| It’s an important way for wheat improvement through distant hybridization, but a number of sister lines were usually acquired during selection of stable novel germplasm. Therefore, it’s an urgent problem how to make use of these sister lines scientifically. In this study, 205 innovation germplasm sister lines named "Pubing2011" were obtained through wheat-Agropyron cristatum distant hybridization. We analyzed these sister lines from many aspects including agronomic characters, powdery mildew, stripe rust resistance, HMW-GS composition, vernalization and photoperiod genes and genome scanning by wheat 90 K SNP array. These results we got from these research will provide theoretical guidance for the effective utilization of different innovated sister lines.1. Evaluation of agronomic traits of sister lines of Pubing2011. Sixteen agronomic traits such as plant height, effective tiller number, under spike stalk, spike length, spikelet number per spike, sterile spikelet number, kernel number per spikelet, grain number per spikelet, thousand grain weight, flag leaf length, flag leaf width, heading date, flowering date and cold resistance were investigated in 205 Pubing2011 sister lines in Shunyi district of Beijing and Xinxiang of Henan province from 2012 to 2014. BLUP analysis and genetic similarity analysis of sib-lines of Pubing2011 showed that, 205 sister lines were very similar, with the genetic similarity coefficient in the range of 0.985~0.999, however, sister lines in a single trait showed considerable differences that the coefficient of variation of different characters was in the range of 0.54%~20.21%. Of the 205 sister lines, Pubing2011-2 phenotypically performed so excellent and outstanding that it’s plant height was 71.4cm, the effective tiller number was 12.8, the grain number per spikelet was 55, the thousand grain weight was 45.06 g, it’s flag leaf was a little wider(1.8cm), and that it was highly resistant to cold(the green rate is over 95%). In addition, 5 sister lines had strong tillering ability, and the effective tiller number per plant was in the range of 19.2~22.2; 20 sister lines had few sterile spikelets with the number of 1.3. These accessions could provide excellent germplasm resources for breeding new varieties of wheat.2. Identification of disease resistance of sister lines of Pubing2011. Several isolated races were used to evaluate the resistance against powdery mildew and stripe rust of sister lines of Pubing2011 at seedling and adult-plant stages. The results showed that 203 sister lines were susceptible to different races of powdery mildew and stripe rust at the seedling stage with the IT of 3 or 4, but they conferred resistance to powdery mildew and stripe rust at the adult-plant stage with the grades of R, MR or HR. The powdery mildew resistance at the seedling and adult-plant stage of the other two sisters 2011-2 and 2011-158 was similar to the above 203 lines. But their stripe rust resistance showed striking differences. Pubing2011-2 was resistant to CYR31, CYR32 and CYR33 at seedling stage with the IT of 1, 0; and 2, but was susceptible to stripe rust at adult-plant stage, while Pubing2011-158 was resistant to CYR33 with the IT of 2 at seedling stage, and resistant to the disease at adult-plant stage. Therefore, 205 Pubing2011 sib-lines carried resistance genes of stripe rust and powdery mildew. They can be used as parents to improve modern wheat varieties, and provide excellent gene resources for breeding sustainable resistance wheat and exploring new disease resistance genes.3. Analysis of the composition of HMW-GS of sister lines of Pubing2011. High molecular weight glutenin subunits were detected by SDS-PAGE in 205 sister lines of Pubing2011. It turned out that sister lines Pubing2011 showed some polymorphism with a total of 5 subunit types and 3 different combinations. High quality subunits 5+10 was detected in 112 sister lines, including 4 samples with high quality subunits 2* and 5+10, the subunit on Glu-B1 loci of 205 sister lines was 7*+9. Thus, sister lines with high quality subunits can provide excellent resources for the cultivation of high-quality wheat varieties.4. Detection of vernalization and photoperiod genes of sister lines of Pubing2011. We used molecular markers of vernalization and photoperiod genes to detect the 205 sister lines, their compositions of vernalization genes consisted of two types. 204 of them were facultative(vrn-A1, vrn-B1, vrn-D1, vrn-B3), while the compositions of vernalization genes of 2011-2 was(vrn-A1, vrn-B1, Vrn-D1, vrn-B3) with the development characteristics of weakly spring; the photoperiod gene at the Ppd-D1 locus of the 205 lines was Ppd-D1 a with non-sensitive character. In addition to 2011-2, Pubing2011 sister lines were facultative accessions and insensitive to photoperiod, exhibiting wide adaptability.5. Yield test of sister lines Pubing2011. The yield of the 205 lines was tested(the harvested area is 0.9m2) in Shunyi district of Beijing and Xinxiang of Henan province in years 2013~2014. The results showed that the average yield of 205 accessions was 640 g, which was higher than that of the control variety Jingdong8(460g) and Yanzhan4110(596g), the yield of the 205 lines were in the range of 518~787g, and the coefficient of variation was 7.89%. The GGE biplot analysis of high and stable yield showed that seven sister lines(2011-2, 34, 159, 96, 29, 14, 112) could be directly used for field application because of the high and stable yield of 727~787g and better lodging resistance.6. SNP detection of sister lines of Pubing2011. The wheat 90 K SNP array was used to analyze the 34 mixed pool built by extremely significant different accessions in 17 traits including plant height, under spike stalk, spikelet number per spike, spikelet density, sterile spikelet number, kernel number per spikelet, grain number per spikelet spike, thousand grain weight, plot yield, effective tillers, flag leaf length, flag leaf width, flag leaf area, heading date, flowering date and cold resistance. The results revealed that 852 homozygous sites were associated with seventeen different phenotypes, and they were located on chromosomes 2A(93), 3A(157), 5A(25), 2B(69), 3B(30), 5B(34), 6B(24), 3D(22). 465 of the 852 sites were multiple loci associated with 3 or 10 traits. Obviously, detecting the mixed pool built by different sister lines with wheat SNP 90 K array contributed to obtain sites associated with the target traits quickly and efficiently, providing efficient and convenient method for the QTL mapping of target traits.7. Comprehensive analysis of sister lines of Pubing2011. According to the strong ability of effective tillering, few sterile spikelet, high quality, high resistance to disease, general adaptability and high yield, several excellent sister lines were selected from the 205 Pubing2011 sister lines. There were certain phenotypic differences between weakly spring accession 2011-2 and other sister lines that Pubing2011-2 was of high yield, full grain, 3.9 spikelet per spike, short and wide flag leaf. It is suitable for sowing in Yellow and Huai River valley winter wheat zone and the middle and lower Yangtze valley winter wheat zone in China. Another two high yield sister lines 2011-14 and 2011-34 were facultative accessions with the yield of 729 g and 743 g, respectively, good stability and lodging resistance. One of them(Pubing2011-14) was a high quality line in which the subunit 5+10 was detected. Where they suitable for sowing was mainly in Yellow and huai river valley winter wheat zone in China. The above three sister lines performed so stably in the field that they could be directly used in breeding. In addition, sister lines of few sterile spikelets, high quality and seedling resistance to disease could be used as parents to improve wheat varieties.In conclusion, there were abundant variations in the 205 Pubing2011 sister lines, with superior agronomic traits including strong tillering ability, little sterile spikelet number, good disease resistance, high quality subunits 2* and 5+10, high and stable yield, and wide adaptability. It is thus evident that producing different sister lines could provide a vast space for breeding and improving new wheat varieties of high yield, wide adaptability, good quality, and disease resistance. Therefore, during germplasm innovation by distant hybridization, keeping more sister lines focus on the target character would contribute to the efficient use of these novel germplasm. |
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