Number Of Grains Research Articles

Evaluation of integrated nitrogen and phosphorous management using the TT biplot method in soybean

To investigate the effects of integrated nutrient management on oil, protein, grain yield and some traits of soybean, we conducted a factorial experiment involving 4 bio-fertilizer (no inoculation, inoculation with Barvar-2, inoculation with Biosoy and dual inoculation with Biosoy and Barvar-2) and 3 chemical fertilizer levels (no chemical fertilizer, 66 kg ha-1 diammonium phosphates + 50 kg ha-1 urea, 132 kg ha-1 diammonium phosphates + 100 kg ha-1 urea) with 100% chemical fertilizer (200 kg ha-1 diammonium phosphates + 150 kg ha-1 urea) as control base in a randomized complete block with four replications at the research farm of the University of Mohaghegh Ardabili, Iran. Analysis of variance showed that treatment combinations affected most of the traits (P>0.01). We used the biplot analysis as the treatment ? trait (TT) biplot to determine the best treatment combinations and traits. The first two principal components (PC1 and PC2) explained 94 and 96% of the total variant of the standardized data in 2017 and 2018, respectively. Accordingly, application of Biosoy and 150 kg ha-1 urea + 200 kg ha-1 diammonium phosphate significantly increased stem height at harvest, number of grains per plant, biomass, hundred-grain weight, oil and protein yield, protein percent and grain yield compared to the other treatment combinations. The results showed that there were positive correlations between these traits. Also, non-inoculated plants and no chemical fertilizer treatments significantly increased oil percent. The results indicate that higher-yielding treatment combinations had lower oil percent. The biplot was used for ranking of treatment combinations based on a single trait. These study results suggest that bio-fertilizers had a positive influence on soybean and that they could diminish the use of chemical fertilizers. The study reveals that the TT biplot was able to graphically show the interrelationships between traits and support visual comparison of treatments.

Determination of the post-anthesis nitrogen status using ear critical nitrogen dilution curve and its implications for nitrogen management in maize and wheat

Abstract Nitrogen (N) accumulation in plant reproductive organs during the post-anthesis growth phase of maize and wheat plays a crucial role in the formation of grain yield and quality. However, little is known about the effect of crop pre-anthesis and post-anthesis N status on ear N accumulation (NAE). This study endeavored to extend the crop N dilution theory already developed for vegetative growth period to determine ear critical N concentration (%NcE) during post-anthesis period of crop growth for analyzing the difference of NAE under various N levels. The data including the weight of dry mass (W) and N concentration of entire plant and ear, post-anthesis plant N uptake (PANU) from soil, grain number (GN), and grain weight (GW) were collected on wheat (two cultivars) and maize (three cultivars) from eight N rates (0–300 kg N ha−1) field experiments. The results revealed that the process of %N dilution exists in ear and it is plausible to extend the concept of %NcE curve till crop post-anthesis period. The %NcE curves as function of ear dry mass (WE) of wheat (%NcE = 2.85WE-0.17) and maize (%NcE = 2.22WE-0.26) were lower than those developed in maize and wheat on whole plant basis. This study revealed that the ear has the potential to diagnose ear N status under different N conditions and the increases in ear N nutrition index (NNIE) during the post-anthesis period with increasing N rate were well synchronized with plant NNI (NNIp) at anthesis. GN and GW of maize and wheat showed significantly positive correlation with NNIp at anthesis and NNIE at maturity under N-limiting treatments, and GN and GW could keep relatively stable under non-N limiting treatments. NNIp and NNIE showed the potential capacity to predict GN and GW of maize and wheat under N limiting condition. Ear critical N accumulation (NAcE) was calculated using ear Nc curve to investigate the differences mechanism of NAE under different N conditions. The difference of NAcE under different N treatments was deduced from the pre-anthesis N status of maize and wheat by determining GN. The ear N deficiency (NDE) between NAcE and NAE was co-regulated by plant pre-anthesis and post-anthesis N status, which in turn have potential to explain the variance of GW at maturity in both crops. The significantly attenuated effect of pre-anthesis N deficiency on ear potential N demand in maize and wheat indicated that the post-anthesis N management must consider the pre-anthesis N status and the corresponding reduction of the post-anthesis N input to prevent N loss under N limiting treatment in both crops. Maize was more dependent on post-anthesis N status while wheat was more reliant on pre-anthesis N status for satisfying ear growth and producing optimum GN owing to the differential values of PANU/NAE in maize and wheat during post-anthesis period. This study provides a new viewpoint on post-anthesis N management of maize and wheat for enhancing N use efficiency and grain yield.

QTLs for cell membrane stability and flag leaf area under drought stress in a wheat RIL population

A population of 206 recombinant inbred lines (RILs F9–F10) derived from wheat cross WL711/C306 was phenotyped for morpho-physiological traits such as flag leaf area (FLA), flag leaf length (FLL), flag leaf width (FLW), and cell membrane stability (CMS) under water deficit stress (WDS) environment. High yielding cultivar, WL711 had higher FLA than the medium yielding cultivar C306 across trials under both environments. Parent cultivar C306 maintained membrane integrity while WL711 showed higher membrane damage under WDS. The RIL population showed considerable variation, normal distribution and transgressive segregation for FLA, FLL, FLW and CMS under WDS. The genetic linkage map of WL711/C306 RIL population was constructed comprising of 346 markers. The total map distance was 4526.8 cM with an averaged interval of 12.9 cM between adjacent markers. Major consistent QTL for FLA, FLL, FLW, and CMS were identified on chromosomes 2DS and 3BS respectively in the WL711/C306 RIL population under WDS. The major QTL for FLA, qFLAWD.2D.1 which expressed in multiple environments and for CMS, qCMSWD.3B.3 and qCMSWD.3B.4, accounted for a large proportion of phenotypic variance (PV) with positive allele being contributed by C306, a drought resistant (DR) parent. QTL qFLAWD.2D.1 for FLA co-located with QTL for grain number (GN) and days to flowering (DTF) while QTL qCMSWD.3B.3 and qCMS.3B.4 co-located with QTL for grain yield and its components, days to flowering, canopy temperature and coleoptiles length as reported in our previous publications on the WL711/C306 population (Shukla et al. in Euphytica 203:449–467, 2015; Singh et al. in J Plant Biochem Biotechnol 24:324–330, 2015). Two candidate genes Ghd7 for grain yield and heading date and OsCDK4 for calcium dependent protein kinases were identified in the 2DS and 3BS QTL regions respectively on comparison with gene content of rice chromosomes 7 and 1 respectively. Hence, QTLs qFLAWD.2D.1 and qCMSWD.3B.3 are potential target regions for fine mapping and marker assisted selection for FLA and CMS respectively in wheat under water deficit environments.

Wheat grain number and yield: The relative importance of physiological traits and source-sink balance in southern Australia

Grain number (GN) is determined by spike growth rate (SGR), fruiting efficiency (FE) and the duration of spike growth period (Ds). However, these three traits are not independent of each other and therefore quantifying their relative contribution to GN is important for improving yield potential. This study aimed to model GN as a function of SGR, FE and Ds in bread wheat and investigate the relative importance of these three traits in determining GN. A large number of commercial varieties, elite wheat breeding lines, and a Multiparent Advanced Generation InterCross population were evaluated for GN, SGR, Ds, and FE in six Australian environments in 2014 and 2015. The model explained 43–98% of the variation in GN in individual environments and 88% of the variation in GN across the six environments. The percentage of GN variance explained by the model was significantly higher than those explained by correlating GN to individual traits. The relative importance of the contribution of the three traits to GN was different and ranked as SGR > FE > Ds. The negative correlation between FE and spike dry weight at anthesis (SDWa) appears to be spurious, suggesting that there was no causality between high FE and low SDWa and vice versa. Thus, FE can be used as an independent trait to increase GN in addition to SGR and Ds. We also investigated if the wheat crop had enough source to fill the increased sink size in the southern Australian high rainfall environment. The source-sink balance analysis indicates that the available source, consisting of concurrent photosynthetic assimilate and stored water-soluble carbohydrate at anthesis, was sufficient to fill the established sink but no surplus assimilates were available to fill a larger sink in southwestern Australia. However, the opportunity to increase yield potential by further increasing grain number might exist in south-eastern Australia environments.

Effect of micronutrient foliar application on morphology, yield and iron and zinc grain concentration of durum wheat genotypes

Durum wheat has a comparative adaptive advantage over bread wheat under hot and dry conditions. Accordingly, it feeds millions of people in the Middle East and North Africa. Under these conditions, the deficiency of nutrients, including micronutrients, is a major concern for many reasons, including calcareous soil under drought stress conditions. Therefore, growth, yield, iron (Fe) and zinc (Zn) concentration in durum wheat cultivar grains were investigated. A factorial experiment based on a randomized complete block design with three replications was conducted in the Dryland Agricultural Research Institute (DARI) - Moghan. The first factor comprised spraying at four levels, including the control and foliar spraying with Fe, Zn, and Fe+Zn and the second factor consisted of genotypes at four levels: Dehdasht (G1), Seymareh (G2), and two new genotypes (G3 and G4). Solutions of Fe and Zn fertilizers were sprayed at the tillering, early ear emergence, and milk stages, with a ratio of 2 and 1.5 g fertilizer/1000 ml solution (W/V), respectively. The results showed that genotypes G1, G3 and G4 produced higher grain yield per square meter than G2. This increase was due to the higher weight of 1000 grains in G3 and G4 genotypes and 1000-grain weight with a higher grain number in G1. G1 and G2 had greater spike length, number of grains per spike and spikelet than G3 and G4 genotypes. In all studied traits, except Fe and Zn concentration, the combination of Fe+Zn showed the highest and control had the lowest performance. Also, the application of Zn was superior to Fe. The highest Fe concentration of G1, G2, G3, and G4 was observed at Fe+Zn, control, Zn, and Fe levels, respectively. The highest Zn concentrations were observed in the G3 genotype when only Zn was used or in combination with Fe. According to the results, the Fe and Zn spray application increased durum wheat yield on Fe and Zn deficient soil.

Fruiting efficiency differences between cereal species

Grain number (GN) is critical for yield determination, and understanding its physiology may be instrumental to further improving yield. Studying similarities and differences in yield physiology among cereals may highlight physiological traits that might become critical for understanding some constitutive differences between them. Recently it has been proposed that fruiting efficiency (FE, grains set per unit of inflorescence dry weight at anthesis IDWa) would be a relevant trait to further increase GN. In this research we report for the first time a comparison of GN determination due to IDWa and/or FE between five winter cereals crops (wheat, rye, barley, oats and triticale), analysing likely physiological bases for them and possible trade-offs. First, we performed a literature search and found a small number of papers on FE, mostly in wheat with limited data available for barley and triticale and nothing on oats and rye. Then, we conducted four experiments in which treatments consisted of the five small-grained cereal crops; in two of the experiments genotypes were combined with two levels of soil nitrogen availability. In triticale and barley the relationships between GN and either IDWa or FE were not significant implying that in these two cereals the environmental conditions affected in some cases one, while in other cases the other, physiological determinant of grain number. In wheat and rye, however, the relationships were clearer (and more significant) with FE than with SDWa, while for oats it was the other way around. Triticale and wheat showed the lowest FE values, rye exhibited the highest, and barley and oats were intermediate. When compared across cereals, FE was negatively related to the average spike- or panicle-DWa, indicating a trade-off in interspecific determination of GN. No relationship was found between FE and grain set percentage: differences in FE were mainly due to variation in the efficiency of setting fertile florets during pre-flowering inflorescence growth. The results also evidenced that this efficiency for setting fertile florets was related to the proportion of inflorescence resources partitioned to the growth of floret primordia. We observed no trade-off between FE and grain weight within each of the species, but an overall negative relationship when comparing across cereals (the latter likely explaining constitutive differences in grain weight among species). Therefore, it seemed that manipulations of FE within each of the species would not necessarily bring about compensations through reductions in grain weight and that to further increase fruiting efficiency cereal breeders may benefit from identifying prospect parents with an allocation of resources away from structural parts of the spikelets in favour of survival of labile florets.

Improvement in Brazilian wheat breeding: changes in developmental phases and ecophysiological traits

Understanding the processes responsible for genetic progress in grain yield and relating them to the growth and developmental phases of the wheat plant are essential for improving yield potential. This study aimed to evaluate the duration of developmental phases and eco-physiological traits associated to grain yield in Brazilian wheat cultivars released in different decades. Wheat cultivars released from 1940 to 2009 were evaluated during 2010 and 2011 in Pato Branco, Parana, Brazil. The length of the following periods was compared: sowing-emergence (SW-EM), emergence-double ridge (EM-DR), double ridge-terminal spikelet (DR-TS), terminal spikelet-anthesis (TS-ANT), anthesis-physiological maturity (ANT-PM), sowing-anthesis (SW-ANT) and sowing-physiological maturity (SW-PM). Yield components were also measured. Breeding has reduced the days until anthesis by 14.2%, while it has extended the grain-filling period by 7.6%, compared to the first cultivars released in the country, thereby contributing to a significant increase in 1000-grain weight (12.4 and 9.0% in 2010 and 2011, respectively). The TS-ANT phase was the only phase prior to anthesis exhibiting an extension from old to modern cultivars; this phase increased 1.56 °Cd syear−1. Spike fertility index (SFI) showed increases of 37.8 and 23.8% in 2010 and 2011, respectively. Shortening of the time to flowering, shifting of critical phases of wheat development to better environmental conditions (i.e., TS-ANT phase), and selection for shorter cultivars have been directly responsible for the increase in spike dry weight at anthesis (SDWa) and SFI [i.e., grain number (GN)].

Correction to: Genetic analysis of multi-environmental spring wheat trials identifies genomic regions for locus-specific trade-offs for grain weight and grain number.

Unfortunately, the Fig.1 of this original article was incorrectly published. The corrected Fig.1 is given below.

Genome scan identifies flowering-independent effects of barley HsDry2.2 locus on yield traits under water deficit.

Increasing crop productivity under conditions of climate change requires the identification, selection, and utilization of novel alleles for breeding. In this study, we analysed the genotype and field phenotype of the barley HEB-25 multi-parent mapping population under well-watered and water-limited environments for two years. A genome-wide association study (GWAS) for genotype × environment interactions was performed for 10 traits including flowering time (heading time, HEA) and plant grain yield (PGY). Comparison of the GWAS for traits per se (i.e. regardless of the environment) with a study for quantitative trait loci (QTLs) × environment interactions (Q×E), indicates the prevalence of Q×E mostly for reproductive traits. One Q×E locus on chromosome 2, Hordeum spontaneum Dry2.2 (HsDry2.2), showed a positive and conditional effect on PGY and grain number (GN). The wild allele significantly reduced HEA; however, this earliness was not conditioned by water deficit. Furthermore, BC2F1 lines segregating for the HsDry2.2 locus showed that the wild allele conferred an advantage over the cultivated allele in PGY, GN, and harvest index, as well as modified shoot morphology, a longer grain-filling period, and reduced senescence (only under drought). This suggests the presence of an adaptation mechanism against water deficit rather than an escape mechanism. The study highlights the value of evaluating wild relatives in search of novel alleles and provides clues to resilience mechanisms underlying crop adaptations to abiotic stress.

Variability, correlation, path analysis and stepwise regression for yield components of different wheat genotypes

In order to evaluate the variability and relationship between different wheat yield components, a randomized complete block design experiment with ten genotypes of wheat had been carried out during three growing seasons (2010-2012). The number of spikelet per spike and grain weight per spike had low genotypic and phenotypic variability, while plant height had the highest one. High heritability was observed for plant height (h2=93.1%), spike length (h2=92.3%) and spike density (h2=92.9%). The low heritability was found for grain weight per spike (h2=35.6%). Grain weight per spike was in significant positive genotypic and phenotypic correlation with all the traits (plant height, spike height, number of spikelet per spike, number of grain per spike and spike weight) except spike density. The spike weight had the highest phenotypic (rp=0.988), while number of spikelet per spike had the highest genotypic correlation with grain weight per spike (rg=0.981). Path coefficient analysis revealed that all the traits had highly significant direct effect on grain weight per spike, except spike length. The stepwise regression revealed that 87.1% of the grain weight per spike variation was explained by model which excludes spike length. Spike weight and plant height had the highest shared and unique contribution to grain weight per spike.

Genetic analysis of multi-environmental spring wheat trials identifies genomic regions for locus-specific trade-offs for grain weight and grain number.

GWAS on multi-environment data identified genomic regions associated with trade-offs for grain weight and grain number. Grain yield (GY) can be dissected into its components thousand grain weight (TGW) and grain number (GN), but little has been achieved in assessing the trade-off between them in spring wheat. In the present study, the Wheat Association Mapping Initiative (WAMI) panel of 287 elite spring bread wheat lines was phenotyped for GY, GN, and TGW in ten environments across different wheat growing regions in Mexico, South Asia, and North Africa. The panel genotyped with the 90K Illumina Infinitum SNP array resulted in 26,814 SNPs for genome-wide association study (GWAS). Statistical analysis of the multi-environmental data for GY, GN, and TGW observed repeatability estimates of 0.76, 0.62, and 0.95, respectively. GWAS on BLUPs of combined environment analysis identified 38 loci associated with the traits. Among them four loci-6A (85cM), 5A (98cM), 3B (99cM), and 2B (96cM)-were associated with multiple traits. The study identified two loci that showed positive association between GY and TGW, with allelic substitution effects of 4% (GY) and 1.7% (TGW) for 6A locus and 0.2% (GY) and 7.2% (TGW) for 2B locus. The locus in chromosome 6A (79-85cM) harbored a gene TaGW2-6A. We also identified that a combination of markers associated with GY, TGW, and GN together explained higher variation for GY (32%), than the markers associated with GY alone (27%). The marker-trait associations from the present study can be used for marker-assisted selection (MAS) and to discover the underlying genes for these traits in spring wheat.

Trade-off between grain weight and grain number in wheat depends on GxE interaction: A case study of an elite CIMMYT panel (CIMCOG)

Abstract Identifying the functionally linked mechanisms of grain yield (GY) and its components —i.e. grain number (GN) and grain weight (GW) is necessary for boosting GY potential of wheat. The objectives of the current study were to: (i) analyze the trade-off between GW and GN in 27 elite wheat genotypes grown in two contrasting locations with different yield potential, (ii) assess its causes, and (iii) gain a better understanding of the physiology behind the trade-off between GW and GN. A set of 27 elite wheat genotypes was evaluated during three years in Ciudad Obregon, Mexico (CO), and two years in Valdivia, Chile (Val). GY was higher in Val than CO (783 g m −2 and 665 g m −2 , respectively) and positively associated with above-ground biomass (BM) in both locations. In CO, 15,850 grains m −2 were recorded and 15,197 grains m −2 in Val, while thousand-grain weight (TGW) was higher (P y13 and 6.5% and 9.6% in Val y14 , respectively. In conclusion, the lack of association between GY and GN found in CO was due to the trade-off between the two main yield components (GW and GN), which was mainly explained by higher average temperature and lower photothermal quotient during grain filling recorded in this location than in Val. These results highlight the need to employ different strategies aimed at increasing yield potential depending on the environment. The increase of grain number could be proposed for environments with favorable growing conditions as in Val. On the contrary, increasing GW would be the objective in environments with little chance of taking advantage of increased GN such as CO.

Does the pre-flowering period determine the potential grain weight of sunflower?

Grain weight (GW) is an important component of grain yield and quality of sunflower and the improvement of this trait has been proposed as an aim for breeding of this crop. There is strong evidence suggesting the pre-flowering period as key to determining GW in different crops; however, the key traits and mechanisms controlling GW during this phase are still largely unknown in sunflower. This study conducted a detailed survey of how the pre-flowering period determines grain growth dynamics by assessing the early developmental process during the growth of reproductive organs and the sensitivity of GW, grain number (GN) and grain oil concentration to different source–sink manipulations immediately before flowering. Two experiments were carried out under field conditions in two growing seasons. In Exp. 1 two sunflower oilseed hybrids contrasting in GW (Alybro and SG) were sown at the Experimental Station of the Universidad Austral de Chile in Valdivia (39°47′S, 73°14′W), Chile. In Exp. 2, the same hybrids plus a confectionery genotype (RHA) were evaluated in the Experimental Station where two source–sink treatments were performed: a control (without manipulation) and a shading treatment starting 16days previous to anthesis, i.e. during the R2-R5 period. Crop development, average and individual GW, GN and oil concentration of grains were assessed at harvest. Also, flower and grain traits and their dynamics were measured from early reproductive stage (ovary at R3) to harvest in different grain positions from the capitulum (e.g., fresh and dry weight and dimensions of grains, pericarp and embryo and grain oil concentration). GW was significantly affected by genotype and shading treatments imposed at pre-anthesis, but no statistical effect of the lower source–sink ratio was found on GN. Contrary to GW, grain oil of oilseed genotypes was highly conservative under the source–sink reduction in our study. Positive associations were found between final GW and: ovary weight at R3, at anthesis (R5), ovary growth rate, grain dimensions and water content. Final GW also showed a linear association with ovary growth rate. This study is the first to evaluate the ovary weight from the early development stage and the ovary growth rate during the pre-anthesis period in sunflower and the effect of source reduction at pre-anthesis on grain oil concentration, supporting the importance of the maternal tissues on the setting of potential and actual GW in sunflower.

Application of photochemical parameters and several indices based on phenotypical traits to assess intraspecific variation of oat (Avena sativa L.) tolerance to drought

Functionality of the photosynthetic system under water stress is of major importance in drought tolerance. Oat (Avena sativa L.) doubled haploid (DH) lines obtained by pollination of F1 oat crosses with maize were used to assess the differences in plant genotypic response to soil drought. The investigations were based on the measurements of gas exchange and chlorophyll a fluorescence kinetics. Drought was applied to 17-day-old seedlings by withholding water for 14 days and subsequent plant recovery. Non-stressed optimally watered plants served as controls. Yield components were determined when plants reached full maturity. It was shown differences among the oat lines with respect to drought stress susceptibility (SI) and stress tolerance index mean productivity and drought susceptibility index. Sensitivity to drought of individual DH lines was significantly different, as demonstrated by the correlation between drought susceptibility index and yield components, such as dry weight (GW) or grain number (GN) of the harvested plants. GW and GN were lower in drought-sensitive genotypes exposed to drought stress compared to those resistant to drought. The principal component analysis allow to separate three groups of lines differing in their sensitivity to drought stress and indicated that tolerance to drought in oat has a common genetic background.

QTL analysis and dissection of panicle components in rice using advanced backcross populations derived from Oryza Sativa cultivars HR1128 and 'Nipponbare'.

Panicle traits are among the most important agronomic characters which directly relate to yield in rice. Grain number (GN), panicle length (PL), primary branch number (PBN), and secondary branch number (SBN) are the major components of rice panicle structure, and are all controlled by quantitative trait loci (QTLs). In our research, four advanced backcross overlapping populations (BIL152, BIL196a, BIL196b, and BIL196b-156) carrying introgressed segments from chromosome 6 were derived from an indica/japonica cross that used the super-hybrid rice restorer line HR1128 and the international sequenced japonica cultivar ‘Nipponbare’ as the donor and recurrent parents, respectively. The four panicle traits, GN, PL, PBN, and SBN, were evaluated for QTL effects using the inclusive composite interval mapping (ICIM) method in populations over two years at two sites. Results showed that a total of twelve QTLs for GN, PL, PBN, and SBN were detected on chromosome 6. Based on marker loci physical positions, the QTLs were found to be tightly linked to three important chromosomal intervals described as RM7213 to RM19962, RM20000 to RM20210, and RM412 to RM20595. Three QTLs identified in this study, PL6-5, PBN6-1, and PBN6-2, were found to be novel compared with previous studies. A major QTL (PL6-5) for panicle length was detected in all four populations at two locations, and its position was narrowed down to a 1.3Mb region on chromosome 6. Near isogenic lines (NILs) carrying PL6-5 will be developed for fine mapping of the QTL, and our results will provide referable information for gene excavation of panicle components in rice.

Effect of water stress and plant density on canopy temperature, yield components and protein concentration of red bean (Phaseolus vulgaris L. cv. Akhtar)

In order to study the effects of different irrigation regimes and plant density on yieldcomponent and protein concentration and crop water stress index (CWSI), under research fieldconditions a split plot arrangement was conducted in completely randomized block designduring two years. The first factor of variables was the effects of 4 irrigation levels 120% (I1),100% (I2), 80% (I3) and 60% (I4) of Standard evapotranspiration and the second factor was thespacing of 5 cm (D1), 10 cm (D2) and 15 cm (D3) between plants within a row. Results indicatethat the number of pods in each plant and the grains in each pod decreased when densityincreased, but the hundred-grains-weight and the height of bean plants increased. Whenirrigation increased, various increases were observed in the yield, the number of pods in eachplant, the grains in each pod, the hundred-grains-weight and the height of bean plants, but thegrain protein decreased. Protein concentration increased with more severe water deficit in thesoil. The protein concentration directly correlated with total irrigation water during the growingseason (TI) and the exponential equation P=33* e -4E-04TI can be used for protein concentrationprediction. The effect of the irrigation water was significant and CWSI increased with increasedsoil water deficit. The effect of the density for CWSI was not significant. Grain yield (GY)directly correlated with CWSI and the exponential equation, GY=696.2(CWSI)-0.51 can be usedfor the prediction of grain yield. The CWSI value is useful for evaluating crop water stress inbeans and thus it could be useful in timing the irrigation. Results of this research indicate thatyield components such as height of bean plant, the number of pods in each plant and the numberof grains in each pod were significantly different by applying the different irrigation strategies atthe three different lengths of plant spacing within a row.

Genomic Prediction with Pedigree and Genotype × Environment Interaction in Spring Wheat Grown in South and West Asia, North Africa, and Mexico.

Developing genomic selection (GS) models is an important step in applying GS to accelerate the rate of genetic gain in grain yield in plant breeding. In this study, seven genomic prediction models under two cross-validation (CV) scenarios were tested on 287 advanced elite spring wheat lines phenotyped for grain yield (GY), thousand-grain weight (GW), grain number (GN), and thermal time for flowering (TTF) in 18 international environments (year-location combinations) in major wheat-producing countries in 2010 and 2011. Prediction models with genomic and pedigree information included main effects and interaction with environments. Two random CV schemes were applied to predict a subset of lines that were not observed in any of the 18 environments (CV1), and a subset of lines that were not observed in a set of the environments, but were observed in other environments (CV2). Genomic prediction models, including genotype × environment (G×E) interaction, had the highest average prediction ability under the CV1 scenario for GY (0.31), GN (0.32), GW (0.45), and TTF (0.27). For CV2, the average prediction ability of the model including the interaction terms was generally high for GY (0.38), GN (0.43), GW (0.63), and TTF (0.53). Wheat lines in site-year combinations in Mexico and India had relatively high prediction ability for GY and GW. Results indicated that prediction ability of lines not observed in certain environments could be relatively high for genomic selection when predicting G×E interaction in multi-environment trials.

Strategies for yield determination of bread wheat and two-row barley growing under different environments: A comparative study

Grain yield variations in bread wheat and two-row barley are better explained by changes in grain number (GN) than mean grain weight. However, the strategies for building GN are different in both species because in two-row barley the variations in GN are more frequently related to the number of spikes m−2, due to its higher tillering capacity than wheat, whereas in bread wheat both grain number spike−1 and the number of spikes m−2 contribute to the establishment of GN. The higher tillering capacity and leaf area index at the beginning of the crop cycle in two-row barley allows a higher radiation accumulation than in bread wheat. We hypothesize that the higher early vigor of two-row barley, associated with its greater leaf area exposure relative to wheat, represents an initial advantage that is capitalized at the end of the cycle as higher biomass accumulation driven by a larger GN and consequently higher grain yield. The main objective of this work was to compare different physiological traits of bread wheat and two-row barley growing together under different temperature and radiation conditions. We evaluated two genotypes of each species, with similar phenology, growing under four different environments without water or nutritional deficiencies. Numerical yield components, biomass, radiation interception and harvest index were measured. Despite no differences being observed between genotypes of bread wheat and two-row barley in terms of total grain yield and total grain number when exposed to different environments, each species had a different strategy for establishing the final yield. Although two-row barley showed initial advantages in radiation interception, bread wheat genotypes accumulated more intercepted photosynthetic active radiation (iPAR) and used it in a more efficient way than two-row barley, thus allowing a higher biomass accumulation. Both species showed a reduction in grain weight due to increases in mean night and high temperatures. Grain weight reductions were higher in bread wheat than in two-row barley, and were directly associated with shortening of the duration of grain filling without consequences for the grain-filling rate. This suggested a direct effect of temperature on grain development rather than a growth limitation due to a lack of source.

N:P:S stoichiometry in grains and physiological attributes associated with grain yield in maize as affected by phosphorus and sulfur nutrition

Balanced nutrition is necessary to reduce yield gaps in maize. Simultaneous phosphorus (P) and sulfur (S) deficiencies may be present in soils, so a P×S interaction is expected. In maize, yield is closely related to grain number (GN); thus, nutrient deficiencies impacting crop growth during GN formation can consequently impact yields. Grain nutrient concentration may reflect soil supplying capacity, and nutrient stoichiometry in grains can be used as an indirect indicator of nutrient deficiency for a retrospective diagnosis of sites responsive to P or S fertilization. The objectives of this study were to: i) determine maize response to increasing S fertilizer rates and to P addition; ii) analyze the effects of P, S, and their interaction on mechanisms involved in yield determination of maize; and iii) evaluate the effects of P and S shortage on stoichiometric relationships among N, P, and S content in maize grains. Two fertilization experiments were conducted on-farming conditions in 19 sites-year (SY) for analyzing grain yield response to increasing S fertilizer rates (E1), and studying the interaction between P and S fertilization on grain yield and physiological attributes associated with grain yield determination (E2), i.e. CGRCP, IPARCP, RUECP and biomass at R6. Also N (%N), S (%S) and P (%P) concentration in grains were determined. Stoichiometric relationships among N, P and S in both P or S fertilized and unfertilized treatments in all SY were analyzed. Average grain yield response due to S and P addition was ca. 13 and 20%, respectively. Grain yield increased up to S fertilizer rates around 10kgSha−1. P addition increased CGRCP by 15–60% in 8 SY while S addition 12–16% in 2 SY. Both, RUECP and IPARCP were positively associated with biomass production. P fertilization increased IPARCP by 4%, but no S effect was observed. Before silking, P addition boosted cumulated radiation by 7%, but after silking no P or S effects were observed. A significant P×S interaction was observed for RUECP, since S fertilization increased RUECP by 14% only when P was not added. Independently of P or S shortage, grain N content scaled almost isometrically with grain S content, while N:P and P:S showed allometric relationships. Phosphorus deficiency did not modify N:S, N:P nor P:S stoichiometry. Likewise, S addition did not modify the N:P or N:S stoichiometry. A significant change in the intercept of the P:S relationship was observed in response to fertilization and may be used as a tool for identifying S responsive sites using grain nutrient analysis.

Analysis of variability, heritability, and interrelationships among grain yield and related characters in barley advanced lines

The main goal of this study was to improve pure lines for low input agricultural areas of the semi-arid region of Iran and similar environmental conditions. Forty barley pure lines provided from ICARDA along with three check cultivars were evaluated under rain-fed conditions in a semi-arid region of Iran during two years (2011-2013). The experiments were conducted in a randomized complete block design with four replications to estimate genetic variation and heritability for agro-morphological traits. The highest values of phenotypic and genotypic coefficients of variation were observed for the number of grains per spike followed by peduncle length, early vigor and grain yield. The broad heritability estimates ranged from 24% for grain yield to 96% for the number of grains per spike. The highest and lowest expected genetic advance, observed for days to physiological maturity and the number of grains per spike, respectively. Results of stepwise regression and path analysis showed that hectoliter grain weight and thousand grain weight exhibited the highest direct effects on grain yield, respectively. Comparisons between the pure lines and check cultivars indicated that out of 40 pure lines, 27 lines had a higher grain yield. Also, the pure lines No. 29, 13, 9 and 33 were identified as the superior lines for semi-arid environmental conditions. Our results indicate that check cultivars could be improved by selecting for pure lines with taller peduncle and the number of grains per spike, but with heavier grains. Therefore, these lines can be used as genetic material to broaden the genetic basis of barley breeding programs all over the world.