Early Vigour Research Articles

Electromagnetic application for stimulation of wheat seed germination and early seedling growth

The effects of electromagnetic field treatments of wheat seeds on germination and early seedling growth were studied under controlled conditions. Dried seeds were exposed to magnetic field of strength from 0 to 1.5 T in steps of 0.3 T for different time periods of 5 to 20 min in steps of 5 min. Thereafter, the seeds were incubated for a total period of 7 days to germinate. The germinating seeds were counted every 24 h during the incubation period of 7 days. Germination percentage, mean germination time, vigor index were evaluated. Most of seed treatments resulted in improved germination speed and spread, root and shoot length, seed soluble sugars and a-amylase activity. The results indicated that the effects of treatment depended on strength and period of exposure to magnetic field. Treatment of wheat seeds in these magnetic fields increased mean germination time, seedling length and seedling dry weight. The greatest increases of the various treatments were obtained for plants exposed to 0.3 and 1.2 T for 10 min. The higher enzyme activity in magnetic-field-treated wheat seeds could be triggering the fast germination and early vigor of seedlings. The results suggest that magnetic field treatments of wheat seeds have the potential to enhance germination, early growth and biochemical parameters of seedlings.

Quantification of critical factors affecting fitness of the sugary1 mutant in maize

AbstractFitness of sugary1 (su1) is affected by some critical traits that depend on the genotypes and environments, while their effects have not been quantified with convincing statistical methods. The objective of this work was to identify and quantify the critical factors of su1 fitness with different genotypes and environments. We used two pairs of field corn inbreds that differentially affected su1 viability to develop F1, F2, BC1 and BC2. After selfing, Su1 and su1 kernels were evaluated under controlled environmental conditions and in field trials. Multiple regressions showed that dry weight of juvenile plant was affected by early vigour (plant size, colour and health) and emergence in cold conditions; ear weight by plant appearance, number of plants and chlorophyll content; number of ears by plant appearance, number of plants, chlorophyll content and female flowering; and kernel weight by ear weight, number of plants, row number and ear length. The main critical factors for su1 fitness were early vigour and emergence under cold conditions at initial stages, while several adult traits were related with final fitness.

Plant vigour at establishment and following defoliation are both associated with responses to drought in perennial ryegrass (Lolium perenne L.).

Periodic drought events present a significant and, with climate change, increasing constraint on temperate forage plants' production. Consequently, improving plants' adaptive response to abiotic stress is a key goal to ensure agricultural productivity in these regions. In this study we developed a new methodology, using both area-based comparison and soil water content measurements of individual non-irrigated and irrigated clones, to assess performance of perennial ryegrass (Lolium perenne L.) genotypes subjected to moisture stress in a simulated competitive environment. We applied this method to the evaluation of a full-sibling population from a pair cross between genotypes from a New Zealand cultivar and a Moroccan ecotype. Our hypothesis was that: (i) both leaf lamina regrowth after defoliation (LR) and plant vigour affect plant performance during drought and rehydration; and (ii) quantitative trait loci (QTLs) associated with plant performance under moisture stress could be identified. Differences amongst genotypes in dry matter (DM) production, early vigour at establishment, leaf elongation rate and LR were measured. LR explained most of the variation in DM production during exposure to moisture deficit and rehydration followed by plant vigour, indicated by initial DM production in both treatments and subsequent measures of DM production of irrigated clones. We identified two main QTL regions associated with DM production and LR, both during drought exposure and rehydration. Further research focused on these regions should improve our understanding of the genetic control of drought response in this forage crop and potentially other grass species with significant synteny, and support improvement in performance through molecular breeding approaches.

Agronomic performance of an IR64 introgression line with large leaves derived from New Plant Type rice in aerobic culture

Aerobic culture is a promising water-saving technology in irrigated rice ecosystems, but the vulnerability of plants to fluctuations in soil moisture constrains leaf expansion and yield. The objective of this study was to examine whether an aboveground architecture with large leaves and reduced tillering is associated with vigorous leaf growth in aerobic rice culture. In a series of field experiments, we evaluated the agronomic performance of an IR64 introgression line, YTH323 (IR84640-11-27-1-9-3-2-4-2-2-2-B), with fewer tillers and larger leaves than IR64, derived from New Plant Type rice, under various water and nitrogen conditions. In flooded culture, YTH323 yielded the same as IR64 and 38% more than IR65564-44-51 (a New Plant Type rice) (9.0 vs. 6.6tha−1). In aerobic culture, in contrast, it yielded 81% more than IR64 in slightly dry soils (5.1 vs. 2.8tha−1). YTH323 had a higher leaf area index than IR64 and IR65564-44-51 under slightly dry soil conditions and under a range of nitrogen conditions. The higher and more stable yield of YTH323 in aerobic culture was attributable to greater early vigor, high specific leaf area, a high ratio of leaf weight to total biomass, and larger leaves, along with the characteristics of high-yield cultivars such as high responsiveness to fertilizers and good grain filling. We conclude that genetic modification of the aboveground architecture of IR64, a typical tropical lowland rice cultivar, to reduce tiller and leaf number improves adaptation to aerobic culture.

Clustering of Greengram (Vigna radiata(L.) Wilczek) Genotypes Based on Qualitative Characters

Greengram is an important grain legume of the arid and semiarid regions. This crop has enough genetic diversity both for quantitative and qualitative characters. The qualitative traits using minimal descriptors was developed by NBPGR. Enough work had been done in characterising the greengram using quantitative characters. In this study, fifteen qualitative characters were chosen for phenotyping the 40 greengram germplasm. The fifteen characters Early plant vigour, Plant growth habit, Leaf colour, Terminal leaf length (cm), Leaflet shape, Plant surface, Branching pattern, Flower colour, Leafiness, Flowering tendency, Raceme position, Pod pubescence, Pod colour, Seed colour, Hypocotyl colour. The crop was raised in Randomised Block Design with three replications at AC & RI, Madurai during kharif 2012. The data was subjected to statistical analysis and the results revealed that 40 greengram genotypes were grouped into six clusters at 40% level. The variety ADT 1 is the distinct one differing from the other genotypes studied. It could be inferred from the present study that the geographical origin of most of the greengram germplasm is from the southern states of India having enough genetic variability in germplasm.

Adaptations for growing wheat in the drying climate of Western Australia

This study investigated the effects of predicted changes in rainfall distribution in marginal (≤325 mm annual rainfall) parts of the south-west Australian wheatbelt and options for management and adaptation of the wheat crop. Field experiments with rain-out shelters and irrigation were conducted in 2008 and 2009 to investigate the interactions of rainfall distribution, row spacing, genotype and timing of nitrogen application on growth, water use and grain yield of spring wheat. Water storage before seeding showed potential to maintain or increase yields despite lower in-season rainfall. Widening row spacing reduced biomass and slowed water use but did not increase grain yield, because of increased soil evaporation and water left in the soil at crop maturity. The Agricultural Production Systems Simulator (APSIM) wheat model was used to investigate the effects of recent and projected climate change on yield in relation to row spacing, phenology and nitrogen. Two climate-change scenarios were applied to historical climatic data to create two plausible future climates (‘optimistic’ and ‘pessimistic’) for the year 2030. None of the strategies tested increased wheat yield under the predicted climate scenarios. Simulated yields at wider row spacings were consistently lower due to insufficient biomass, increased soil evaporation and the inability of the crop to use all of the available water before maturity. Simulated yields of short-season genotypes were always greater than yields of longer season genotypes. Nitrogen regimes had little effect in this study. This study points to several genotypic traits that could improve the performance of wheat grown at wider row spacings. These include early vigour to reduce soil evaporation and increase competition with weeds, greater tillering/biomass to reduce limitation by sink size, and a vigorous root system with appropriate lateral spread and growth to depth to access available soil water.

Use of remote sensing to determine the relationship of early vigour to grain yield in canola (Brassica napus L.) germplasm

Early crop vigour in canola, as in other crops, is likely to result in greater competition with weeds, more rapid canopy closure, improved nutrient acquisition, improved water-use efficiency, and, potentially, greater final grain yield. Laborious measurements of crop biomass over time can be replaced with newer remote-sensing technology to aid data acquisition. Normalised difference vegetation index (NDVI) is a surrogate for biomass accumulation that can be recorded rapidly and repeatedly with inexpensive equipment. In seven small-plot field experiments conducted over a 4-year period with diverse canola germplasm (n = 105), we have shown that NDVI measures are well correlated with final grain yield. We found NDVI values were most correlated with yield (r >0.7) if readings were taken when the crop had received 210–320 growing degree-days (usually the mid-vegetative phase of growth). It is suggested that canola breeders may use NDVI to objectively select for vigorous genotypes that are more likely to have higher grain yields.

Suitability of A European Nuclear Collection of Brassica oleracea L. Landraces to Grow at High Temperatures

AbstractStatistical models predict that global warming will have a negative impact in crop yields in the next decades. Especially vulnerable are winter crops such as kales or cabbages (Brassica oleracea L.). We evaluated the impact of high temperatures in morphological and biochemical traits of a B. oleracea core collection during early development. When grown at 30 °C, plants showed a reduction in chlorophyll content, early vigour and biomass compared with values observed on plants grown at 20 °C. Likewise, the total content of glucosinolates shows a reduction at high temperatures. The alboglabra group showed the best general performance at 30 °C for both morphological traits and glucosinolate content. Based on a cluster analysis, we selected four populations (MBG0072, MBG0464, MBG0535 and HRIGRU5555) as the most promising to be used in further breeding programs for heat tolerance.

Genetically vigorous wheat genotypes maintain superior early growth in no-till soils

Reduced tillage is widely used in maintaining sustainable agricultural systems. Early growth of wheat (Triticum aestivum L.) is often impaired in the high strength soils typical of no-till. This may reflect the intrinsically reduced vigour of commercial wheat varieties. We investigated how genotypes selected for greater early vigour performed relative to a broader range of wheat genotypes for shoot and root growth in cultivated and no-till conditions. We assessed a range of cereal germplasm varying for early growth (establishment and leaf area development) under contrasting tillage conditions in a very favourable season, and then the performance of a selected subset validated in repacked soil cores in controlled environments. We measured above- and belowground growth, and parameters associated with adaptation to increasing soil strength. High strength soil reduced early shoot and root growth. There were no effects on plant number at emergence and coleoptile length was unimportant. Increased soil strength reduced early growth of all genotypes including genetically vigourous wheats. However, the ranking for vigour was maintained with high strength soil suggesting breeding lines and populations containing genes for greater early growth may still be beneficial in selection for improved performance in no-till. Genotypic increases in specific leaf area and leaf breadth were both associated with genetically greater seedling leaf area and biomass, and potential for greater root growth in no-till. Early growth of all wheats was reduced with no till and the harder, high strength soil associated with this tillage system. Genetic variation was large in no-till and cultivated soils alike. In high strength and no-till soils, the relationship with shoot and root vigour was positive indicating selection for greater early growth in breeding programs may increase leaf area and improve root growth.

Genetic Correlations among Haploids, Doubled Haploids, and Testcrosses in Maize

ABSTRACTDoubled haploid (DH) lines produced via in vivo haploid induction have become an indispensable tool in maize (Zea mays L.) breeding and research. To determine the predictive value of the per se performance of haploid and DH lines in population and hybrid breeding, genetically balanced sets of haploid and DH lines along with testcrosses of the DH lines were evaluated in field trials across four locations over 2 yr in Germany. Suitable material sets were provided by three collaborating breeders. Each set comprised 54 to 58 DH lines developed from a proprietary elite dent single cross. These DH lines were crossed with one or two flint testers and subjected to haploid induction for production of corresponding haploid versions. Haploid lines, DH lines, and testcrosses were grown in separate but adjacent blocks. Haploid lines were surrounded by a mixture of inbred lines functioning as pollen source. Most haploid plants were male sterile but showed a certain degree of female fertility. Highly significant genetic variation reflected by high heritability coefficients existed in all material sets for all traits. Genetic correlations between haploid and DH lines were moderate to strong (0.5 < genetic correlation coefficient [rg] < 0.9) for early vigor, silking date, plant height, and stover weight per plant. Correlations between DH lines and testcrosses varied from nonsignificant to moderately strong for grain yield but were strong for silking date, plant height, stover yield, and grain moisture content. Silking date, early vigor, and plant height of haploid lines were moderately but significantly associated with grain yield of testcrosses. Somewhat higher estimates were obtained for the corresponding correlations between DH lines and testcrosses. In conclusion, selection for silking date, early vigor, plant height, and stover weight at the haploid level is expected to result in positive correlated genetic gain for various traits not only at the DH but also at the testcross level. Likewise, selection at the DH level may substantially speed up progress in combining ability.

Tillage system and genotype effects on early vigor and water use in bread wheat in the Mediterranean region

The southern part of the Mediterranean basin is among the regions that are characterized by recurrent droughts and it is threatened by the effects of climate change. To deal with these problems in wheat, improved techniques of rain water conservation and adapted varieties need to be developed. Combining zero tillage and varieties with early vigor can reduce evaporation and improve transpiration and water productivity and hence increase yields. To test this hypothesis, a field trial was conducted at ICARDA’s research station at Tel Hadya, Aleppo, Syria in 2008/2009 and 2011/2012. The treatments tested were “zero tillage vs. conventional tillage” and five genotypes of bread wheat. In 2008/2009, results showed that zero tillage improved leaf area index, specific leaf area, above ground biomass production and actual evapotranspiration at the beginning of stem elongation. The values increased, respectively for these parameters, from 2.34 to 3.25, 202.9 to 226.5 cm2 g-1, 1799 to 2333 kg ha-1 and from 91 to 101 mm. Water productivity was improved by 15%, on average. In year 2011/2012, the effect of tillage system on all the parameters was not statistically significant. In general, all genotypes responded positively to zero tillage for these measured variables. From this study, we can conclude that zero tillage under dry conditions is a technique that can improve the early vigor of the seedlings. This enhanced early growth can ensure a good canopy cover that reduces the loss of rainwater by evaporation and increases transpiration in relatively early dry years. The non disturbance of soil by tillage reduces water loss by evaporation. However, under wet conditions due to high rainfall, the positive effect of zero tillage on soil moisture and plant growth disappears. Key words: Wheat, zero tillage, genotype, leaf area, biomass, evapotranspiration.

Wheat genotypes with high early vigour accumulate more nitrogen and have higher photosynthetic nitrogen use efficiency during early growth.

Genotypic differences in early growth and nitrogen (N) uptake among 24 wheat (Triticum aestivum L.) genotypes were assessed in a field trial. At late tillering, large genetic variation was observed for shoot biomass (23-56gm-2 ground area) and N uptake (1.1-1.8gm-2 ground area). A strong correlation between aboveground biomass and N uptake was observed. Variation around this relationship was also found, with some genotypes having similar N uptake but large differences in aboveground biomass. A controlled environment experiment was conducted to investigate the underlying mechanisms for this variation in aboveground biomass using three vigorous genotypes (38-19, 92-11 and CV97) and a non-vigorous commercial cultivar (Janz). Vigorous genotypes had lower specific leaf N in the youngest fully expanded leaf than Janz. However, there was no difference in chlorophyll content, maximum Rubisco activity or the rate of electron transport per unit area. This suggests that Janz invested more N in non-photosynthetic components than the vigorous lines, which could explain the higher photosynthetic N use efficiency of the vigorous genotypes. The results suggest that the utilisation of wheat genotypes with high early vigour could improve the efficiency of N use for biomass production in addition to improving N uptake during early growth.

Comparative performance of the stable isotope signatures of carbon, nitrogen and oxygen in assessing early vigour and grain yield in durum wheat – CORRIGENDUM

Comparative performance of the stable isotope signatures of carbon, nitrogen and oxygen in assessing early vigour and grain yield in durum wheat – CORRIGENDUM

Genetics of early growth vigour in lentil (Lens culinaris Medik.)

Genetics of early growth vigour was studied in two crosses of lentil (Lens culinaris ssp. culinaris) involving ILL6002 and ILL7663 as rapid early growth vigour parents and DPL15 as slow early growth vigour parent. The early growth vigour was measured on the basis of seedling length and data was recorded on 114 and 834 individual F2 plants derived from DPL15 × ILL6002 and DPL15 × ILL7663 crosses, respectively. Frequency distribution of F2 plants appeared to be normal for seedling length, but it was skewed towards slow early growth vigour. Hence, analysis of early growth vigour as a qualitative trait in F2 and F3 revealed that slow early growth vigour was dominant over rapid early growth vigour and a single recessive gene controlled the rapid early growth vigour in lentil. However, occurrence of transgressive segregants for seedling length indicated that some minor genes also interacted with one major gene for early growth vigour. Therefore, QTL analysis for early growth vigour can help to identify major and minor gene(s), for making genetic improvement in lentil by the use of marker assisted selection. Lentil is an important cool season food legume crop of rainfed agriculture and it is one of important pulse crops for diversifying cereal-based cropping systems worldwide. Presently, it occupies 3.74 million ha area producing 3.40 million tons grains in the world with an average yield of 915 kg/ha (Erskine et al. 2011). The major geographical regions of lentil production are South Asia and China (44.3%), northern great plains in North America (41%), west Asia and north Africa (6.7%), sub-Saharan Africa (3.5%) and Australia (2.5%) (FAOSTAT 2010). Among countries, India accounts for the largest global area under lentil with 1.48 million ha area and 1.01 million ton production (AICRP 2010–2011). The present productivity of lentil in India is very low as it is mostly grown as post-rainy season crop under receding soil moisture conditions during the winter

Comparative performance of the stable isotope signatures of carbon, nitrogen and oxygen in assessing early vigour and grain yield in durum wheat

SUMMARYThe present paper studied the performance of the stable isotope signatures of carbon (δ13C), nitrogen (δ15N) and oxygen (δ18O) in plants when used to assess early vigour and grain yield (GY) in durum wheat growing under mild and moderate Mediterranean stress conditions. A collection of 114 recombinant inbred lines was grown under rainfed (RF) and supplementary irrigation (IR) conditions. Broad sense heritabilities (H2) for GY and harvest index (HI) were higher under RF conditions than under IR. Broad sense heritabilities for δ13C were always above 0·60, regardless of the plant part studied, with similar values for IR and RF trials. Some of the largest genetic correlations with GY were those shown by the δ13C content of the flag leaf blade and mature grains. Under both water treatments, mature grains showed the highest negative correlations between δ13C and GY across genotypes. Flag leaf δ13C was negatively correlated with GY only under RF conditions. The δ13C in seedlings was negatively correlated, under IR conditions only, with GY but also with early vigour. The sources of variation in early vigour were studied by stepwise analysis using the stable isotope signatures measured in seedlings. The δ13C was able to explain almost 0·20 of this variation under RF, but up to 0·30 under IR. In addition, nitrogen concentration in seedlings accounted for another 0·05 of variation, increasing the amount explained to 0·35. The sources of variation in GY were also studied through stable isotope signatures and biomass of different plant parts: δ13C was always the first parameter to appear in the models for both water conditions, explaining c. 0·20 of the variation. The second parameter (δ15N or N concentration of grain, or biomass at maturity) depended on the water conditions and the plant tissue being analysed. Oxygen isotope composition (δ18O) was only able to explain a small amount of the variation in GY. In this regard, despite the known and previously described value of δ13C as a tool in breeding, δ15N is confirmed as an additional tool in the present study. Oxygen isotope composition does not seem to offer any potential, at least under the conditions of the present study.

Optimizing triticale sowing densities across the Mediterranean Basin

Triticale and wheat are similar crops, but triticale represents a valuable alternative to wheat due to its greater biomass production and grain yield in Mediterranean-type growing conditions. However, despite the higher yield potential and increasing importance of this crop, there are no dynamic crop models available to assist triticale adaptation via simulation experiments. In a previous study, the APSIM-Nwheat model was parameterized for triticale resulting in a new APSIM-Triticale model but the new model was never compared with detailed experimental triticale data in a one-to-one comparison. Here, the new model was tested with detailed field experimental observations. APSIM-Triticale was able to reproduce phenology, biomass, grain yields and soil water dynamics. The model performed well over several years and management options that included different sowing densities, sowing dates and a short and tall cultivar. The tested model was then used to explore management options to maximize triticale yield across the Mediterranean Basin. The response to sowing density was cultivar and rainfall-environment dependent. The simulation analysis indicated that there was no yield advantage with higher sowing densities with a tall cultivar type in high yielding environments, despite its higher biomass growth rates. The highest yields were achieved at the early sowing date at the sowing densities between 100 and 300plants/m2 in the high rainfall regions for both short and the tall cultivars. The simulation study suggests that sowing a short cultivar with a reduced radiation use efficiency but early vigour growth could increase current yields across different regions, seasons and management options in the Mediterranean climate.

Can early vigour occur in combination with drought tolerance and efficient water use in rice genotypes?

Selection for early vigour can improve rice (Oryza sativa L.) seedlings' access to resources, weed competitiveness and yield. Little is known about the relationships between early vigour and drought tolerance. This study explored a panel of 176 rice genotypes in a controlled environment regarding a diversity of traits and trait combinations related to early vigour and water use under drought. The design excluded genotypic differences for root depth. We hypothesised that early vigour (as determined by biomass accumulation under well-watered conditions) was not independent from drought tolerance (determined by biomass accumulation maintenance under drought). Leaf size, developmental rate (DR) and tiller number contributed positively to shoot DW and leaf area, and thus vigour. Early vigour was negatively correlated with growth maintenance and water use efficiency under drought, suggesting tradeoffs. Three clusters of genotypes were identified based on the constitutive traits DR, specific leaf area, tiller number and leaf size. The less drought-tolerant cluster, mainly with lowland O. sativa indica rices, showed a sensitive transpiration response to the fraction of transpirable soil water; however, under well-watered conditions these genotypes were vigorous, with small leaves, high DR and high tillering. This experiment showed that the tradeoff between early vigour and drought tolerance was physiological and not a matter of access to water. The results are discussed with a view to identify drought adaptation strategies for crop improvement. Further improvement of multitrait phenotyping approaches is proposed.

Genetic Analysis of Vegetative Ground Cover Rate in Winter Wheat Using Digital Imaging

Vegetative vigour is an important physiological trait and selection for greater seedling vigour is a goal of breeding programs,especially in rain-fed regions.This study aimed to identify the genetic variation of early vigour,determine the agronomic traits most closely associated with seedling growth,and detect the major gene-containing region of early vigour in winter wheat.Twenty-eight cultivars and advanced lines at two planting densities(240 plants m 2and 360 plants m 2)were grown in Jinan during2009–2010 and 2010–2011 cropping seasons,with randomized complete block design of three replications.Whole-genome association mapping was employed to identify the chromosome region controlling early vigour using 921 Diversity Array Technology(DArT)and 83 SSR markers.Early vigour was evaluated with vegetative ground cover rate via implementation of photographic image analysis,whereby computer analysis was used to determine percentage ground cover.Significant differences of ground cover rate between two planting densities were detected in pre-winter period,greening-up and booting stages,but not in early stem elongation stage.Ground cover rate in stem elongation stage was significantly and positively associated with maximum tiller number(r = 0.76,P 0.01),leaf area index(r = 0.74,P 0.01),spike number(r = 0.73,P 0.01),and grain yield(r = 0.73,P 0.01).Twelve gene-containing regions for vegetative ground cover rate were detected in two seasons.Most of the regions conditioning the vegetative ground cover rate were not affected by the developmental stages.Ten gene-containing regions identified were consistent with previously reported QTLs for seedling traits,grain yield and disease resistance.Three regions on 5BL,6AS,and 6BL were the same as previously reported loci for seedling traits.Therefore,there is sufficient genetic variation to increase early vigour in winter wheat,and early vigour could be quickly measured through digital image analysis.

Genotypic variability in the response to elevated CO2 of wheat lines differing in adaptive traits.

Atmospheric CO2 levels have increased from ~280ppm in the pre-industrial era to 391ppm in 2012. High CO2 concentrations stimulate photosynthesis in C3 plants such as wheat, but large variations have been reported in the literature in the response of yield and other traits to elevated CO2 (eCO2). Few studies have investigated genotypic variation within a species to address issues related to breeding for specific adaptation to eCO2. The objective of this study was to determine the response to eCO2 of 20 wheat lines which were chosen for their contrasting expression in tillering propensity, water soluble carbohydrate (WSC) accumulation in the stem, early vigour and transpiration efficiency. Experiments were performed in control environment chambers and in a glasshouse with CO2 levels controlled at either 420ppm (local ambient) or 700ppm (elevated). The results showed no indication of a differential response to eCO2 for any of these lines and adaptive traits were expressed in a consistent manner in ambient and elevated CO2 environments. This implies that for these traits, breeders could expect consistent rankings in the future, assuming these results are validated under field conditions. Additional climate change impacts related to drought and high temperature are also expected to interact with these traits such that genotype rankings may differ from the unstressed condition.

Multi-environment analysis and improved mapping of a yield-related QTL on chromosome 3B of wheat

Improved mapping, multi-environment quantitative trait loci (QTL) analysis and dissection of allelic effects were used to define a QTL associated with grain yield, thousand grain weight and early vigour on chromosome 3BL of bread wheat (Triticum aestivum L.) under abiotic stresses. The QTL had pleiotropic effects and showed QTL x environment interactions across 21 diverse environments in Australia and Mexico. The occurrence and the severity of water deficit combined with high temperatures during the growing season affected the responsiveness of this QTL, resulting in a reversal in the direction of allelic effects. The influence of this QTL can be substantial, with the allele from one parent (RAC875) increasing grain yield by up to 12.5% (particularly in environments where both heat and drought stress occurred) and the allele from the other parent (Kukri) increasing grain yield by up to 9% in favourable environments. With the application of additional markers and the genotyping of additional recombinant inbred lines, the genetic map in the QTL region was refined to provide a basis for future positional cloning.