged by short photoperiod in LD crops and long photoperiod in SD crops. There was, however, significant genotypic variation within a species for such effects. The post-flowering LD treatment caused abscission of flowers and pods and the resumption of vegetative growth in Adzuki bean. The post-flowering LD treatment also delayed the shoot senescence of one of the two potato varieties and decreased the number of tubers per plant in both varieties. The LD treatment delayed maturation of rice and mungbean, and decreased seed yield and 100-seed weight of peanut, although the shoot senescence of peanut was not apparently affected. Rapeseed, wheat, cotton and corn genotypes in this study did not show any sensitivity to post-flowering photoperiod. In triticale (an LD crop) exposure to short photoperiod post-flowering increased the number of spikes per plant perhaps due to a greater assimilate accumulation over a longer duration. The results from the current study as well as those from our previous experiments suggest that post-flowering photoperiod responses do exist in diverse field crops, and that there are strong genotypic differences in sensitivity and magnitude of response to post-flowering photoperiod. Photoperiod after flowering substantially regulates the source/sink relationship, and promotes partitioning and accumulation of assimilates to storage organs of crops when it favours the reproductive development of crops.  相似文献   

19.
Genetic architecture of seedling drought tolerance is complex and needs to be better understood. To address this challenge, we developed a protocol to identify the most promising drought-tolerant genotypes at the seedling stage in winter wheat. A population of 146 recombinant inbred lines (F9) derived from a cross between wheat cultivars, ‘Harry’ (seedling drought tolerant) and ‘Wesley’ (seedling drought susceptible) were used in this study. All genotypes were sown in three replications in a randomized complete block design under controlled conditions in a greenhouse. Seven traits were scored and grouped into tolerance traits; days to wilting, leaf wilting, and stay green and survival traits; days to regrowth, regrowth, drought survival rate, and recovery after irrigation. Three selection indices were calculated (1) tolerance index, (2) survival index, and (3) drought tolerance index (DTI). The same set of genotypes were also tested for grain yield in two low rainfall environments for two seasons. High genetic variation was found among all genotypes for all seedling traits scored in this study. Correlations between tolerance and survival traits were weak or did not exist. Heritability estimates ranged from 0.53 to 0.88. DTI had significant phenotypic and genotypic correlations with all seedling traits. Genotypes were identified with a high drought tolerance at the seedling stage combined with high grain yield in low rainfall. Breeding for tolerance and survival traits should be taken into account for improving winter wheat drought tolerance at seedling stage. The selected genotypes can be used for to further improve drought tolerance in high yielding wheat for Nebraska.  相似文献   

20.
烯效唑对花生生长调节作用研究   总被引：3，自引：0，他引：3  
为了明确烯效唑对花生生长发育和产量性状的影响,于花生盛花期采用田间常规喷雾的方法,研究烯效唑对花生生物性状、经济性状及品质的影响。结果表明：盛花期经过烯效唑处理的花生主茎高度低于清水对照,对株高的抑制率在7.95%~12.27%之间;与产量相关的经济性状各处理区均高于对照处理;药剂处理区增产率9.5%~13.8%,增产效果显著。烯效唑对花生营养生长的抑制持续期较多效唑长,有利于花生的生殖生长,对花生经济产量的形成具有积极的促进作用。  相似文献   

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