| Wheat(Triticum aestivum L.) is a major staple food worldwide. However, with global climate change, the stability and productivity of wheat are affected by various stresses. In addition, domestication and selective breeding has limited the genetic diversity of wheat, leading to cultivars adapted to artificial environments which resulted in reduced resistance to both biotic and abiotic stresses. Wild relatives of wheat contain abundant genetic resources. By distant hybridization and chromosome engineering, a lot of alien chromosome germplasm including wheat addition lines and triticale have been created. In most cases, those germplasm are used as genetic tools, and their characteristics and utilization potential have been little known.In order to understand the properties and potential utilization of wheat alien chromosome germplasm, the effects of additional chromosomes on phenotypic traits, drought resistance, nitrogen and phosphorus efficiency, stripe rust and dwarf bunt resistance were evaluated. Meanwhile, the F4:5 and F5:6 lines derived from two crosses using hexaploid triticale Certa as female, common wheat Jinmai 47 and Xinong 389 as pollen donor were identified and evaluated. The main results in this study were as follows:1. Effects of alien chromosomes on phenotypic traits of common wheatThe phenotypic traits of 82 wheat alien chromosomes addition lines were evaluated, compared with their common reception parent Chinese Spring(CS), it was showed that most of the alien chromosomes decreased plant height, grain number spike-1 and SDS sedimentation value, increased kernel hardness and gluten content, while had little effect on seedling root traits, photosynthetic rate at grain-filling stage, growth stage, and moisture, starch, fiber content in grains. And also there was a variation in awn type, glume color and grain size. Alien chromosomes Lemus racemosus I, Lemus racemosus H, Lemus racemosus F, Psathyrostachys huashanica A, Psathyrostachys huashanica C, Aegilops longissima 1S and Agropyron intermedium G significantly increased seedling total root length, surface area and volume. Alien chromosomes Agropyron elongatum 4E and Elymus trachycaulus 5S improved yield components. Alien chromosomes Lemus racemosus 7Lr#1 advanced flowering date while 2R and 3R delayed flowering date. Addition lines with Aegilops peregrina 3UV had a strong ability in photosynthetic rate. Aline chromosomes Aegilops umbellulata 6U, Aegilops umbellulata 2U, Aegilops umbellulata 5U, Aegilops geniculata 4Ug, Lemus racemosus 7Lr#1, Aegilops searsii 5SS, Aegilops searsii 1SS, Elymus trachycaulus 6H and Hordeum chilense 5Hch improved grain hardness and gluten content in grains.2. Evaluation on drought resistance of wheat addition linesThe drought resistances of 82 wheat alien chromosome addition lines along with their common parent CS were evaluated on 10 agronomic traits under both well-watered and water-stressed conditions. It was found that spike length was the most stable trait while biomass plant-1 was the most sensitive trait when subjected to drought stress. Evaluation of heritability and correlations with yield plant-1 suggested that plant height, peduncle length, distance between spike and flag leaf, grain number spike-1 and 1000-grain weight could be used as indicators of drought resistance. The drought resistance index(DI) based on yield plant-1 indicated that 10 addition lines were classified as both drought resistance and greater grain yield, which could be used in moderate stressed areas for improving drought resistance. Among them, addition lines with alien chromosomes of Aegilops peregrina 4SV and Aegilops peregrina 3UV showed excellent performance under water stress and could be further investigated in drought resistance studies or breeding programs. The membership function value of drought resistance(MFVD) based on the 5 secondary traits and grain yield plant-1, indicated 26 of the 82 wheat addition lines expressed high drought resistance. Higher MFVD was observed in the Agropyron elongatum 3E addition line in two years, and it was considered as the most drought resistant material. Analysis of the yield plant-1 suggested that the drought resistant addition lines identified by MFVD were drought resistant but not high-yielding, thus they could be used to improve germplasm with high-yield potential but low drought resistance.3. Evaluation on nitrogen and phosphorus efficiency at seedling stage of wheat addition linesTo identify alien chromosome or germplasm with high Nitrogen(N) or phosphorus(P) efficiency, 43 wheat addition lines along with their common parent CS were cultured by hydroponics, and their phenotypic traits, N/P uptake and utilization efficiency were investigated at seedling stage under both N/P moderate and deficient conditions. The phenotypic variation in different treatments showed that N deficiency decreased plant height, shoot dry weight and total dry weight, while increased root length, number of leaves, SPAD value and root to shoot ratio. P deficiency decreased all the measured traits except root dry weight and root to shoot ratio. By comparing the total dry weight with CS, 13 addition lines were identified as N-efficient and 5 lines were supposed as P-efficient germplasm. The introgression of alien chromosomes affected N/P uptake and utilization efficiency. Significantly higher N uptake and utilization efficiency was found in 9 and 4 addition lines, respectively under low N treatment. And higher P uptake and utilization efficiency was observed in 4 and 2 addition lines under low P condition, respectively. The screened addition lines could be further used in study or breeding program for improving N/P efficiency.4. Evaluation on resistances to strip rust and dwarf bunt of wheat alien chromosome germplasmCompared with CS, most of the addition lines increased the resistance to stripe rust at adult stage. Five and 43 lines appeared high and moderate resistance to CYR32; four and 42 lines appeared immune and moderate resistance to CYR33; and 57 lines appeared moderate resistance to mixed races(CYR29, CYR31, CYR32, CYR33, Sull-4 and Sull-7), respectively. Totally, there were 33 lines performing moderate resistance to both CYR32 and CYR33; 27 lines appearing moderate resistance to CYR32, CYR33 and mixed races. Most of the alien chromosomes in the resistant lines were derived from Aegilops, Leymus and Agropyron. Though covering all the 7 homoeologous groups, most of the alien chromosomes carrying resistant genes were from homoeologous group 2.By inoculating 177 wheat alien chromosome germplasm with Tilletia contraversa J.G. Kühn, 50 lines appeared resistant(incidence ≤ 3%) to dwarf bunt, in which 32 lines showed immune to dwarf bunt. It was found that most of the alien chromosomes in the 35 lines with the same background of CS were derived from Aegilops, and belonging to homoeologous group 1, 7 and 5.5. Identification and evaluation of lines derived from hexaploid triticale Certa and common wheatThe F4:5 lines derived from Certa/Jinmai 47//Jinmai 47 and F5:6 lines derived Certa/Xinong 389 were investigated using sequential fluorescence in situ hybridization(FISH) karyotyping. One and 5 lines from Certa/Xinong 389 were identified as 1B/1R substitution line and 1BL.1RS translocation lines, respectively. There was no Secale chromatin observed in lines from Certa/Jinmai 47//Jinmai 47, indicating that the intergrating ability of R chromosomes depended on the background of common wheat, and the occurrence frequency of chromosome 1R was higher than that of other R chromosomes. The A-genome and B-genome chromosomes in the offspring lines were from both triticale and common wheat. Furthermore, plentiful alterations of wheat chromosomes were also detected. The presence of a storage protein locus ω-secalin was detected in lines carrying 1RS, and one 1BL.1RS translocation line was found lack of ω-secalin locus. There were wide variations in agronomic traits among those lines, of which the photosynthetic capability was increase while little was improved in grain quality. Their resistance to stripe rust at adult stage was increased in lines from Certa/Jinmai 47//Jinmai 47, while decreased in lines from Certa/Xinong 389, indicating that the genes involving resistance to stripe rust on 1RS may lost resistance to the epidemic races.In summary, the screened alien chromosomal germplasm performed well in drought resistance, nutrition use efficiency or disease resistance, and the substitution or translocation lines with improved traits derived from hexaploid triticale and common wheat could be used in the genetic research and wheat breeding program. |
PDF Full Text Request