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1.
Crosses between Gossypium barbadense L and Gossypium hirsutum L. (Upland cotton) have produced limited success in introgressing fiber quality genes into the latter. Chromosome substitution lines (CSBL) have complete chromosomes or chromosome arms from G. barbadense, line 3-79, substituted for the corresponding chromosome or arms in G. hirsutum in a near isogenic background of TM-1. We top crossed nine CSBL and their parents (TM-1 and 3-79) with five cultivars. Parental lines and their F2 populations were evaluated in four environments for agronomic and fiber quality traits. The CSBL and their F2 hybrids showed wide ranges for both agronomic and fiber traits of economic importance. Genetic analysis showed that additive variances were larger than dominance variances for lint percentage, boll weight, lint yield, fiber length, strength, elongation, micronaire, and yellowness; whereas, dominance variances were larger than additive variances only for uniformity of fiber length and equal for fiber reflectance. For all traits, except boll weight and lint yield, significant additive effects of one or more chromosomes from 3-79 in TM-1 background were greater than the corresponding TM-1 chromosome. In addition, we identified specific chromosomes from G. barbadense (3-79) that carry alleles for improvements in specific fiber quality traits in Upland cotton. Favorable additive effects of individual chromosomes or chromosome segments from 3-79 relative to corresponding chromosomes or chromosomes segments from TM-1 were identified in this study as follows: Lint percentage, chromosome/arms 10, 16-15; longer fibers, chromosome/arms 01, 11sh, 26Lo; more uniform fibers, chromosomes/arms 01, 11sh, 10, 17-11; stronger fibers, chromosome/arms 01, 11sh, 12sh, 26Lo, 17-11; fiber elongation, chromosomes/arms 01, 11sh, 26Lo, 10, 17-11; reduced fiber micronaire, chromosome/arms 01, 12sh, 4-15, 16-15, 17-11; fibers with more reflectance, chromosome/arms 10, 4-15, 16-15, 17-11; fiber with less yellowness, chromosome arms 4-15, 17-11. Based on the present study, we concluded that by using CSBL, favorable fiber quality alleles can be introgressed into Upland cotton, thus greatly improving the breeder’s ability for improvement of Upland cotton for a variety of traits. These data should provide useful genetic information to the cotton breeding industry at large.  相似文献   

2.
Improving fiber quality properties of cotton is important for increasing the efficiency of manufacturing textiles, including enhancing yarn quality and spinning performance. This study was conducted to determine if we could identify valuable cotton cultivars to use as parents in breeding programs with the goal of improving fiber properties. Seven parents were combined in a diallel design and selfed to obtain 21 F2 populations. Positive general and specific combining ability effects were observed for all traits. General combining ability tended to be larger than specific combining ability, indicating these traits are controlled primarily by additive genetic effects. Correlations among traits were generally positive except for lint yield correlations with fiber strength and length. For improving the fiber quality measures of strength and length, line 7235 shows excellent general combining ability effects. SG125 would provide elite germplasm to increase agronomic measures of lint yield and lint percent. The MD51 genotype has the highest potential among the genotypes tested here to provide germplasm combining both improved yield and fiber strength. These parents, or their selected progeny, should be useful in a breeding program to generate variability from which selection can be used to identify lines with improved fiber and/or agronomic properties.  相似文献   

3.
The ovules at the stage of fiber initiation from −1 to +1 days post-anthesis (dpa) were studied, using scanning electron microscopy (SEM), in five Upland cotton (Gossypium hirsutum L.) cultivars varying in lint percentage from 28.53% to 43.10%. Our results indicated that on −1 days post-anthesis (−1 dpa), fiber cell protrusions were found in all cultivars, but these protrusions varied among different materials and the differences did not correlate with ultimate lint percentage of each cultivar. At 0 days post-anthesis (dpa), a large amount of fiber cell protrusions appeared on the ovular surface of all samples, and these protrusions had been elongated significantly by +1 dpa. Interestingly, fiber density at +1 dpa of almost all samples was always significantly lower than that at 0 dpa except Simian3, the cultivar with the highest lint percentage 43.10%. This observation suggests that with the expanding of the cotton ovular volume, fiber “diluting” degree on the ovular surfaces might be related to higher or lower lint percentage. Qiannong465, the cultivar with the lowest lint percentage (28.53%), was found to exhibit the fewest fiber protrusions. Rather, many sunken, morphologically abnormal protrusions were observed on the ovular surface at 0 dpa. Correlation analysis suggested that either fiber protrusion density at 0 dpa or fiber elongation density at +1 dpa had a highest positive correlation with lint percentage, secondly with lint index. The grey relational analysis was essentially consistent with these findings. Thus we have identified two important parameters that could provide invaluable predictive information for cotton breeding.  相似文献   

4.
Gossypium barbadense L. cotton has significantly better fiber quality than Upland cotton (G. hirsutum L.); however, yield and environmental adaptation of G. barbadense is not as wide as Upland. Most cotton in the world is planted to Upland cultivars. Many attempts have been made, over a considerable number of years, to introgress fiber quality alleles from G. barbadense into Upland. However, introgression barriers, primarily in the form of interspecific incompatibility, have limited these traditional approaches. The use of chromosome substitution lines (CSL) as a bridge should provide a more efficient way to introgress alleles from G. barbadense into Upland. We crossed 18 G. barbadense CSL to three cultivars and developed a random mated population. After five cycles of random mating followed by one generation of self-pollination to increase the seed supply, we grew the random mated population and used 139 G. barbadense chromosome specific SSR markers to assess a random sample of 96 plants for introgression. We recovered 121 of 139 marker loci among the 96 plants. The distribution of the G. barbadense alleles ranged from 10 to 28 alleles in each plant. Among the 96 plants we found individual plants with marker loci from 6 to 14 chromosomes or chromosome arms. Identity by descent showed little relatedness among plants and no population structure was indicated by a heat map. Using CSL we were able to develop a mostly Upland random mated population with considerable introgression of G. barbadense alleles which should be useful for breeding.  相似文献   

5.
Developing chromosome segments substitution lines (CSSLs) is an effective method for broadening the cotton germplasm resource, and improving the fiber quality and yield traits. In this study, the 1054 F2 individual plants and 116 F2:3 lineages were generated from the two parents of MBI9749 and MBI9915 selected from BC5F3:5 lines which originated from hybridization of CCRI36 and Hai1, and advanced backcrossing and repeated selfing. Genotypes of the parents and F2 population were analyzed. The results showed that 19 segments were introgressed for MBI9749 and 12 segments were introgressed for MBI9915, distributing on 17 linkage groups. The average background recovery rate to the recurrent parent CCRI36 was 96.70% for the two parents. An average of 16.46 segments was introgressed in F2 population. The average recovery rate of 1054 individual plants was 96.85%, and the mean length of sea island introgression segments was 157.18 cM, accounting for 3.15% of detection length. QTL mapping analysis detected 22 QTLs associated with fiber quality and yield traits in the F2 and F2:3 populations. These QTLs distributed on seven chromosomes, and the phenotypic variation was explained ranging from 1.20 to 14.61%. Four stable QTLs were detected in F2 and F2:3 populations, simultaneously. We found that eight QTLs were in agreement with the previous research. Six QTL-clusters were identified for fiber quality and yield traits, in which five QTL-clusters were on chromosome20. The results indicated that most of QTL-clusters always improve the fiber quality and have negative additive effect for yield related traits. This study demonstrated that CSSLs provide basis for fine mapping of the fiber quality and yield traits in future, and could be efficiently used for pyramiding favourable alleles to develop the new germplasms for breeding by molecular marker-assisted selection.  相似文献   

6.
Wei Zhu  Kui Liu  Xue-De Wang 《Euphytica》2008,164(1):283-291
Leaf shape is an important factor affecting canopy structure, photosynthetic characteristics, and yield. Introducing okra leaf shape is considered an important strategy in cotton heterosis breeding. The objective of the study was to evaluate the heterosis in okra leaf cotton hybrid F1s, which were developed by crossing two sterile near isolines and three restorer near isolines. A normal leaf check hybrid F1, Zhongza 29, and four newly developed okra leaf oriented hybrid F1s, including the super-okra (severely cleft and narrowly lobed leaf), okra (deeply cleft and narrowly lobed leaf), semi-okra (intermediate leaf lobe), and sub-okra (large leaf lobe) hybrids were selected in this experiment. Okra leaf oriented cotton hybrids significantly reduced leaf area index (LAI) (P < 0.0001), thus more light penetrated into the lower canopy. The LAIs for the super-okra and okra hybrids, however, were too small to supply adequate photosynthate, thus resulting in early maturity, short boll filling period, and low yield. As the LAI increases, the semi-okra and sub-okra hybrids showed certain heterosis. The semi-okra hybrid showed 7–12% heterosis over the check hybrid in lint percent, 6–11% in boll weight, 2–147% in canopy light intensity, 1–10% in net photosynthetic rate (Pn), and −3 to 3% in lint yield. As well, all tested okra leaf hybrids improved fiber quality such as micronaire compared with the normal leaf check hybrid. The results suggested that adopting okra leaf parental lines in cotton breeding provided potentials in increasing fiber quality with comparable lint yield.  相似文献   

7.
Verticillium wilt (VW, Verticillium dahliae) is a worldwide destructive soil-borne fungal disease and employment of VW resistant cultivars is the most economic and efficient method in sustainable cotton production. However, information concerning VW resistance in current commercial cotton cultivars and transfer of VW resistance from Pima (Gossypium barbadense) to Upland (Gossypium hirsutum) cotton is lacking. The objective of the current study was to report findings in evaluating commercial cotton cultivars and germplasm lines for VW resistance in field and greenhouse (GH) experiments conducted in 2003, 2006, and 2007. In the study, 267 cultivars and germplasm lines were screened in the GH, while 357 genotypes were screened in the field. The results indicated that (1) VW significantly reduced cotton yield, lint percentage, 50% span length and micronaire, but not 2.5% span length and fiber strength, when healthy and diseased plants in 23 cultivars were compared; (2) some commercial cotton cultivars developed by major cotton seed companies in the US displayed good VW resistance; (3) many Acala cotton cultivars released in the past also had good VW resistance, but not all Acala cotton germplasm are resistant; (4) Pima cotton possessed higher levels of VW resistance than Upland cotton, but the performance was reversed when the root system was wounded after inoculation; (5) VW resistance in some conventional cultivars was transferred into their transgenic version through backcrossing; and (6) some advanced backcross inbred lines developed from a cross between Upland and Pima cotton showed good VW resistance. The successful development of VW resistant transgenic cultivars and transfer of VW resistance from Pima to Upland cotton implies that VW resistance is associated with a few genes if not a major one.  相似文献   

8.
Sticky cotton causes severe processing problems at textile mills and can be caused by plant sugars deposited directly from the plant to the lint in the absence of insects. A partial diallel design was used to investigate the combining ability of six upland cotton, Gossypium hirsutum L., genotypes in Lubbock, Texas. Sucrose and glucose on fibers were measured as well as more mechanical fiber properties including stickiness ratings. Variance component analysis indicated significant differences among genotypes for all fiber traits and for sugar content. The greatest differentiation occurred in samples taken from more immature fruiting forms. Moreover, significant GCA and SCA differences were determined among parental lines for fiber traits including stickiness ratings. Findings suggest that breeding efforts could be directed toward lines with a low likelihood of producing sticky cotton.  相似文献   

9.
Quantitative trait loci (QTL) associated with four milling recovery properties, two chemical properties, six paste properties of grain, and six textural parameters of cooked rice were identified using an introgression line (IL) population of rice developed from an interspecific cross over two years. The IL population consisted of 121 lines from a cross between wild rice (O. rufipogon Griff.) and a japonica cultivar. A total of 28 QTLs were identified for the 14 traits using inter mapping. Of these, 10 were significant over two years indicating that these QTLs are stable across years and environments. For eight (21%) of the QTLs identified, the O. rufipogonderived alleles contributed a desirable effect on amylose content, protein content, minimum viscosity, final viscosity, and consistency. Among these, pc3 for protein content and ac7 for amylose content were significant in both years and showed an R2 value of 25.5 and 30.9%, respectively. The markers closely associated with these useful alleles can be used to trace the inheritance of specific chromosome segments in the IL population and also offer a starting point for map-based cloning of genes underlying these traits.  相似文献   

10.
Late blight (Phytophthora infestans) can have devastating effects on tomato production over the whole world. Most of the commercial cultivars of tomato, Solanum lycopersicum, are susceptible. Qualitative and quantitative resistance has been described in wild relatives of tomato. In general qualitative resistance can more easily be overcome by newly evolved isolates. Screening of three S. habrochaites accessions (LA1033, LA2099 and LA1777) through a whole plant assay showed that accession LA1777 had a good level of resistance to several isolates of P. infestans. To explore the potential in this wild species, an introgression line (IL) population of S. habrochaites LA1777 was used to screen individual chromosome regions of the wild species by a detached leaf assay. Two major isolates (T1,2 and T1,2,4) were used and two parameters were measured: lesion size (LS), and disease incidence (DI). Substantial variation was observed between the individual lines. QTLs were identified for LS but not for DI. The presence of five QTLs derived from LA1777 (Rlbq4a, Rlbq4b, Rlbq7, Rlbq8 and Rlbq12) results in unambiguous higher levels of resistance. All QTLs co-localized with previously described QTLs from S. habrochaites LA2099 except QTL Rlbq4b, which is therefore a novel QTL.  相似文献   

11.
The Texas High Plains often has extended periods between rainfall events, which can lead to a reduction in the yield and fiber quality of cotton (Gossypium hirsutum L.). It is known that cultivated cotton suffers from low levels of genetic diversity due to the over-use in breeding of similar gene pools, which may hinder breeding for drought tolerance. In this study, for the first time the novel variability or genetic diversity of morphological and agronomic traits possibly created by the chemical mutagen ethyl methanesulfonate (EMS) was evaluated to improve drought tolerance in cotton by traits’ response to different irrigation regimes. EMS is a chemical mutagen that has been shown to cause point mutations in the DNA of many model plants and crop species. Three EMS treated lines were advanced from the M1 to M4 generation as bulk-harvested populations. A diverse selection scheme was applied to capture most of the genetic trait-variability or diversity and superior lines in these populations. In 2014–2016 the diversity of these populations was evaluated based on four agronomic and thirteen morphological traits to determine differences in response to multiple irrigation rates. Analyses of these traits showed statistically significant (p?≤?0.05) differences between and within populations when compared to the original non-treated EMS source, with most of the variability being observed in the high irrigation rate. However, none of the EMS treated populations had significantly (p?≤?0.05) better lint yield than the commercial cultivar (control) in 2016. EMS yield performance was possibly constrained by the applied diverse selection scheme of this study. Traits such as total number of bolls, bolls retained at node 7 and below, and those retained between nodes 8 and 12, and bolls retained at node of first fruiting branch may be predictors to improve cotton production (yield) in water limiting environments.  相似文献   

12.
A phytase gene (phyA), isolated from Aspergillus ficuum (AF537344), was introduced into cotton (Gossypium hirsutum L.) by Agrobacterium-mediated transformation to increase the phosphorus (P) acquisition efficiency of cotton. Southern and Northern blot analyses showed that the phyA was successfully incorporated into the cotton genome and expressed in transgenic lines. After growing for 45 days with phytate (Po) as the only P source, the shoot and root dry weights of the transgenic plants all increased by nearly 2.0-fold relative to those of wild-type plants, but were similar to those of transgenic plants supplied with inorganic phosphorus. The phytase activities of root extracts prepared from transgenic plants were 2.4- to 3.6-fold higher than those from wild-type plants, and the extracellular phytase activities of transgenic plants were also 4.2- to 6.3-fold higher. Furthermore, the expressed phytase was secreted into the rhizospheres as demonstrated by enzyme activity staining. The transgenic plants accumulated much higher contents of total P (up to 2.1-fold after 30 days of growth) than the wild-type plants when supplied with Po. These findings clearly showed that cotton plant transformed with a fungal phytase gene was able to secret the enzyme from the root, which markedly improved the plant’s ability to utilize P from phytate. This may serve as a promising step toward the development of new cotton cultivars with improved phosphorus acquisition.  相似文献   

13.
Reduced leaf senescence (stay-green) has been demonstrated to improve tolerance of post-flowering moisture stress in grain sorghum. A number of quantitative trait loci (QTLs) associated with stay-green have been identified in sorghum, to facilitate transfer of this trait into adapted genetic backgrounds. This study reports initial evaluations, in both well watered and post-flowering stress environments, following partial introgression (BC2F3/BC1F4 generations) of four stable stay-green QTLs (StgB, Stg1, Stg3 and Stg4) from donor parent B35 to senescent variety R 16. The majority of the introgression lines had higher leaf chlorophyll levels at flowering (a distinctive trait of the donor parent) and a greater percentage green leaf area during the latter part of grain filling, than did R 16, indicating that the stay-green QTLs were expressed phenotypically in the R 16 background. None of the QTL introgression lines achieved the same level of stay-green as B35, however. Maintenance of a greater relative green leaf area during the latter half of grain filling was related to a greater relative grain yield in two of three post-flowering moisture deficit environments in which the materials were evaluated (r 2 = 0.34 in 2004–2005 and r 2 = 0.76 in 2005–2006), as was a direct measure of leaf chlorophyll in one of the post-flowering stress environments in which this was measured (r 2 = 0.42, P < 0.05). Thus the study provided useful evidence that the marker-assisted backcross transfer of stay-green QTLs from B35 into an adapted, but senescent background has the potential to enhance tolerance of post-flowering drought stress in sorghum.  相似文献   

14.
Direct seeding of rice is increasingly being practiced in both rainfed and irrigated areas because of labor shortage for transplanting and opportunities for crop intensification. However, poor crop establishment remains a major obstacle facing its large-scale adoption in areas prone to flooding. Screening of over 8,000 gene bank accessions and breeding lines identified a few tolerant genotypes. One of these, Khao Hlan On, was selected for mapping QTLs associated with tolerance using a backcross population with IR64 as a recurrent parent. Survival of BC2F2 lines varied from 0 to 68%, and averaged about 28%. A linkage map of 1475.7 cM with an average interval of 11.9 cM was constructed using 135 polymorphic SSRs and 1 indel marker. Five putative QTLs were detected, on chromosomes 1 (qAG-1-2), 3 (qAG-3-1), 7 (qAG-7-2), and 9 (qAG-9-1 and qAG-9-2), explaining 17.9 to 33.5% of the phenotypic variation, and with LOD scores of 5.69–20.34. Khao Hlan On alleles increased tolerance of flooding during germination for all the QTLs. Graphical genotyping of the lines with highest and lowest survival verified the detected QTLs that control tolerance and some QTLs co-localize with previously identified QTLs for traits relevant to tolerance, which warrant further studies.  相似文献   

15.
In order to implement reliable marker-assisted selection systems for the restorer-of-fertility locus (Ms) in onions (Allium cepa L.), simple PCR-based codominant markers linked to the Ms locus were developed. Based on the EST probe sequences of previously reported RFLP markers, full-length genomic sequences of the gene encoding putative oligopeptide transporter (OPT) was obtained by RACE. The first intron contained two 108 and 439-bp indel polymorphisms between the two Ms allele-linked OPT alleles. A simple PCR marker for OPT was developed by designing a primer pair on the flanking regions of the 108-bp indel which is created by two tandem repeats. The second simple PCR marker was developed from the EST probe encoding photosystem I subunit O (PsaO). Two 14 and 39-bp tandem repeats were identified from the 5′ upstream sequences of the PsaO-coding gene, which were isolated by genome walking. Three different compositions of these tandem repeats were identified from diverse onion germplasm. A primer set binding to the flanking sequence of these polymorphic repeats was used to amplify three different marker haplotypes. The OPT marker was tightly linked to the Ms locus at a distance of 1.5 cM, but the analysis of the linkage relationship showed little linkage disequilibrium between the marker and the Ms locus. Even so, these simple PCR markers are valuable tools for the marker-assisted selection of segregating individuals in onion F1 hybrid breeding programs.  相似文献   

16.
A genetic analysis of blast resistance in upland rice variety is very crucial. In this study, we performed a linkage mapping of quantitative trait loci (QTLs) for blast resistance using an advanced backcross population from a cross between Way Rarem (susceptible indica variety) and Oryzica Llanos 5 (durable resistant indica variety). A transgressive segregation was observed in the advanced backcross population of Way Rarem//Oryzica Llanos 5. A total of 16 QTLs have been identified along chromosomes 1, 3, 5, 6, 7, 8, 9, and 11 against eight blast pathogen isolates. Each QTL accounted from 11.31 to 45.11% of the variation in blast resistance. Most QTLs showed race specificity, demonstrating the small effect of such QTLs. Unexpectedly, several superior blast resistance alleles were contributed by Way Rarem, the susceptible-recurrent parent. Among eight candidate defense response genes detected in several loci, a single gene (oxalate oxidase) present on chromosome 3 was found to be associated with blast resistance in upland indica rice. Ultimately, these advanced backcross lines with resistance to blast tagged by markers might be useful for pyramiding blast resistance alleles in upland rice.  相似文献   

17.
Investigation of cotton nutritional components is important because its seeds provide a useful nutritional profile and can possibly serve as a biofuel resource. In this study, five cultivars, 13 cotton chromosome substitution (CS-B) lines, their donor parent, '3-79', and their recurrent parent, 'TM-1', were evaluated for seed traits over four environments. A mixed linear model approach with the jackknife method was employed to estimate variance components and to predict genotypic effects for each seed trait. Genotypic effects were more important than genotype by environment interaction for all seed traits. Chromosome associations with these seed traits were detected using the comparative method by comparing the differences between each CS-B line and TM-1. For example, chromosome 4 of 3-79 in TM-1 background was associated with reduced seed index (SI), embryo percentage, protein percentage while associated with increased seed oil percentage and seed fiber percentage. Other chromosome associations with these seed traits were also observed in this study. SI was highly correlated with three seed index traits: seed protein index, seed oil index (OI), and seed fiber index. Lint percentage, boll number, and lint yield were positively correlated with protein percentage while negatively correlated with SI and OI. SI and seed fiber content exhibited negative correlations with micronaire but positive correlations with fiber length and strength. Results suggested that agronomic traits and seed nutrition components can be improved simultaneously.  相似文献   

18.
Molecular markers have been successfully used in rice breeding however available markers based on Oryza sativa sequences are not efficient to monitor alien introgression from distant genomes of Oryza. We developed O. minuta (2n = 48, BBCC)-specific clones comprising of 105 clones (266–715 bp) from the initial library composed of 1,920 clones against O. sativa by representational difference analysis (RDA), a subtractive cloning method and validated through Southern blot hybridization. Chromosomal location of O. minuta-specific clones was identified by hybridization with the genomic DNA of eight monosomic alien additional lines (MAALs). The 37 clones were located either on chromosomes 6, 7, or 12. Different hybridization patterns between O. minuta-specific clones and wild species such as O. punctata, O. officinalis, O. rhizomatis, O. australiensis, and O. ridleyi were observed indicating conservation of the O. minuta fragments across Oryza spp. A highly repetitive clone, OmSC45 hybridized with O. minuta and O. australiensis (EE), and was found in 6,500 and 9,000 copies, respectively, suggesting an independent and exponential amplification of the fragment in both species during the evolution of Oryza. Hybridization of 105 O. minuta specific clones with BB- and CC-genome wild Oryza species resulted in the identification of 4 BB-genome-specific and 14 CC-genome-specific clones. OmSC45 was identified as a fragment of RIRE1, an LTR-retrotransposon. Furthermore this clone was introgressed from O. minuta into the advanced breeding lines of O. sativa.  相似文献   

19.
A recombinant inbred line (RIL) population with 305 lines derived from a cross of Hanxuan 10 × Lumai 14 was used to identify the dynamic quantitative trait loci (QTL) for plant height (PH) in wheat (Triticum aestivum L.). Plant heights of RILs were measured at five stages in three environments. Total of seven genomic regions covering PH QTL clusters on different chromosomes identified from a DH population derived from the same cross as the RIL were used as the candidate QTLs and extensively analyzed. Five additive QTLs and eight pairs of epistatic QTLs significantly affecting plant height development were detected by unconditional QTL mapping method. Six additive QTLs and four pairs of epistatic QTLs were identified using conditional mapping approach. Among them, three additive QTLs (QPh.cgb-1B.3, QPh.cgb-4D.1, QPh.cgb-5B.2) and three pairs of epistatic QTLs (QPh.cgb-1B.1–QPh.cgb-1B.3, QPh.cgb-2A.1–QPh.cgb-2D.1, QPh.cgb-2D.1–QPh.cgb-5B.2) were common QTLs detected by both methods. Three QTLs (QPh.cgb-4D.1, QPh.cgb-5B.3, QPh.cgb-5B.4) were expressed under both drought and well-water conditions. The present data are useful for wheat genetic manipulations through molecular marker-assisted selection (MAS), and provides new insights into understanding the genetic mechanism and regulation network underlying the development of plant height in crops. Our result in this study indicated that combining unconditional and conditional mapping methods could make it possible to reveal not only the stable/conserved QTLs for the developmental traits such as plant height but also the dynamic expression feature of the QTLs.  相似文献   

20.
It is well known that genetic mutation could be generated by physical treatment (for example, γ-irradiation) and chemical treatment (for example methylnitrosourea and ethyl methanesulfonate). Here we reported identification of a virescent mutation (vsp) after exposing the upland cotton (Gossypium hirsutum L.) CCRI58 seeds in space environments. vsp mutant was characterized at the morphological, agronomic, cellular and genetic levels. vsp mutant showed an earlier virescence and specific only to true leaves. Agronomic traits of vsp mutant, such as plant height, number of bolls, boll weight, yield and fiber quality were significantly lower than those of CCRI 58. Chlorophyll level, carotenoid level and photochemical efficiency of vsp mutant true leaves were significantly lower compared to CCRI 58 at young leave stage. Anatomical studies of chloroplasts showed that vsp mutant lacked grana in the thylakoids of the mesophyll cells at young leave stage, while CCRI 58 showed normal grana in the thylakoids of the mesophyll cells at young leave stage. This indicated that chlorophyll and carotenoid levels were related with chloroplast structure. Genetic analysis indicated that vsp was controlled by one recessive gene in nucleus. Allelic tests showed that vsp was nonallelic to 12 virescent genes currently available at Anyang, China. In summary, we identified a vsp mutant after exposing the upland cotton (Gossypium hirsutum L.) seeds in space environments. vsp could be a newly identified virescent gene. vsp may also be used as a marker in cotton breeding programs. Exposing seeds in space environments could cause new spectrum of genetic mutations and could be used for breeding programs.  相似文献   

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