Number Of Fertile Spikelets Research Articles

A rare natural variation in TaFT-D2 underlies QTss.cas-3D associated with increased total spikelet number per spike in wheat

Total spikelet number per spike (TSS) is a crucial yield component in wheat. Dissecting and characterizing major stable quantitative trait loci (QTL) associated with TSS can significantly enhance the genetic improvement of yield potential. In a previous study, we identified a stable major QTL for TSS, named QTss.cas-3D. In the present study, we conducted fine mapping of QTss.cas-3D, interval to approximately 6.35 Mb, ranging from 105.03 to 111.38 Mb, based on the IWGSC RefSeq v2.1. Through genome re-sequencing and gene function annotation, we identified TraesCS3D03G0308000 (TaFT-D2) as the candidate gene. Phenotypic evaluation with paired near-isogenic lines revealed that this locus predominantly increases kernel number per spike by enhancing TSS and fertile spikelet number per spike, without significantly affecting thousand-kernel weight or tiller number. The presence of the TaFT-D2 allele in the parent P3228, which is rare in nature populations, highlights its potential value. This study provides a valuable gene resource and functional marker for wheat molecular breeding aimed at improving TSS and establishes a foundation for gene functional analysis of TaFT-D2.

Systematic identification of wheat spike developmental regulators by integrated multi-omics, transcriptional network, GWAS, and genetic analyses

The spike architecture of wheat plays a crucial role in determining grain number, making it a key trait for optimization in wheat breeding programs. In this study, we used a multi-omic approach to analyze the transcriptome and epigenome profiles of the young spike at eight developmental stages, revealing coordinated changes in chromatin accessibility and H3K27me3 abundance during the flowering transition. We constructed a core transcriptional regulatory network (TRN) that drives wheat spike formation and experimentally validated a multi-layer regulatory module involving TaSPL15, TaAGLG1, and TaFUL2. By integrating the TRN with genome-wide association studies, we identified 227 transcription factors, including 42 with known functions and 185 with unknown functions. Further investigation of 61 novel transcription factors using multiple homozygous mutant lines revealed 36 transcription factors that regulate spike architecture or flowering time, such as TaMYC2-A1, TaMYB30-A1, and TaWRKY37-A1. Of particular interest, TaMYB30-A1, downstream of and repressed by WFZP, was found to regulate fertile spikelet number. Notably, the excellent haplotype of TaMYB30-A1, which contains a C allele at the WFZP binding site, was enriched during wheat breeding improvement in China, leading to improved agronomic traits. Finally, we constructed a free and open access Wheat Spike Multi-Omic Database (http://39.98.48.156:8800/#/). Our study identifies novel and high-confidence regulators and offers an effective strategy for dissecting the genetic basis of wheat spike development, with practical value for wheat breeding.

Genetic dissection of major QTL for grain number per spike on chromosomes 5A and 6A in bread wheat (Triticum aestivum L.).

Grain number per spike (GNS) is a crucial component of grain yield and plays a significant role in improving wheat yield. To identify quantitative trait loci (QTL) associated with GNS, a recombinant inbred line (RIL) population derived from the cross of Zhongkemai 13F10 and Chuanmai 42 was employed to conduct QTL mapping across eight environments. Based on the bulked segregant exome sequencing (BSE-Seq), genomic regions associated with GNS were detected on chromosomes 5A and 6A. According to the constructed genetic maps, two major QTL QGns.cib-5A (LOD = 4.35-8.16, PVE = 8.46-14.43%) and QGns.cib-6A (LOD = 3.82-30.80, PVE = 5.44-12.38%) were detected in five and four environments, respectively. QGns.cib-6A is a QTL cluster for other seven yield-related traits. QGns.cib-5A and QGns.cib-6A were further validated using linked Kompetitive Allele Specific PCR (KASP) markers in different genetic backgrounds. QGns.cib-5A exhibited pleiotropic effects on productive tiller number (PTN), spike length (SL), fertile spikelet number per spike (FSN), and ratio of grain length to grain width (GL/GW) but did not significantly affect thousand grain weight (TGW). Haplotype analysis revealed that QGns.cib-5A and QGns.cib-6A were the targets of artificial selection during wheat improvement. Candidate genes for QGns.cib-5A and QGns.cib-6A were predicted by analyzing gene annotation, spatiotemporal expression patterns, and orthologous and sequence differences. These findings will be valuable for fine mapping and map-based cloning of genes underlying QGns.cib-5A and QGns.cib-6A.

The wheat sucrose synthase gene TaSus1 is a determinant of grain number per spike

Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight (TGW) in wheat (Triticum aestivum L.). However, no mutations have been identified within the gene to test this association. The effects of TaSus1 on grain number per spike (GNS) also are largely unknown. Our previous genome-wide association study identified TaSus-A1 as a candidate gene controlling fertile spikelet number per spike (FSN). In the present study, we generated two independent mutants for the three TaSus1 homoeologs by CRISPR/Cas9-mediated genome editing. The triple mutants displayed lower FSN, GNS, grain number per spikelet (GNST), and TGW than wild-type plants. In 306 hexaploid wheat accessions, two single-nucleotide polymorphisms in TaSus-A1 contributed differently to GNS. Introgression of the two alleles into a wheat genetic background confirmed their effects. The alleles differed in geographical distribution among the accessions.

Bioaccumulation and Translocation of Heavy Metals in Paddy (Oryza sativa L.) and Soil in Different Land Use Practices

Rice tends to accumulate heavy metals present in soil that have been introduced by human activities and pass them up the food chain. The present study aimed to evaluate the accumulation of selected trace elements (Cu, Zn, and Pb) in paddy and soil and the transfer of these metals from soil to rice by analysing the bioconcentration factor (BCF), bioaccumulation factor (BAF), and translocation factor (TF) of heavy metals in paddy (Oryza sativa L.) and soil. Samples of matured paddy and the substrates were collected from three different areas located near a rural point (RP), a transportation point (TP), and an industrial point (IP). Heavy metal concentrations present in the soil and various parts of the plants were ascertained using an atomic absorption spectrophotometer (AAS). Cu, Zn, and Pb accumulation in the soil were detected in increasing orders of RP > TP > IP, IP > TP > RP, and IP > RP > TP, respectively. The BCFshoot, BAF, and transfer factor of both Zn and Pb from soil to rice were detected in the order of TP > IP > RP, which was different from Cu, where BCFshoot and TF showed the order of RP > IP > TP but the BAF indicated IP > RP > TP. TF > 1 was discovered for Zn and Pb at the TP, and for Cu at the RP, which could be attributed to the TP’s strongly acidic soil and Cu’s abundance in the RP’s soil. Paddy height and yield traits were the most significant at the IP site, showing the highest number of fertile spikelets, the average weight of a 1000-paddy spikelet, and the harvest index (0.56). These findings can be related to the normal range of Zn and Pb found in rice plants that support growth. Thus, the findings of this study demonstrated that soil properties and metal abundance in soil from certain land use practices can partially influence the mobility and transfer of metals through soil–plant pathways.

Night warming increases wheat yield by improving pre-anthesis plant growth and post-anthesis grain starch biosynthesis

Global climate change is characterized by asymmetric warming, i.e., greater temperature increases in winter, spring, and nighttime than in summer, autumn, and daytime. Field experiments were conducted using four wheat cultivars, namely 'Yangmai 18' (YM18), 'Sumai 188' (SM188), 'Yannong 19' (YN19), and 'Annong 0711' (AN0711), in the two growing seasons of 2019–2020 and 2020–2021, with passive night warming during different periods in the early growth stage. The treatments were night warming during the tillering–jointing (NWT–J), jointing–booting (NWJ–B), and booting–anthesis (NWB–A) stages, with ambient temperature (NN) as the control. The effects of night warming during different stages on wheat yield formation were investigated by determining the characteristics of dry matter accumulation and translocation, as well as sucrose and starch accumulation in wheat grains. The wheat yields of all four cultivars were significantly higher in NWT–J than in NN in the 2-year experiment. The yield increases of semi-winter cultivars YN19 and AN0711 were greater than those of spring cultivars YM18 and SM188. Treatment NWT–J increased wheat yield mainly by increasing the 1,000-grain weight and the number of fertile spikelets, and it increased dry matter accumulation in various organs of wheat at the anthesis and maturity stages by increasing the growth rate at the vegetative growth stage. The flag leaf and spike showed the largest increases in dry matter accumulation. NWT–J also increased the grain sucrose and starch contents in the early and middle grain-filling stages, promoting yield formation. Overall, night warming between the tillering and jointing stages increased the pre-anthesis growth rate, and thus, wheat dry matter production, which contributed to an increase in wheat yield.

Identification and validation of two major QTLs for spikelet number per spike in wheat (Triticum aestivum L.).

The total number of spikelets (TSPN) and the number of fertile spikelets (FSPN) affect the final number of grains per spikelet in wheat. This study constructed a high-density genetic map using 55K single nucleotide polymorphism (SNP) arrays from a population of 152 recombinant inbred lines (RIL) from crossing the wheat accessions 10-A and B39. Twenty-four quantitative trait loci (QTLs) for TSPN and 18 QTLs for FSPN were localized based on the phenotype in 10 environments in 2019-2021. Two major QTLs, QTSPN/QFSPN.sicau-2D.4 (34.43-47.43 Mb) and QTSPN/QFSPN.sicau-2D.5(32.97-34.43 Mb), explained 13.97%-45.90% of phenotypic variation. Linked kompetitive allele-specific PCR (KASP) markers further validated these two QTLs and revealed that QTSPN.sicau-2D.4 had less effect on TSPN than QTSPN.sicau-2D.5 in 10-A×BE89 (134 RILs) and 10-A×Chuannong 16 (192 RILs) populations, and one population of Sichuan wheat (233 accessions). The alleles combination haplotype 3 with the allele from 10-A of QTSPN/QFSPN.sicau-2D.5 and the allele from B39 of QTSPN.sicau-2D.4 resulted in the highest number of spikelets. In contrast, the allele from B39 for both loci resulted in the lowest number of spikelets. Using bulk-segregant analysis-exon capture sequencing, six SNP hot spots that included 31 candidate genes were identified in the two QTLs. We identified Ppd-D1a from B39 and Ppd-D1d from 10-A and further analyzed Ppd-D1 variation in wheat. These results identified loci and molecular markers with potential utility for wheat breeding and laid a foundation for further fine mapping and cloning of the two loci.

Climate warming extends the effective growth period of winter wheat and increases grain protein content

Climate warming causes an impact on the protein supplied to grains by affecting the winter wheat growth period and yield formation; however, research on the effects of warming on protein formation of winter wheat grains is limited. We investigated this phenomenon by conducting no-tillage (NT) and conventional tillage (CT) field warming trials in the North China Plain for four consecutive years (2017–2020). The results showed that warming significantly advanced the re-greening period and extended the effective growth period of winter wheat. Warming also improved the physiological characteristics of winter wheat as well as N accumulation in the stems and leaves during anthesis, facilitating the transport of N to the grains. Moreover, warming reduced the number of fertile spikelets in winter wheat and diverted N that would otherwise be supplied to produce more grains to the final effective grains, resulting in a significant increase in grain protein content (15.75% in CT, 19.11% in NT; p < 0.05). Our findings suggest that winter wheat can partially counteract the adverse effects of climate warming on its grain protein content. This study further elucidates the effect of climate warming on the protein content of winter wheat grains.

Principal component and cluster analyses for assessing agro-morphological diversity in rice

Forty-five rice genotypes were evaluated for determining the pattern of variation and relationship among 14 yield contributing traits. Four principal components (PCs) exhibited eigen values &gt;1.0 and explained about 79.5 % of the total phenotypic variability. From rotated component matrix it has been observed that the highest positive eigen vector was taken by secondary branches (0.945), followed by total spikelet number (0.945), fertile spikelet number (0.889), primary branches (0.676) and harvest index (0.632) in PC1, indicating the major effects in the overall variation among the genotypes. Seven groups were formed after cluster analysis. Cluster I had lowest average for days to 50% flowering, Cluster II had highest mean value for harvest index, Cluster III had highest mean for flag leaf area, test weight, and straw and grain yield per plant, and Cluster V had highest mean value for primary branches, total spikelet number, fertile spikelet number and fertility %. So, desirable genotypes fromdifferent cluster can be selected and hybridization programme may be initiated to utilize heterosis in F1 generation and wide spectrum of recombinants in segregating generations for selection of promising segregants.

Identification and validation of quantitative trait loci for fertile spikelet number per spike and grain number per fertile spikelet in bread wheat (Triticum aestivum L.)

A major and stable QTL for fertile spikelet number per spike and grain number per fertile spikelet identified in a 4.96-Mb interval on chromosome 2A was validated in different genetic backgrounds. Fertile spikelet number per spike (FSN) and grain number per fertile spikelet (GNFS) contribute greatly to wheat yield improvement. To detect quantitative trait loci (QTL) associated with FSN and GNFS, we used a recombinant inbred line population crossed by Zhongkemai 13F10 and Chuanmai 42 in eight environments. Two Genomic regions associated with FSN were detected on chromosomes 2A and 6A using bulked segregant exome sequencing analysis. After the genetic linkage maps were constructed, four QTL QFsn.cib-2A, QFsn.cib-6A, QGnfs.cib-2A and QGnfs.cib-6A were identified in three or more environments. Among them, two major QTL QFsn.cib-2A (LOD = 4.67-9.34, PVE = 6.66-13.05%) and QGnfs.cib-2A (LOD = 5.27-11.68, PVE = 7.95-16.71%) were detected in seven and six environments, respectively. They were co-located in the same region, namely QFsn/Gnfs.cib-2A. The developed linked Kompetitive Allele Specific PCR (KASP) markers further validated this QTL in a different genetic background. QFsn/Gnfs.cib-2A showed pleiotropic effects on grain number per spike (GNS) and spike compactness (SC), and had no effect on grain weight. Since QFsn/Gnfs.cib-2A might be a new locus, it and the developed KASP markers can be used in wheat breeding. According to haplotype analysis, QFsn/Gnfs.cib-2A was identified as a target of artificial selection during wheat improvement. Based on haplotype analysis, sequence differences, spatiotemporal expression patterns, and gene annotation, the potential candidate genes for QFsn/Gnfs.cib-2A were predicted. These results provide valuable information for fine mapping and cloning gene(s) underlying QFsn/Gnfs.cib-2A.

Determination of Yield and Yield Characteristics of Some Barley (Hordeum vulgare L.) Genotypes Under Supplemental Irrigation Conditions in Van

This research was carried out to investigate the adaptability abilities of some barley varieties in Van ecological conditions in the winter growing season of 2020-2021. Sixteen genotypes were grown according to randomized block design with three replications. The quantity of supplemental irrigation was equivalent to a total precipitation of 114 mm. According to the results obtained, the number of days to spike was 167.67-175.66 days, plant height 63.37-91.85 cm, number of spikes per square meter 403.67-619.67, lodging 0-10%, chlorophyll ​​​​45.34- 53.09 SPAD units, maturity period 36.0-36.7 days, canopy temperature 30.0-30.4 oC, spike length 7.30-9.96 cm, number of spikelets per spike 33.8-21.7, number of fertile spikelets 7.13-15.73, thousand grain weight 36.67-45.83 g, hectolitre weight 62.30 – 66.10 kg/hl, biological yield ​​20.36-20.45 t/ha, and grain yield 3.08–6.98 t/ha. The highest grain yield was obtained from two row barley varieties; Calabey, Akar, Tosunpasa and Asil. The highest biological yield was measured in Anka-11 and Aydanhanim cultivars.

Yield performance of normal and late sown wheat in response to seed priming and foliar applied nutrients

An investigation was carried out to determine the impact of seed priming i.e. non-primed and primed seed with 2.0% KCl for 12 hr and twice foliar nutrition i.e. no spray, 0.5% ZnSO4, 0.5% CaCl2, 0.5% KNO3, and 2.0% urea on yield execution of normal sown (November 28) and late sown (Late sown) wheat. The results revealed that in both years of study, wheat planted on November 28 produced significantly higher grain yield with a comparable difference in number of spikes per square meter, spike length, number of fertile spikelets per spike, number of grains per spike, and 1000-grain weight. There was 23.0% and 24.0% decrease in grain yield for the late sowing on Late sown when compared with normal sowing on November 28 in first year and second year, respectively. Primed seeds were not significantly impacted in comparison to the non-primed seed. In contrast with no spray, spraying of various nutrients twice at maximum tillering and 80% flowering recorded significant improvement in yield of wheat crop. Highest yields were recorded with a foliar spray of 2.0% urea followed by 0.5% ZnSO4, 0.5% KNO3, and 0.5% CaCl2. The significant interaction between sowing dates and foliar spraying demonstrates that foliar spray of urea at the rate of 2.0% and ZnSO4 at the rate of 0.5% at maximum tillering and 80% flowering stage were financially more reasonable choices for both the planting dates and can increase grain yield.

SSR Linkage Maps and Identification of QTL Controlling Morpho-Phenological Traits in Two Iranian Wheat RIL Populations.

Wheat is one of the essential grains grown in large areas. Identifying the genetic structure of agronomic and morphological traits of wheat can help to discover the genetic mechanisms of grain yield. In order to map the morpho-phenological traits, an experiment was conducted in the two cropping years of 2020 and 2021 on the university farm of the Faculty of Agriculture, GonbadKavous University. This study used two F8 populations, including 120 lines resulting from Gonbad × Zagros and Gonbad × Kuhdasht. The number of days to physiological maturity, number of days to flowering, number of germinated grains, number of tillers, number of tillers per plant, grain filling periods, plant height, peduncle length, spike length, awn length, spike weight, peduncle diameter, flag leaf length and weight, number of spikelets per spike, number of grains per spike, grain length, grain width, 1000-grain weight, biomass, grain yield, harvest index, straw-weight, and number of fertile spikelets per spike were measured. A total of 21 and 13 QTLs were identified for 11 and 13 traits in 2020 and 2021, respectively. In 2020, qGL-3D and qHI-1A were identified for grain length and harvest index on chromosomes 3D and 1A, explaining over 20% phenotypic variation, respectively. qNT-5B, qNTS-2D, and qSL-1D were identified on chromosomes 5B, 2D, and 1D with the LOD scores of 4.5, 4.13, and 3.89 in 2021, respectively.

A Novel Wheat-Rye 2R (2D) Disomic Substitution Line Pyramids Two Types of Resistance to Powdery Mildew.

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is a devastating disease of wheat that seriously affects yield and quality worldwide. Because of the extensive growth of wheat cultivars with homogeneous genetic background, exploring novel resistant resources from wheat relatives has become important for increasing the genetic diversity of wheat. Rye (Secale cereale) is a wheat relative possessing abundant resistance genes because of its high variation. Wheat line AL69, resistant to powdery mildew, was developed by crossing, backcrossing, and self-pollination for multiple generations between hexaploid triticale Zhongsi 237 and common wheat cultivar Zimai 17. Through genomic in situ hybridization (GISH) and multicolor fluorescence in situ hybridization (FISH), nondenaturing FISH, multicolor GISH, and selection with specific molecular markers, AL69 was determined to be a wheat-rye 2R (2D) disomic substitution line. Testing with different B. graminis f. sp. tritici isolates and genetic analysis showed that the all-stage resistance (also called seedling resistance) of AL69 was conferred by the cataloged powdery mildew resistance gene Pm4b derived from Zimai 17, and its adult-plant resistance was derived from the alien chromosome 2R of Zhongsi 237, which was found to be different from the previously reported rye-derived Pm genes, including Pm7 on 2RL. In addition, AL69 showed improved spike number per plant, spike length, fertile spikelet number per spike, kernel number per spike, and grain yield per plant compared with its wheat parent Zimai 17. An elite line S251 combining powdery mildew resistance with excellent agronomic performance was selected from the progenies of AL69 and wheat cultivar Jimai 22. Therefore, AL69 has two types of resistance genes to powdery mildew and improved agronomic traits through pyramiding and thus can be used as a promising genetic stock for wheat breeding.

Analysis of Genetic Regions Related to Field Grain Number per Spike From Chinese Wheat Founder Parent Linfen 5064.

Wheat founder parents have been important in the development of new wheat cultivars. Understanding the effects of specific genome regions on yield-related traits in founder variety derivatives can enable more efficient use of these genetic resources through molecular breeding. In this study, the genetic regions related to field grain number per spike (GNS) from the founder parent Linfen 5064 were analyzed using a doubled haploid (DH) population developed from a cross between Linfen 5064 and Nongda 3338. Quantitative trait loci (QTL) for five spike-related traits over nine experimental locations/years were identified, namely, total spikelet number per spike (TSS), base sterile spikelet number per spike (BSSS), top sterile spikelet number per spike (TSSS), fertile spikelet number per spike (FSS), and GNS. A total of 13 stable QTL explaining 3.91–19.51% of the phenotypic variation were found. The effect of six of these QTL, Qtss.saw-2B.1, Qtss.saw-2B.2, Qtss.saw-3B, Qfss.saw-2B.2, Qbsss.saw-5A.1, and Qgns.saw-1A, were verified by another DH population (Linfen 5064/Jinmai 47), which showed extreme significance (P < 0.05) in more than three environments. No homologs of reported grain number-related from grass species were found in the physical regions of Qtss.saw-2B.1 and Qtss.saw-3B, that indicating both of them are novel QTL, or possess novel-related genes. The positive alleles of Qtss.saw-2B.2 from Linfen 5064 have the larger effect on TSS (3.30%, 0.62) and have 66.89% in Chinese cultivars under long-term artificial selection. This study revealed three key regions for GNS in Linfen 5064 and provides insights into molecular marker-assisted breeding.

Assessment of genetic diversity for yield and quality traits of rice landraces of Telengana by multivariate analyses

The present investigation on ‘Assessment of genetic diversity for yield and quality traits of rice landraces of Telengana by multivariate analyses’, was conducted during the kharif-2021, which characterize 23 rice landraces with 21 yield and quality traits. All the genotypes were significantly different for every trait. The genetic variability studies emulated, high PCV and GCV was absorbed for the traits followed, number of fertile spikelets per panicle, elongation ratio, kernel length breadth ratio, protein content, water uptake ratio, harvest index, number of effective tillers per plant, alkali spread value, biological yield and grain yield per plant. High heritability coupled with high genetic advance was observed on the following characters viz., harvest index, grain breadth, alkali spread value, protein content, number of fertile spikelets per panicle, grain yield per plant, grain length, biological yield, plant height, kernel length breadth ratio, amylose content and thousand grain weight. It explains that there is scope of improvement through selection in these characters. Principal Component Analysis revealed usage of Akshaya ponni, Nagara, Halla batta, Gadakadhiya Mahi, Aashudhee, Ghalima and Kukuda Munde would be rewarding in crop improvement for good yield, likewise, Bhairojlu, Daddigha, Gadakadhiya Mahi, Kaala Jeera, Krishtampeta gold and Kumar Gorla would be rewarding in improvement of quality traits.

Effects of organic and microbiological fertilizers on morphological and productive characteristics of triticale in the organic farming system

The aim of the study was to examine the impact of microbiological and organic fertilizers on morphological and productive characteristics of triticale during a three-year period (2009/10-2011/12). A two-factorial field experiment was arranged using a randomized block design with four replications. The object of the study was the triticale winter cultivar Odisej, and the following treatments were applied: a control variant without fertilization, microbiological fertilizer ?Slavol? (Agrounik Serbia) 5.0 l ha-1, organic fertilizer ?Biohumus Royal offert? (Altamed RS) 3.0 t ha-1 + microbiological fertilizer ?Slavol? (Agrounik Serbia) 5.0 l ha-1. The results showed that the expression of the characteristics was significantly affected by the environment. The lowest values were obtained in the first year when the most unfavourable meteorological conditions were observed. The application of microbiological fertilizer had no impact on the stem length and grain weight per spike, but it significantly increased the number of fertile spikelets (3.7%), spike length (7.7%) and grain yield (18.6%). The combined application of fertilizers provided better results for all the examined characteristics, while in comparison with the control, the differences ranged from 4.3% for the number of fertile spikelets to 46.5% for grain yield. The strongest correlation was determined between the spike length and the number of fertile spikelets (r = 0.939**). The obtained results lead to the conclusion that under variable environmental conditions, the application of fertilizers has a significant impact on morphological and productive characteristics of triticale, and consequently on the stability of this crop production in the organic farming system.

Screening barley varieties tolerant to drought stress based on tolerant indices

With regards to the importance of drought stress and genotype screening under stress conditions, the current study was conducted to evaluate barley varieties in response to drought stress and find the tolerant ones, along with the determination of the influential ratio of each yield component on grain yield under both conditions. Accordingly, 25 barley varieties were evaluated under two water regimes including 100% (normal condition) and 50% (drought stress) of field capacity. Cluster analysis grouped the genotypes into four and three clusters under normal and stressful conditions, respectively, indicating that drought might limit the phenotypic variability among the verities. Based on the feature selection, spike weight, leaf area, and grain number per spike under normal condition, and the number of fertile spikelets and grain number per spike under water deficit conditions were the most influential traits on grain yield which verifies the impact of drought on the relationship among the agronomic traits. The overall results of biplot showed that varieties Danesiah, Eram, and Yoosef, which had higher grain yield than average for both conditions, were suitable varieties in order to be screened for both normal and drought stress conditions. Finally, according to the results of correlation of tolerance indices with grain yield, stress tolerance index (STI), harmonic mean productivity (HMP), and mean productivity (MP) which showed high correlations with grain yield under both conditions can be introduced as proper indices for screening tolerance genotypes of barley.

Silicon nutrition stimulates Salt-Overly Sensitive (SOS) pathway to enhance salinity stress tolerance and yield in rice

In rice (Oryza sativa), Si nutrition is known to improve salinity tolerance; however, limited efforts have been made to elucidate the underlying mechanism. Salt-Overly Sensitive (SOS) pathway contributes to salinity tolerance in plants in a major way which works primarily through Na+ exclusion from the cytosol. SOS1, a vital component of SOS pathway is a Na+/H+ antiporter that maintains ion homeostasis. In this study, we evaluated the effect of overexpression of Oryza sativa SOS1 (OsSOS1) in tobacco (cv. Petit Havana) and rice (cv. IR64) for modulating its response towards salinity further exploring its correlation with Si nutrition. OsSOS1 transgenic tobacco plants showed enhanced tolerance to salinity as evident by its high chlorophyll content and maintaining favorable ion homeostasis under salinity stress. Similarly, transgenic rice overexpressing OsSOS1 also showed improved salinity stress tolerance as shown by higher seed germination percentage, seedling survival and low Na+ accumulation under salinity stress. At their mature stage, compared with the non-transgenic plants, the transgenic rice plants showed better growth and maintained better photosynthetic efficiency with reduced chlorophyll loss under stress. Also, roots of transgenic rice plants showed reduced accumulation of Na+ leading to reduced oxidative damage and cell death under salinity stress which ultimately resulted in improved agronomic traits such as higher number of panicles and fertile spikelets per panicle. Si nutrition was found to improve the growth of salinity stressed OsSOS1 rice by upregulating the expression of Si transporters (Lsi1 and Lsi2) that leads to more uptake and accumulation of Si in the rice shoots. Metabolite profiling showed better stress regulatory machinery in the transgenic rice, since they maintained higher abundance of most of the osmolytes and free amino acids.

Identification of eight QTL controlling multiple yield components in a German multi-parental wheat population, including Rht24, WAPO-A1, WAPO-B1 and genetic loci on chromosomes 5A and 6A

Key messageQuantitative trait locus (QTL) mapping of 15 yield component traits in a German multi-founder population identified eight QTL each controlling ≥2 phenotypes, including the genetic loci Rht24, WAPO-A1 and WAPO-B1.Grain yield in wheat (Triticum aestivum L.) is a polygenic trait representing the culmination of many developmental processes and their interactions with the environment. Toward maintaining genetic gains in yield potential, ‘reductionist approaches’ are commonly undertaken by which the genetic control of yield components, that collectively determine yield, are established. Here we use an eight-founder German multi-parental wheat population to investigate the genetic control and phenotypic trade-offs between 15 yield components. Increased grains per ear was significantly positively correlated with the number of fertile spikelets per ear and negatively correlated with the number of infertile spikelets. However, as increased grain number and fertile spikelet number per ear were significantly negatively correlated with thousand grain weight, sink strength limitations were evident. Genetic mapping identified 34 replicated quantitative trait loci (QTL) at two or more test environments, of which 24 resolved into eight loci each controlling two or more traits—termed here ‘multi-trait QTL’ (MT-QTL). These included MT-QTL associated with previously cloned genes controlling semi-dwarf plant stature, and with the genetic locus Reduced height 24 (Rht24) that further modulates plant height. Additionally, MT-QTL controlling spikelet number traits were located to chromosome 7A encompassing the gene WHEAT ORTHOLOG OF APO1 (WAPO-A1), and to its homoeologous location on chromosome 7B containing WAPO-B1. The genetic loci identified in this study, particularly those that potentially control multiple yield components, provide future opportunities for the targeted investigation of their underlying genes, gene networks and phenotypic trade-offs, in order to underpin further genetic gains in yield.