Home About us Contact
|
Home About us Contact | ||
|
|
||
Doubled Haploid (doubled + haploid)
Terms modified by Doubled Haploid Selected AbstractsQuantitative Trait Loci for Panicle Layer Uniformity Identified in Doubled Haploid Lines of Rice in Two EnvironmentsJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2009Liangyong Ma Abstract Uniformity of stem height in rice directly affects crop yield potential and appearance, and has become a vital index for rice improvement. In the present study, a doubled haploid (DH) population, derived from a cross between japonica rice Chunjiang 06 and indica rice TN1 was used to analyze the quantitative trait locus (QTL) for three related traits of panicle-layer-uniformity; that is, the tallest panicle height, the lowest panicle height and panicle layer disuniformity in two locations: Hangzhou (HZ) and Hainan (HN). A total of 16 QTLs for three traits distributed on eight chromosomes were detected in two different environments. Two QTLs, qTPH -4 and qTPH -8 were co-located with the QTLs for qLPH -4 and qLPH -8, which were only significant in the HZ environment, whereas the qTPH -6 and qLPH -6 located at the same interval were only significant in the HN environment. Two QTLs, qPLD -10-1 and qPLD -10-2, were closely linked to qTPH-10, and they might have been at the same locus. One QTL, qPLD -3, was detected in both environments, explaining more than 23% of the phenotypic variations. The CJ06 allele of qPLD -3 could increase the panicle layer disuniformity by 9.23 and 4.74 cm in the HZ and HN environments. Except for qPLD -3, almost all other QTLs for the same trait were detected only in one environment, indicating that these three traits were dramatically affected by environmental factors. The results may be useful for elucidation of the molecular mechanism of panicle-layer-uniformity and marker assisted breeding for super-rice. [source] A Genetic Map Constructed Using a Doubled Haploid Population Derived from Two Elite Chinese Common Wheat VarietiesJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 8 2008Kun-Pu Zhang Abstract Genetic mapping provides a powerful tool for the analysis of quantitative trait loci (QTLs) at the genomic level. Herein, we report a new genetic linkage map developed from an F1 -derived doubled haploid (DH) population of 168 lines, which was generated from the cross between two elite Chinese common wheat (Triticum aestivum L.) varieties, Huapei 3 and Yumai 57. The map contained 305 loci, represented by 283 simple sequence repeat (SSR) and 22 expressed sequence tag (EST)-SSR markers, which covered a total length of 2141.7 cM with an average distance of 7.02 cM between adjacent markers on the map. The chromosomal locations and map positions of 22 new SSR markers were determined, and were found to distribute on 14 linkage groups. Twenty SSR loci showed different chromosomal locations from those reported in other maps. Therefore, this map offers new information on the SSR markers of wheat. This genetic map provides new opportunities to detect and map QTLs controlling agronomically important traits. The unique features of this map are discussed. [source] Quantitative Trait Loci Mapping for Chlorophyll Fluorescence and Associated Traits in Wheat (Triticum aestivum)JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 5 2007De-Long Yang Abstract Parameters of chlorophyll fluorescence kinetics (PCFKs) under drought stress condition are generally used to characterize instincts for dehydration tolerance in wheat (Triticum aestivum L.). Therefore, it is important to map quantitative trait loci (QTLs) for PCFKs in wheat genetic improvement for drought tolerance. A doubled haploid (DH) population with 150 lines, derived from a cross between two common wheat varieties, Hanxuan 10 and Lumai 14, was used to analyze the correlation between PCFKs and chlorophyll content (ChlC) and to map QTLs at the grain-filling stage under conditions of both rainfed (drought stress, DS) and well-watered (WW), respectively. QTLs for these traits were detected by QTLMapper version 1.0 based on the composite interval mapping method of the mixed-linear model. The results showed a very significant positive correlation between Fv, Fm, Fv/Fm and Fv/Fo. The correlation coefficients were generally higher under WW than under DS. Also, there was a significant or a highly significant positive correlation between Fv, Fm, Fv/Fm, Fv/Fo and ChlC. The correlation coefficients were higher in the DS group than the WW group. A total of 14 additive QTLs (nine QTLs detected under DS and five QTLs under WW) and 25 pairs of epistatic QTLs (15 pairs detected under DS and 10 pairs under WW) for PCFKs were mapped on chromosomes 6A, 7A, 1B, 3B, 4D and 7D. The contributions of additive QTLs for PCFKs to phenotype variation were from 8.40% to 72.72%. Four additive QTLs (two QTLs detected under DS and WW apiece) controlling ChlC were mapped on chromosomes 1A, 5A and 7A. The contributions of these QTLs for ChlC to phenotype variation were from 7.27% to 11.68%. Several QTL clusters were detected on chromosomes 1B, 7A and 7D, but no shared chromosomal regions for them were identified under different water regimes, indicating that these QTLs performed different expression patterns under rainfed and well-watered conditions. (Handling editor: Yong-Biao Xue) [source] Histopathology and PR-protein markers provide insight into adult plant resistance to stripe rust of wheatMOLECULAR PLANT PATHOLOGY, Issue 2 2008JENNIFER MOLDENHAUER SUMMARY Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a serious disease of wheat. The spring wheat cultivar Kariega expresses complete adult plant resistance to stripe rust, whereas Avocet S is susceptible. In former studies, quantitative trait loci (QTL) analysis of doubled haploid lines derived from a Kariega × Avocet S cross revealed two major QTL (QYr.sgi-7D and QYr.sgi-2B.1) and two minor QTL (QYr.sgi-1A and QYr.sgi-4A.1) responsible for the adult resistance of Kariega in the field. Avocet S contains none of these QTL. In the present study, stripe rust development was compared, by means of fluorescence and confocal laser scanning microscopy, in flag leaves of Kariega, Avocet S and six doubled haploid (DH) lines, containing all four, none or one QTL. Depending on the QTL present, the infection types of the DH lines ranged from resistant to fully susceptible. No differences in fungal growth were observed during the first 5 days post inoculation (dpi), whereas the mean length of the fungal colonies started to differ at 6 dpi. Interestingly, MP 51 carrying QYr.sgi-7D responded with lignification to the fungal growth without restricting it, whereas MP 35 containing QYr.sgi-2B.1 did not show lignified host tissue, but fungal growth was restricted. RT PCR experiments with sequences of pathogenesis-related (PR) proteins resulted in a slightly stronger induction of PR 1, 2 and 5, known markers for the hypersensitive reaction, and peroxidases in MP 51, whereas a second band for chitinases was detected in MP 35 only. [source] Identification and inheritance of a partially dominant gene for yellow seed colour in Brassica napusPLANT BREEDING, Issue 1 2005X. P. Liu Abstract A yellow-seeded doubled haploid (DH) line no. 2127-17, derived from a resynthesized Brassica napus L., was crossed with two black-seeded Brassica cultivars ,Quantum' and ,Sprint' of spring type. The inheritance of seed colour was investigated in the F2, and BC1 populations of the two crosses and also in the DH population derived from the F1 of the cross ,Quantum'× no. 2127-17. Seed colour analysis was performed with the colorimeter CR-300 (Minolta, Japan) together with a visual classification system. The immediate F1 seeds of the reciprocals in the two crosses had the same colour as the self-pollinated seeds of the respective black- and yellow-seeded female parents, indicating the maternal control of seed colour. The F1 plants produced yellow-brown seeds that were darker in colour than the seeds of no. 2127-17, indicating the partial dominance of yellow seed over black. In the segregating BC1 progenies of the two crosses, the frequencies of the black- and yellow-seeded plants fit well with a 1 : 1 ratio. In the cross with ,Quantum', the frequencies of yellow-seeded and black-seeded plants fit with a 13 : 3 ratio in the F2 progeny, and with a 3 : 1 ratio in the DH progeny. However, a 49 : 15 segregation ratio was observed for the yellow-seeded and black-seeded plants in the F2 progeny of the cross with ,Sprint'. It was postulated from these results that seed colour was controlled by three pairs of genes. A dominant yellow-seeded gene (Y) was identified in no. 2127-17 that had epistatic effects on the two independent dominant black-seeded genes (B and C), thereby inhibiting the biosynthesis of seed coat pigments. [source] Development of yellow-seeded Brassica napus of double low qualityPLANT BREEDING, Issue 6 2001M. H. Rahman Abstract Two yellow-seeded white-petalled Brassica napus F7 inbred lines, developed from interspecific crosses, containing 26,28% emcic acid and more than 40 ,mol glucosinolates (GLS)/g seed were crossed with two black/dark brown seeded B. napus varieties of double low quality and 287 doubled haploid (DH) lines were produced. The segregation in the DH lines indicated that three to four gene loci are involved in the determination of seed colour, and yellow seeds are formed when all alleles in all loci are in the homozygous recessive state. A dominant gene governed white petal colour and is linked with an erucic acid allele that, in the homozygous condition, produces 26,28% erucic acid. Four gene loci are involved in the control of total GLS content where low GLS was due to the presence of recessive alleles in the homozygous condition in all loci. From the DH breeding population a yellow-seeded, yellow-petalled, zero erucic acid line was obtained. This line was further crossed with conventional B. napus varieties of double low quality and, following pedigree selection, a yellow seeded B. napus of double low quality was obtained. The yellow seeds had higher oil plus protein content and lower fibre content than black seeds. A reduction of the concentration of chromogenic substances was found in the transparent seed coat of the yellow-seeded B. napus. [source] Effect of mannitol pretreatment to improve green plant regeneration on isolated microspore culture in Triticum turgidum ssp. durum cv. ,Jennah Khetifa'PLANT BREEDING, Issue 6 2007Z. Labbani Abstract The use of doubled haploids improves the efficiency of cultivar development in many crops and can be helpful in genetic and molecular studies. The major problem with this approach is the low efficiency of green plant regeneration. We describe here an efficient method for inducing embryos and regenerating green plants directly from isolated microspores of durum wheat cv. ,Jennah Khetifa'. Tillers from donor plants were pretreated in 0.3 m mannitol and were stored at 4°C at various times: 3, 5, 6, 7, 8, 10 and 12 days. Our results showed clearly that the novel pretreatment combined mannitol 0.3 m and cold for 7 days had a strong effect on the number of embryos produced and regenerated green plants. Under this condition 13 475 mature embryos were produced from 2 693 500 microspores. Moreover, 85 green plants were obtained. High green plants regeneration frequency was recorded. As an average 11.55 green plants were produced per 100 000 microspores (about the equivalent of six plants per spike). Therefore, this study showed clearly that our results are the best ones published until now in durum wheat. [source] | ||||||||||