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排序方式: 共有117条查询结果,搜索用时 248 毫秒
1.
Dennis N. Lozada R. Esten Mason Md Ali Babar Brett F. Carver Gina-Brown Guedira Keith Merrill Maria Nelly Arguello Andrea Acuna Lucas Vieira Amanda Holder Christopher Addison David E. Moon Randal G. Miller Susanne Dreisigacker 《Euphytica》2017,213(9):222
Genome-wide association studies (GWAS) are useful to facilitate crop improvement via enhanced knowledge of marker-trait associations (MTA). A GWAS for grain yield (GY), yield components, and agronomic traits was conducted using a diverse panel of 239 soft red winter wheat (Triticum aestivum) genotypes evaluated across two growing seasons and eight site-years. Analysis of variance showed significant environment, genotype, and genotype-by-environment effects for GY and yield components. Narrow sense heritability of GY (h 2 = 0.48) was moderate compared to other traits including plant height (h 2 = 0.81) and kernel weight (h 2 = 0.77). There were 112 significant MTA (p < 0.0005) detected for eight measured traits using compressed mixed linear models and 5715 single nucleotide polymorphism markers. MTA for GY and agronomic traits coincided with previously reported QTL for winter and spring wheat. Highly significant MTA for GY showed an overall negative allelic effect for the minor allele, indicating selection against these alleles by breeders. Markers associated with multiple traits observed on chromosomes 1A, 2D, 3B, and 4B with positive minor effects serve as potential targets for marker assisted breeding to select for improvement of GY and related traits. Following marker validation, these multi-trait loci have the potential to be utilized for MAS to improve GY and adaptation of soft red winter wheat. 相似文献
2.
Effects of simulated acid rain and root-knot nematode on tomato 总被引:1,自引:1,他引:1
Effects were examined of simulated acid rain and of root-knot nematode, Meloidogyne incognita race 1, on plant growth, yield, photosynthetic pigments and leaf epidermal characters of tomato ( Lycopersicon esculentum cv. Pusa Ruby). Sequential inoculation exposures (pre-, post-, and concomitant with nematode inoculation) were carried out in a greenhouse. Intermittent treatments of simulated acid rain at pH 3.2 caused white-to-tan irregular lesions on both the upper and lower surfaces of tomato leaves. The foliar symptoms were more pronounced on nematode-infected plants. Simulated acid rain (pH 3.2) and/or nematode infection suppressed plant growth, yield and pigment synthesis, the effects being greatest in post-inoculation treatments compared with simulated acid rain at pH 6.8. The total weight of fruits per plant was greatly suppressed owing to simulated acid rain or nematode infection. Chlorophyll a was found to be more sensitive to simulated acid rain or nematode infection than other leaf pigments. Root penetration, galling, egg mass production, and fecundity (number of eggs per egg mass) of M. incognita were enhanced at pH 5.6 and suppressed at pH 3.2 compared with pH 6.8. Nematode infection or simulated acid rain at pH 3.2 suppressed stomata and trichome development (number and size). Simulated acid rain treatments at pH 5.6 had a positive effect on number and size of trichomes, but a negative effect on stomata. The apertures of stomata were wider on tomato leaves exposed to simulated acid rain, especially at pH 3.2, than at pH 6.8. 相似文献
3.
Mohamed M’BAYE Guohua HUA Hamid Ali KHAN Liguo YANG 《The Journal of reproduction and development》2015,61(5):391-397
Inhibins are members of the TGFβ superfamily and act as suppressors
of follicle stimulating hormone (FSH) secretion from pituitary glands
via a negative feedback mechanism to regulate folliculogenesis. In
this study, the INHBB gene was knocked down by three
RNAi-Ready pSIREN-RetroQ-ZsGreen vector- mediated recombinant plasmids
to explore the effects of INHBB silencing on
granulosa cell (GC) cell cycle, apoptosis and steroid production
in vitro. Quantitative real-time polymerase chain
reaction, Western blot, flow cytometry and ELISA were performed to
evaluate the role of INHBB in the mouse GC cell
cycle, apoptosis and steroid production in vitro. The
results showed that the relative mRNA and protein expression of
INHBB in mouse GCs can be significantly reduced by
RNAi with pshRNA-B1, pshRNA-B2 and pshRNA-B3 plasmids, with pshRNA-B3
having the best knockdown efficiency. Downregulation of the expression
of INHBB significantly arrests cells in the G1 phase
of the cell cycle and increases the apoptosis rate in GCs. This was
further confirmed by downregulation of the protein expressions of
Cyclin D1, Cyclin E and Bcl2, while the protein expression of Bax was
upregulated. In addition, specific downregulation of
INHBB markedly decreased the concentration of
estradiol and progesterone, which was further validated by the
decrease in the mRNA levels of CYP19A1and
CYP11A1. These findings suggest that inhibin βB is
important in the regulation of apoptosis and cell cycle progression in
granulosa cells. Furthermore, the inhibin βB subunit has a role in the
regulation of steroid hormone biosynthesis. Evidence is accumulating
to support the concept that inhibin βB is physiologically essential
for early folliculogenesis in the mouse. 相似文献
4.
Expression profiling of transgenes (Cry1Ac and Cry2A) in cotton genotypes under different genetic backgrounds 下载免费PDF全文
Kashif NOOR Hafiza Masooma Naseer CHEEMA Asif Ali KHAN Rao Sohail Ahmad KHAN 《农业科学学报》2022,21(10):2818-2832
Transgenic cotton carrying the Cry1Ac gene has revolutionized insect pest control since its adoption, although the development of resistance in insect pests has reduced its efficacy. After 10 years of cultivating Bacillus thuringiensis (Bt) cotton with a single Cry1Ac gene, growers are on the verge of adopting Bt cotton that carries the double gene (Cry1Ac+Cry2A) due to its better effectiveness against insect pests. Thus, the current study was designed to evaluate the role of each gene in the effectiveness of Bt cotton carrying the double gene. The expression levels of the Cry1Ac and Cry2A genes were evaluated in the leaves of 10 genotypes (2 parents and 8 F1 hybrids) at 30 days after sowing (DAS), while samples of leaves, bolls and flowers were taken from the upper and lower canopies at 70 and 110 DAS. The F1 hybrids were developed through reciprocal crosses between two Bt (CKC-1, CKC-2) and two non-Bt (MNH-786, FH-942) parents. The differential expression of transgenes was evaluated through Enzyme Linked Immuno-Sorbent Assay (ELISA). The results showed that the MNH786×CKC-1 hybrid had the highest concentrations of Cry1Ac gene at 30 DAS (3.08 µg g–1) and 110 DAS (1.01 µg g–1) in leaves. In contrast, the CKC-2×MNH-786 hybrid showed the lowest concentrations of Cry1Ac gene at 30 DAS (2.30 µg g–1) and 110 DAS (0.86 µg g–1). The F1 hybrid FH-942×CKC-2 showed the highest concentrations of Cry2A gene at 30 DAS (8.39 µg g–1) and 110 DAS (7.74 µg g–1) in leaves, while the CKC-1×MNH-786 hybrid expressed the lowest concentrations of Cry2A gene at 30 DAS (7.10 µg g–1) and 110 DAS (8.31 µg g–1). A comparison between the two stages of plant growth showed that leaves had the highest concentrations at 30 DAS, whereas the lowest concentrations were observed at 110 DAS for both genes in leaves. When the expression pattern was compared between various plant parts in genotype CKC-2, it was found that leaves had higher concentrations of Cry1Ac (3.12 µg g–1) and Cry2A (8.31 µg g–1) at 70 DAS, followed by bolls (Cry1Ac (1.66 µg g–1) and Cry2A (8.15 µg g–1)) and flowers (Cry1Ac (1.07 µg g–1) and Cry2A (7.99 µg g–1)). The genotype CKC-2 had higher concentrations of Cry1Ac (3.12 µg g–1) and Cry2A (8.31 µg g–1) in the upper canopy but less accumulation (2.66 µg g–1 of Cry1Ac, 8.09 µg g–1 of Cry2A) in the lower canopy at 70 DAS. Similarly, at 110 DAS, the expression levels of Cry1Ac and Cry2A in upper and lower canopy leaves were 1.52 and 7.92 µg g–1, and 0.99 and 7.54 µg g–1, respectively. Hence, the current study demonstrates that different genotypes showed variable expression for both of the Cry1Ac and Cry2A genes during plant growth due to different genetic backgrounds. The Cry2A gene had three-fold higher expression than Cry1Ac with significant differences in expression in different plant parts. The findings of this study will be helpful for breeding insect-resistant double-gene genotypes with better gene expression levels of Cry1Ac and Cry2A for sustainable cotton production worldwide. 相似文献
5.
Dynamics of organic carbon and nitrogen in deep soil profile and crop yields under long-term fertilization in wheat-maize cropping system 下载免费PDF全文
Muhammad QASWAR LI Dong-chu HUANG Jing HAN Tian-fu Waqas AHMED Sehrish ALI Muhammad Numan KHAN Zulqarnain Haider KHAN XU Yong-mei LI Qian ZHANG Hui-min WANG Bo-ren Ahmad TAUQEER 《农业科学学报》2022,21(3):826-839
Soil organic carbon (SOC) and nitrogen (N) are two of the most important indicators for agricultural productivity. The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile (up to 100 cm) and their relationships with crop productivity under the influence of long-term (since 1990) fertilization in the wheat-maize cropping system. Treatments included CK (control), NP (inorganic N and phosphorus (P) fertilizers), NPK (inorganic N, P and potassium fertilizers), NPKM (NPK plus manure), and M (manure). Crop yield and the properties of topsoil were measured yearly from 2001 to 2009. C and N contents were measured at five different depths in 2001 and 2009. The results showed that wheat and maize yields decreased between 2001 and 2009 under the inorganic fertilizer (NP and NPK) treatments. The average yield between 2001 and 2009 under the NP, NPK, NPKM, and M treatments (compared with the CK treatment) increased by 38, 115, 383, and 381%, respectively, for wheat and 348, 891, 2 738, and 1 845%, respectively, for maize. Different long-term fertilization treatments significantly changed coarse free particulate (cfPOC), fine free particulate (ffPOC), intramicroaggregate particulate (iPOC), and mineral-associated (mSOC) organic carbon fractions. In the experimental years of 2001 and 2009, soil fractions occurred in the following order for all treatments: mSOC>cfPOC>iPOC>ffPOC. All fractions were higher under the manure application treatments than under the inorganic fertilization treatments. Compared to the inorganic fertilization treatments, manure input enhanced the stocks of SOC and total N in the surface layer (0–20 cm) but decreased SOC and N in the deep soil layer (80–100 cm). This reveals the efficiency of manure in increasing yield productivity and decreasing risk of vertical loss of nutrients, especially N, compared to inorganic fertilization treatments. The findings provide opportunities for understanding deep soil C and N dynamics, which could help mitigate climate change impact on agricultural production and maintain soil health. 相似文献
6.
Rokibul Islam KHAN Sada ANDO Toshihiro TAKAHASHI Tetsuo MORITA Ryoji ONODERA 《Animal Science Journal》2003,74(4):313-319
Suspensions of mixed rumen bacteria (B), protozoa (P), and mixed rumen microorganisms (BP) prepared from rumen contents of fistulated goats were anaerobically incubated with 1 mM p‐hydroxyphenylacetic acid (HPA) at 39°C for 24 h. Tyrosine (Tyr), phenylalanine (Phe), tryptophan (Trp) and other related compounds in both supernatants and hydrolyzates of microbial cells in all incubations were analyzed by HPLC. Large amounts of Tyr (32.1, 42.7 and 36.1% of disappeared HPA in B, P and BP, respectively) were produced from HPA during a 12 h incubation period. The formation of Tyr in P (178.6 µmol/g MN) was 1.5 and 2 times higher than in B and BP, respectively. Phe (7–11% of the disappeared HPA) and Trp (3–6% of the disappeared HPA) were also synthesized from HPA in B, P, and BP. Phe synthesis in P (46.3 µmol/g MN) was 1.7 times higher than in B but, in contrast, Trp synthesis in B, was 1.6 times higher than in P. The metabolites p‐hydroxyphenylpyruvic acid (in the range of 5–14% of disappeared HPA), phenylacetic acid (1–11%), p‐hydroxybenzoic acid (3–7%) and benzoic acid (1–6%) were produced from HPA in B, P and BP. Phenylpropionic acid (6% of the disappeared HPA) was produced only in B and BP. 相似文献
7.
The isolation and purification of an immediate precursor of bacterial cellulose was confirmed with glucose randomly labeled with carbon-14. The glucose appears to be bound within the cell to a lipid, is carried across the bacterial cell wall, and is incorporated enzymatically into cellulose extracellularly. 相似文献
8.
9.
M. S. KHAN 《Aquaculture Research》1994,25(2):167-174
Abstract Apparent digestibility coefficients were determined for six feedstuffs, subsequent to their processing into pelleted feed for tropical freshwater catfish, Mystus nemurus (Cuvier & Valenciennes), using a reference diet and test diets composed of 70% reference diet and 30% test ingredient. It was found that most ingredients were fairly well digested except maize and chicken viscera. Digestibility coefficient for protein (P), dry matter (DM) and energy (E) were: (1) fish meal: 97·8% P,97% DM. 77·88% E: (2) soybean meal: 86% P,95·55% DM, 67·89% E: (3) rice bran: 81% P,85·81% DM, 67·93% E: (4) copra meal: 79·90% P, 86% DM, 71·89% E: (5) maize: 51·93% P, 49·0% DM, 63·40% E and (6) chicken viscera: 37% P,29% DM, 52% E. Digestibility coefficients for feedstuffs indicated that animal protein product, such as fish meal and grain by-product, such as rice bran were more digestible than starchy and fibrous feed, e.g. maize. Chicken viscera was poorly digested largely due to inefficient processing. As most feedstuffs were well digested, ingredient selection should, therefore, be based primarily on their protein content, amino acid composition and palatability. 相似文献
10.
Abstract The data on breeding and performance records (3830) of 1134 Lohi ewes kept at an Institutional Livestock Experiment Station, Okara in Punjab province during the period from 1972 through 2001 were used to study the influence of some non-genetic factors such as year and season of birth/lambing, age and weight at first service sex of lamb born, birth type, age of dam on various reproductive traits. The age of ewes at first service averaged 615.6±8.2 days and was not significantly affected by the year and season of birth of the ewes. The ewes born during spring season had comparatively low (613.6±7.9 days) age at first service than autumn born (617.5±9.8 days). The type of birth did not significantly influence age at first service. The least squares mean for the weight at first service was 42.10±0.24 kg and was significantly (P<0.01) influenced by the ewe's year and season of birth. The spring-born ewes were heavier (42.3±0.3 kg) at first service than autumn-born ewes (41.9±0.3 kg). The weight at first service was also significantly affected by the age at first service. The type of birth did not significantly influence weight at first service. The number of services per conception averaged 1.29±0.03 and varied significantly (P<0.01) between seasons. The number of services per conception was higher (1.37±0.02) in ewes bred during autumn than those bred in spring (1.16±0.06). The effects of years and weight at service on the number of services per conception were non-significant. The number of services per conception significantly increased with advancing age. Mean gestation period was 152.31±0.08 days and it was significantly affected by the years and seasons of lambing and the age of the ewe at lambing. However, gestation length was not significantly affected due to birth type and sex of the lamb born. 相似文献