Grain Yield Of Rice Research Articles

Resistance to Planthoppers and Southern Rice Black-Streaked Dwarf Virus in Rice Germplasms.

The damage caused by the white-back planthopper (WBPH, Sogatella furcifera) and brown planthopper (BPH, Nilaparvata lugens), as well as southern rice black-streaked dwarf virus (SRBSDV), considerably decreases the grain yield of rice. Identification of rice germplasms with sufficient resistance to planthoppers and SRBSDV is essential to the breeding and deployment of resistant varieties and, hence, the control of the pests and disease. In this study, 318 rice accessions were evaluated for their reactions to the infestation of both BPH and WBPH at the seedling stage using the standard seed-box screening test method; insect quantification was further conducted at the end of the tillering and grain-filling stages in field trials. Accessions HN12-239 and HN12-328 were resistant to both BPH and WBPH at all tested stages. Field trials were conducted to identify resistance in the collection to SRBSDV based on the virus infection rate under artificial inoculation. Rathu Heenati (RHT) and HN12-239 were moderately resistant to SRBSDV. In addition, we found that WBPH did not penetrate stems with stylets but did do more probing bouts and xylem sap ingestion when feeding on HN12-239 than the susceptible control rice Taichung Native 1. The resistance of rice accessions HN12-239, HN12-328, and RHT to BPH, WBPH, and/or SRBSDV should be valuable to the development of resistant rice varieties.

Panicle Architecture in Enhancing Grain Yield in Rice (Oryza sativa L.)

The architecture of the rice panicle is a crucial focus in breeding for both high yield and quality. It stands as a significant agronomic trait that influences the number of grains per panicle, playing a direct role in contributing to the overall yield of rice grains. Unravelling the genetic basis of panicle architecture is crucial for improving the grain yield in rice. In this study, the panicle architecture traits were meticulously dissected into five distinct components viz., number of primary rachis, number of secondary rachis, grain number on primary rachis, grain number on secondary rachis and total grain number. These components were systematically phenotyped in F2 and F3 population derived from a cross between DRR Dhan 48 and Maudamani. ‘DRR Dhan 48’ is a biofortified elite fine grain medium slender grain type cultivar with high zinc (22 ppm in polished rice) and low glycemic index (51.1). It has resistance to bacterial blight with the incorporation of xa5, xa13 and Xa21 in the background of Improved Samba Mahsuri. ‘Maudamani’ is a high yielding cultivar with high grain number and short bold grain type. Analysis of variance, histograms and boxplots revealed highly significant variation for the studied traits. Grain number in F2 population ranged from 29 to 333 grain with a mean of 162.72 whereas in F3, its varied from 49 to 368 with a mean of 184.17. Correlation analysis revealed significant correlation among the studied traits. The continuous variation observed in the population for panicle traits indicates that genetic control is governed by multiple minor loci. The presence of superior transgressive segregants highlights a complementary gene action influencing panicle architecture traits. The present investigation on panicle architecture offers scope for improving rice varieties and creating new germplasm resources and provides valuable information for further unravelling the genetic basis determining rice panicle architecture.

Loss-of-function gs3 allele decreases methane emissions and increases grain yield in rice

Rice paddies are a major source of methane emissions. To meet the food demand of the growing population and to cope with global warming, reducing greenhouse gases and enhancing yields are critical. Here we demonstrate that a loss-of-function rice allele, gs3, mitigates methane emissions from methanogens by allocating more photosynthates to the grain and less to the root and increases yield by enlarging grain size and weight.

Exploring the physiological efficiencies of promising rice (Oryza sativa) accessions for increasing grain yield

High grain yield in rice (Oryza sativa L.) is a cumulative contribution of different morphological and physiological traits. However, the selection of high-yielding genotypes based on physiological traits is difficult where a large set of genotypes is used. Therefore, a study was carried out during rainy (kharif) seasons of 2019 and 2020 at research farm of ICAR-National Rice Research Institute, Cuttack, Odisha to assess the physiological efficiency of 211 elite rice genotypes having varying yield potential. The elite genotypes were classified into high, medium, and low categories based on their field performance. The results revealed that 29, 41, 34, 31, 49, 35, 39, 29, and 30 genotypes showing high values for FLA (>51.51 cm2), TCC (>3.99 mg/g fresh weight), PN (>20.79), gs (>0.97), E (>9.03), TB (>15.95 t/ ha), GY (>6.27 t/ha), PR (>0.29 kg/cm), and CS (>42.12 g/stem) respectively. Among them, 3 genotypes i.e. IG-020, IG-211 and IG-010 were identified to be highly efficient in 4 traits, 2 genotypes i.e., IG-044 and IG-186 in 5 traits, and 2 genotypes; IG-008 and IG-161 were found to be superior in 7 traits along with high grain yield. The selection of these genotypes with superior morphological and physiological traits could be beneficial in the breeding programme in terms of increasing yield potential in rice.

Deletion of the OsLA1 Gene Leads to Multi-Tillering and Lazy Phenotypes in Rice

Plant architecture, one of the key factors that determine grain yield in rice, is mainly affected by components such as plant height, tiller number, and panicle morphology. For this paper, we obtained a multi-tillering and lazy mutant from a japonica rice cultivar, Wuyunjing 7 (WYJ7), via treatment with a heavy ion beam. Compared to WYJ7, the mutant showed a significant increase in tiller angle, tiller number, number of primary and secondary branches, and number of grains; however, the plant height and grain thickness of the mutant was significantly decreased. Phenotypic analysis of the F1 hybrids revealed that the multi-tillering and lazy mutant phenotypes were regulated by a recessive gene. The segregation ratio of 1׃3 of the mutant phenotype and the wild-type plant in the F2 population indicated that the former was controlled by a single gene named Multi-Tillering and Lazy 1 (MTL1). Bulked segregant analysis was performed using the individual plants with extremely typical tiller angles in the F2 population. The MTL1 gene was initially mapped within a region of 5.58–17.64 Mb on chromosome 11. By using the F2 segregated population for fine mapping, the MTL1 gene was ultimately fine mapped within the range of 66.67 kb on chromosome 11. The analysis of genes in this region revealed the presence of the previously identified LAZY1 (LA1) gene. Genomic PCR amplification and semi-quantitative RT-PCR assays showed that the LA1 gene could not be amplified and was not expressed, thus indicating that the MTL1 gene might be identical to the LA1 gene. This study suggests that the multi-tillering and lazy mutant phenotypes might be caused by the deletion of LA1 function. This finding can guide further investigations on the functional mechanisms of the LA1 gene, thus enriching the theoretical knowledge of plant architecture in relation to rice.

Effect of one or more microorganisms on the yield components of upland rice under greenhouse conditions

The use of beneficial microorganisms is an important strategy to improve rice production in a sustainable way. The study was carried out to determine the effect of single and combined beneficial microorganism on the development of upland rice. The experiment was performed in greenhouse and arranged in a completely randomized design with 29 treatments and 4 replications. Treatments consisted of rice seeds cultivar BRS A501 CL treated with single and combined multifunctional microorganisms (1 (Serratia marcescens), 2 (Bacillus toyonensis), 3 (Phanerochaete australis), 4 (Trichoderma koningiopsis), 5 (Azospirillum brasilense), 6 (Azospirillum sp.), 7 (Bacillus sp.), 8 to 28 (combination of all these microorganisms in pairs) and 29 (control)). Inoculation of upland rice with sole and combined microorganism on upland rice increased the roots and shoots development, yield components and grain yield of upland rice. The combinations of Bacillus sp. (BRM 63573) and A. brasilense (AbV5), Azospirillum sp. (BRM 63574) + B. toyonensis (BRM 32110) and Phanerochaete australis (BRM 62389) + Serratia marcenscens (BRM 32114) led to improved roots and shoots development; increased number of panicles and grains per pot, 1000 grains weight and grain yield of rice plants. Besides, the combinations allow helped in increased accumulation of nutrients in roots, shoots and grains of rice plants.

Overexpression of OsGS1;2 for improved nitrogen use efficiency and grain yield of rice: A field test

Overexpression of OsGS1;2 for improved nitrogen use efficiency and grain yield of rice: A field test

Individual and combined influences of salinity and drought stress on the agro-physiological traits and grain yield of rice

Because of inadequate water resources and poor irrigation facilities, salinity and drought stresses often co-occur in rice production in saline lands. Nevertheless, little information is available on the agro-physiological traits and grain yield of rice when subjected to combined salinity × drought stress. We evaluated the individual and interactive influences of salinity and drought on rice yield and agro-physiological characteristics using two rice cultivars, Nanjing 9108 (salinity-tolerant rice) and Wuyunjing 30 (salinity-susceptible rice). This experiment was conducted under non-salinity (NS) and salinity (S) conditions and three drought levels from jointing to heading (CC, control condition; MD, moderate drought; SD, severe drought). Individual salinity and drought treatments and their combination shortened the total growth duration by 3–4 days and 4–6 days in Nanjing 9108 and Wuyunjing 30, respectively. Both salinity and drought treatments reduced (P < 0.01 or P < 0.05) rice yield by 12.9%−40.9% and 28.1%−35.0% across the two cultivars, respectively, and the combined salinity × drought treatment resulted in a more pronounced yield loss of 53.1%−113.3%. A greater reduction in grain yield caused by the combined salinity × drought stress was detected in Wuyunjing 30 than in Nanjing 9108. The poor grain yield performance of rice under combined salinity × drought stress was mainly attributable to the following: (1) yield components, panicle length, and single panicle weight were lower than they were under an individual stress; (2) combined stress caused greater reductions in shoot biomass, leaf area index (LAI), and nonstructural carbohydrate (NSC) content in the stem at heading and maturity, although harvest index and NSC remobilization reserve were increased; (3) each stress and especially combined stress increased Na+/K+ ratio in the leaf, while reducing leaf photosynthetic rate and SPAD values after heading, and total accumulation of nitrogen (N), phosphorus (P), and potassium (K). Our results suggested that the combined salinity × drought stress was more damaging than either stress alone, and resulted in a greater yield penalty of rice. In terms of grain yield, salinity-susceptible rice was more responsive to the combined stress than salinity-tolerant rice.

Identification of natural allelic variation in TTL1 controlling thermotolerance and grain size by a rice super pan-genome.

Continuously increasing global temperatures present great challenges to food security. Grain size, one of the critical components determining grain yield in rice (Oryza sativa L.), is a prime target for genetic breeding. Thus, there is an immediate need for genetic improvement in rice to maintain grain yield under heat stress. However, quantitative trait loci (QTLs) endowing heat stress tolerance and grain size in rice are extremely rare. Here, we identified a novel negative regulator with pleiotropic effects, Thermo-Tolerance and grain Length 1 (TTL1), from the super pan-genomic and transcriptomic data. Loss-of-function mutations in TTL1 enhanced heat tolerance, and caused an increase in grain size by coordinating cell expansion and proliferation. TTL1 was shown to function as a transcriptional regulator and localized to the nucleus and cell membrane. Furthermore, haplotype analysis showed that hapL and hapS of TTL1 were obviously correlated with variations of thermotolerance and grain size in a core collection of cultivars. Genome evolution analysis of available rice germplasms suggested that TTL1 was selected during domestication of the indica and japonica rice subspecies, but still had much breeding potential for increasing grain length and thermotolerance. These findings provide insights into TTL1 as a novel potential target for the development of high-yield and thermotolerant rice varieties.

The transcription factor MYB110 regulates plant height, lodging resistance, and grain yield in rice.

The high-yielding Green Revolution varieties of cereal crops are characterized by a semidwarf architecture and lodging resistance. Plant height is tightly regulated by the availability of phosphate (Pi), yet the underlying mechanism remains obscure. Here, we report that rice (Oryza sativa) R2R3-type Myeloblastosis (MYB) transcription factor MYB110 is a Pi-dependent negative regulator of plant height. MYB110 is a direct target of PHOSPHATE STARVATION RESPONSE 2 (OsPHR2) and regulates OsPHR2-mediated inhibition of rice height. Inactivation of MYB110 increased culm diameter and bending resistance, leading to enhanced lodging resistance despite increased plant height. Strikingly, the grain yield of myb110 mutants was elevated under both high- and low-Pi regimes. Two divergent haplotypes based on single nucleotide polymorphisms in the putative promoter of MYB110 corresponded with its transcript levels and plant height in response to Pi availability. Thus, fine-tuning MYB110 expression may be a potent strategy for further increasing the yield of Green Revolution cereal crop varieties.

Correlation and Path Analysis for Yield and Grain Yield Attributing Quality Characters of Rice (Oryza sativa L.) Genotypes under Irrigated Condition

During the kharif season of 2022, a set of 27 rice genotypes were evaluated for the study of "Correlation and path coefficient analysis for yield and grain yield contributing characters in rice (Oryza sativa L.) genotypes" using an RBD with three replications at the research field of Department of Genetics and Plant breeding, Sam Higginbottom University of Agriculture, Technology and Sciences, Naini Allahabad, U.P. Analysis of variance showed significant differences among genotypes for all 13 characters indicating that the material has adequate genetic variability to support the breeding programme for improving the grain yield of rice. Out of 27 rice genotypes evaluated for various characters, four genotypes were found superior for different characters. These four genotypes were found to be better for more than one character. Among the lines SIVA (26.83), KRISHNA (26.19g), RDR-8702 (25.79g) andSS-999 (24.48g) recorded high grain yield per hill. All these genotypes recorded significantly high yield as compared to the check NDR-359 (CHECK) (22.67g). High estimate of heritability coupled with high genetic advance as percent of mean was recorded for spikelets per panicle, biological yield, harvest index, test weight and grain yield per hill. These traits are governed by additive gene effects and therefore, may be improved through direct selection. Grain yield per hill correlated positively and significantly with flag leaf width, biological yield, harvest index, and test weight. Harvest index, biological yield, days to maturity, and number of panicles per hill all had a significant positive direct effect on grain yield per hill at both genotypic and phenotypic levels. Thus, selections for these characters will be proved efficient for the improvement of grain yield of rice.

Influence of organic amendments and different levels of nitrogen on production potential, economics and energetics of rice (Oryza sativa)–wheat (Triticum aestivum) cropping system

A field experiment was conducted during 2018–19 and 2019–20 at the Punjab Agricultural University, Ludhiana and Research Station, Dyal Bharang, Amritsar, to study the influence of organic amendments and nitrogen levels on rice (Oryza sativa L.)-wheat (Triticum aestivum L.) cropping system. In rice, main plot treatments were green manuring (GM), farmyard manure (FYM), poultry manure (PM) and control (NA). Nitrogen levels in sub-plots comprised control (N1), 50 kg N/ha (N2),75 kg N/ha (N3) and 100 kg N/ha (N4). In wheat, residual effect of organic amendments and nitrogen levels applied to preceding rice was evaluated. The statistically highest grain yield of rice was obtained with PM (8.29 t/ha), followed by GM (8.02 t/ha) which was at par with FYM (7.90 t/ha). The lowest rice grain yield was obtained with NA (5.16 t/ha) and its subsequent wheat crop recorded significantly higher grain yield with PM (6.14 t/ha), followed by FYM (5.88 t/ha) and GM (5.72 t/ha). Treatment N4 recorded significantly higher yield than N2 and was at par with N3. Maximum rice-equivalent yield (14.7 t/ha) was recorded with PM, while the highest energy-use efficiency of rice was recorded with green-manure (16.2) as compared to the other treatments. Treatment with the application of PM and N4 recorded significantly the highest economic parameters and system productivity for both rice and wheat crops compared to rest of the treatments.

Hydrothermal carbonization of biogas slurry and cattle manure into soil conditioner mitigates ammonia volatilization from paddy soil

Hydrothermal carbonization of biogas slurry and animal manure into hydrochar could enhance waste recycling waste and minimize ammonia (NH3) volatilization from paddy fields. In this study, cattle manure-derived hydrochar prepared in the presence of Milli-Q water (CMWH) and biogas slurry (CMBSH), and biogas slurry-based hydrochar embedded with zeolite (ZHC) were applied to rice-paddy soil. The results demonstrated that CMBSH and ZHC treatments could significantly mitigate the cumulative NH3 volatilization and yield-scale NH3 volatilization by 27.9–45.2% and 28.5−45.4%, respectively, compared to the control group (without hydrochar addition), and significantly correlated with pH and ammonium–nitrogen (NH4+–N) concentration in floodwater. Nitrogen (N) loss via NH3 volatilization in the control group accounted for 24.9% of the applied N fertilizer, whereas CMBSH- and ZHC-amended treatments accounted for 13.6−17.9% of N in applied fertilizer. The reduced N loss improved soil N retention and availability for rice; consequently, grain N content significantly increased by 6.5–14.9% and N-use efficiency increased by 6.4–16.0% (P < 0.05), respectively. Based on linear fitting results, NH3 volatilization mitigation resulted from lower pH and NH4+–N concentration in floodwater that resulted from the acidic property and specific surface area of hydrochar treatments. Moreover, NH3-oxidizing archaea abundance in hydrochar-treated soil decreased by 40.9–46.9% in response to CMBSH and ZHC treatments, potentially suppressing NH4+–N transformation into nitrate and improving soil NH4+–N retention capacity. To date, this study applied biogas slurry-based hydrochar into paddy soil for the first time and demonstrated that ZHC significantly mitigated NH3 and increased N content. Overall, this study proposes an environmental-friendly strategy to recycle the wastes, biogas slurry, to the paddy fields to mitigate NH3 volatilization and increase grain yield of rice.

Acidity and nutrient management practices for enhancing soil nutrient availability, nutrient uptake and grain yield of rice in Vaikom kari soils in Kuttanad, Kerala

A field investigation was conducted during August to December 2015 and 2016 in farmers` fields in Thalayazham panchayat in Kottayam district. The experiment was laid out in randomized block design having 16 treatments in three replications with rice (Oryza sativa L.) var. Uma. The treatments were dolomite, lime + MgSO4 or RHA (rice husk ash) + MgSO4 along with 100% package of practice (POP) alone or with 100% POP + foliar spray of 13-0-45 N-P-K (KNO3) (1%) or borax (0.5%) or 13-0-45 + borax at PI (panicle initiation) stage. Lime + MgSO4 + 75% POP + 13-0-45 + borax as well as lime without MgSO4 + 100% POP combined with 13-0-45 or borax or both were also included as treatments. Higher grain yield of 5.42 and 5.57 t ha-1 during 2015 and 2016 respectively were produced by dolomite + POP + 13-0-45 followed by dolomite + POP + 13-0-45 + borax and lime + POP + MgSO4 + 13-0-45. The treatments involving dolomite and lime with or without MgSO4 produced taller plants, higher tiller number m-2 and higher Leaf Area Index during both the years. Dolomite + POP + 13-0-45 produced the highest number of panicles m-2. Higher test weight and lower percentage of unfilled grains were observed with dolomite + POP + 13-0-45 and dolomite + POP + 13-0-45 + borax. Lime and dolomite treatments were more effective in reducing soil acidity and improving dehydrogenase activity and nutrient availability in the soil than RHA treatments during both the years. However, the effect of liming materials applied as basal and at 30 DAS diminishes after the crop and this necessitates application of liming materials in every crop season. Availability of soil N improved by treatments involving lime + POP without MgSO4 at PI and harvest stages. The treatments involving dolomite + POP and lime + POP with or without MgSO4 recorded higher available P during PI stage. In general, higher status of available K was registered by the treatments involving dolomite or lime application and lower K status registered by the treatment with 75% POP fertilizer. All treatments involving lime or dolomite registered higher soil available Ca and those involving dolomite or lime + MgSO4 showed higher availability of Mg in the soil. The treatments involving dolomite registered lower status of soil available Fe and higher status of available B. Higher status of available Zn was registered by the treatments involving dolomite or lime + MgSO4. Soil pH was significantly and positively correlated with available P, Ca and Mg and significantly and negatively correlated with available Fe in the soil. In general, higher uptake of macronutrients was observed with dolomite or lime + MgSO4 treatments along with 100% POP during both the years. Foliar spray of 13-0-45 recorded higher N and K uptake. Significant and positive correlation of grain yield with uptake of macro nutrients was also observed.

Plant Growth-Promoting Bacteria and Crop Residue in Rice–Wheat System Cultivated with Favorable Tillage Influence Crop Productivity, Nutrient Uptake, Soil Quality, and Profitability in the Terai Agro-Ecological Zone of West Bengal, India

A field study was conducted from 2021 to 2023 in a rice–wheat cropping system in the Terai agro-ecological zone of West Bengal, India, using different management practices, i.e., tillage (conventional tillage, CT, and zero tillage, ZT), crop residue (R), and plant growth-promoting bacteria (B). This study was a part of long-term research on resource conservation technology (conservation agriculture, CA), undertaken on a research farm in Uttar Banga Krishi Viswavidyalaya, Pundibari (Cooch Behar), West Bengal. The project was established in 2006 in acidic alluvial soil. The aim of this study was to evaluate rice–wheat productivity, nutrient uptake, soil quality, and profitability after the 16th and 17th crop cycles under the above-mentioned management practices. The results revealed that the pooled yield of rice grain and straw was significantly higher under the CT + R + B treatment than under the other treatments (ZT, ZT + B, ZT + R, ZT + R + B, CT, CT + B, and CT + R). However, the wheat grain and straw yields were significantly greater under the ZT + R + B treatment than under other treatments. The system’s grain yield and straw yield were significantly higher under the CT + R + B treatment, on par with ZT + R + B, compared to the other treatments. Nutrient uptake (nitrogen, N; phosphorus, P; and potassium, K) was increased by retaining R and inoculating B compared to the sample without R and without B. Soil properties, including organic carbon, available N, available P, and available K, were improved in all the treatments compared to the initial values, but the impact was greater in the treatments with R and B than in those without R and without B. In the 5–10-cm soil layer, the above-mentioned soil properties were also improved over the initial (2006) values by 37, 126, 65 and 60%, respectively, by applying the best treatment (ZT + R + B). In economic terms, the benefit–cost ratio was significantly higher under the CT + R + B treatment for rice crops (2.99) and ZT + R + B for wheat crops (3.37). Therefore, we can conclude that, after 17 years of cultivation, for rice, CT performs better than ZT; meanwhile, for wheat cultivation, ZT produces greater yields than CT in the Terai agro-ecological zone of West Bengal, India.

A Structure Variation in qPH8.2 Detrimentally Affects Plant Architecture and Yield in Rice.

Plant height is an important agronomic trait associated with plant architecture and grain yield in rice (Oryza sativa L.). In this study, we report the identification of quantitative trait loci (QTL) for plant height using a chromosomal segment substitution line (CSSL) population with substituted segments from japonica variety Nipponbare (NIP) in the background of the indica variety 9311. Eight stable QTLs for plant height were identified in three environments. Among them, six loci were co-localized with known genes such as semidwarf-1 (sd1) and Grain Number per Panicle1 (GNP1) involved in gibberellin biosynthesis. A minor QTL qPH8.2 on chromosome 8 was verified and fine-mapped to a 74 kb region. Sequence comparison of the genomic region revealed the presence/absence of a 42 kb insertion between NIP and 9311. This insertion occurred predominantly in temperate japonica rice. Comparisons on the near-isogenic lines showed that the qPH8.2 allele from NIP exhibits pleiotropic effects on plant growth, including reduced plant height, leaf length, photosynthetic capacity, delayed heading date, decreased yield, and increased tiller angle. These results indicate that qPH8.2 from temperate japonica triggers adverse effects on plant growth and yield when introduced into the indica rice, highlighting the importance of the inter-subspecies crossing breeding programs.

Effect of Polythene Covering on Seedling Quality and It’s Carryover Effect on Field Duration and Grain Yield of Rice

Boro rice cultivation is often limit due to lack of a farmer's friendly technique for raising quality seedling in irrigated ecosystem. Experiment was conducted in Boro 2019-20 at R/S Rangpur to compare different polythene covering treatment on raising quality seedling of BRRI dhan88 and BRRI dhan89 and to measure it’s carryover effect on growth duration and grain yield of rice. The treatments were as T1: Day polythene cover (from10:00 am to Sunset), T2: Night polythene cover (Sunset to Sunrise), T3: Day-night polythene cover but round shape opening (30 cm diameter) at both sides and T4: No polythene cover (control). Seedbed was covered by transparent polythene from seeding to 30 days after seeding (DAS). Seedling strength was higher on 01 December seeding than 15 December in both the tested varieties. Day cover always had the lowest seedling strength in both varieties. Day-night polythene cover treatment (T3) produced significantly tallest seedling than other polythene covering treatments for both the plantings dates. Seedling mortality was higher in 30 January planting than 15 January planting for both the tested varieties due to prevailing low temperature (below 10°C for eight days). In 15 January planting, BRRI dhan88 and BRRI dhan89 produced higher number of tillers with day cover and night cover treatment, respectively. In 30 January planting, BRRI dhan88 produced higher tiller with day-night and control treatment but day cover had the lowest. Tiller production rate was sharply increased from 35 – 45 DAT and then decreased. Up to 45 DAT, it was statistically similar in both the varietiers with all treatments. Although, tiller number was higher in T1, T2 and T4 than T3 but productive tiller (%) was satistically similar among the treatments for both the varieties and planting dates. There was no significant difference in grain yield among the treatments for planting dates and varieties. Day-night polythene cover treatment (T3) reduces growth duration by 2-3 days over other treatments. This treatment (T3) is farmer's friendly for raising quality seedling in cold prone areas of Bangladesh. Bangladesh Rice J.26 (1): 59-68, 2022

Mining the candidate genes of rice panicle traits via a genome-wide association study.

Panicle traits are important for improving the panicle architecture and grain yield of rice. Therefore, we performed a genome-wide association study (GWAS) to analyze and determine the genetic determinants of five panicle traits. A total of 1.29 million single nucleotide polymorphism (SNP) loci were detected in 162 rice materials. We carried out a GWAS of panicle length (PL), total grain number per panicle (TGP), filled grain number per panicle (FGP), seed setting rate (SSR) and grain weight per panicle (GWP) in 2019, 2020 and 2021. Four quantitative trait loci (QTLs) for PL were detected on chromosomes 1, 6, and 9; one QTL for TGP, FGP, and GWP was detected on chromosome 4; two QTLs for FGP were detected on chromosomes 4 and 7; and one QTL for SSR was detected on chromosome 1. These QTLs were detected via a general linear model (GLM) and mixed linear model (MLM) in both years of the study period. In this study, the genomic best linear unbiased prediction (BLUP) method was used to verify the accuracy of the GWAS results. There are nine QTLs were both detected by the multi-environment GWAS method and the BLUP method. Moreover, further analysis revealed that three candidate genes, LOC_Os01g43700, LOC_Os09g25784, and LOC_Os04g47890, may be significantly related to panicle traits of rice. Haplotype analysis indicated that LOC_Os01g43700 and LOC_Os09g25784 are highly associated with PL and that LOC_Os04g47890 is highly associated with TGP, FGP, and GWP. Our results offer essential genetic information for the molecular improvement of panicle traits. The identified candidate genes and elite haplotypes could be used in marker-assisted selection to improve rice yield through pyramid breeding.

Suppressing a phosphohydrolase of cytokinin nucleotide enhances grain yield in rice

Suppressing a phosphohydrolase of cytokinin nucleotide enhances grain yield in rice

Effect of Manures and Phosphorus on Yield and Quality under Rice-Blackgram Cropping Sequence

A field experiment was conducted on phosphorus dynamics in relation to nutrient management in rice- blackgram cropping sequence with respect to yield and quality as influenced by effect of organic manures and inorganic phosphorus at Agricultural College Farm, Bapatla. The results revealed that grain yield of rice was significantly higher with the application of 100% RDNK in combination with Dhaincha @10t ha-1 (M3) and it was on par with that of application of RDNK along with sunhemp @10t ha-1 (M2). However significantly lower was recorded in RDNK alone (M0) during both the years of the study. Among the P levels, the treatment P5 (120 kg P2O5 ha-1) recorded significantly highest grain yield and it was on par with P4 (90 kg P2O5 ha-1) and P3 (60 kg P2O5 ha-1) and lowest was recorded in P1 (0 kg P2O5 ha-1). In succeeding blackgram seed yield was significantly influenced by the organic manures and phosphorus levels imposed to preceding rice crop. The seed yield was significantly higher with the application of 100% RDNK in combination with Dhaincha @10t ha-1 (M3) and it was on par with that of application of RDNK along with sunhemp @10t ha-1 (M2) and RDNK+ FYM @ 5t ha-1 (M1). However significantly lower was recorded in RDNK alone (M0) during both the years of the study. Among the P levels, the treatment P4 (90 kg P2O5 ha-1) recorded significantly highest seed yield and it was on par with P5 (120 kg P2O5 ha-1), P3 (60 kg P2O5 ha-1) and P2 (30 kg P2O5 ha-1), while lowest was recorded in P1 (0 kg P2O5 ha-1). Regarding quality parameters of rice grain viz., amylose and protein were recoeded significantly higher in RDNK+Dhaincha @10t ha-1 (M3) and this was on par with that of application of RDNK along with sunhemp @10t ha-1 (M2), while M2 was remain on par with RDNK+ FYM @ 5t ha-1 (M1). Among the P levels, the treatment P5 (23.86 and 24.71%) registered significantly higher amylose content and lower was registered in P1 (21.59 and 22.43%). However, protein content was slightly increased from 0 to 120 kg P2O5 ha-1 but not significantly differed. Similarly the data regarding influence of organics and P levels applied to preceeding rice crop on protein content of succeeding blackgram followed same trend as in rice.