Reduction In Grain Yield Research Articles

Wheat variety carrying 2NvS chromosomal segment provides yield advantage through lowering terminal heat-induced oxidative stress.

A 2NvS chromosomal segment carrying bread wheat variety, BARI Gom 33 ('BG33'), showed tolerance to terminal heat stress andhigher yield over a heat-tolerant non-2NvS BARI Gom 26 ('BG26') and a heat-susceptible Pavon 76 ('Pavon'). This study aimed to ascertain the potential of the 2NvS 'BG33' in terminal heat-induced oxidative stress tolerance compared to non-2NvS 'BG26' and heat-susceptible 'Pavon' under two heat regimes at the reproductive stages viz. control (optimum sowing time) and heat stress (late sowing). We found that both 'BG26' and 'BG33' showed significantly higher tolerance to oxidative stress by limiting the generation of reactive oxygen species (ROS), methylglyoxal under heat stress. During terminal heat stress, both 'BG33' and 'BG26' exhibited greater cellular homeostasis than heat-susceptible 'Pavon', which was maintained by the increased accumulation of osmolytes, nonenzymatic antioxidants, and enzymes associated with ROS scavenging, ascorbate-glutathione cycle, and glyoxalase system. Lesser cellular damage in 'BG26' and 'BG33' was eventually imitated in a smaller reduction in grain yield (15 and 12%, respectively) than in 'Pavon', which had a 33% reduction owing to heat stress. Collectively, our findings revealed that the chromosomal segment 2NvS provides yield advantage to 'BG33' under terminal heat stress by lowering oxidative damage. As 2NvS translocation contains multiple nucleotide-binding domain leucine-rich repeat containing, cytochrome P450, and other gene families associated with plant stress tolerance, further studies are warranted to dissect the underlying molecular mechanisms associated with higher heat stress tolerance of 2NvS carrying 'BG33'.

Identification of a novel major QTL from Chinese wheat cultivar Ji5265 for Fusarium head blight resistance in greenhouse.

A novel major QTL for FHB resistance was mapped to a 6.8Mb region on chromosome 2D in a Chinese wheat cultivar Ji5265, and diagnostic KASP markers were developed for detecting it in a worldwide wheat collection. Fusarium head blight (FHB) is a serious disease in wheat (Triticum aestivumL.) and causes significant reductions in grain yield and quality worldwide. Breeding for FHB resistance is the most effective strategy to minimize the losses caused by FHB; therefore, identification of major quantitative trait loci (QTLs) conferring FHB resistance and development of diagnostic markers for the QTLs are prerequisites for marker-assisted selection (MAS). Ji5265 is a Chinese wheat cultivar resistant to FHB in multiple environments. An F6 population of 179 recombinant inbred lines (RILs) was developed from Ji5265 × Wheaton. The population was genotyped by genotyping-by-sequencing (GBS) and phenotyped for FHB Type II resistance in greenhouses. A major QTL, designatedas QFhb-2DL, was mapped in a 6.8Mb region between the markers GBS10238 and GBS12056 on the long arm of chromosome 2D in Ji5265 and explained ~ 30% of the phenotypic variation for FHB resistance. The effect of QFhb-2DL on FHB resistance was validated using near-isogenic lines (NILs) derived from residual heterozygotes from an F6 RIL of Ji5265 × Wheaton. The two flanking markers were converted into Kompetitive allele-specific PCR (KASP) markers (KASP10238 and KASP12056) and validated to be diagnostic in a collection of 2,065 wheat accessions. These results indicate that QFhb-2DL is a novel major QTL for resistance to FHB spread within a spike (Type II) and the two KASP markers can be used for MAS to improve wheat FHB resistance in wheat breeding programs.

Impact of Pre-Anthesis Drought Stress on Physiology, Yield-Related Traits, and Drought-Responsive Genes in Green Super Rice.

Optimum soil water availability is vital for maximum yield production in rice which is challenged by increasing spells of drought. The reproductive stage drought is among the main limiting factors leading to the drastic reduction in grain yield. The objective of this study was to investigate the molecular and morphophysiological responses of pre-anthesis stage drought stress in green super rice. The study assessed the performance of 26 rice lines under irrigated and drought conditions. Irrigated treatment was allowed to grow normally, while drought stress was imposed for 30 days at the pre-anthesis stage. Three important physiological traits including pollen fertility percentage (PFP), cell membrane stability (CMS), and normalized difference vegetative index (NDVI) were recorded at anthesis stage during the last week of drought stress. Agronomic traits of economic importance including grain yield were recorded at maturity stage. The analysis of variance demonstrated significant variation among the genotypes for most of the studied traits. Correlation and principal component analyses demonstrated highly significant associations of particular agronomic traits with grain yield, and genetic diversity among genotypes, respectively. Our study demonstrated a higher drought tolerance potential of GSR lines compared with local cultivars, mainly by higher pollen viability, plant biomass, CMS, and harvest index under drought. In addition, the molecular basis of drought tolerance in GSR lines was related to upregulation of certain drought-responsive genes including OsSADRI, OsDSM1, OsDT11, but not the DREB genes. Our study identified novel drought-responsive genes (LOC_Os11g36190, LOC_Os12g04500, LOC_Os12g26290, and LOC_Os02g11960) that could be further characterized using reverse genetics to be utilized in molecular breeding for drought tolerance.

A crucial role for a node-localized transporter, HvSPDT, in loading phosphorus into barley grains.

Grains are the major sink of phosphorus (P) in cereal crops, accounting for 60-85% of total plant P, but the mechanisms underlying P loading into the grains are poorly understood. We functionally characterized a transporter gene required for the distribution of P to the grains in barley (Hordeum vulgare), HvSPDT (SULTR-like phosphorus distribution transporter). HvSPDT encoded a plasma membrane-localized Pi/H+ cotransporter. It was mainly expressed in the nodes at both the vegetative and reproductive stages. Furthermore, its expression was induced by inorganic phosphate (Pi) deficiency. In the nodes, HvSPDT was expressed in both the xylem and phloem region of enlarged and diffuse vascular bundles. Knockout of HvSPDT decreased the distribution of P to new leaves, but increased the distribution to old leaves at the vegetative growth stage under low P supply. However, knockout of HvSPDT did not alter the redistribution of P from old to young organs. At the reproductive stage, knockout of HvSPDT significantly decreased P allocation to the grains, resulting in a considerable reduction in grain yield, especially under P-limited conditions. Our results indicate that node-based HvSPDT plays a crucial role in loading P into barley grains through preferentially distributing P from the xylem and further to the phloem.

The establishment of winter wheat root system architecture in field soils: The effect of soil type on root development in a temperate climate.

Winter wheat (Triticum aestivum L.) is an important cereal crop in the temperate climates of western Europe. Root system architecture is a significant contributor to resource capture and plant resilience. However, the impact of soil type on root system architecture (RSA) in field structured soils is yet to be fully assessed. This work studied the development of root growth using deep cultivation (250mm) during the tillering phase stage (Zadock stage 25) of winter wheat across three soil types. The three sites of contrasting soil types covered a geographical area in the UK and Ireland in October 2018. Root samples were analysed using two methods: X-ray computed tomography (CT) which provides 3D images of the undisturbed roots in the soil, and a WinRHIZO™ scanner used to generate 2D images of washed roots and to measure further root parameters. Important negative relationships existed between soil bulk density and root properties (root length density, root volume, surface area and length) across the three sites. The results revealed that despite reduced root growth, the clay (Southoe) site had a significantly higher crop yield irrespective of root depth. The loamy sand (Harper Adams) site had significantly higher root volume, surface area and root length density compared with the other sites. However, a reduction in grain yield of 2.42Mt ha-1 was incurred compared with the clay site and 1.6Mt ha-1 compared with the clay loam site. The significantly higher rooting characteristics found in the loamy sand site were a result of the significantly lower soil bulk density compared with the other two sites. The loamy sand site had a lower soil bulk density, but no significant difference in macroporosity between sites (p>0.05). This suggests that soil type and structure directly influence crop yield to greater extent than root parameters, but the interactions between both need simultaneous assessment in field sites.

Identification of drought tolerant, high yielding rice genotypes for rainfed upland ecosystem of Uttarakhand hills through different drought tolerance indices

Aim: To identify drought tolerant rice genotypes for rainfed upland hills at reproductive stage through different drought tolerance indices, PCA Biplot Analysis and Cluster Analysis. Methodology: Forty eight rainfed upland genotypes were evaluated under drought stress at reproductive stage and non-stress (irrigated) conditions. Different drought tolerance indices viz., drought tolerance efficiency (DTE), mean productivity index (MPI), relative efficiency (REI), mean relative performance (MRP), stress tolerance index (STI), drought yield index(DYI), stress tolerance (TOL), stress susceptibility index (SSI) and Schneider’s stress susceptibility index (SSSI)were used for screening genotypes. Results: The reduction in grain yield was observed in all the genotypes grown under drought stress condition and the per cent reduction in grain yield between stress and non-stress trial varied from 23.62% to 67.69%. The highest value of DTE was recorded in VL 20541 (76.38%) whereas VL 20441 showed the highest value for MPI (2656), REI (1.478), MRP (2.44) and STI (0.79). The lowest value of DYI (1.31), TOL (625), SSI (0.51) and SSSI (-0.23) was observed in VL 20541. Highest value for DTE, MPI, REI, MRP, STI and lowest value for DYI, TOL, SSI, SSSI are preferred and desirable as it indicate drought tolerance. A positive and highly significant correlation was exhibited by grain yield under stress (YS) with DTE, MPI, REI, MRP, STI and highly negative significant with DYI, TOL, SSI SSSI indicating that selection of low DYI, TOL, SSI, SSSI value and high DTE, MPI, REI, MRP, STI for screening of rice genotypes under drought stresses condition. Principal component analysis revealed that PC1 and PC2 accounted for 80.05% and 19.40% of the total variations, respectively. Cluster analysis grouped the 48 rice genotypes into two main clusters. Interpretation: On the basis of drought tolerant indices, PCA Biplot analysis and Cluster analysis six genotypes viz., VL 20441, VL 20225, VL 20541, VL 20468, VL 8549, and VL 20316 were identified as drought tolerant.

Impact of Drought Stress on Grains Filling in Rice and its Management: A Review

Rice (Oryza sativa L.) is the world’s single most important staple food source for over half of the world’s population, whose demand is expected to increase as human population increases almost exponentially every year. There are different kinds of abiotic and biotic stresses that a rice plant endures. Among the different forms of environmental stresses, drought hampers the production of rice grains notably. The reality of climate change is so stark that more and more droughts are expected to be evident in the distant future. Water, being a requisite for rice cultivation, is gradually becoming a highly limited resource across the earth. In comparison to other cereal crops, rice is more sensitive to the soil water content. Decrease of soil water content or the unavailability of water triggers drought stress in rice. Therefore, the management of drought stress for the growth of rice plants is essential as even moderate stress during reproductive growth may result in a drastic reduction of grain yield. The distinct changes brought about by drought stress not only range from morphological to physiological changes but also from biochemical to molecular changes as well. A number of starch synthesis related enzymes like granule bound starch synthase I (GBSSI), soluble starch synthase IIa (SSIIa) play important role in grain filling, which are also affected by limited water under drought environment. Due to water scarcity, the rate of photosynthesis decreases, as a result of which dry matter accumulation decreases, which ultimately affects grain filling in rice. Drought causes delayed flowering as well as spikelet sterility, followed by low grain yield during harvesting. The prevalence of drought over longer periods causes reactive oxygen species to form within the rice plants which subsequently denatures proteins and nucleic acids. In many places where drought continues for longer periods, rice plants die resulting in huge loss of grain yields. The effective strategies that have been adopted involves-the development of stable drought tolerant rice varieties through plant breeding programs, the development of short duration rice cultivars which have short growing cycle and harvesting periods that may help the plant to escape drought, the development of rice plants having deep root system such that it can penetrate the soil to find the available moisture and water required for growth, as well as the development of transgenic drought tolerant rice plants which over express specific genes to withstand drought, are few of the effective management strategies that need special attention. Thus, it can be said that drought management for rice production is a crucial step towards food security and food production in the world. The present discussions will emphasize on the negative impact of drought in rice plants and also discuss possible key management practices that can address the existing and imminent drought related problems on rice plants.

Insufficient Zn uptake reduces rice grain yield in integrated rice-crayfish culture – a case study in the Jianghan Plain, China

ABSTRACT China has recently seen a substantial increase in integrated rice-crayfish (Procambarus clarkii) culture (IRCC). However, grain yield reductions (GYR) with rice plants having normal vegetative growth but failed filling are becoming common in IRCC, and the driving factors remain unclear. Here, we tried to identify the mechanisms behind this GYR mode in the Jianghan Plain, China, by investigating the soil properties, grain yield parameters, and plant mineral content in five IRCC plots experiencing GYR and an adjacent paddy-upland rotation plot (CK). The results showed slight to extreme GYR (11–82%) in the IRCC plots compared to those in CK. The translocation of phosphorus from shoot to grain during the productive stage of rice plants was inhibited in IRCC plots (26–71%) compared to CK (75%). The grain yield and phosphorus translocation coefficient correlated strongly (r > 0.95) with zinc uptake in aboveground rice organs which was significantly lower in IRCC than in CK. We conclude that this GYR in IRCC plots is not due to decreased macronutrients availability or heavy metals toxicity in IRCC soils, but the insufficient uptake of zinc by IRCC rice plants. We recommend Zn foliar spray or introducing Zn efficient rice cultivars as potential mitigation measures.

Stacking of Pup1 QTL for low soil phosphorus tolerance and bacterial blight resistance genes in the background of APMS6B, the maintainer line of rice hybrid DRRH-3

Phosphorus (P) is one of the macronutrients essential for plant growth and development. Rice (Oryza sativa L.) is sensitive to P starvation and its deficiency influences many key plant functions, resulting in crop yield penalties. Although the hybrid rice segment is well-known for its yield heterosis, P deficiency and bacterial leaf blight diseases are evident limitations. APMS6B, the female parent of DRRH-3 is susceptible to low P and bacterial blight disease. In the present study, the improvement of APMS6B to P starvation and resistance to bacterial leaf blight (BB) was carried out using the marker-assisted backcross breeding approach. Kasalath (+Pup1 QTL) was used as a donor, and a promising IL (ATR 594-1) at BC1F4 generation was identified with 81.15% of recurrent parent genome recovery. Concurrently, this IL was intercrossed with GU-2 (+Xa21 and Xa38). Intercross F1s (ICF1) hybridity was confirmed through foreground selection having maximum RPGR (88.29%) and was selfed to produce ICF2. The resultant progenies were phenotyped for BB using Xoo inoculum (IX-020), simultaneously genotyped with gene-specific functional SSR markers forXa21 and Xa38. The identified BB-resistant plants were subjected to foreground selection for Pup1. Four promising ICF3 plants (BP-10-1, BP-10-3, BP-10-5, and BP-10-15 with Xa21, Xa38, and Pup1) along with parents and checks were screened both in low P plot (< 2 kg P2O5 ha−1) as well as in normal plot (> 25 kg P2O5 ha−1) during dry and wet seasons 2018. The field evaluation identified four promising intercrossed lines with better root growth in the primary root length of extracted zone and root volume. In addition, fewer reductions in grain yield (39.10%) under P starvation and less susceptibility indices values (< 1) for BB were observed. These lines may be exploited in the CMS conversion and development of climate-resilient, biotic and abiotic stress-tolerant rice hybrids.

Transcriptomics Analysis of Wheat Tassel Response to Tilletia laevis Kühn, Which Causes Common Bunt of Wheat.

Tilletia laevis Kühn [synonym T. foetida (Wallr.) Liro] can lead to a wheat common bunt, which is one of the most serious diseases affecting kernels, a serious reduction in grain yield, and losses can reach up to 80% in favorable environments. To understand how wheat tassels respond to T. laevis, based on an RNA-Seq technology, we analyzed a host transcript accumulation on healthy wheat tassels and on tassels infected by the pathogen. Our results showed that 7,767 out of 15,658 genes were upregulated and 7,891 out of 15,658 genes were downregulated in wheat tassels. Subsequent gene ontology (GO) showed that differentially expressed genes (DEGs) are predominantly involved in biological processes, cellular components, and molecular functions. Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that 20 pathways were expressed significantly during the infection of wheat with T. laevis, while biosynthesis of amino acids, carbon metabolism, and starch and sucrose metabolism pathways were more highly expressed. Our findings also demonstrated that genes involved in defense mechanisms and myeloblastosis (MYB) transcription factor families were mostly upregulated, and the RNA-seq results were validated by quantitative real-time polymerase chain reaction (qRT-PCR). This is the first report on transcriptomics analysis of wheat tassels in response to T. laevis, which will contribute to understanding the interaction of T. laevis and wheat, and may provide higher efficiency control strategies, including developing new methods to increase the resistance of wheat crops to T. laevis-caused wheat common bunt.

Influence of Silicon Forms on Nutrients Accumulation and Grain Yield of Wheat Under Water Deficit Conditions

Wheat productivity is severely hampered by drought, owing to its negative impacts on crop growth and development. For obtaining better yield, the impacts of drought should be ameliorated. Therefore, the current study scrutinizes the potential of different silicon (Si) forms to minify the drought-associated reduction in yield and the changes in nutrients accumulation. In a strip plots design based on randomized complete block arrangement using 3 replicates, two field experiments were carried out in 2019/20 and 2020/21 seasons. Three silicon (Si) forms (potassium silicate, calcium silicate, and aluminum silicate), in addition to the control (tap water) were sprayed. Also, three irrigation regimes were applied as ratio of crop evapotranspiration (60, 80 and 100%, denoted Irr60, Irr80 and Irr100, respectively). Findings clarified that application of aluminum silicate in both seasons, in addition to calcium silicate in the second season recorded the maximum accumulation of Si in wheat plants. Supplying wheat plants with different forms of Si reduced zinc (Zn) and manganese (Mn) and increased Si compared to the control (no Si application). Irr100 possessed increase in accumulation of Si in plant tissues greater than Irr80 or Irr60. Significant increases in all agronomic traits of wheat were obtained owing to spraying any Si form compared to the control. The differences between potassium silicate, calcium silicate, and aluminum silicate were not significant in flag leaf greenness (SPAD value), grains weight spike−1, weight of 1000 grains, and grain yield ha−1 in 2020/21 season. Irr100 was the effective treatment for enhancing SPAD value, spike length, grains weight spike−1, weight of 1000 grains, and grain yield ha−1. When irrigation water was reduced by 20% (Irr80), the lowest reduction in grain yield was obtained with potassium silicate compared to other forms of Si. It could be concluded that since lower accumulation of Si in plant tissues under water deficit than well-watered was recorded, the spraying of Si is great of importance to be applied under drought stress.

Rice husk and melaleuca biochar additions reduce soil CH 4 and N 2O emissions and increase soil physicochemical properties.

Background: Biochar is a promising material in mitigating greenhouse gases (GHGs) emissions from paddy fields due to its remarkable structural properties. Rice husk biochar (RhB) and melaleuca biochar (MB) are amendment materials that could be used to potentially reduce emissions in the Vietnamese Mekong Delta (VMD). However, their effects on CH 4 and N 2O emissions and soil under local water management and conventional rice cultivation have not been thoroughly investigated. Methods: We conducted a field experiment using biochar additions to the topsoil layer (0-20 cm). Five treatments comprising 0 t ha -1 (CT0); 5 t ha -1 (RhB5) and 10 t ha -1 (RhB10), and 5 t ha -1 (MB5) and 10 t ha -1 (MB10) were designed plot-by-plot (20 m 2) in triplicates. Results: The results showed that biochar application from 5 to 10 t ha -1 significantly decreased cumulative CH 4 (24.2-28.0%, RhB; 22.0-14.1%, MB) and N 2O (25.6-41.0%, RhB; 38.4-56.4%, MB) fluxes without a reduction in grain yield. Increasing the biochar application rate further did not decrease significantly total CH 4 and N 2O fluxes but was seen to significantly reduce the global warming potential (GWP) and yield-scale GWP in the RhB treatments. Biochar application improved soil Eh but had no effects on soil pH. Whereas CH 4 flux correlated negatively with soil Eh ( P <0.001; r 2 = 0.552, RhB; P <0.001; r 2 = 0.502, MB). Ameliorating soil aeration and functions by adding RhB and MB resulted in improving soil physicochemical properties, especially significant SOM and AN boosting, which indicate better soil health, structure, and fertility. Conclusions: Biochar supplementation significantly reduced CH 4 and N 2O fluxes and improved soil mineralization and physicochemical properties toward beneficial for rice plants. The results suggest that the optimal combination of biochar-application rates and effective water-irrigation techniques for soil types in the MD should be further studied in future works.

Rice husk and melaleuca biochar additions reduce soil CH 4 and N 2O emissions and increase soil physicochemical properties

Background: Biochar is a promising material in mitigating greenhouse gases (GHGs) emissions from paddy fields due to its remarkable structural properties. Rice husk biochar (RhB) and melaleuca biochar (MB) are amendment materials that could be used to potentially reduce emissions in the Vietnamese Mekong Delta (VMD). However, their effects on CH 4 and N 2O emissions and soil under local water management and conventional rice cultivation have not been thoroughly investigated. Methods: We conducted a field experiment using biochar additions to the topsoil layer (0-20 cm). Five treatments comprising 0 t ha -1 (CT0); 5 t ha -1 (RhB5) and 10 t ha -1 (RhB10), and 5 t ha -1 (MB5) and 10 t ha -1 (MB10) were designed plot-by-plot (20 m 2) in triplicates. Results: The results showed that biochar application from 5 to 10 t ha -1 significantly decreased cumulative CH 4 (24.2-28.0%, RhB; 22.0-14.1%, MB) and N 2O (25.6-41.0%, RhB; 38.4–56.4%, MB) fluxes without a reduction in grain yield. Increasing the biochar application rate further did not decrease significantly total CH 4 and N 2O fluxes but was seen to significantly reduce the global warming potential (GWP) and yield-scale GWP in the RhB treatments. Biochar application improved soil Eh but had no effects on soil pH. Whereas CH 4 flux correlated negatively with soil Eh ( P < 0.001; r 2 = 0.552, RhB; P < 0.001; r 2 = 0.502, MB). Ameliorating soil aeration and functions by adding RhB and MB resulted in improving soil physicochemical properties, especially significant SOM and AN boosting, which indicate better soil health, structure, and fertility. Conclusions: Biochar supplementation significantly reduced CH 4 and N 2O fluxes and improved soil mineralization and physicochemical properties toward beneficial for rice plants. The results suggest that the optimal combination of biochar-application rates and effective water-irrigation techniques for soil types in the MD should be further studied in future works.

Effect of Sunflower Crop Residue on Weed Suppression in Direct-Seeded Aus Rice Under Rice – Sunflower-Rice Cropping Pattern

In Bangladesh direct-seeded Aus rice is a conventional rice cultivation practice and weed infestation is a severe problem in direct-seeded rice production due to the existence of favorable environment during this period. So, by minimizing the use of herbicides and replace them with eco-friendly and environmentally sustainable herbicides based on natural plant products or allelochemicals, a factorial experiment based on randomized complete block design with three replications was performed at the research field of Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh from July 2018 to August 2019 to evaluate effect of sunflower crop residue on weeds growth and yield of direct seeded Aus rice in Transplanting Aman-Sunflower-Aus cropping pattern. Weed population and weed dry weight were significantly affected by crop residues treatment. Weed population was significantly lower in C3 (Direct sowing of Aus after 7 days of Sunflower residue incorporation) treatment than the control C1 (Direct sowing of Aus without Sunflower residue incorporation) treatment. The lowest weed dry weight (90.5 g m-2) was also obtained from C4 (Direct sowing of Aus after 14 days of Sunflower residue incorporation). The highest reduction of grain yield was obtained from without crop residue and no weeding treatments. The highest number of effective tillers m-2 (403.33), grain panicle-1 (114.67), tillers hill-1 (16.36), and grain yield (3.32 t ha-1) were observed from the treatments where sunflower residue was incorporated and the plots that were weed free. Results of this study indicate that sunflower residues showed potentiality to inhibit weed growth and it has a significant effect on the yield and yield parameters of direct seeded rice. Again weeds played a significant role in the reduction of yield of direct seeded rice. Thus, sunflower residues might be substitute for weed management practice as well as obtaining higher yield of direct seeded rice.&#x0D; Bangladesh Agron. J. 2021, 24(2): 115-125

Assessing congenial soil temperature and its impact on root growth, grain yield of summer rice under varying water stress condition in Lower Gangetic Plain of India

Abstract Increasing winter temperature in lower Gangetic Plain of India has put a threat to the cultivation of summer rice along with decreasing fresh water availability. Increasing ambient temperature also increase the soil temperature in the root zone of the crop. Thus, the effect of soil temperature over an optimum value may be detrimental for the root growth which turns into reduction of grain yield. Keeping in mind this situation, an experiment was carried out during 2014 and 2015 on summer rice in University Research Farm. Three transplanting dates and four irrigation regimes were chosen so that the crop experiences extreme weather as well as water stress condition. It is found that the mean soil temperature has a gradual increasing trend with advancement of crop growth. A significant and exponential increase in root weight was recorded with the increase in soil temperature. It is found that root growth was reduced when soil temperature increased beyond a critical value of 34 °C due to delayed transplanting and reduction of grain yield was noticed. So the summer-rice farmers are advised to complete transplanting within first fortnight of February to avoid yield reduction due to delay.

Influence of Sowing Time on the Quality and Micronutrient Contents of Bread Wheat (Triticum aestivum L)

Background: Wheat is a staple crop that feeds millions of people, but its productivity is significantly reduced under high temperatures. Maintaining grain quality under climate change is critical for human nutrition, end - use functional properties and commodity value. The current study aimed at assessing the quality and micronutrient contents under two environments for variability, correlation and path analysis.&#x0D; Research Methodology: The research was carried in the experimental area of Wheat and Barley Section, Department of Genetics and Plant Breeding, CCSHAU, Hisar during 2019-20. The assessement was done for 48 wheat genotypes under two temperature levels (timely and late sown environment) in RBD design with three replications.&#x0D; Results: Heat stress caused a significant reduction in grain yield, grain appearance score, hectoliter weight, sedimentation value, iron and zinc content whereas an increase in crude protein, total gluten content, wet gluten content, total soluble sugar. In the present study, total soluble sugar, wet gluten content, total gluten content showed highest values of variability, heritability, genetic advance as % of mean and thus are the most important quantitative traits to be taken into consideration for effective selection. A positive correlation was seen between grain yield and hectoliter weight in timely sown environment. Path analysis revealed highest positive direct effect for hectoliter weight and sedimentation value in timely sown condition while sedimentation value and iron content for late sown environment and thus in the process of selection much attention should be given to them as these characters are helpful for indirect selection.&#x0D; Conclusion: A negative association between high yield and good quality should be an important target for the next breeding efforts or to determine a quality parameter that performs consistently in both environments.

Climate change impact on wheat and maize growth in Ethiopia: A multi-model uncertainty analysis.

Ethiopia’s economy is dominated by agriculture which is mainly rain-fed and subsistence. Climate change is expected to have an adverse impact particularly on crop production. Previous studies have shown large discrepancies in the magnitude and sometimes in the direction of the impact on crop production. We assessed the impact of climate change on growth and yield of maize and wheat in Ethiopia using a multi-crop model ensemble. The multi-model ensemble (n = 48) was set up using the agroecosystem modelling framework Expert-N. The framework is modular which facilitates combining different submodels for plant growth and soil processes. The multi-model ensemble was driven by climate change projections representing the mid of the century (2021–2050) from ten contrasting climate models downscaled to finer resolution. The contributions of different sources of uncertainty in crop yield prediction were quantified. The sensitivity of crop yield to elevated CO2, increased temperature, changes in precipitations and N fertilizer were also assessed. Our results indicate that grain yields were very sensitive to changes in [CO2], temperature and N fertilizer amounts where the responses were higher for wheat than maize. The response to change in precipitation was weak, which we attribute to the high water holding capacity of the soils due to high organic carbon contents at the study sites. This may provide the sufficient buffering capacity for extended time periods with low amounts of precipitation. Under the changing climate, wheat productivity will be a major challenge with a 36 to 40% reduction in grain yield by 2050 while the impact on maize was modest. A major part of the uncertainty in the projected impact could be attributed to differences in the crop growth models. A considerable fraction of the uncertainty could also be traced back to different soil water dynamics modeling approaches in the model ensemble, which is often ignored. Uncertainties varied among the studied crop species and cultivars as well. The study highlights significant impacts of climate change on wheat yield in Ethiopia whereby differences in crop growth models causes the large part of the uncertainties.

Cold plasma can alleviate cadmium stress by optimizing growth and yield of wheat (Triticum aestivum L.) through changes in physio-biochemical properties and fatty acid profile.

Cold plasma (CP) application has increasing interest due to its environmental-friendly, high efficient, and low cost aspects to mitigate deletion effects of heavy metals on plants. A pot experiment was carried out to evaluate the CP application on yield, physiological, and fatty acid profile of wheat (Triticum aestivum L.) in a completely randomized design (CRD) with five replicates. Cadmium (Cd) was applied at four levels (0, 50, 100, and 150 μM), and CP were used on germinated seeds at three levels (0, 60, and 120 s) in a hydroponic system. The results showed CP alleviated the Cd accumulation in roots, shoots, and grains. The significant reduction of grain yield (GY) and thousand grain yield (TGY) was observed in plants exposed to 100 and 150 μM compared with the control plants; however, CP improved GY and TGY particularly at severe Cd stress. The minimum chlorophyll (Chl) and relative water content (RWC) were observed in plants exposed in 100 μM Cd and non-CP treatments. Proline increased by Cd stress but decreased with CP in most treatments. Unlike proline, methionine showed significant reduction under Cd stress. The fatty acid profile of wheat represented that severe Cd stress decreased monounsaturated fatty acid (MUFA) but increased polyunsaturated fatty acid (PUFA). Heat map (HM) showed that GY and methionine were the most sensitive traits under treatments of Cd and CP. Totally, we suggest the use of 120 s of CP to mitigate Cd stress on wheat plants.

A putative SUBTILISIN-LIKE SERINE PROTEASE 1 (SUBSrP1) regulates anther cuticle biosynthesis and panicle development in rice

IntroductionPanicle abortion is a severe physiological defect and causes a reduction in grain yield. ObjectivesIn this study, we aim to provide the characterization and functional analysis of a mutant apa1331 (apical panicle abortion1331). MethodsThe isolated mutant from an EMS-mutagenized population was subjected to SSR analysis and Mutmap assay for candidate gene mapping. We performed phenotypic analysis, anthers cross-sections morphology, wax and cutin profiling, biochemical assays and phylogenetic analysis for characterization and evaluation of apa1331. We used CRISPR/Cas9 disruption for functional validation of its candidate gene. Furthermore, comparative RNA-seq and relative expression analysis were performed to get further insights into mechanistic role of the candidate gene. ResultsThe anthers from the apical spikelets of apa1331 were degenerated, pollen-less and showed defects in cuticle formation. Transverse sections of apa1331 anthers showed defects in post-meiotic microspore development at stage 8–9. Gas Chromatography showed a significant reduction of wax and cutin in anthers of apa1331 compared to Wildtype (WT). Quantification of H2O2 and MDA has indicated the excessive ROS (reactive oxygen species) in apa1331. Trypan blue staining and TUNEL assay revealed cell death and excessive DNA fragmentation in apa1331. Map-based cloning and Mutmap analysis revealed that LOC_Os04g40720, encoding a putative SUBTILISIN-LIKE SERINE PROTEASE (OsSUBSrP1), harbored an SNP (A > G) in apa1331. Phenotypic defects were only seen in apical spikelets due to highest expression of OsSUBSrP1 in upper panicle portion. CRISPR-mediated knock-out lines of OsSUBSrP1 displayed spikelet abortion comparable to apa1331. Global gene expression analysis revealed a significant downregulation of wax and cutin biosynthesis genes. ConclusionsOur study reports the novel role of SUBSrP1 in anther cuticle biosynthesis by ROS-mediated programmed cell death in rice.

Monitoring Lodging Extents of Maize Crop Using Multitemporal GF-1 Images

Maize crop lodging is a recurrent phenomenon which results in significant reduction of grain yield and quality in addition to the impediment of mechanical harvesting. The large-scale monitoring of maize crop lodging is important for production policy adjustment and agricultural insurance compensation. In this article, we derived a variety of features from multitemporal GaoFen-1 (GF-1) images before and after maize crop lodging. We screened the most sensitive features of the spectrum, texture, and vegetation index to monitor maize crop lodging. The recursive feature elimination method based on cross-validation and mutual information were compared to obtain the optimal feature combination for monitoring the lodging extents of maize crop. The random forest classifier was used to classify the lodging extents. The results showed that the most sensitive features of the spectrum, texture, and vegetation indices of lodging extents included the difference of reflectance in blue, green, and red bands, the difference of normalized difference vegetation index, the difference of ratio vegetation index, the difference of enhanced vegetation index difference, the difference of mean value of blue band, the difference of mean value of green band, and the difference of mean value of red band. The total accuracy of lodging extents classification was 87.50%, and the Kappa coefficient was 0.83 for testing samples. Based on multiple features derived from GF-1 images before and after lodging, the lodging extents of maize crop can be monitored on a large scale.