Grain Yield Of Rice Research Articles

Wheat Straw Incorporation Coupled With Direct Seeding Method Influence Nitrogen Uptake and Translocation in Rice

ABSTRACTOn‐farm trials were performed to investigate the nitrogen (N) uptake, N translocation, and grain yield of rice planted via different direct seeding methods into a field after wheat straw incorporation. The study conducted using two direct seeding methods, dry direct seeding of rice (DDSR) and wet direct seeding of rice (WDSR), in a field without or with straw incorporation demonstrated that straw incorporation negatively influenced both grain yield and N uptake in direct‐seeded rice. Compared with WDSR, DDSR suffered significant negative effects, with a 7.2% decrease in grain yield and an 8.0% decrease in N uptake. Additionally, N uptake in direct‐seeded rice with straw addition decreased by 6.5% at the middle stage and 9.5% at the late stage compared with that without straw incorporation. Straw incorporation prolonged the initial phase of growth and thus shortened the N uptake days in the last two phases. Moreover, the total N uptake of rice was positively associated with the uptake rate and the uptake days during the latter stages. Specifically, WDSR exhibited a higher N uptake rate, N uptake days, and N translocation ability than DDSR, which increased the N uptake in stem and panicle, total N uptake, and grain yield at maturity. These results indicated that straw incorporation decreased grain yield and N uptake, which was related to the fewer N uptake days in the latter stages caused by the prolonged early growth stage for direct‐seeded rice. Nevertheless, using WSDR in a field incorporated with straw alleviated the losses in N uptake and grain yield.

Imprints of Soil Microbial Activity Accredited to Residue-Management and Tillage Practices for Boosting Rice and Wheat Production

The sustainable productivity of rice–wheat cropping systems relies on soil health, and soil health can be positively influenced by treating previous crop residues using conservation tillage practices. The present study examined the impact of three rice residue-management practices under zero-tilled wheat (ZTW) and conventionally tilled wheat (CTW), along with two rice-sowing practices, during rice cultivation on soil functional microbial diversity, physiological profiling, and grain yields of rice and wheat. Anchored residues (ARs) under ZTW exhibited significantly (p ≤ 0.05) high average well color development—31.43% more than CTW with no residue (NR). CTW with residue burning (BUR) showed a 5.42% increase in the Shannon diversity index compared to CTW-NR. Substrate richness was 10.02% higher in CTW-BUR compared to CTW-NR. CTW-BUR demonstrated the highest 17.98% increase in the Shannon evenness index compared to CTW-NR. The direct-seeded rice (DSR) system generally surpassed puddled transplanted rice (PTR) in most indices, except for the Shannon evenness index values. ZTW-AR exhibited the highest utilization of amino acids, carboxylic acids, and phenolic compounds, while CTW-BUR exhibited the highest utilization of carbohydrates and polymers utilization, and ZTW with no-residue (NR) exhibited the highest utilization of amines. Rice and wheat grain yields were highest with full residue in ZTW and lowest in CTW-NR. PTR supported higher rice yields, while DSR was superior for wheat. These findings highlight the favorable role of residue retention with no tillage during wheat cultivation in the maintenance of soil quality and rice–wheat productivity.

OsPP2C49, a Negative Regulatory Factor in the Abscisic Acid Signaling Pathway, Positively Regulates Grain Yield in Rice

Clade A type 2C protein phosphatases (PP2Cs) are crucial components of the abscisic acid (ABA) signaling pathway. Research on clade A PP2Cs has focused more on their roles related to ABA signaling and stress responses than on the molecular mechanisms mediating their effects on plant growth and grain yield. Rice (Oryza sativa L.) is an important food crop worldwide. We previously determined that OsPP2C49, which encodes a rice clade A PP2C family member, negatively controls rice responses to drought, salt, and high-temperature stresses. In this study, we investigated the regulatory effects of OsPP2C49 on ABA responses and rice grain yield. By analyzing potential interactions with core ABA components, including pyrabactin resistance 1 (PYR1)/PYR1-like (PYL)/regulatory component of the ABA receptor (RCAR) and stress-activated protein kinases (SAPKs), we confirmed that OsPP2C49 is involved in the ABA signaling pathway. OsPP2C49 overexpression led to decreased ABA sensitivity and increased rice grain yield; the opposite phenotypes were observed in the ospp2c49 knockout mutants. Therefore, OsPP2C49 negatively regulates ABA responses, but positively modulates rice grain yield. Furthermore, we found that OsPP2C49 can interact with and dephosphorylate five OsSAPKs in vitro. Unlike OsPP2C49, these OsSAPKs positively modulate ABA responsiveness, but negatively affect rice yield. These findings indicate that OsPP2C49 may partially regulate ABA responses and rice grain production by dephosphorylating OsSAPKs. This study preliminarily explored the molecular basis of the regulatory effects of OsPP2C49 on rice plant growth and grain yield.

Exogenous Uniconazole promotes physiological metabolism and grain yield of rice under salt stress.

Salt stress severely inhibit plant growth and development. Uniconazole has been considered to significantly increase plant stress tolerance. However, the mechanism by which Uniconazole induces salt tolerance in rice seedlings and its impact on yield is still unclear. In this study, the effects of exogenous Uniconazole on morphogenesis, physiological metabolism, and yield of rice seedlings under salt stress were analyzed using the salt-tolerant rice variety HD961 and the salt-sensitive rice variety 9311. The results showed that salt stress significantly inhibited rice growth, disrupted the antioxidant system and pigment accumulation, and reduced photosynthesis, and yield. There were corresponding percent decreases of 13.0% and 24.1% in plant height, 31.6% and 55.8% in leaf area, 65.7% and 85.3% in root volume, respectively for HD961 and 9311. spraying However, compared to salt stress, the US treatment increased the percentage to 4.7% and 139.0% in root volume, 7.5% and 38.0% in total chlorophyll, 4.5% and 14.3% in peroxidase (POD) of leaves, 14.4% and 54.2% in POD of roots, 18.7% and 22.7% in catalase (CAT) of leaves, and 22.6% and 53.9% in CAT of roots, respectively, for HD961 and 9311. In addition, it also significantly enhanced photosynthesis at the reproductive stage, promoted the transport of carbohydrate to grains. And US treatment significantly increased the percentage to 9.0% in panicle length, 28.0% in panicle number per hole, 24.0% in filled grain number, 3.0% in 1000-grain weight, and 26.0% in yield per plant, respectively, for HD961, compared to salt stress. In summary, applying Uniconazole at the seedling stage can alleviate the damage induced by NaCl stress on rice by regulating the physiological metabolism of rice plants. This reduces the negative effects of salt stress, enhance salt tolerance, and boost rice production.

OsRopGEF10 Attenuates Cytokinin Signaling to Regulate Panicle Development and Grain Yield in Rice

Cytokinins, which play crucial roles in shoot development, substantially affect grain yield. In rice, the OsRopGEF10-OsRAC3 module is associated with cytokinin signaling and crown root development. However, the effects of RopGEF-mediated cytokinin signaling on rice shoot development and grain yield remain unclear. In this study, we investigated the role of OsRopGEF10 in SAM development and the underlying mechanism. We showed that overexpression of OsRopGEF10 inhibited SAM and panicle development, leading to decreased grain yield. Intriguingly, the overexpression of a specific amino acid mutant of OsRopGEF10, designated gef10-W260S, was found to promote panicle development and grain yield. Further analysis using the BiFC assay revealed that the gef10-W260S mutation disrupted the recruitment of rice histidine phosphotransfer proteins (OsAHP1/2) to the plasma membrane (PM), thereby promoting cytokinin signaling. This effect was corroborated by a dark-induced leaf senescence assay, which revealed an increased cytokinin response in the gef10-W260S ectopic expression lines, whereas the overexpression lines presented a suppressed cytokinin response. Moreover, we revealed that the enhanced panicle development in the gef10-W260S lines was attributable to the upregulated expression of several type-B response regulators (RRs) that are crucial for panicle development. Collectively, these findings revealed the negative regulatory function of OsRopGEF10 in the development of the shoot apical meristem (SAM) via interference with cytokinin signaling. Our study highlights the promising role of OsRopGEF10 as a potential target for regulating SAM and panicle development in rice, revealing a valuable breeding strategy for increasing crop yield.

Effect of Chinese Milk Vetch on Zinc Content and Zinc Absorption of Rice in Purple Tidal Mud Soil

Rice is a staple food crop that feeds billions globally. Addressing Zn deficiency in rice is crucial for improving nutrition and food security. Zn deficiency in rice is a widespread issue, especially in purple tidal mud substrates, which often exhibit low Zn availability. The objective of this two-year pot study was to explore the relationship between Zn content, yield components, and Zn absorption in rice grown in purple tidal mud substrate with varying amounts of Chinese milk vetch (Astragalus sinicus L.) incorporation. The experimental design consisted of seven treatments: an unfertilized control, a Chinese milk vetch control, a chemical fertilizer control, and four treatment variations incorporating Chinese milk vetch alongside chemical fertilizer applications. The results indicated that planting and applying Chinese milk vetch improved the grain yield of rice in purple tidal mud substrate, and the yield increased with higher levels of Chinese milk vetch applied. The increased grain yield resulted in higher Zn absorption in rice grains. The application of Chinese milk vetch, both solely and in combination with chemical fertilizers, had varying effects on zinc uptake and grain zinc formation efficiency in early and late rice, with the control and low-level Chinese milk vetch treatments generally exhibiting the highest performance across the two-year period. By introducing Chinese milkvetch following the use of chemical fertilizers, the Zn content in rice grains increased starting from the second year. The treatment with Chinese milkvetch applied at a rate of 2.25 t/hm2 showed the best results in increasing the Zn content in rice grains. The increase in Zn content and Zn uptake by the rice plants gave rise to a lowering of the DTPA-extractable Zn content in the purple tidal mud substrate. Sole Chinese milk vetch application and using Chinese milk vetch following chemical fertilizer application both increased Zn content extracted by DTPA in purple tidal mud substrate.

Effect of Transplanting Dates and Nutrient Management Options on Nutrient Partitioning and Accumulation in Rice

ABSTRACT Rice is the most important crop in India and additionally the hub of food security of the worldwide population. Integrated application of manures and fertilizers played a pivotal role for improvement of soil physico-chemical properties under different cropping systems as well as nutrient accumulation and grain yield in rice. The present investigation was conducted in sandy loam soil at Agronomy Research Farm of Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, India during 2018–2019 having sub-humid climate. Field experiment was designed to evaluate the effect of two date of transplanting, which were allotted to main plots and three combinations of nutrient management options allotted for sub plots on rice crop (var. Naveen). Among all the plant parts, leaf showed higher accumulation of nitrogen (3.69, 1.92%), stem showed higher accumulation of both phosphorus (0.43, 0.35%) and potassium (2.59, 2.09%) than other plant parts during vegetative stages, while panicle showed higher accumulation of nitrogen (1.22%), phosphorus (0.28%) during harvesting stages of the rice crop. Significantly higher nitrogen accumulation in different plant parts were optimized under Soil Test Based Fertilizer Recommendation (STBFR) + Green Manure (GM; Sesbania rostrata) (0.99, 0.46, 1.28%) method of nutrient management, while phosphorus (0.10, 0.11, 0.28%) and potassium (1.00, 1.64, 0.33%) accumulation were found to be significantly higher in different plant parts under STBFR + Farm Yard Manure (FYM) method of nutrient management. Thus, early transplanting and application of STBFR + GM/FYM could be recommended for higher nutrient accumulation in rice crop.

Effect of Heat Stress during Reproductive Stage on Plant Growth, Total Biomass Production and their Correlation with Grain Yield in Rice

Rice (Oryza sativa L.) is highly sensitive to high temperature during its reproductive stages. This study aims to elucidate the effects of heat stress during reproductive stage on plant growth, total dry matter accumulation, and their correlation with grain yield in diverse rice genotypes. A field experiment in split plot design was conducted at G.B.P.U.A.& T., Pantnagar during rainy season 2022-23, where high temperature stress was imposed on 15 rice genotypes during reproductive stage (after panicle initiation till maturity) using a polytunnel. The results showed that heat stress lead to reduction in dry matter accumulation and harvest index in 10 genotypes, although with different magnitude. The genotypes were screened into tolerant and susceptible based on yield reduction by comparing with the genotype N-22, which was used as a check for heat stress. It was observed that the genotypes, IET 29415, MTU-1282, MTU-1121, NLR-40042 and US-314 maintaining higher biomass and HI under heat stress conditions were able to maintain grain yield. The identified genotypes with better performance under heat stress conditions offer valuable genetic resources for breeding programs aimed at improving heat tolerance in rice.

The dual role of casein kinase 1, DTG1, in regulating tillering and grain size in rice

Tiller number and grain size are important agronomic traits that determine grain yield in rice. Here, we demonstrate that DEFECTIVE TILLER GROWTH 1 (DTG1), a member of the casein kinase 1 protein family, exerts a co-regulatory effect on tiller number and grain size. We identified a single amino acid substitution in DTG1 (I357K) that caused a decrease in tiller number and an increase in grain size in NIL-dtg1. Genetic analyses revealed that DTG1 plays a pivotal role in regulation of tillering and grain size. The DTG1I357K allelic variant exhibited robust functionality in suppressing tillering. We show that DTG1 is preferentially expressed in tiller buds and young panicles, and negatively regulates grain size by restricting cell proliferation in spikelet hulls. We further confirm that DTG1 functioned in grain size regulation by directly interacting with Grain Width 2 (GW2), a critical grain size regulator in rice. The CRISPR/Cas9-mediated elimination of DTG1 significantly enhanced tiller number and grain size, thereby increasing rice grain yield under field conditions, thus highlighting potential value of DTG1 in rice breeding.

LATA1, a RING E3 ligase, modulates the tiller angle by affecting auxin asymmetric distribution and content in rice.

The tiller angle is an important agronomic trait that determines plant architecture and grain yield in rice (Oryza sativa L.). However, the molecular regulation mechanism of the rice tiller angle remains unclear. Here, we identified a rice tiller angle gene, LARGE TILLER ANGLE 1 (LATA1), using the MutMap approach. LATA1 encodes a C3H2C3-type RING zinc finger E3 ligase and the conserved region of the RING zinc finger is essential for its E3 activity. LATA1 was highly expressed in the root and tiller base and LATA1-GFP fusion protein was specifically localized to the nucleus. The mutation of LATA1 significantly reduced indole-3-acetic acid content and attenuated lateral auxin transport, thereby resulting in defective shoot gravitropism and spreading plant architecture in rice. Further investigations found that LATA1 may indirectly affect gravity perception by modulating the sedimentation rate of gravity-sensing amyloplasts upon gravistimulation. Our findings provide new insights into the molecular mechanism underlying the rice tiller angle and new genetic resource for the improvement of plant architecture in rice.

Assessing the productive potential of high-yielding rice varieties on acid sulfate soils in the tidal swampland of Central Kalimantan

Abstract Tidal swampland holds significant agricultural potential including cultivating rice. Farmers in these regions typically cultivate local rice varieties. Breeding rice techniques have led to the development of superior rice well-suited to thrive in tidal swamplands. This research was conducted on acid sulfate soil within a tidal swampland located in Terusan Karya Village, Kapuas Regency, Central Kalimantan, during the 2021 dry season. The study employed a completely randomized block design with two replications. The experimental treatments comprised nine high-yielding rice varieties: Inpari IR Nutri Zinc, Cakrabuana Agritan, Inpari 3, Inpari 32, Inpari 42, Inpari 47, Inpara 2, Inpara 8, and Inpara 10. The parameters were observed, including plant height, panicle number per hill, panicle length, and grain yield. The high-yielding varieties of rice planted in acid sulfate tidal swamplands exhibit varying growth and yield performances. Grain yields of rice ranged from 5.45 to 7.30 t ha−1 of dry-milled grain. The highest grain yield was shown by Inpari 3 (7.30 t ha−1) and Inpari 32 (7.04 t ha−1). High heritability values are indicated by the traits of dry harvest and milled grains, while wide variability is shown by characters such as plant height, panicle length, grain dry harvest, and dry milled.

Identification and Fine Mapping of Quantitative Trait Loci for Tiller Angle Using Chromosome Segment Substitution Lines in Rice (Oryza Sativa L.)

The tiller angle, which is an important agronomic trait, determines plant architecture and greatly influences the grain yield of rice. In this study, a population of chromosome segment substitution lines derived from a cross between a japonica variety with a compact plant architecture—Koshihikari—and an indica variety with a spread-out plant architecture—Nona Bokra—was used to investigate the genetic basis of the tiller angle. Five quantitative trait loci (qTA1, qTA5, qTA9-1, qTA9-2, and qTA11) for the tiller angle were detected on chromosomes 1, 5, 9, 9, and 11 in two different environments. The phenotypic variation in these QTLs ranged from 3.78% to 8.22%. Two pairs of digenic epistatic QTLs were detected in Lingshui. The epistatic interaction explained 15.19% and 13.60% of the phenotypic variance, respectively. Among the five QTLs, qTA9-2 was detected in both environments. An F2 mapping population containing the qTA9-2 QTL was established. The location of qTA9-2 was narrowed down to a 187 kb region between InDel markers M9 and M10 on chromosome 9. Thirty open reading frames (ORFs), including TAC1, a gene known to regulate the tiller angle, were identified in this region. The gene sequencing results suggested that a base substitution from G to A at position 1557 in the 3′-untranslated region led to a difference in the expression of qTA9-2 in Koshihikari and Nona Bokra. These findings provide a potential gene resource for the improvement of rice plant architecture.

The effect on the carbon footprint of the rice-wheat system of substituting chemical fertilizers by pig manure: The results of a field experiment

Livestock manure is widely recycled to enhance intensive agricultural production. Nevertheless, the environmental and agronomic benefits of liquid manure, such as biogas slurry, have rarely been comprehensively evaluated. To boost food production while maintaining environmental sustainability, a field experiment was performed to assess the effects of solid and liquid manure substitution for chemical fertilizer on direct greenhouse gas (GHG) emissions, soil organic carbon (SOC), grain yield, and carbon footprints (CF) in a rice-wheat system. The treatments involved only chemical fertilizer (NPK), 50 % NPK + 50 % pig manure (50 % PM), 100 % pig manure (100%PM), 50 % NPK + 50 % biogas slurry from PM (50 % PS), and 100 % biogas slurry from PM (100 % PS) in the circumstances of equal nitrogen fertilization. The results showed that rice CH4 emissions dominated the direct GHG emissions, and followed the order of 100%PM > 50%PM > 50%PS = NPK = 100%PS on average of three years. The 100%PM had the highest area-scaled CF with 11.84 Mg CO2-eq ha−1 due to high CH4 emissions and carbon emissions from pig manure production and compost indirectly without considering the changes in SOC stock. Meanwhile, 100%PM significantly increased SOC stock at 0–30 cm depth by 49.1 %, 11.8 %, 44.8 %, and 56.5 % compared with NPK, 50%PM, 50%PS, and 100%PS, respectively (P < 0.05). Notably, 100 % PM had the lowest area-scaled CF with 0.99 Mg CO2-eq ha−1 when considering the changes in SOC stock, followed by 50%PM. The 50%PM significantly increased the annual grain yield of rice and wheat from 2010 to 2018, with an average of 4.9 %, 4.5 %, and 5.7 % compared with NPK, 100%PM, and 100%PS, respectively (P < 0.05). Overall, although there was a trade-off between SOC sequestration and CH4 emissions under pig manure, pig manure substitution for chemical fertilizer significantly decreased yield-scaled CF, followed by biogas slurry substitution relative to NPK (P < 0.05). Thus, pig manure substitution for chemical fertilizer is recommended for environmental and yield benefits simultaneously considering the whole chain of production process in a rice-wheat system. In future, strategic fertilizer management based on PM and PS could potentially offer a sustainable solution to mitigate the trade-off and sustain the respective benefits of PM (i.e. SOC and grain yield) and PS (i.e. CH4 emissions).

Impairment in a member of AP2/ERF and F-box family protein enhances complete panicle exsertion in rice.

Complete panicle exsertion (CPE) is an economically important quantitative trait that contributes to grain yield in rice. We deployed an integrated approach for understanding the molecular mechanism of CPE using a stable ethyl methanesulfonate mutant line, CPE-109 of the Samba Mahsuri (SM) variety of rice (Oryza sativa), which exhibits CPE. Two consistent genomic regions were identified for CPE through quantitative trait locus (QTL) mapping [qCPE-4 (28.24-31.22 Mb) and qCPE-12 (2.30-3.18 Mb)] and QTL-sequencing [chr 4 (31.21-33.69 Mb) and chr 12 (0.12-3.15 Mb)]. Two non-synonymous single nucleotide polymorphisms, namely KASP 12-12 (T→C; chr12:1269983) in Os12g0126300, encoding an AP2/ERF transcription factor, and KASP 12-16 (G→A; chr12:1515198) in Os12g0131400, encoding an F-box domain-containing protein, explained 81.05% and 59.61% of the phenotypic variance, respectively, and exhibited strong co-segregation with CPE in F2 mapping populations, advanced generation lines, and CPE-exhibiting SM mutants through KASP assays. Down-regulation of these genes in CPE-109 compared with SM (wild type) was observed in transcriptome sequencing of flag leaves, which was validated through qRT-PCR. We propose that the abrogation of Os12g0126300 and Os12g0131400 in CPE-109 combinatorially influences down-regulation of ethylene biosynthetic genes, Os01g0192900 (ACC synthase) and Os05g0497300 (ethylene-responsive factor-2), and up-regulation of a gibberellic acid synthetic gene, Os06g0569900 (ent-kaurene synthase) and the two cytokinin biosynthetic genes Os07g0486700 (cytokinin-O-glucosyltransferase 2) and Os10g0479500 (similar to carboxy-lyase), which results in complete panicle exsertion.

Polypeptide urea increases rice yield and nitrogen use efficiency through root growth improvement

ContextElucidating rice root growth and development characteristics is essential for improving nitrogen use efficiency (NUE) and grain yield (GY) of crops, particularly in light of innovations such as polyaspartic acid (PASP)–urea formulations. However, the effectiveness of PASP–urea on the morphological properties of rice roots is insufficiently explored. ObjectiveWe aimed to examine the effect of PASP–urea on root morphology properties, NUE, and grain yield of mid-season rice in southwest China. MethodsIn 2016 and 2017, a two-factor randomized block design experiment was conducted in Sichuan, China, during the rice planting season. Three N treatments: no N (control), conventional urea [CU], and polyaspartic acid–urea [PU] were administered to two rice varieties: Yixiangyou 2115 and Fyou 498. ResultsOur findings showed that grain yield and nitrogen recovery efficiency (NRE) of rice were closely related to the root surface area density (RSAD), root length density (RLD), and root volume density (RVD) of rice. Compared to the CU treatment, the PU application significantly boosted the root dry matter weight, RLD, RVD, and RSAD of both varieties by 12.00–16.87 %, 0.16–28.98 %, 12.41–37.06 %, and 8.14–33.66 % at the jointing, heading, and maturity stages, respectively. This contributed to a 0.37–15.63 % and 23.45–48.12 % increase in grain yield and NRE, respectively, in both years, and a 12.26–15.69 % increase in N partial productivity efficiency (NPPE) in 2017 by improving the effective panicle number per unit area, spikelets per panicle, and N uptake. ConclusionNRE and grain yield of rice were significantly increased by PU application by improving the rice root system. ImplicationsThe study findings offer insight on how PASP–urea application influences the root morphology of rice and its relationship with grain yield and NRE while offering novel strategies and concepts for optimizing N use in rice cultivation.

MORN motif-containing protein OsMORN1 and OsMORN2 are crucial for rice pollen viability and cold tolerance.

The pollen viability directly affects the pollination process and the ultimate grain yield of rice. Here, we identified that the MORN motif-containing proteins, OsMORN1 and OsMORN2, had a crucial role in maintaining pollen fertility. Compared with the wild type (WT), the pollen viability of the osmorn1 and osmorn2 mutants was reduced, and pollen germination was abnormal, resulting in significantly lower spikelet fertility, seed-setting rate, and grain yield per plant. Further investigation revealed that OsMORN1 was localized to the Golgi apparatus and lipid droplets. Lipids associated with pollen viability underwent alterations in osmorn mutants, such as the diacylglyceride (18:3_18:3) was 5.1-fold higher and digalactosyldiacylglycerol (18:2_18:2) was 5.2-fold lower in osmorn1, while the triacylglycerol (TG) (16:0_18:2_18:3) was 8.3-fold higher and TG (16:0_18:1_18:3) was 8.5-fold lower in osmorn2 than those in WT. Furthermore, the OsMORN1/2 was found to be associated with rice cold tolerance, as osmorn1 and osmorn2 mutants were more sensitive to chilling stress than WT. The mutants displayed increased hydrogen peroxide accumulation, reduced antioxidant enzyme activities, elevated malondialdehyde content, and a significantly decreased seedling survival rate. Lipidomics analysis revealed distinct alterations in lipids under low temperature, highlighting significant changes in TG (18:2_18:3_18:3) and TG (18:4_18:2_18:2) in osmorn1, TG (16:0_18:2_18:2) and PI (17:2_18:3) in osmorn2 compared to the WT. Therefore, it suggested that OsMORN1 and OsMORN2 regulate both pollen viability and cold tolerance through maintaining lipid homeostasis.

A transthyretin-like protein acts downstream of miR397 and LACCASE to regulate grain yield in rice.

Increasing grain yield is a major goal of breeders due to the rising global demand for food. We previously reported that the miR397-LACCASE (OsLAC) module regulates brassinosteroid (BR) signaling and grain yield in rice (Oryza sativa). However, the precise roles of laccase enzymes in the BR pathway remain unclear. Here, we report that OsLAC controls grain yield by preventing the turnover of TRANSTHYRETIN-LIKE (OsTTL), a negative regulator of BR signaling. Overexpressing OsTTL decreased BR sensitivity in rice, while loss-of-function of OsTTL led to enhanced BR signaling and increased grain yield. OsLAC directly binds to OsTTL and regulates its phosphorylation-mediated turnover. The phosphorylation site Ser226 of OsTTL is essential for its ubiquitination and degradation. Overexpressing the dephosphorylation-mimic form of OsTTL (OsTTLS226A) resulted in more severe defects than did overexpressing OsTTL. These findings provide insight into the role of an ancient laccase in BR signaling and suggest that the OsLAC-OsTTL module could serve as a target for improving grain yield.

Variation in WIDTH OF LEAF AND GRAIN contributes to grain and leaf size by controlling LARGE2 stability in rice.

Grain and flag leaf size are two important agronomic traits that influence grain yield in rice (Oryza sativa). Many QTLs and genes that regulate these traits individually have been identified, however, few QTLs and genes that simultaneously control these two traits have been identified. In this study, we conducted a genome-wide association analysis in rice and detected a major locus, WIDTH OF LEAF AND GRAIN (WLG), that associated with both grain and flag leaf width. WLG encodes a RING-domain E3 ubiquitin ligase. WLGhap.B, which possesses five SNP variations compared to WLGhap.A, encodes a protein with enhanced ubiquitination activity that confers increased rice leaf width and grain size, whereas mutation of WLG leads to narrower leaves and smaller grains. Both WLGhap.A and WLGhap.B interact with LARGE2, a HETC-type E3 ligase, however, WLGhap.B exhibits stronger interaction with LARGE2, thus higher ubiquitination activity towards LARGE2 compared with WLGhap.A. Lysine1021 is crucial for the ubiquitination of LARGE2 by WLG. Loss-of-function of LARGE2 in wlg-1 phenocopies large2-c in grain and leaf width, suggesting that WLG acts upstream of LARGE2. These findings reveal the genetic and molecular mechanism by which the WLG-LARGE2 module mediates grain and leaf size in rice, and suggest the potential of WLGhap.B in improving rice yield.

Himalayas farmer participatory evaluation of balanced application of nutrients in rice (Oryza sativa)–wheat (Triticum aestivum) system in Kumaon hills

A study was conducted by involving 24 farmers in their fields during 2011–13 in lower Kumaon hills, to study the response of rice (Oryza sativa L.)–wheat (Triticum aestivum L.) system to balanced nutrient application. The highest mean grain yields of rice (7.21 t/ha) and of wheat (5.14 t/ha) were recorded with the recommended doses of nitrogen, phosphorus and potassium (120, 60 and 40 kg/ha respectively, to both the crops) applied along with the sulphur @ 20 kg/ha followed by recommended NPK alone without micronutrients (7.01 and 5.01 t/ha, respec tively, for rice and wheat). During both the years, grain yields of rice and wheat under the farmers’ practice of nu trient application were significantly lower than the other treatments except control and N alone. In rice crop, appli cation of recommended doses of N, P and K provided additional mean grain yield of 1.50 t/ha over the farmers’ practice, whereas it was 1.04 t/ha in wheat. Application of sulphur @ 20 kg/ha over the recommended dose of NPK to both the crops resulted in additional grain yield of rice and wheat by 200 and 130 kg/ha, respectively, it also resulted in the highest production efficiency (45.4 kg/ha/day). The highest net returns were found under the treatment receiving recommended dose of NPK along with sulphur @ 20 kg/ha ( 150.15 × 103/ha) and it was 54.8% higher over the farmers’ practice of fertilizer application. The soil fertility status after harvesting of wheat in rice–wheat cropping system revealed that highest available nitrogen (298 kg/ha), phosphorus (16.9 kg/ha) and po tassium (200 kg/ha) were observed with recommended doses of N, P and K along with sulphur @ 20 kg/ha to rice and wheat crops in sequence.

Effect of Different Boron Application Schedules on Yields, Boron Concentration and Uptake of Rice-Wheat Rotation and Changes in Chemical Fractions of Soil Boron

ABSTRACT The yields realized under rice-wheat rotation are generally low in the geographical regions prone to B deficiency and a sound B application schedule recommendation is required for the sustainable yields and enhanced soil fertility. The effect of different B application schedules involving different dosages and frequency of B application was investigated on yields and B nutrition of rice-wheat rotation and changes in the chemical fractions of B in soil in six years field study carried out on a sandy loam (Typic hapludoll). Based on the average grain yields of rice and wheat during the period of experimentation, application of 1.5 kg B as borax ha−1 to rice crop on alternate years was the profitable practice for mollisols as it gave an average yearly production of 5.51 t of rice grain and 4.28 t of wheat grain ha−1. The average concentration of B in flag leaves and grains of rice was much lower compared to wheat crop. The recommended schedule of B application to rice-wheat rotation resulted in a Benefit: Cost ratio of 11: 1 and also maintained the optimum level of B in soil. Most of the added B markedly increased specifically bound (0.05 M KH2PO4 extractable), ammonium oxalate (pH 3.3) extractable fractions followed by residual and organically bound fraction in the soil.