山东省农业科学院

As China's High-Standard Farmland Construction Program advances,many dryland wheat fields can now receive a one-off irrigation during the growing season(hereafter,one-off irrigation).To evaluate the effects of tillage practices and nitrogen(N)rates on wheat yield and quality under one-off irrigation,we conducted a two-factor split-plot experiment from 2020 to 2022 at three sites in Luoyang,Henan province(Xiaolangdi town,Mengjin county;Yaling town,Yichuan county;and Xiaojie town,Luoning county).Tillage practice was the main-plot factor—rotary tillage(RT),subsoiling(SS),and plough tillage(PT)—and N rate was the subplot factor at 0(N0),120(N120),180(N180),and 240(N240)kg hm-2.We measured grain yield,protein content and protein fractions,grain Zn content,and key processing-quality traits.Tillage practice and N rate significantly affected wheat yield and quality;their interaction significantly influenced grain yield,protein yield,and the contents of all protein components except albumin.Compared with PT and RT,SS increased grain yield by 6.9%and 12.6%,respectively,and increased protein yield by 7.7%and 14.5%,while generally improving protein content,most protein fractions,processing quality,and grain Zn content(with a few site-year exceptions).Relative to PT,SS increased albumin,globulin,gliadin,and glutenin contents as well as dough development time,stability time,wet gluten content,sedimentation value,extensibility,maximum resistance,and grain Zn content by 21.9%,19.0%,12.5%,8.0%,18.6%,28.4%,8.2%,26.4%,10.1%,14.0%,and 12.6%,respectively;compared with RT,the corresponding increases were 22.0%,19.6%,19.7%,15.0%,19.5%,32.8%,9.1%,27.8%,10.3%,22.6%,and 23.2%,respectively.Across all tillage practices,increasing N rate led to an initial increase followed by a plateau in yield,protein yield,protein frac-tions,processing-quality traits,and grain Zn content.In most cases,N180 and N240 did not differ significantly,and both outper-formed N120.Except for grain yield at the Xiaolangdi site and gliadin content in 2021-2022,SSN180 achieved similar yield,quality,economic returns,and input-output ratio to SSN240,while outperforming the other treatments in most comparisons.Overall,subsoiling combined with 180 kg hm-2 N is recommended for dryland regions where one-off irrigation is available,as it can simultaneously improve wheat yield,quality,and economic benefits.

Powdery mildew(PM)is one of the major diseases threatening wheat production worldwide.Accurate identification of powdery mildew resistance in wheat cultivars and dissection of its genetic basis are crucial for breeding and deploying dis-ease-resistant cultivars.In this study,we evaluated seedling-and adult-plant resistance to powdery mildew in 326 wheat ac-cessions.We then used 11 molecular markers targeting Pm genes that are commonly used in breeding or confer high levels of resistance,including Pm2b,Pm4,Pm8,and Pm21,to detect resistance alleles.To identify additional Pm loci,we also performed a genome-wide association study(GWAS)using a wheat 16K SNP array.The results showed that 10 cultivars(e.g.,Jinfeng 3,Shengmai 104,and Linmai 5311)were resistant to the Bgt isolate E09,indicating an overall lack of seedling resistance among the evaluated accessions.At the adult stage,29 cultivars(e.g.,Yunhei 28,Yaomai 30,and Yunhei 14207)were resistant to mixed Bgt isolates,and only four cultivars(Shengmai 104,JT176,Linmai 5311,and Jinfeng 3)displayed good resistance at both the seed-ling and adult stages.Multi-isolate tests of seedling resistance further indicated that Jinfeng 3,Shengmai 104,and JT176 were highly resistant to most isolates evaluated,representing valuable germplasm for powdery mildew resistance breeding.Marker-based analysis suggested that Shanxi wheat has a narrow genetic basis for powdery mildew resistance and tends to carry only one major Pm gene.Of the 11 Pm genes assayed,seven genes(e.g.,Pm2b,Pm5e,and Pm6)were detected,whereas Pm1a,Pm24,Pm60,and Pm69 were not detected.In total,108 accessions carried only one of the tested Pm genes;Pm8 was the most frequent,occurring in 14.11%of accessions.For gene pyramiding,the most common combinations were Pm5e+Pm8 and Pm6+Pm8,and only one cultivar carried four Pm genes.GWAS identified 15 stable loci across eight chromosomes;haplo-type-phenotype analyses revealed significant associations at loci on chromosomes 1A,2D,4B,and 6A,and loci on 2D,4B,7B,and 7D may harbor novel powdery mildew resistance loci.

Peroxidase(POD)activity in wheat grains strongly influences processing quality and the color of wheat-based products,and is therefore an important target for quality improvement.In this study,151 wheat varieties(lines)from domestic and international sources were used to systematically characterize allelic variation at the Pod-A1,Pod-D1,and Pod-2D loci using molecular markers.Together with multi-year,multi-location measurements of grain POD activity,we evaluated the effects of individual alleles and their combinations on POD activity.Grain POD activity showed substantial genetic variation,with a mean of 674.39 U g-1 min-1,a range of 431.30-954.81 U g-1 min-1,and a coefficient of variation of 15.52%.Environ-ment,genotype,and their interaction all had highly significant effects on POD activity(P<0.01).All three loci significantly affected grain POD activity,and the favorable alleles were Pod-A1b,Pod-D1b,and Pod-2D-GG,respectively.In total,12 alle-lic combinations were identified and classified into high-,medium-,and low-activity combination types based on grain POD activity.POD activity differed significantly among the three types(P<0.05),whereas no significant differences were detected within each type.The genetic effects of the three loci on grain POD activity followed the order Pod-2D>Pod-A1>Pod-D1.Grain POD activity increased significantly with the number of favorable alleles(R2=0.9681,P<0.05);varieties(lines)pyramiding 2-3 favorable alleles had significantly higher POD activity than those carrying 0-1 favorable allele(P<0.05).Significant regional differences were observed in POD activity,allelic variation,and allelic-combination frequencies.Nine varieties,including Liangxing 66,Lankao 24,and Jimai 22,were identified as carrying all three favorable alleles and exhibi-ting POD activity above 800 U g-1 min-1.These findings provide a theoretical basis and germplasm resources for molecular marker-assisted breeding to optimize wheat grain POD activity.

To further identify agronomic traits influencing mechanical shelling quality in peanut and explore their genetic basis,this study evaluated 63 advanced-generation lines and focused on three pod-or kernel-related traits:shelling percentage,pod crushing force,and kernel crushing force.Correlation analysis revealed that only kernel crushing force was significantly associ-ated with the damaged kernel rate.Two lines(D9 and E10)with low damaged kernel rates(<2.50%)were identified.Additionally,a recombinant inbred line(RIL)population of 181 individuals derived from a cross between cultivars Huayu 36 and 6-13 was used for QTL mapping of the kernel crushing force trait.Phenotypic data were collected from 2020 to 2023 across four locations:Yantai,Weihai,Dongying,and Qingdao.The trait exhibited continuous variation and transgressive segregation in the RIL popula-tion,with a broad-sense heritability of 0.88.Using a previously published high-density genetic map,eight additive QTLs associ-ated with kernel crushing force were identified,explaining 6.04%to 28.30%of the phenotypic variation.Among them,two major QTLs,qKCF7 and qKCF16.1,were stably expressed across multiple environments,with favorable alleles derived from Huayu 36.In addition,12 pairs of epistatic QTLs involving 24 SNP intervals were detected,explaining 1.55%to 4.01%of the phenotypic variation.These findings provide valuable genetic targets and germplasm resources for the future genetic improvement of traits related to mechanical shelling quality in peanut.

Aims Saline alkali land is an important reality and potential agricultural resource to solve the shortage of arable land in China.Efficient utilization of saline alkali land resources to develop peanut(Arachis hypogaea)planting in such environments and achieve high and stable yield has become an urgent demand for ensuring peanut production.Under saline alkali stress habitat,arbuscular mycorrhizal fungi(AMF)can effectively develop potential productivity of host plants and improve their salt resistance and tolerance.Although it has been demonstrated that AMF enhanced peanut salt tolerance under salt stress,however,there have been limited reports on the effects of AMF on the growth and development of salt-tolerant and salt-sensitive peanut. Methods This study was investigated the response mechanisms of peanut growth and rhizosphere soil environment to AMF under saline-alkali conditions,aiming to provide theoretical basis and technical support for AMF application in peanut production in saline alkali soils.The experiment used salt-tolerant cultivar'HY25'and salt-sensitive cultivar'HY22'as experimental materials,with AMF seed coating treatment applied under saline alkali and normal soil conditions. Important findings Under two soil conditions,salt-tolerant and salt-sensitive peanut cultivars demonstrated differential response mechanisms to AMF inoculation.Under both soil environments,AMF improved the agronomic characteristics in'HY25',optimized photosynthetic parameters,and significantly increased pod yield.While AMF exhibited partial inhibitory effects on agronomic traits in'HY22'in normal soil,it notably improved leaf photosynthetic performance and elevated both pod yield and quality.Significant differences were found in the response of root growth of two cultivars to AMF including:1)In normal soil,the promoting effect of AMF on the growth of'HY25'root system initiated during the flowering-pegging stage and continued to until maturation stage.Under saline-alkaline soil,AMF significantly increased total root length,root surface area,and root volume in'HY25'at pod-setting stage.2)Salt-sensitive cultivar'HY22'exhibited greater sensitive to AMF inoculation.Under both normal and saline-alkali soils,AMF demonstrated inhibitory effects on root growth in'HY22'during flowering-pegging and/or pod-setting stages,with significantly stronger inhibition observed under saline-alkali soil than normal soil.Moreover,AMF effects on rhizosphere soil properties included:1)significant elevation in available phosphorus contents in both cultivars under two soil conditions;2)increased soil catalase,phosphatase,and invertase activities in both cultivars in saline alkali soil;whereas 3)significant inhibition of soil enzymatic activities in'HY22'under normal soil.These results indicated that compared to salt-sensitive cultivar,salt-tolerant cultivar might serve as more efficient symbiotic partner for AMF.AMF might demonstrate superior growth promotion in salt-tolerant cultivar,effectively exerting the synergistic effect of microbial regulation under saline-alkali soil.