scholarly journals Genetic dissection of heterosis of indica–japonica by introgression line, recombinant inbred line and their testcross populations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenqing Yang ◽  
Fan Zhang ◽  
Sundus Zafar ◽  
Junmin Wang ◽  
Huajin Lu ◽  
...  
Keyword(s):  
Grain Yield ◽  
Recombinant Inbred ◽  
Genetic Basis ◽  
Recombinant Inbred Lines ◽  
Introgression Line ◽  
Successful Implementation ◽  
Genetic Dissection ◽  
Single Nucleotide ◽  
Panicle Number ◽  
Main Effect

AbstractThe successful implementation of heterosis in rice has significantly enhanced rice productivity, but the genetic basis of heterosis in rice remains unclear. To understand the genetic basis of heterosis in rice, main-effect and epistatic quantitative trait loci (QTLs) associated with heterosis for grain yield-related traits in the four related rice mapping populations derived from Xiushui09 (XS09) (japonica) and IR2061 (indica), were dissected using single nucleotide polymorphism bin maps and replicated phenotyping experiments under two locations. Most mid-parent heterosis of testcross F1s (TCF1s) of XS09 background introgression lines (XSILs) with Peiai64S were significantly higher than those of TCF1s of recombinant inbred lines (RILs) with PA64S at two locations, suggesting that the effects of heterosis was influenced by the proportion of introgression of IR2061’s genome into XS09 background. A total of 81 main-effect QTLs (M-QTLs) and 41 epistatic QTLs were identified for the phenotypic variations of four traits of RILs and XSILs, TCF1s and absolute mid-parent heterosis in two locations. Furthermore, overdominance and underdominance were detected to play predominant effects on most traits in this study, suggesting overdominance and underdominance as well as epistasis are the main genetic bases of heterosis in rice. Some M-QTLs exhibiting positive overdominance effects such as qPN1.2, qPN1.5 and qPN4.3 for increased panicle number per plant, qGYP9 and qGYP12.1 for increased grain yield per plant, and qTGW3.4 and qTGW8.2 for enhanced 1000-grain weight would be highly valuable for breeding to enhance grain yield of hybrid rice by marker-assisted selection.

Overdominant Epistatic Loci Are the Primary Genetic Basis of Inbreeding Depression and Heterosis in Rice. I. Biomass and Grain Yield

Genetics ◽  
2001 ◽  
Vol 158 (4) ◽  
pp. 1737-1753 ◽  
Author(s):  
Zhi-Kang Li ◽  
L J Luo ◽  
H W Mei ◽  
D L Wang ◽  
Q Y Shu ◽  
...  
Keyword(s):  
Grain Yield ◽  
Inbreeding Depression ◽  
Genetic Basis ◽  
Mixed Model ◽  
Recombinant Inbred Lines ◽  
Hybrid Breakdown ◽  
Mixed Model Approach ◽  
Epistatic Qtl ◽  
Main Effect ◽  
Mapping Populations

AbstractTo understand the genetic basis of inbreeding depression and heterosis in rice, main-effect and epistatic QTL associated with inbreeding depression and heterosis for grain yield and biomass in five related rice mapping populations were investigated using a complete RFLP linkage map of 182 markers, replicated phenotyping experiments, and the mixed model approach. The mapping populations included 254 F10 recombinant inbred lines derived from a cross between Lemont (japonica) and Teqing (indica) and two BC and two testcross hybrid populations derived from crosses between the RILs and their parents plus two testers (Zhong 413 and IR64). For both BY and GY, there was significant inbreeding depression detected in the RI population and a high level of heterosis in each of the BC and testcross hybrid populations. The mean performance of the BC or testcross hybrids was largely determined by their heterosis measurements. The hybrid breakdown (part of inbreeding depression) values of individual RILs were negatively associated with the heterosis measurements of their BC or testcross hybrids, indicating the partial genetic overlap of genes causing hybrid breakdown and heterosis in rice. A large number of epistatic QTL pairs and a few main-effect QTL were identified, which were responsible for >65% of the phenotypic variation of BY and GY in each of the populations with the former explaining a much greater portion of the variation. Two conclusions concerning the loci associated with inbreeding depression and heterosis in rice were reached from our results. First, most QTL associated with inbreeding depression and heterosis in rice appeared to be involved in epistasis. Second, most (~90%) QTL contributing to heterosis appeared to be overdominant. These observations tend to implicate epistasis and overdominance, rather than dominance, as the major genetic basis of heterosis in rice. The implications of our results in rice evolution and improvement are discussed.

scholarly journals Genetic dissection of QTLs associated with spikelet-related traits and grain size in sorghum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hideki Takanashi ◽  
Mitsutoshi Shichijo ◽  
Lisa Sakamoto ◽  
Hiromi Kajiya-Kanegae ◽  
Hiroyoshi Iwata ◽  
...  
Keyword(s):  
Grain Size ◽  
Recombinant Inbred ◽  
Genetic Basis ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Thickness Ratio ◽  
Width Ratio ◽  
Genetic Dissection ◽  
Sessile Spikelet ◽  
Length Width

AbstractAlthough spikelet-related traits such as size of anther, spikelet, style, and stigma are associated with sexual reproduction in grasses, no QTLs have been reported in sorghum. Additionally, there are only a few reports on sorghum QTLs related to grain size, such as grain length, width, and thickness. In this study, we performed QTL analyses of nine spikelet-related traits (length of sessile spikelet, pedicellate spikelet, pedicel, anther, style, and stigma; width of sessile spikelet and stigma; and stigma pigmentation) and six grain-related traits (length, width, thickness, length/width ratio, length/thickness ratio, and width/thickness ratio) using sorghum recombinant inbred lines. We identified 36 and 7 QTLs for spikelet-related traits and grain-related traits, respectively, and found that most sorghum spikelet organ length- and width-related traits were partially controlled by the dwarf genes Dw1 and Dw3. Conversely, we found that these Dw genes were not strongly involved in the regulation of grain size. The QTLs identified in this study aid in understanding the genetic basis of spikelet- and grain-related traits in sorghum.

scholarly journals Recombinant inbred lines derived from cultivars of pea for understanding the genetic basis of variation in breeders' traits

2018 ◽  
Vol 16 (5) ◽  
pp. 424-436 ◽  
Author(s):  
Carol Moreau ◽  
Maggie Knox ◽  
Lynda Turner ◽  
Tracey Rayner ◽  
Jane Thomas ◽  
...  
Keyword(s):  
Recombinant Inbred ◽  
Seed Weight ◽  
Genetic Basis ◽  
Recombinant Inbred Lines ◽  
Field Trials ◽  
Genetic Maps ◽  
Genotypic Differences ◽  
Phenotypic Data ◽  
Growing Seasons ◽  
Randomized Field Trials

AbstractIn order to gain an understanding of the genetic basis of traits of interest to breeders, the pea varieties Brutus, Enigma and Kahuna were selected, based on measures of their phenotypic and genotypic differences, for the construction of recombinant inbred populations. Reciprocal crosses were carried out for each of the three pairs, and over 200 F2 seeds from each cross advanced to F13. Bulked F7 seeds were used to generate F8–F11 bulks, which were grown in triplicated plots within randomized field trials and used to collect phenotypic data, including seed weight and yield traits, over a number of growing seasons. Genetic maps were constructed from the F6 generation to support the analysis of qualitative and quantitative traits and have led to the identification of four major genetic loci involved in seed weight determination and at least one major locus responsible for variation in yield. Three of the seed weight loci, at least one of which has not been described previously, were associated with the marrowfat seed phenotype. For some of the loci identified, candidate genes have been identified. The F13 single seed descent lines are available as a germplasm resource for the legume and pulse crop communities.

scholarly journals Genetic dissection of climacteric fruit ripening in a melon population segregating for ripening behavior

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Lara Pereira ◽  
Miguel Santo Domingo ◽  
Valentino Ruggieri ◽  
Jason Argyris ◽  
Michael A. Phillips ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
Ethylene Production ◽  
Genome Wide Association Study ◽  
Recombinant Inbred Lines ◽  
Introgression Line ◽  
Complex Trait ◽  
Chromosome 8 ◽  
Genetic Dissection ◽  
Climacteric Fruit ◽  
A Genome

Abstract Melon is as an alternative model to understand fruit ripening due to the coexistence of climacteric and non-climacteric varieties within the same species, allowing the study of the processes that regulate this complex trait with genetic approaches. We phenotyped a population of recombinant inbred lines (RILs), obtained by crossing a climacteric (Védrantais, cantalupensis type) and a non-climcteric variety (Piel de Sapo T111, inodorus type), for traits related to climacteric maturation and ethylene production. Individuals in the RIL population exhibited various combinations of phenotypes that differed in the amount of ethylene produced, the early onset of ethylene production, and other phenotypes associated with ripening. We characterized a major QTL on chromosome 8, ETHQV8.1, which is sufficient to activate climacteric ripening, and other minor QTLs that may modulate the climacteric response. The ETHQV8.1 allele was validated by using two reciprocal introgression line populations generated by crossing Védrantais and Piel de Sapo and analyzing the ETHQV8.1 region in each of the genetic backgrounds. A Genome-wide association study (GWAS) using 211 accessions of the ssp. melo further identified two regions on chromosome 8 associated with the production of aromas, one of these regions overlapping with the 154.1 kb interval containing ETHQV8.1. The ETHQV8.1 region contains several candidate genes that may be related to fruit ripening. This work sheds light into the regulation mechanisms of a complex trait such as fruit ripening.

scholarly journals Genetic dissection of yield-related traits and mid-parent heterosis for those traits in maize (Zea mays L.)

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Qiang Yi ◽  
Yinghong Liu ◽  
Xianbin Hou ◽  
Xiangge Zhang ◽  
Hui Li ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Recombinant Inbred Lines ◽  
Kernel Weight ◽  
Genetic Dissection ◽  
Hybrid Mapping ◽  
Maize Breeding ◽  
Phenotypic Variations ◽  
Selection For ◽  
Genomic Regions ◽  
Mapping Populations

Abstract Background Utilization of heterosis in maize could be critical in maize breeding for boosting grain yield. However, the genetic architecture of heterosis is not fully understood. To dissect the genetic basis of yield-related traits and heterosis in maize, 301 recombinant inbred lines derived from 08 to 641 × YE478 and 298 hybrids from the immortalized F2 (IF2) population were used to map quantitative trait loci (QTLs) for nine yield-related traits and mid-parent heterosis. Results We observed 156 QTLs, 28 pairs of loci with epistatic interaction, and 10 significant QTL × environment interactions in the inbred and hybrid mapping populations. The high heterosis in F1 and IF2 populations for kernel weight per ear (KWPE), ear weight per ear (EWPE), and kernel number per row (KNPR) matched the high percentages of QTLs (over 50%) for those traits exhibiting overdominance, whereas a notable predominance of loci with dominance effects (more than 70%) was observed for traits that show low heterosis such as cob weight per ear (CWPE), rate of kernel production (RKP), ear length (EL), ear diameter (ED), cob diameter, and row number (RN). The environmentally stable QTL qRKP3–2 was identified across two mapping populations, while qKWPE9, affecting the trait mean and the mid-parent heterosis (MPH) level, explained over 18% of phenotypic variations. Nine QTLs, qEWPE9–1, qEWPE10–1, qCWPE6, qEL8, qED2–2, qRN10–1, qKWPE9, qKWPE10–1, and qRKP4–3, accounted for over 10% of phenotypic variation. In addition, QTL mapping identified 95 QTLs that were gathered together and integrated into 33 QTL clusters on 10 chromosomes. Conclusions The results revealed that (1) the inheritance of yield-related traits and MPH in the heterotic pattern improved Reid (PA) × Tem-tropic I (PB) is trait-dependent; (2) a large proportion of loci showed dominance effects, whereas overdominance also contributed to MPH for KNPR, EWPE, and KWPE; (3) marker-assisted selection for markers at genomic regions 1.09–1.11, 2.04, 3.08–3.09, and 10.04–10.05 contributed to hybrid performance per se and heterosis and were repeatedly reported in previous studies using different heterotic patterns is recommended.

scholarly journals Association mapping and genetic dissection of drought-induced canopy temperature differences in rice

2019 ◽  
Vol 71 (4) ◽  
pp. 1614-1627 ◽  
Author(s):  
Giovanni Melandri ◽  
Ankush Prashar ◽  
Susan R McCouch ◽  
Gerard van der Linden ◽  
Hamlyn G Jones ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Grain Yield ◽  
Canopy Temperature ◽  
Leaf Temperature ◽  
Genetic Dissection ◽  
Single Nucleotide ◽  
Genome Wide ◽  
A Genome ◽  
Snp Map ◽  
Trait Locus

Abstract Drought-stressed plants display reduced stomatal conductance, which results in increased leaf temperature by limiting transpiration. In this study, thermal imaging was used to quantify the differences in canopy temperature under drought in a rice diversity panel consisting of 293 indica accessions. The population was grown under paddy field conditions and drought stress was imposed for 2 weeks at flowering. The canopy temperature of the accessions during stress negatively correlated with grain yield (r= –0.48) and positively with plant height (r=0.56). Temperature values were used to perform a genome-wide association (GWA) analysis using a 45K single nucleotide polynmorphism (SNP) map. A quantitative trait locus (QTL) for canopy temperature under drought was detected on chromosome 3 and fine-mapped using a high-density imputed SNP map. The candidate genes underlying the QTL point towards differences in the regulation of guard cell solute intake for stomatal opening as the possible source of temperature variation. Genetic variation for the significant markers of the QTL was present only within the tall, low-yielding landraces adapted to drought-prone environments. The absence of variation in the shorter genotypes, which showed lower leaf temperature and higher grain yield, suggests that breeding for high grain yield in rice under paddy conditions has reduced genetic variation for stomatal response under drought.

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