Recipient Parent Research Articles

Genetic Variability and Association Studies for Morpho-floral Traits in Backcross Introgression Lines of Rice (Oryza sativa L.)

Background: Wild introgressions are pivotal in enriching the genetic diversity of cultivated varieties by introducing novel alleles beneficial for crop improvement. Understanding insights into genetic variability and association studies of morphological and floral traits are crucial for enhancing hybrid seed production in rice. Methods: 290 backcross introgression lines (BC4F2) from inter-specific cross of CRMS 32B (maintainer of male sterile line as low stigma exsertion recipient parent) cv. Oryza sativa with Oryza longistaminata (wild rice as high stigma exsertion donor parent) were assessed for 12 morpho-floral traits. The experiment was laid out in randomized complete block design (RCBD) at Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, during Kharif, 2019. Result: ANOVA results showed significant differences among lines for all examined traits. The phenotypic coefficient of variation (PCV) was slightly greater than genotypic coefficient of variation (GCV) for each trait. High PCV, GCV, heritability and genetic advance as percentage of mean were observed for dual stigma exsertion percentage (DSE%) and total stigma exsertion percentage (TSE%), whereas moderate to high values of these parameters were noted for single stigma exsertion percentage (SSE%), grain yield per plant (GYPP), effective tillers per plant (ETPP) and grains per panicle (GPP) traits. Most traits showed positive skewness, except traits SFP (spikelet fertility percentage), SSE% and TSE%. Most traits recorded leptokurtic kurtosis, whereas plant height (PH), GYPP and TSE% exhibited platykurtic kurtosis. TSE% displayed a highly significant positive association with SSE% and DSE%, while GYPP showed a significant positive correlation with ETPP and GPP, presenting a promising opportunity for simultaneous selection of these traits.

QTL mapping for seed vigor-related traits under artificial aging in common wheat in two introgression line (IL) populations

Background Seed vigor recognized as a quantitative trait is of particular importance for agricultural production. However, limited knowledge is available for understanding genetic basis of wheat seed vigor. Methods The aim of this study was to identify quantitative trait loci (QTL) responsible for 10 seed vigor-related traits representing multiple aspects of seed-vigor dynamics during artificial aging with 6 different treatment times (0, 24, 36, 48, 60, and 72 h) under controlled conditions (48 °C, 95% humidity, and dark). The mapping populations were two wheat introgression lines (IL-1 and IL-2) derived from recipient parent (Lumai 14) and donor parent (Shaanhan 8675 or Jing 411). Results A total of 26 additive QTLs and 72 pairs of epistatic QTLs were detected for wheat seed-vigor traits. Importantly, chromosomes 1B and 7B contained several co-located QTLs, and chromosome 2A had a QTL-rich region near the marker Xwmc667, indicating that these QTLs may affect wheat seed vigor with pleiotropic effects. Furthermore, several possible consistent QTLs (hot-spot regions) were examined by comparison analysis of QTLs detected in this study and reported previously. Finally, a set of candidate genes for wheat seed vigor were predicted to be involved in transcription regulation, carbohydrate and lipid metabolism. Conclusion The present findings lay new insights into the mechanism underlying wheat seed vigor, providing valuable information for wheat genetic improvement especially marker-assisted breeding to increase seed vigor and consequently achieve high grain yield despite of further investigation required.

QTL Mapping of Fiber- and Seed-Related Traits in Chromosome Segment Substitution Lines Derived from Gossypium hirsutum × Gossypium darwinii.

A narrow genetic basis limits further the improvement of modern Gossypium hirsutum cultivar. The abundant genetic diversity of wild species provides available resources to solve this dilemma. In the present study, a chromosome segment substitution line (CSSL) population including 553 individuals was established using G. darwinii accession 5-7 as the donor parent and G. hirsutum cultivar CCRI35 as the recipient parent. After constructing a high-density genetic map with the BC1 population, the genotype and phenotype of the CSSL population were investigated. A total of 235 QTLs, including 104 QTLs for fiber-related traits and 132 QTLs for seed-related traits, were identified from four environments. Among these QTLs, twenty-seven QTLs were identified in two or more environments, and twenty-five QTL clusters consisted of 114 QTLs. Moreover, we identified three candidate genes for three stable QTLs, including GH_A01G1096 (ARF5) and GH_A10G0141 (PDF2) for lint percentage, and GH_D01G0047 (KCS4) for seed index or oil content. These results pave way for understanding the molecular regulatory mechanism of fiber and seed development and would provide valuable information for marker-assisted genetic improvement in cotton.

Genetic Regulatory Perturbation of Gene Expression Impacted by Genomic Introgression in Fiber Development of Allotetraploid Cotton.

Interspecific genomic introgression is an important evolutionary process with respect to the generation of novel phenotypic diversity and adaptation. A key question is how gene flow perturbs gene expression networks and regulatory interactions. Here, an introgression population of two species of allopolyploid cotton (Gossypium) to delineate the regulatory perturbations of gene expression regarding fiber development accompanying fiber quality change is utilized. De novo assembly of the recipient parent (G. hirsutum Emian22) genome allowed the identification of genomic variation and introgression segments (ISs) in 323 introgression lines (ILs) from the donor parent (G. barbadense 3-79). It documented gene expression dynamics by sequencing 1,284 transcriptomes of developing fibers and characterized genetic regulatory perturbations mediated by genomic introgression using a multi-locus model. Introgression of individual homoeologous genes exhibiting extreme low or high expression bias can lead to a parallel expression bias in their non-introgressed duplicates, implying a shared yet divergent regulatory fate of duplicated genes following allopolyploidy. Additionally, the IL N182 with improved fiber quality is characterized, and the candidate gene GhFLAP1 related to fiber length is validated. This study outlines a framework for understanding introgression-mediated regulatory perturbations in polyploids, and provides insights for targeted breeding of superior upland cotton fiber.

Nitrogen deficiency tolerance conferred by introgression of a QTL derived from wild emmer into bread wheat

Key messageGenetic dissection of a QTL from wild emmer wheat, QGpc.huj.uh-5B.2, introgressed into bread wheat, identified candidate genes associated with tolerance to nitrogen deficiency, and potentially useful for improving nitrogen-use efficiency.Nitrogen (N) is an important macronutrient critical to wheat growth and development; its deficiency is one of the main factors causing reductions in grain yield and quality. N availability is significantly affected by drought or flooding, that are dependent on additional factors including soil type or duration and severity of stress. In a previous study, we identified a high grain protein content QTL (QGpc.huj.uh-5B.2) derived from the 5B chromosome of wild emmer wheat, that showed a higher proportion of explained variation under water-stress conditions. We hypothesized that this QTL is associated with tolerance to N deficiency as a possible mechanism underlying the higher effect under stress. To validate this hypothesis, we introgressed the QTL into the elite bread wheat var. Ruta, and showed that under N-deficient field conditions the introgression IL99 had a 33% increase in GPC (p < 0.05) compared to the recipient parent. Furthermore, evaluation of IL99 response to severe N deficiency (10% N) for 14 days, applied using a semi-hydroponic system under controlled conditions, confirmed its tolerance to N deficiency. Fine-mapping of the QTL resulted in 26 homozygous near-isogenic lines (BC4F5) segregating to N-deficiency tolerance. The QTL was delimited from − 28.28 to − 1.29 Mb and included 13 candidate genes, most associated with N-stress response, N transport, and abiotic stress responses. These genes may improve N-use efficiency under severely N-deficient environments. Our study demonstrates the importance of WEW as a source of novel candidate genes for sustainable improvement in tolerance to N deficiency in wheat.

Accelerated breeding strategies for biochemical marker-assisted backcross breeding and mapping population development in bread wheat (Triticum aestivum L.)

In order to rapidly adapt to the evolving climate and sustainably nourish the growing global population, plant breeders are actively investigating more efficient strategies to enhance crop yields. In this study, we present the development of a bread wheat mapping population and backcross breeding program, serving as a valuable genetic resource for mapping the effects of different alleles on trait performance. We employed innovative methodologies to rapidly introgress traits into the bread wheat cultivar. Specifically, we utilized two parents, including Tosunbey x Tahirova2000, in a recombinant inbred line population, in addition, a backcross strategy was applied with line 148 (obtained by crossing Tosunbey x Tahirova2000 with high gluten quality) as the recipient parent of the Nevzatbey cv., known for its awnless feature. The two most important applications of the rapid breeding method are extending the light period and breaking dormancy in early harvested seeds. Both applications were successfully implemented in our study. Our vegetation periods ranging from approximately 50–60 days. Additionally, an early genotype in our developed population was harvested in 40 days. Considering that the genotype underwent a 15-day vernalization period, the generation cycle, including vernalization, drying, and refrigeration, was completed in a total of 64 days. Notably, we employed not only biochemical markers for selection but also incorporated the rapid generation advance technology known as ‘speed breeding’, allowing us to develop BC5F1 within a span of two years. We posit that this approach proves instrumental in swiftly transferring genes for multiple target traits into adapted wheat cultivars or in pyramiding desirable traits within elite breeding material.

Growth Evaluation of Backcross Progenies BC2F1 Experiencing Submerg-ence and Non-submergence at BC1F1 and its Parents

The utilization of dual-resistant varieties that are resistant to soaking and drought in certain periods is an alternative to rice cultivation in swampy land. Inpara 8 is a variety that is confirmed to have SUB 1 gene, resistant to submerged stress and Inpago 5 is identified to be resistant to drought stress. Crosses were made between Inpara 8 (donor parent) with Inpago 5 (recipient parent), resulting in F1, then F1 was crossed back with Inpago 5 and produced BC1F1, then crossed back with Inpago 5 to become BC2F1. This paper contains an evaluation of the growth of BC2F1, which in the BC1F1 stage experienced submerged stress in the vegetative phase and which did not experience submerged stress. The research was carried out in August 2021 - January 2022 at the Greenhouse of the Department of Agricultural Cultivation, Faculty of Agriculture, Sriwijaya University. The results showed that in the vegetative phase, progeny BC2F1 TR has an average value of the highest per plant (113.64 cm) and the average per plant height Inpara 8 (3.93). In the generative phase, the fastest flowering time on the accession of BC2F1 TR (68 days), the fastest harvest time on Inpara 8 (122.93 days), while for the amount of grain per panicle, the amount of grain per clump, and dry weight on Inpago 5 (529.60 g, 2648 g, and 11.62 g). The average yield of BC2F1 progeny is more similar to Inpago 5 as the recipient parent. Both progeny have the same Sub 1 gene in them and can survive to produce, but Accessions that have experienced previous submerged stress are more vulnerable to growth so they have an impact on the resulting production.

Reproductive Characteristics and Suitability of Sterile dead end Knockout Nibe Croaker as a Recipient for Intraperitoneal Germ Cell Transplantation.

The use of sterile recipients is crucial for efficiently producing donor-derived offspring through surrogate broodstock technology for practical aquaculture applications. Although knockout (KO) of the dead end (dnd) gene has been used in previous studies as a sterilization method, it has not been reported in marine fish. In this study, nibe croaker was utilized as a model for marine teleosts that produce small pelagic eggs, and the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (CRISPR/Cas9) system was utilized to produce dnd KO fish. The F1 generation, which carried a nonsense mutation in the dnd gene, was produced by mating founder individuals with wild-type counterparts. Subsequently, the F2 generation was produced by mating the resulting males and females. Among the F2 generations, 24.0% consisted of homozygous KO individuals. Histological analysis revealed that primordial germ cells (PGCs) were present in homozygous KO individuals at 10days post-hatching (dph), similar to wild-type individuals. However, by 20 dph, PGCs were absent in KO individuals. Furthermore, no germ cells were observed in the gonads of both sexes of homozygous KO individuals at 6months old, which is the typical maturity age for wild-type individuals of both sexes. In addition, when cryopreserved donor nibe croaker testicular cells were transplanted, only donor-derived offspring were successfully obtained through the spontaneous mating of homozygous KO recipient parents. Results indicate that dnd KO nibe croaker lacks germ cells and can serve as promising recipients, producing only donor-derived gametes as surrogate broodstock.

Donor-linking provisions in New Zealand: counselling roles, concerns and needs

Donor-linking where those genetically related through donor conception (e.g. donor-conceived persons (DCP), donors and siblings), or recipient parents, search for and connect with each other, is increasingly common, both in identity-release jurisdictions where donors’ identifying information may be released to DCP, usually when they become adults - and in anonymous jurisdictions, e.g. as a result of direct-to-consumer DNA testing. In this paper, we explore New Zealand fertility clinic counsellors’ views regarding their donor-linking roles and their concerns and needs in relation to current and anticipated service provision. Counsellors believed that fertility service providers had a longer-term responsibility to offer donor-linking services to ensure the wellbeing of all parties affected by donor conception. They perceived their role as complex and multifaceted, encompassing psychoeducation, mediation, advocacy, facilitation, relationship counselling, and therapeutic intervention. They identified significant service provision challenges however, including inadequate staffing, training, time and prioritisation of donor-linking, and inadequate legislative provisions to support practice. Counsellors called for clarity in legislation addressing different contexts of donation and providing measures to ensure the recording of and access to identifying information. They expressed a need for comprehensive, funded donor-linking services, therefore facilitating choice, and services staffed by professionally trained and supported staff.

Comparison of Blast, Bacterial Leaf Blight and Brown Plant Hopper Introgressed Lines for Yield and Morphological Traits Over Original Line

Rice as a staple food for very large population suffers from various biotic and abiotic stresses. Among the biotic stresses, Blast, Bacterial leaf blight and Brown plant hopper (BPH) are considered to most potential threats that significantly affect the rice productivity. The use of chemical usage for controlling these diseases and pest attacks is not environmentally friendly and is expensive. Using Molecular Marker assisted backcross breeding program we have improved one of our hybrid parental line with 5 genes (xa13, Xa21, Pi54, Bph20 and Bph21). We have developed 15 near isogenic lines having similar agronomical characters as of recipient parent, they are promising for their direct induction in breeding program. Our results indicated that out of fifteen lines, Six lines i.e. GK 101-12, GK 101-15, GK 101-9, GK 101-5 and GK 101-2 out-performed in all the three locations tested, they had not only have very high level of resistance to BLB, Blast and BPH but also showed significantly higher yield compared to susceptible check as well as recipient parent. These lines may be used for improvement of our existing hybrid and also for developing of new hybrids with other CMS lines. These lines are also useful for developing new set of restorer lines through (R x R) and also useful for introgression of wide spectrum of resistance to the varieties/hybrid.

PERCEPTION OF PARENT-STAKEHOLDERS IN THE SCHOOLS' READINESS AND IMPLEMENTATION OF DISTANCE LEARNING MODALITIES AT EASTERN SAMAR NATIONAL COMPREHENSIVE HIGH SCHOOL

The prime purpose of the study is to highlight the relationship between perceived schools readiness for distance learning and the perceived effectiveness of schools implementation of distance learning modalities of parents in Eastern Samar National Comprehensive High School, Borongan City Division, province of Eastern Samar, among parents whose children are recipients of the Pantawid Pamilyang Pilipino Program (4Ps) and officially enrolled during the school year 2021-2022. As a result, the researcher decided to investigate how well-prepared and successful the schools were at integrating distance learning modes from the perspective of the parents of students enrolled in ESNCHS. The researcher investigated the correlational relationship between readiness and perceived effectiveness of the three primary distance learning modalities in terms of curriculum support, instructional support, and overall learning program among Pantawid Pamilyang Pilipino Program (4Ps) recipient parents of Eastern Samar National Comprehensive High School for the School Year 2020-2021. The results appear to make sense due to the ready and very effective perceptions of the respondents based on the previously presented results. The finding implies the need to continuously implement good practices in monitoring learners learning activities even if they are not in school; that the teacher-parent relationship be strengthened through focus group activities to identify their strengths and weaknesses in assisting their children; and to regularly review the preparation, distribution, and retrieval of learning modules mechanism to cater the learning needs of the students better. KEYWORDS: Distance learning, Readiness of implementation, parent-stakeholders, COVID-19 Pandemic

Exploring horticultural traits and disease resistance in Capsicum baccatum through segmental introgression lines.

Segmental introgression and advanced backcross lines were developed and validated as important tools for improving agronomically important traits in pepper, offering improved sensitivity in detecting quantitative trait loci for breeding. Segmental introgression lines (SILs) and advanced backcross lines (ABs) can accelerate genetics and genomics research and breeding in crop plants. This study presents the development of a complete collection of SILs and ABs in pepper using Capsicum annuum cv. 'CM334' as the recipient parent and Capsicum baccatum 'PBC81', which displays various agronomically important traits including powdery mildew and anthracnose resistance, as donor parent. Using embryo rescue to overcome abortion in interspecific crosses, and marker-assisted selection with genotyping-in-thousands by sequencing (GT-seq) to develop SILs and ABs containing different segments of the C. baccatum genome, we obtained 63 SILs and 44 ABs, covering 94.8% of the C. baccatum genome. We characterized them for traits including powdery mildew resistance, anthracnose resistance, anthocyanin accumulation, trichome density, plant architecture, and fruit morphology. We validated previously known loci for these traits and discovered new sources of variation and quantitative trait loci (QTLs). A total of 15 QTLs were identified, including four for anthracnose resistance with three novel loci, seven for plant architecture, and four for fruit morphology. This is the first complete collection of pepper SILs and ABs validated for agronomic traits and will enhance QTL detection and serve as valuable breeding resources. Further, these SILs and ABs will be useful for comparative genomics and to better understand the genetic mechanisms underlying important agronomic traits in pepper, ultimately leading to improved crop productivity and sustainability.

Segregation of molecular markers associated with Bph3 gene in BC5F2 population derived from Ciherang rice variety as the recipient parent

Brown planthopper (BPH), an important insect pest of rice, can cause severe damage and significant yield loss. An efficient and environmentally friendly method to control this pest is by planting resistant varieties. The brown planthopper resistance gene Bph3 from Rathu Heenati variety is closely linked to the Waxy gene that regulates amylose synthesis, the primary determinant of rice eating and cooking quality. The purposes of this study were to analyze the segregation ratio of SSR markers associated with Bph3 gene and to identify individual plants carrying homozygous allele for Bph3 gene in a BC5F2 population derived from a backcross that used Ciherang as the recurrent recipient parent. Analyses using RM589, RM586, and RM588 markers linked to Bph3 gene and RM190 marker linked to the Waxy gene indicated that the ratio of genotype segregation for each marker related to Bph3 gene did not deviate from the expected ratio with the χ 2 value was 0.956, 0.587, and 1.467 for RM589, RM586, and RM588, respectively (χ2 table = 5.991, α=0,05). All individual plants had a homozygous allele from Ciherang for Waxy gene based on the RM190 marker. As many as 25 individual plants which have homozygous Bph3 allele from Rathu Heenati and homozygous Waxy allele from Ciherang can be further developed as promising BPH-resistant rice varieties with eating and cooking quality similar to Ciherang.

QGL3.4 controls kernel size and plant architecture in rice.

Kernel size and plant architecture play important roles in kernel yield in rice. Cloning and functional study of genes related to kernel size and plant architecture are of great significance for breeding high-yield rice. Using the single-segment substitution lines which developed with Oryza barthii as a donor parent and an elite indica cultivar Huajingxian74 (HJX74) as a recipient parent, we identified a novel QTL (quantitative trait locus), named qGL3.4, which controls kernel size and plant architecture. Compared with HJX74, the kernel length, kernel width, 1000-kernel weight, panicle length, kernels per plant, primary branches, yield per plant, and plant height of near isogenic line-qGL3.4 (NIL-qGL3.4) are increased, whereas the panicles per plant and secondary branches per panicle of NIL-qGL3.4 are comparable to those of HJX74. qGL3.4 was narrowed to a 239.18 kb interval on chromosome 3. Cell analysis showed that NIL-qGL3.4 controlled kernel size by regulating cell growth. qGL3.4 controls kernel size at least in part through regulating the transcription levels of EXPANSINS, GS3, GL3.1, PGL1, GL7, OsSPL13 and GS5. These results indicate that qGL3.4 might be beneficial for improving kernel yield and plant architecture in rice breeding.

Pyramiding resistance genes for bacterial leaf blight (Xanthomonas oryzae pv. Oryzae) into the popular rice variety, Pratikshya through marker assisted backcrossing.

Bacterial leaf blight (BLB) is one of the major biotic stress in rice cultivation. Management techniques, such as the development of BLB-resistant cultivars, are required to lessen the severity of the disease attack and yield losses. Pratikshya was selected in the present investigation as the recipient parent, as it is one of the popular high-yielding rice varieties of Odisha, India, which is having excellent grain as well as cooking quality. However, Pratikshya is highly susceptible to BLB which is prevalent in Eastern Indian region. Three major BLB resistance genes xa5, xa13, and Xa21 from the donor source Swarna MAS (CR Dhan 800) were attempted to introduce into Pratikshya through a marker-assisted backcross breeding program. Those markers closely linked to the target genes were employed for foreground selection in the segregating generations till BC2F3. In each backcross generation, progenies containing all three targeted resistance genes and phenotypically more similar to the recipient parent, Pratikshya were selected and backcrossed. Screening of 1,598 plants of the BC2F2 population was conducted against BLB using Xoo inoculum and 35 resistant plants similar to Pratikshya were carried forward to the next generation. In the BC2F3 generation, 31 plants were found to possess all the three resistance genes. For background selection of plants carrying resistance genes 45 polymorphic SSR markers were employed. Evaluation of the pyramided lines at BC2F4 generation exhibited that, most pyramided lines were similar to Pratikshya in terms of morphological features and yield parameters, and some lines were superior to the recurrent parent in terms of morphological features and yield parameters. The three-gene pyramided lines showed a high level of resistance to BLB infection and are anticipated to offer a significant yield advantage over the recipient parent Pratikshya.The pyramided lines can further be used for multi-location trial, so as to be released as a variety or can be used as a potential donor for BLB resistance genes.

GS6.1 controls kernel size and plant architecture in rice.

A novel QTL GS6.1 increases yield per plant by controlling kernel size, plant architecture, and kernel filling in rice. Kernel size and plant architecture are critical agronomic traits that greatly influence kernel yield in rice. Using the single-segment substitution lines (SSSLs) with an indica cultivar Huajingxian74 as a recipient parent and American Jasmine as a donor parent, we identified a novel quantitative trait locus (QTL), named GS6.1. Near isogenic line-GS6.1 (NIL-GS6.1) produces long and narrow kernels by regulating cell length and width in the spikelet hulls, thus increasing the 1000-kernel weight. Compared with the control, the plant height, panicles per plant, panicle length, kernels per plant, secondary branches per panicle, and yield per plant of NIL-GS6.1 are increased. In addition, GS6.1 regulates the kernel filling rate. GS6.1 controls kernel size by modulating the transcription levels of part of EXPANSINs, kernel filling-related genes, and kernel size-related genes. These results indicate that GS6.1 might be beneficial for improving kernel yield and plant architecture in rice breeding by molecular design.

“Tango for Two”: Women’s Interviews in Clinical Reproductive Practice

This article attempts to combine data obtained through interviews by a psychologist of female donors participating in an assisted reproductive technology program and interpret them through narrative analysis and communicative situation analysis. The article describes the structure of an oocyte-donor which has never been done before with reference to Russian-language material. An ethical platform for the study is openness to a new type of scientific knowledge that results from the interpretation of the informants’ answers who try to comprehend their motives to donate. The narrative analysis of 21 transcripts helps determine the roles of the interviewer and the informant at each stage and their contribution to the discussion-testing communicative situation. The interview includes several stages, such as “a window to the past”, at which the autobiographical narrative is recorded as comprehensively as possible; a description of the donor’s current state which focuses on strategies for solving problem situations; the interview ends with a series of thought experiments that allow the psychologist to assess the emotional stability of the potential donor and make a forecast regarding the prospects for long-term cooperation with the reproductive medicine clinic. The paper outlines the cases of participants’ cooperation and mismatches in building a credible and value-consistent autobiographical narrative that includes the donation experience. The authors seek to fit this experience into a broader value context, including a compensatory one related to the urgent problems of potential donors. Women’s answers help specify the concept of donor ‘multi-motivation’. The ambiguity of public opinion regarding donation as a reproductive medicine phenomenon is expressed in the fact that the availability of information for those who are aware of the issue co-exists with donors’ persistent reluctance to display their activity outside the inner circle. Research perspectives include the need to consider the narrative contribution of each participant in the situation of reproduction, i. e. physicians, donors, and recipient parents, and its further use in practice.

Transfer of Stress Resilient QTLs and Panicle Traits into the Rice Variety, Reeta through Classical and Marker-Assisted Breeding Approaches.

Reeta is a popular late-maturing high-yielding rice variety recommended for cultivation in the eastern Indian states. The cultivar is highly sensitive to submergence stress. Phosphorus deficiency is an additional constraint for realizing high yield. The quantitative trait loci (QTLs), Sub1, for submergence and Pup1 for low phosphorus stress tolerance along with narrow-grained trait, GW5 were introgressed into the variety from the donor parent, Swarna-Sub1 through marker-assisted breeding. In addition, phenotypic selections for higher panicle weight, grain number, and spikelet fertility were performed in each segregating generation. Foreground selection detected the 3 target QTLs in 9, 8 and 7 progenies in the BC1F1, BC2F1, and BC3F1 generation, respectively. Recurrent parent's genome recovery was analyzed using 168 SSR polymorphic markers. The foreground analysis in 452 BC3F2 progenies showed five pyramided lines in homozygous condition for the target QTLs. No donor fragment drag was noticed in the Sub1 and GW5 QTLs carrier while a segmentwas observed in the Pup1 carrier chromosome. The developed lines were higher yielding, had submergence, and had low phosphorus stress-tolerance alongwith similar to the recipient parent in the studied morpho-quality traits. A promising pyramided line is released in the name of Reeta-Panidhan (CR Dhan 413) for the flood-prone areas of Odisha state.

Parental Polymorphism between Samba Mahsuri and False Smut Tolerant Landraces using SSR and InDel Markers

In the present study, 868 SSR and 475 InDel markers were selected to study parental polymorphism of two different crosses between recipient parent Samba Mahsuri and false smut donor linesIC379047 and IC334233 at ICAR-Indian Institute of Rice Research, Rajendranagar, Hyderabad. Out of 1343 markers used for parental polymorphism, 100 markers were polymorphic between parental lines Samba Mahsuri and landrace IC379047 and the total polymorphism percentage recorded was 7.44%. Ninety-nine markers exhibited polymorphism between parental lines Samba Mahsuri and IC334233 and 7.37% of total polymorphism percentage was recorded between the parents. The identified polymorphic markers could be further used for QTL mapping studies in false smut resistance.

Development of novel gene-based markers for waxy1 gene and their validation for exploitation in molecular breeding for enhancement of amylopectin in maize.

Waxy corn possessing high amylopectin is widely employed as an industrial product. Traditional corn contains ~ 70-75% amylopectin, whereas waxy corn with the mutant waxy1 (wx1) gene possesses ~ 95-100% amylopectin. Marker-assisted breeding can greatly hasten the transfer ofthe wx1 allele into normal corn. However, the available gene-based marker(s) for wx1 are not always polymorphic between recipient and donor parents, thereby causing a considerable delay in the molecular breeding program. Here, a 4800bp sequence ofthe wx1 gene was analyzed among seven wild-type and seven mutant inbreds employing 16 overlapping primers. Three polymorphisms viz., 4bp InDel (at position 2406bp) in intron-7 and two SNPs (C to A at position 3325bp in exon-10 and G to T at position 4310bp in exon-13) differentiated the dominant (Wx1) and recessive (wx1) allele. Three breeder-friendly PCR markers (WxDel4, SNP3325_CT1, and SNP4310_GT2) specific to InDel and SNPs were developed. WxDel4 amplified 94bp among mutant-type inbreds, while 90bp was amplified among wild-type inbreds. SNP3325_CT1 and SNP4310_GT2 revealed the presence-absence polymorphisms with an amplification of 185bp and 189bp of amplicon, respectively. These newly developed markers showed 1:1 segregation in both BC1F1 and BC2F1 generations, while 1:2:1 segregation was observed in BC2F2. The recessive homozygotes (wx1wx1) of BC2F2 identified by the markers possessed significantly higher amylopectin (97.7%) compared to the original inbreds (Wx1Wx1: 72.7% amylopectin). This is the first report of novel wx1 gene-based markers. The information generated here would help in accelerating the development of waxy maize hybrids.