scholarly journals Mapping Quantitative Trait Loci for Days-to-heading, and Culm, Panicle and Internode Lengths in a BC1F3 Population Using an Elite Rice Variety, Koshihikari, as the Recurrent Parent.

2001 ◽  
Vol 51 (2) ◽  
pp. 63-71 ◽  
Author(s):  
Toshio Yamamoto ◽  
Fumio Taguchi-Shiobara ◽  
Yasuo Ukai ◽  
Takuji Sasaki ◽  
Masahiro Yano
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Rice Variety ◽  
Recurrent Parent ◽  
Days To Heading ◽  
Trait Loci

scholarly journals Chlorophyll Retention and High Photosynthetic Performance Contribute to Salinity Tolerance in Rice Carrying Drought Tolerance Quantitative Trait Loci (QTLs)

Agriculture ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 620
Author(s):  
Noppawan Nounjan ◽  
Wuttipong Mahakham ◽  
Jonaliza L. Siangliw ◽  
Theerayut Toojinda ◽  
Piyada Theerakulpisut
Keyword(s):  
Salt Stress ◽  
Quantitative Trait Loci ◽  
Salt Tolerance ◽  
Drought Tolerance ◽  
Quantitative Trait ◽  
Photosynthetic Performance ◽  
Chromosome 8 ◽  
Recurrent Parent ◽  
Putative Gene ◽  
Trait Loci

Jasmine rice (Oryza sativa L.), or Khao Dawk Mali 105 (KDML105), is sensitive to drought and salt stresses. In this study, two improved drought-tolerant chromosome segment substitution lines (CSSLs) of KDML105 (CSSL8-103 and CSSL8-106), which carry drought tolerance quantitative trait loci (QTLs) on chromosome 8, were evaluated for salt tolerance and were compared with KDML105 and the QTL donor DH103, their parents and the salt-tolerant genotype Pokkali. After being subjected to salt stress for 6 days, 3-week-old seedlings of Pokkali showed the highest salt tolerance. Parameters related to photosynthesis were less inhibited in both CSSLs and the donor DH103, while these parameters were more severely damaged in the recurrent parent KDML105. Albeit a high ratio of Na+/K+, CSSLs and DH103 showed similar or higher contents of soluble sugar and activity of superoxide dismutase (SOD; EC1.15.1.1) compared with Pokkali, indicating possible mechanisms of either tissue or osmotic tolerance in these plants. The expression of a putative gene Os08g41990 (aminotransferase), which is located in DT-QTL and is involved in chlorophyll biosynthesis, significantly decreased under salt stress in KDML105 and CSSL8-103, while no obvious change in the expression of this gene was observed in Pokkali, DH103 and CSSL8-106. This gene might play a role in maintaining chlorophyll content under stress conditions. Taken together, the results of this study indicate that DT-QTL could contribute to the enhancement of photosynthetic performance in CSSL lines, leading to changes in their physiological ability to tolerate salinity stress.

The relationship between loci for mating system and fitness-related traits in Mimulus (Scrophulariaceae): A test for deleterious pleiotropy of QTLs with large effects

Genome ◽  
2000 ◽  
Vol 43 (4) ◽  
pp. 628-633 ◽  
Author(s):  
Jing-Zhong Lin
Keyword(s):  
Quantitative Trait Loci ◽  
Mating System ◽  
Quantitative Trait ◽  
Random Amplified Polymorphic Dna ◽  
Germination Rate ◽  
Pleiotropic Effects ◽  
Wild Plants ◽  
Recurrent Parent ◽  
Backcross Population ◽  
Trait Loci

Loci with large phenotypic effects are generally not thought to be important in the evolution of quantitative traits because of their deleterious pleiotropic effects, yet empirical studies of such pleiotropic effects are lacking. Here I use molecular markers to test the extent of deleterious pleiotropy of quantitative trait loci (QTLs) that have large effects on mating system differences between the wild plants Mimulus guttatus and M. platycalyx (Scrophulariaceae). Six fitness-related traits, namely germination rate (GR), number of nodes (NN), number of flowers (NF), plant height (HT), above-ground biomass (WT), and flowering time (FT) were examined in a growth chamber for a backcross population between M. guttatus and M. platycalyx (with M. platycalyx as recurrent parent). Interval mapping based upon a linkage map consisting of isozyme and random amplified polymorphic DNA (RAPD) markers detected no QTL for fitness-related traits near the mating system QTLs. Single-marker analysis based upon 13 markers flanking the mating system QTLs detected three significant marker-fitness trait associations, and these associations indicate beneficial effects of mating system loci. This suggests that QTLs with large effects on mating system traits do not have significant deleterious pleiotropic effects, and that they could be important factors in adaptive evolution of Mimulus.Key words: pleiotropy, mating system, fitness, quantitative trait loci, molecular marker.

Comparison of salt tolerance during seed germination and vegetative growth in tomato by QTL mapping

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 727-734 ◽  
Author(s):  
M R Foolad
Keyword(s):  
Quantitative Trait Loci ◽  
Salt Tolerance ◽  
Seed Germination ◽  
Lycopersicon Esculentum ◽  
Quantitative Trait ◽  
Vegetative Growth ◽  
Developmental Stages ◽  
Phenotypic Correlation ◽  
Recurrent Parent ◽  
Trait Loci

The purpose of this study was to determine the genetic relationship between salt tolerance during seed germination and vegetative growth in tomato by comparing quantitative trait loci (QTLs) which confer salt tolerance at these two developmental stages. A salt-sensitive Lycopersicon esculentum line (NC84173; maternal and recurrent parent) was hybridized with a salt-tolerant accession (LA722) of Lycopersicon pimpinellifolium, and BC1 and BC1S1 populations were developed. The BC1 population was used for RFLP mapping and the BC1S1 population for evaluation of salt tolerance during germination and vegetative growth. The results indicated the presence of a small but significant correlation (r = -0.22, p < 0.05) between rate of seed germination and the percentage of plant survival under salt stress. Seven and five QTLs were identified for salt tolerance during seed germination and vegetative growth, respectively. While in most cases the location of QTLs for germination was different from that for vegetative growth, there were some coincidences in QTL locations; this was consistent with the small phenotypic correlation observed between the two traits. The overall results indicated that, in these tomato genetic materials, salt tolerance during seed germination was independent of that during vegetative growth. However, simultaneous improvement of tolerance at the two developmental stages should be possible through marker-assisted selection and breeding.Key words: Lycopersicon esculentum, L. pimpinellifolium, salt tolerance, seed germination vegetative growth, restriction fragment length polymorphism (RFLP), quantitative trait loci (QTLs).

scholarly journals Assessment of 16 Peanut (Arachis hypogaea L.) CSSLs Derived from an Interspecific Cross for Yield and Yield Component Traits: QTL Validation

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 583 ◽  
Author(s):  
Hodo-Abalo Tossim ◽  
Joel Romaric Nguepjop ◽  
Cyril Diatta ◽  
Aissatou Sambou ◽  
Maguette Seye ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Seed Size ◽  
Quantitative Trait ◽  
Interspecific Cross ◽  
Yield Component ◽  
Recurrent Parent ◽  
Qtl Validation ◽  
Advanced Backcross ◽  
Lattice Design ◽  
Trait Loci

Cultivated peanut is an allotetraploid (2n = 4× = 40) with narrow genetic diversity. In previous studies, we developed an advanced backcross quantitative trait loci (AB-QTL) population from the cross between the synthetic allotetraploid ((Arachis ipaensis × Arachis duranensis)4×) and the cultivated variety Fleur11, and mapped several quantitative trait loci (QTLs) involved in yield and yield components. We also developed a chromosome segment substitution line (CSSL) population as a way to mendelize the QTLs and analyzing their effects. In this study, 16 CSSLs were used for assessing the contribution of wild alleles in yield performance and stability across environments, as well as validating QTLs for pod and seed size. The CSSLs and the recurrent parent Fleur11, used as a check, were assessed using an alpha lattice design in three locations during two consecutive rainy seasons in Senegal, totaling six environments. Our results showed that the chromosome segments from the wild species, in general, have no yield disadvantage and contributed positive variation to yield-related traits. Most of the QTLs detected for pod and seed size in the AB-QTL on linkage groups A07, A08, A09, and B06 were also found in the CSSLs, showing that the CSSLs used in this study are accurate material for QTL validation. Several new QTLs have also been identified. Two CSSLs (12CS_031 and 12CS_069) showed consistently higher pod and seed size than Fleur11 in all environments, suggesting that the QTLs were consistent and stable. Our study opens the way for pyramiding these QTLs for peanut improvement.

scholarly journals Quantitative Trait Loci (QTL) Analysis of Fruit and Agronomic Traits of Tropical Pumpkin (Cucurbita moschata) in an Organic Production System

Horticulturae ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 14 ◽  
Author(s):  
Angel R. Del Valle Echevarria ◽  
Alexandra Campbell ◽  
Theodore J. K. Radovich ◽  
Tia Silvasy ◽  
Sarah Moore ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Agronomic Traits ◽  
Consumer Preferences ◽  
Organic Production ◽  
Recurrent Parent ◽  
Cucurbita Moschata ◽  
Significant Qtls ◽  
Trait Loci ◽  
Organically Grown

Interest in the development of organically grown vegetable crops has risen over the past decades due to consumer preferences. However, most crops that have desirable consumer traits have been bred in conventional growing conditions, and their transfer to an organic setting is challenging. Here, the organically grown Hawaiian pumpkin (Cucurbita moschata) accession ‘Shima’ was crossed with the conventionally grown Puerto Rican variety ‘Taina Dorada’ to develop a backcross (BC1) population, where ‘Shima’ was the recurrent parent. A total of 202 BC1 (‘Shima’ X F1) progenies were planted in a certified organic field, and twelve traits were evaluated. We used genotype-by-sequencing (GBS) to identify the Quantitative Trait Loci (QTL) associated with insect tolerance along with commercially desirable traits. A total of 1582 single nucleotide polymorphisms (SNPs) were identified, from which 711 SNPs were used to develop a genetic map and perform QTL mapping. Reads associated with significant QTLs were aligned to the publicly available Cucurbita moschata genome and identified several markers linked to genes that have been previously reported to be associated with that trait in other crop systems, such as melon (Cucumis melo L.). This research provides a resource for marker-assisted selection (MAS) efforts in Cucurbita moschata, as well as serving as a model study to improve cultivars that are transitioning from a conventional to an organic setting.

scholarly journals Selection in backcross programmes

2005 ◽  
Vol 360 (1459) ◽  
pp. 1503-1511 ◽  
Author(s):  
Frédéric Hospital
Keyword(s):  
Molecular Markers ◽  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Quantitative Traits ◽  
Recurrent Parent ◽  
Breeding Scheme ◽  
Animal Populations ◽  
Trait Loci ◽  
Donor Parent ◽  
Genetic Value

Backcrossing is a well-known and long established breeding scheme where a characteristic is introgressed from a donor parent into the genomic background of a recurrent parent. The various uses of backcrossing in modern genetics, particularly with the help of molecular markers, are reviewed here. Selection in backcross programmes is used to either improve the genetic value of plant and animal populations or fine map quantitative trait loci. Both cases are helpful in our understanding of the genetic bases of quantitative traits variation.

Selection with Recurrent Backcrossing to Develop Congenic Lines for Quantitative Trait Loci Analysis

Genetics ◽  
1998 ◽  
Vol 148 (3) ◽  
pp. 1341-1352 ◽  
Author(s):  
William G Hill
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Recurrent Parent ◽  
Congenic Lines ◽  
Sewall Wright ◽  
Trait Loci ◽  
Analytical Formulas ◽  
Recurrent Backcrossing ◽  
Dense Set ◽  
Discriminating Ability

Abstract Sewall Wright suggested that genes of large effect on a quantitative trait could be isolated by recurrent backcrossing with selection on the trait. Loci [quantitative trait loci (QTL)] at which the recurrent and nonrecurrent lines have genes of different large effect on the trait would remain segregating, while other loci would become fixed for the gene carried by the recurrent parent. If the recurrent line is inbred and the backcrossing and selection is conducted in a series of replicate lines, in each of which only one backcross parent is selected for each generation, the lines will become congenic to the recurrent parent except for the QTL of large effect and closely linked regions of the genome, and these regions can be identified using a dense set of markers that differ between the parental lines. Such lines would be particularly valuable for subsequent fine-scale mapping and gene cloning; but by chance, even QTL of large effect will be lost from some lines. The probability that QTL of specified effect remain segregating is computed as a function of its effect on the trait, the intensity of selection, and the number of generations of backcrossing. Analytical formulas are given for one or two loci, and simulation is used for more. It is shown that the method could have substantial discriminating ability and thus potential practical value.

Tagging major quantitative trait loci for sheath blight resistance in a rice variety, Jasmine 85

1999 ◽  
Vol 44 (19) ◽  
pp. 1783-1789 ◽  
Author(s):  
Xuebiao Pan ◽  
Junhuang Zou ◽  
Zongxiang Chen ◽  
Jufei Lu ◽  
Hengxiu Yu ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Rice Variety ◽  
Sheath Blight ◽  
Blight Resistance ◽  
Trait Loci ◽  
Sheath Blight Resistance
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