F3 Lines Research Articles

Evaluation of Grain-Quality Related Traits of F5 Lines of Wheat under Terminal Drought Stress Conditions

Evaluation of Grain-Quality Related Traits of F5 Lines of Wheat under Terminal Drought Stress Conditions

Fine mapping of the Hairy glume (Hg) gene in a chromosome variation region at the distal terminus of 1AS.

Trichomes are differentiated epidermal cells and exist on above-ground organs of nearly all land plants with important roles in resistance to a wide range of biotic and abiotic stresses. We attempted to obtain candidate gene (s) for Hairy glume (Hg), responsible for the trichome on wheat glume, by using bulked segregant exome capture sequencing (BSE-Seq), while Hg was only mapped in 0.52–3.26 Mb of 1AS. To further fine map this gene and identify candidate genes in this region, a near isogenic line-derived population consisting of 2,050 F2 lines was generated in the present study. By analyzing this population, Hg was fine mapped into a 0.90 cM region covering a physical distance of ~825.03 Kb encompassing 6 high- and 23 low-confidence genes in the reference genome of Chinese Spring. A presence-absence variation was identified in the fine mapping region through analyses of sequence-tagged sites markers and genome sequences of the hairy glume parent of the near isogenic lines. The results presented here will be useful for further cloning Hg in wheat.

The Inheritance Pattern of Key Desirable Agronomic and Fruit Quality Traits in Elite Red Papaya Genotypes

Knowledge of the heritability, genetic advance, and stability of key traits, such as the height to the first fruit, trunk circumference, number of marketable fruit, wasted fruit, fruit weight, fruit width, fruit length, flesh thickness, cavity width, cavity length, and soluble solid contents, is required. These were determined in ten advanced generation red papaya recombinant inbred lines (RIL; F5 generation). The F5 RIL were grown in four field sites, two each within two distinct agroecological climates: the Tablelands and Coastal regions. At each site, biological replicates (trees) of each RIL and the industry-standard red papaya cultivar, RB1, were grown. Agronomic traits and fruit-specific traits were assessed at five and 10 months, respectively, after seedling transplantation to the field. Height to first fruit, trunk circumference, fruit weight, and soluble solid contents were highly heritable and stable at all field sites (h2b.s, 0.7–0.9) with genetic gains of almost 18% observed for height to first fruit and fruit weight. Across all sites, the trunks of the F5 lines were 37% wider, the trees set fruit 47% closer to the ground and had 20% more marketable fruit with 33% smaller fruit cavity widths, and their fruit was 11% heavier and 12% sweeter than RB1.

Common wheat genotypes with null-alleles at gliadin loci

Aim. The study was aimed at identification and selection of winter common wheat genotypes with null-alleles at the gliadin loci Gli-B1 and Gli-D1. Methods. The search for spontaneous mutants with the absence of synthesis of gliadin blocks was made in winter common wheat hybrid material and cultivars. To identify mutations, APAG electrophoresis and SDS-electrophoresis of seed storage proteins were performed. Results. The frequency of spontaneous mutations resulting in the null-allele at the loci Gli-B1 and Gli-D1 in F2 was 0,1 % and 0,05 %, respectively, in the cross Odesska chervonokolosa × B-16. Via sowing the material with those mutations and marker selection, F6 lines were developed: the line OB-Bnull with the null-allele at the Gli-B1 locus and the line OB-Dnull with the null-allele at the Gli-D1 locus. Another line with the null-allele at Gli-B1 was produced from the cross B3 × D4 by marker selection, as well as a biotype with the null-allele at the Gli-D1 locus was selected from the cultivar Slaven. Conclusions. The developed lines with null-alleles at the gliadin locus Gli-B1 (without omega-5 gliadins) and Gli-D1 (without omega-1,2 gliadins) are initial material for hypoallergenic wheat breeding.

Measuring the frequency and distribution of meiotic crossovers in homozygous barley inbred lines

We report a novel approach for establishing the number and position of CO events in individual homozygous inbred plants by combining low level EMS mutagenesis, speed breeding, whole genome shotgun sequencing and sliding window analysis of the induced molecular variant data. We demonstrate the approach by exploring CO frequency and distribution in self-fertilised progeny of the inbred barley cultivar Bowman and compare these observations to similar data obtained from a Bowman nearly isogenic line (BW230 Hvmlh3) containing a mutation in the DNA mismatch repair gene HvMLH3. We have previously shown that Hvmlh3 decreases both plant fertility and recombination by ~50%. We compare our results to those from previously published traditional genetic analysis of F3 families derived from multiple F2 lines containing WT or mutant alleles of HvMLH3, revealing a high level of correspondence between analyses. We discuss possible applications of the approach in streamlining the assessment of recombination in plant meiosis research.

Transfer of Durable Stripe Rust Resistance Gene Yr39 into Four Chinese Elite Wheat Cultivars Using Marker-Assisted Selection

Wheat gene Yr39 confers durable high-temperature adult-plant (HTAP) resistance to stripe rust caused by Puccinia striiformis f. sp. tritici, one of the most destructive diseases of wheat worldwide. The objective of this study was to transfer Yr39 into four Chinese elite wheat cultivars. Backcross inbred line populations were developed from four Chinese wheat cultivars Chuanmai 42 (CM42), Bainong Aikang 58 (AK58), Han 6172 (H6172) and Zhengmai 9023 (ZM9023) crossed with a Yr39 single-gene line. The F1, BC1F1 and BC1F6 lines were genotyped using resistance gene analogs polymorphism (RGAP) markers Xwgp36, Xwgp44 and Xwgp43, which are closely linked to Yr39. Progeny lines selected with the markers for Yr39 were evaluated in the field for stripe rust resistance and agronomic traits including plant height, tiller numbers, spike grain numbers and thousand-grain weight. Eleven lines were selected with stripe rust resistance and desirable agronomic traits. These lines with production potential can be used for further testing in various wheat production regions and as germplasm resources for breeding new wheat cultivars with durable stripe rust resistance, high yield, and adaptation to different production environments.

Genetic Parameters, Inter-relationship Among Agronomic Traits and Dehulled Rice Morpho-Biochemical Profile of Promising Black Rice x Mentik Wangi Lines

A comprehensive understanding of the genetic parameters and the interrelationship among characters in the breeding population is crucial for selecting low amylose and high antioxidant black rice varieties. Meanwhile, dehulled rice morpho-biochemistry profile can be used to determine the grain quality of F6 and F7 lines of Black Rice x Mentik Wangi var. The objectives of this study were to determine the agronomic traits, figure up the genetic parameters, describe the relationship among agronomic characteristics of the F6 lines, and determine the morpho-biochemical profile of F7 dehulled rice. Agronomic traits showed a difference in each line. Genetic parameters in each trait showed various categories. Path analysis showed that the number of tillers affected the dry weight and grain weight per panicle, but the plant dry weight did not directly affect the weight of 1,000 grain. Directly, the weight of 1,000 grain was only significantly affected by the grain weight per panicle trait. The F7 lines had a difference in grain length and amylose content. The dehulled rice color of the two lines showed the combination of the two parents. Based on the student T-test conducted on F6 and F7 grain, there was no difference in antioxidant content between the two sample groups. The antioxidant activity of all lines was in the range between the antioxidant activities of the two checked varieties. Although further research is still needed, the lines have the potency to be developed as low amylose pigmented rice.

Cloning of a new allele of ZmAMP1 and evaluation of its breeding value in hybrid maize

Gene resources associated with plant stature and flowering time are invaluable for maize breeding. In this study, using an F2:3 population derived from a natural semi-dwarf mutant grmm and a normal inbred line Si 273, we identified a major pleiotropic QTL on the distal long arm of chromosome 1 (qPH1_dla), and found that qPH1_dla controlled plant height, flowering time, ear and yield traits. qPH1_dla was fine-mapped to a 16 kb interval containing ZmAMP1, which was annotated as a glutamate carboxypeptidase. Allelism tests using two independent allelic mutants confirmed that ZmAMP1 was the causal gene. Real-time quantitative PCR and genomic sequence analysis suggested that a nonsynonymous mutation at the 598th base of ZmAMP1 gene was the causal sequence variant for the dwarfism of grmm. This novel ZmAMP1 allele was named ZmAMP1_grmm. RNA sequencing using two pairs of near isogenic lines (NILs) showed that 84 up-regulated and 68 down-regulated genes in dwarf NILs were enriched in 15 metabolic pathways. Finally, introgression of ZmAMP1_grmm into Zhengdan 958 and Xianyu 335 generated two improved F1 lines. In field tests, they were semi-dwarf, early-flowering, lodging-resistant, and high-yielding under high-density planting conditions, suggesting that ZmAMP1_grmm is a promising Green Revolution gene for maize hybrid breeding.

The Effect of Topping and spacing on the production and seeds quality of Cucumber (Cucumis sativus L.)

This research is intended to obtain information on the yield power of these hybrid candidates. This research was conducted in November 2020 – January 2021. Located on the land of PT. Aditya Sentana Agro, Jl. Zentana No. 87, Karangploso District, Malang Regency, East Java. This study used a Randomized Block Design (RCBD) with 1 treatment factor, namely 5 different genotypes consisting of 4 F1 melon lines and 1 comparison variety, namely Melindo-15 F1. 5 genotype, namely M0 : Melindo-15 F1, M1 : 821-41 x 1197- 118, M2 : 1197-19 x 1211-32, M3 : 1197-127 x 821-70, and M4 : 1211-7 x 1197-106. The results showed that the data information of the melon F1 line as a candidate variety with superior characters was significantly different on the parameters of harvest age and not significantly different on all parameters in quantitative research, weight of 1000 grains, weight per fruit, production per Ha. The results of the selection of 4 F1 melon lines that have yield potential exceeding the Melindo-15 F1 variety, namely the type of melon M1 (821-41 x 1197-118) with production per ha of 25.24 tons/ha and M3 (1197-127 x 821- 70) with production per Ha of 21.69 Ton/Ha

Abstract 6207: Ba/F3 kinase mutant cell panel, a powerful cell model for the discovery and development of inhibitors for kinase specific mutation

Abstract Although over 70 protein kinase inhibitors have been approved by FDA since 2001, the protein kinase is still the hot target class of molecularly targeted cancer therapy because of the discovery of new driver kinase fusion mutation and a large number of secondary kinase mutations after the inhibitor treatment in cancer patients with the sequencing technology advancement, the need for new generation specific small molecule kinase inhibitors is still unmet, and it urge the industry to development more accurate, efficient kinase cellular assay models.Ba/F3 line is a popular cell model because many protein kinases and their mutants can transform the Ba/F3 cells to be growth independent of exogenous IL-3 supplement, while their inhibitors can antagonize these effects. Our group have generated a large of cell line panel with over 300 different well validated (sequencing, Western Blot and inhibitor test) Ba/F3 kinase cell lines for kinase inhibitor screening and development, covering several hot kinases, such as EGFR, EML-ALK, FLT3, NTRK, ROS1, HER, BCR-ABL, RET, FGFR1, FGFR2, FGFR3, FGFR4, KRAS, cMET, et al. Except used in in vitro high-throughput compound screening, most of the transformed Ba/F3 lines can grow well in immune-deficient mice and were also used to evaluate the efficacy of drug candidate and its downstream signaling in vivo. Our data indicate that our Ba/F3 cell line panel is a powerful cell model for new kinase inhibitor discovery and development. Citation Format: Yu Wang, Yao Peng, Yao Tang, Lin Zhou, Jinying Ning, Feng Hao. Ba/F3 kinase mutant cell panel, a powerful cell model for the discovery and development of inhibitors for kinase specific mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6207.

Identification and validation of quantitative trait loci for a parameter associated with nitrogen partitioning to grain using a population derived from japonica- and indica-type cultivars of rice (Oryza sativa L.)

ABSTRACT Nitrogen (N) partitioning to grain affects productivity and grain quality in rice. The objectives of this study were to clarify the difference between the rice cultivars ‘Momiroman’ (japonica) and ‘Takanari’ (indica) in the relation between the amount of total N in aboveground parts per grain dry weight (TNA/GW) and grain N concentration (GNC), to identify quantitative trait loci (QTLs) associated with the coefficient characterizing this relation by using populations derived from a cross between Momiroman and Takanari, and to verify the effects of the detected QTLs by using near-isogenic lines (NILs). We used 156 F2 plants grown under high N in 2015 and 156 F3 lines grown under high or low N in 2016, and determined N concentrations and contents in grain and aboveground vegetative parts. We found a logarithmic relation between GNC and TNA/GW in Momiroman and Takanari. The regression coefficient (A) was higher in Takanari. Under each N condition, A was calculated for each population and QTL analysis was performed. QTLs for A were detected on chromosomes (Chrs.) 6 and 10 in all conditions; the Takanari alleles of both QTLs increased the value. NILs with the Takanari allele in each region had higher A than NILs with the Momiroman alleles. We conclude that the QTLs for A are associated with N partitioning to grain in rice. Abbreviations: GNA, amount of N in grain; GNC, grain N concentration; GW, grain dry weight; TNA, amount of N in aboveground parts

Developing and deploying an efficient genotyping workflow for accelerating maize improvement in developing countries

Background: Molecular breeding is an essential tool for accelerating genetic gain in crop improvement, towards meeting the need to feed an ever-growing world population. Establishing low-cost, flexible genotyping platforms in small, public and regional laboratories can stimulate the application of molecular breeding in developing countries. These laboratories can serve plant breeding projects requiring low- to medium-density markers for marker-assisted selection (MAS) and quality control (QC) activities. Methods: We performed two QC and MAS experiments consisting of 637 maize lines, using an optimised genotyping workflow involving an in-house competitive allele-specific PCR (KASP) genotyping system with an optimised sample collection, preparation, and DNA extraction and quantitation process. A smaller volume of leaf-disc size plant samples was collected directly in 96-well plates for DNA extraction, using a slightly modified CTAB-based DArT DNA extraction protocol. DNA quality and quantity analyses were performed using a microplate reader, and the KASP genotyping and data analysis was performed in our laboratory. Results: Applying the optimized genotyping workflow expedited the QC and MAS experiments from over five weeks (when outsourcing) to two weeks and eliminated the shipping cost. Using a set of 28 KASP single nucleotide polymorphisms (SNPs) validated for maize, the QC experiment revealed the genetic identity of four maize varieties taken from five seed sources. Another set of 10 KASP SNPs was sufficient in verifying the parentage of 390 F1 lines. The KASP-based MAS was successfully applied to a maize pro-vitamin A (PVA) breeding program and for introgressing the aflatoxin resistance gene into elite tropical maize lines. Conclusion: This improved workflow has helped accelerate maize improvement activities of IITA's Maize Improvement Program and facilitated DNA fingerprinting for tracking improved crop varieties. National Agricultural Research Systems (NARS) in developing countries can adopt this workflow to fast-track molecular marker-based genotyping for crop improvement.

Assessment of cowpea (<i>Vigna unguiculata (L.</i>) Walp) F<sub>1</sub> lines response to drought tolerance

The objective of this study was to develop cowpea lines and assess them for drought tolerance using the pot screening approach. F1 lines were developed between September and November 2019 at University for Development Studies’ plant house. The drought experiment was conducted between February to March 2020. The F1 lines were developed by an artificial hybridization between the genotype ITK93-503-1 used as a male parent, obtained from the International Institute of Tropical Agriculture. This was crossed to 4 local genotypes used as female parents. The populations raised from the crosses were used to conduct the drought experiment. The experiment was Complete Randomized Design in; a 2 * 5 factorial experiment with 10 experimental units replicated three times, giving a total of 30 experimental units. The factors were; AbF1, GoF1, MF1, SaF1, ITK93-503-1 by Stress and Non-stress conditions. Plants were subjected to water stress for a period of 25 days and various drought related parameters were measured and analyzed. Results showed that water stress significantly (P<0.05) affected the chlorophyll content, leaf area and stem lodging for all F1 lines, however, water stress did not significantly (P>0.05) affect relative leaf water content of the F1 lines. The study showed that F1 lines (AbF1 and GoF1) performed better in chlorophyll content, leaf area, seedling recovery rate and plant main stem lodging. SaF1 recorded the highest relative leaf water content. Identified lines with drought tolerance potential should be further evaluated in subsequent generations to confirm their tolerance to drought for further selection and improvement.

The maize low-lignin brown midrib3 mutant shows pleiotropic effects on photosynthetic and cell wall metabolisms in response to chilling

Maize (Zea mays L.) is one of the major cereal crops in the world and is highly sensitive to low temperature. Here, changes in photosynthetic and cell wall metabolisms were investigated during a long chilling exposure in inbred line F2 and a low-lignin near-isogenic brown midrib3 mutant (F2bm3), which has a mutation in the caffeic acid O-methyltransferase (COMT) gene. Results revealed that the plant biomass was reduced, and this was more pronounced in F2bm3. Photosynthesis was altered in both lines with distinct changes in photosynthetic pigment content between F2bm3 and F2, indicating an alternative photoprotection mechanism between lines under chilling. Starch remobilization was observed in F2bm3 while concentrations of sucrose, fructose and starch increased in F2, suggesting a reduced sugar partitioning in F2. The cell wall was altered upon chilling, resulting in changes in the composition of glucuronorabinoxylan and a reduced cellulose level in F2. Chilling shifted lignin subunit composition in F2bm3 mutant to a higher proportion of p-hydroxyphenyl (H) units, whereas it resulted in lignin with a higher proportion of syringyl (S) residues in F2. On average, the total cell wall ferulic acid (FA) content increased in both genotypes, with an increase in ether-linked FA in F2bm3, suggesting a greater degree of cross-linking to lignin. The reinforcement of the cell wall with lignin enriched in H-units and a higher concentration in cell-wall-bound FA observed in F2bm3 as a response to chilling, could be a strategy to protect the photosystems.

Adult plant leaf rust resistance QTL derived from wheat line CI13227 maps to chromosomes 2AL, 4BS, and 7AL.

The winter wheat (Triticum aestivum L.) line CI13227 has been characterized as having adult plant resistance to leaf rust caused by Puccinia triticina Eriks (Pt). Line CI13227 was crossed with the susceptible spring wheat 'Thatcher' (Tc) and a Tc*2/CI13227 F6 line with adult plant leaf rust resistance designated as 411A was derived. Line 411A was crossed with Tc to develop an F6 recombinant inbred line (RIL) population. The parents and 120 F6 lines were assessed for leaf rust severity at the flag leaf stage in five field plot tests from 2011 through 2015 and were genotyped for single-nucleotide polymorphism (SNP) markers with the Illumina iSelect 90K wheat bead array. A total of 2,384 SNP markers segregated among the RILs. Completely linked SNPs were removed, and 474 markers that covered 2,605 centimorgans (cM) were used for linkage map construction. Quantitative trait loci (QTL) on chromosome 2AL with logarithm of odds (LOD) values 2.34-7.88, on chromosome 4BS with LOD values 1.35- 4.66, and on chromosome 7AL with LOD values 2.92-7.81 were associated with significant reduction in leaf rust severity in the field plot tests. Recombinant inbred lines that had combinations of two or three of the QTL had significantly lower leaf rust severity than RILs that lacked any resistance QTL. Kompetitive allele specific polymerase chain reaction (KASP) markers were developed for the SNPs that were closely linked with the three QTL to facilitate marker-based selection of the leaf rust resistance in breeding programs.

Bulk RNA-Seq Analysis Reveals Differentially Expressed Genes Associated with Lateral Branch Angle in Peanut.

Lateral branch angle (LBA), or branch habit, is one of the most important agronomic traits in peanut. To date, the underlying molecular mechanisms of LBA have not been elucidated in peanut. To acquire the differentially expressed genes (DEGs) related to LBA, a TI population was constructed through the hybridization of a bunch-type peanut variety Tifrunner and prostrate-type Ipadur. We report the identification of DEGs related to LBA by sequencing two RNA pools, which were composed of 45 F3 lines showing an extreme opposite bunch and prostrate phenotype. We propose to name this approach Bulk RNA-sequencing (BR-seq) as applied to several plant species. Through BR-seq analysis, a total of 3083 differentially expressed genes (DEGs) were identified, including 13 gravitropism-related DEGs, 22 plant hormone-related DEGs, and 55 transcription factors-encoding DEGs. Furthermore, we also identified commonly expressed alternatively spliced (AS) transcripts, of which skipped exon (SE) and retained intron (RI) were most abundant in the prostrate and bunch-type peanut. AS isoforms between prostrate and bunch peanut highlighted important clues to further understand the post-transcriptional regulatory mechanisms of branch angle regulation. Our findings provide not only important insights into the landscape of the regulatory pathway involved in branch angle formation but also present practical information for peanut molecular breeding in the future.

Application of 3D-volumetric analysis and hyperspectral imaging systems for investigation of heterosis and cytoplasmic effects in pepper

Compared with the substantial amount of genomics data generated in recent years, phenotypic data availability for crops is largely restricted in spectrum and quantity. High-throughput phenotyping (HTP) platforms have been developed to overcome this limitation, not only by enhancing the speed and accuracy of phenotyping but also by expanding the range of evaluable traits through integration of various imaging systems. Three-dimensional (3D) imaging enables non-destructive estimation of plant volume and structure. Hyperspectral imaging (HSI) generates reflectance data for a broad range of wavelengths that are associated with diverse physiological traits. We performed a pilot study to apply 3D and HSI for investigation of heterosis and cytoplasmic effects that have been evaluated previously based on manually analyzable traits. The plant volumes estimated from 3D images by a customized pipeline quantitatively showed heterosis in three cross combinations between genetically distant pepper (Capsicum annuum) accessions. The normalized difference vegetation index (NDVI) derived from HSI reflectance data also showed differences between parental and F1 lines. The cytoplasmic effects investigated by comparison of F1 lines derived from reciprocal crosses was subtle and thus was not detected in plant volume or NDVI values. However, the difference between F1 lines was detected in a subset of cross combinations at a specific developmental stage based on reflectance for wavelength ranges selected as the most relevant. The results showed the potential utility of HSI data recorded throughout the plant life-span for analysis of cytoplasmic effects. The present study demonstrated the applicability of a HTP platform integrated with 3D and HSI systems for evaluation of combining ability in crops.

Association and Path Analysis of Yield and Its Component Traits for Yield Maximization in Green Gram (Vigna radiata L. Wilczek)

The present investigation was undertaken to estimate the correlation coefficients among thirteen quantitative traits and to study the direct and indirect effects of various yield contributing traits on grain yield by path analysis. Ten genetically diverse genotypes of green gram (Vigna radiata L.) were used as parents in line x tester mating design in addition to their twenty four F2 lines at Educational and Research farm, Department of Genetics and Plant Breeding, Brahmanand P.G. College, Rath (Hamirpur), Uttar Pradesh during zaid, 2019 in a randomized block design with three replications each. The results of association study revealed that grain yield per plant showed highly significant and positive correlation, at both genotypic and phenotypic levels, with number of days to flowering, number of pods per cluster, number of clusters per plant, number of pods per plant and biological yield per plant (g) indicating possibility of simultaneous improvement for these traits. However, yield per plant for parents showed significant negative correlation with primary branches per plant and harvest index at both genotypic and phenotypic levels. In contrast, only clusters per plant, pods per cluster, pods per plant, biological yield per plant, seeds per pod, seed weight per pod and 100 seed weight exhibited significant positive association in F2 generation, indicating existence of linkage. Harvest index had negative association with most of the traits at genotypic as well as phenotypic levels. Path analysis revealed that, biological yield per plant; harvest index and seeds per pod recorded the high direct effect in desirable direction. Their association with grain yield was also significant and positive except with harvest index, indicating true and perfect association between these traits at both genotypic and phenotypic levels. Therefore, direct selection for these characters would help in isolating high yielding genotypes from highly segregating population. Among the traits showing negative direct effects were days to 50% flowering, branches per plant, plant height, pods per plant and seed weight per pod, however, these trait had positive association with yield. Hence, biological yield per plant, harvest index, seeds per pod and clusters per plant may be improved to enhance seed yield per plant and hybridization followed by direct and indirect selection for these traits may be undertaken for breeding high yielding cultivars.

The effects of genetic variation in seed parent lines for high biomass F1 sorghum (Sorghum bicolor) in the breeding process

AbstractThe agronomic traits of sorghum F1 lines from 93 seed parent lines crossed with a fixed pollen parent were evaluated in three different locations, namely, Chiba, Miyazaki and Nagano, in Japan in 2016 and 2017. Genomic DNA extraction from 93 sorghum parental lines and subsequent analysis were performed for determining genetic diversity. Data on single nucleotide polymorphisms (SNPs) were obtained through the Genotyping by Sequencing method. Overall, 3,577 SNPs were obtained from the parent seed lines and were grouped into four clusters characterized by stem length and lodging resistance. Genome‐wide association studies were conducted using field data to identify genes that conferred agronomic traits. There were peaks in stem length, dry matter weight, lodging and aphid damage on Chr. 9, which covered the Dw1 gene locus, suggesting that the gene exerted a multi‐faced effect on agronomic traits. The F1 lines from the seed parent lines with the homozygous dw1 mutant gene were likely to have shorter stem length, lower dry matter weight, resistance to lodging and severer aphid damage.

Screening out the Early Matured ‘Boro Rice’ Genotype for Bangladesh Condition Based on their Physico-chemical Characteristics and Yields

In Bangladesh conditions, the end of the Boro season begins floods and natural calamities and loses more rice in farmer's fields. If we can select early maturity genotypes for the Boro season, we can harvest our rice from the farmer's field before flooding or any other natural calamities. The study attempted to determine the short duration and high yielding rice genotype for Boro season in Bangladesh amongst the 13 Boro rice F6 lines by contrast with two (2) test varieties. Keeping in view this idea, the output of the genotypes studied, the relationship between different morpho-physio-chemical and yield-contributing characteristics between all the genotypes were investigated there under field and laboratory conditions. Among these 15 lines, G11 line showed better in the most yield contributing parameters. It is therefore concluded that the G11 genotype will be considered an appropriate line for the Boro season in Bangladesh.