制种玉米密度对土壤水分及产量构成的影响研究     

刘兴成  彭治云  李永德  陆祥生 《节水灌溉》2015,(2):27-30

通过田间试验,就制种玉米密度对土壤水分、农艺性状、产量构成及产量的影响进行了研究分析。结果表明:1在拔节期以前,低密组的土壤含水量比高密组的高;在拔节期到灌浆期,高密组的比低密组的高。在整个生育期,拔节期前土壤含水量比较高,而后逐渐降低,吐丝期达到最低,然后又逐步上升。2在一定密度范围内,制种玉米株高、亩产量随着密度的增大而增加单株产量产量相反;叶长、穗粗、穗粒数先随着密度的增大而减小,后随着密度的增大而增大;叶宽、穗长、百粒重、出籽率先随着密度的增大而增加,后随着密度的增大而减小;叶面积、茎粗、穗位先随着密度的增大而减小,后随着密度的增大而增加,然后又随着密度的增大而减小,秃顶变化规律相反。  相似文献   

不同灌溉方式下冬小麦穗部性状与产量关系的试验研究   总被引：2，自引：0，他引：2  

汪顺生  刘慧  高传昌  孟鹏涛  黄方平  易嘉成 《灌溉排水学报》2015,34(3)

采用田间试验,以豫麦69为试验材料,研究了不同水分处理下常规灌溉和一体化垄作沟灌的冬小麦产量与穗部性状的相互关系。结果表明,同常规灌溉方式相比,一体化垄作沟灌方式下,冬小麦的穗粒数、籽粒质量及产量分别增加了5.5356%、7.5489%、7.7454%,但穗数减少了0.4302%。常规灌溉和一体化垄作沟灌方式下,产量与穗数、穗粒数以及籽粒质量均正相关,但一体化垄作沟灌方式下的相关系数较常规灌溉方式大。一体化垄作灌溉有利于改善农田小气候、发挥作物的边行优势和提高小麦产量。  相似文献   

Effects of amino acids supplementation in low crude protein diets on growth performance,carcass traits and serum parameters in finishing gilts          下载免费PDF全文

Yanrong Chen  Zhentian Li 《Animal Science Journal》2016,87(10):1252-1257

This study investigated the effects of amino acids (AA) supplementation in low crude protein (CP) diets on growth performance and carcass characteristics in finishing gilts. One hundred and eighty gilts (59.1 ± 5.1 kg) were randomly allotted to one of five diets which consisted of a high CP (15.6%) diet or four low CP (11.6%) diets for 50 days. The low CP diets were supplemented with lysine + threonine + methionine (LCM), LCM + tryptophan (LCT), LCT + valine (LCV) or LCV + isoleucine (LCI), respectively. Gilts were housed at six pigs per pen with six pens per treatment. At the end of the 50‐day experiment, 30 gilts (one pig per pen) with average body weight (BW) of 98 kg were killed to evaluate carcass traits. The pigs fed the diet supplemented with LCV obtained the highest average daily gain (ADG), which was higher than those of pigs fed the diet supplemented with LCM (P < 0.05). Dietary supplementation with tryptophan, valine and isoleucine in low CP diets increased ADG (linear and quadratic effect, P < 0.05), serum levels of valine (quadratic effect, P < 0.05) and isoleucine (linear and quadratic effect, P < 0.05) and immunoglobulin G (IgG) and IgA (linear and quadratic effect, P < 0.05) in finishing gilts. © 2016 Japanese Society of Animal Science  相似文献   

Mechanical and Thermal Sensory Testing in Normal Chondrodystrophoid Dogs and Dogs with Spinal Cord Injury caused by Thoracolumbar Intervertebral Disc Herniations          下载免费PDF全文

A.M. Gorney  S.R. Blau  C.S. Dohse  E.H. Griffith  K.D. Williams  J.‐H. Lim  D. Knazovicky  B.D.X. Lascelles  N.J. Olby 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2016,30(2):627-635

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Impact of heat stress,nutritional restriction and combined stresses (heat and nutritional) on growth and reproductive performance of Malpura rams under semi‐arid tropical environment          下载免费PDF全文

V. P. Maurya  V. Sejian  D. Kumar  S. M. K. Naqvi 《Journal of animal physiology and animal nutrition》2016,100(5):938-946

A study was conducted to assess the combined effect of heat stress and nutritional restriction on growth and reproductive performances in Malpura rams. Twenty‐eight adult Malpura rams (average body weight (BW) 66.0 kg) were used in this study. The rams were divided into four groups: CON (n = 7; control), HES (n = 7; heat stress), NUS (n = 7; nutritional stress) and COS (n = 7; combined stress). The study was conducted for a period of 2 months. CON and HES rams had ad libitum access to their feed while NUS and COS rams were under restricted feed (30% intake of CON rams) to induce nutritional stress. The HES and COS rams were kept in climatic chamber at 42 °C and 55% relative humidity for 6 h a day between 10 : 00 h and 16 : 00 h to induce heat stress. Body weight increased significantly (p < 0.05) in CON as compared to NUS and COS. When compared within groups, scrotal width morning, scrotal width afternoon, scrotal circumference morning and scrotal circumference afternoon were significantly (p < 0.05) larger in CON while smaller in COS rams. The higher testicular length was recorded both during morning (p < 0.05) and afternoon (p < 0.01) in COS rams while the lowest in NUS rams. The highest plasma testosterone concentration was recorded in CON and lowest in COS rams. Semen volume and mass motility also differed significantly (p < 0.05) between the groups. The highest semen volume and mass motility was recorded in CON and NUS while lowest in both HES and COS rams. It can be concluded from this study that when two stressors occur simultaneously, they may have severe impact on reproductive performance of rams.  相似文献   

Two single nucleotide polymorphisms in the promoter of the ovine myostatin gene (MSTN) and their effect on growth and carcass muscle traits in New Zealand Romney sheep          下载免费PDF全文

J. Wang  H. Zhou  J. Hu  S. Li  Y. Luo  J.G.H. Hickford 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2016,133(3):219-226

Myostatin is a negative regulator of muscle growth and development in mammals, and variation in ovine myostatin gene (MSTN) has been demonstrated to be associated with variation in the muscularity of sheep. Polymerase chain reaction–single‐stranded conformational polymorphism (PCR–SSCP) was used to look for single nucleotide polymorphisms (SNPs) in a 304‐bp amplicon from the promoter region of ovine MSTN. Sequence analyses revealed two previously identified SNPs (c.?2449G/C and c. ?2379T/C) that resulted in three haplotypes (H₁ (c.[?2449G; ?2379C]), H₂ (c.[?2449C; ?2379C]) and H₃ (c.[?2449G; ?2379T]). The effect of these SNPs on growth and carcass traits was investigated in 357 NZ Romney lambs. General linear mixed‐effect models revealed that sheep with the genotype c.?2449GC had a higher loin meat yield (p = 0.032) and proportion loin yield (p = 0.028), than those with the genotype c.?2449GG. The genotype c.?2379CC was associated with an increase in three weight traits: birthweight (p = 0.003), tailing weight (p = 0.009) and weaning weight (p = 0.028), when compared with the genotype c.?2379TC, but it was not found to have an association with growth rate. This suggests that c.?2379T/C has an effect that originates at, or before birth. Haplotype H₃ was associated with a decrease in birthweight (p = 0.002), tailing weight (p = 0.003) and weaning weight (p = 0.011). Haplotype H₂ was associated with increased loin yield (p = 0.012) and proportion loin yield (p = 0.002). The SNPs may have value as genetic markers for improved Romney breeding.  相似文献   

An 8bp indel in exon 1 of Ghrelin gene associated with chicken growth   总被引：7，自引：0，他引：7  

Fang M  Nie Q  Luo C  Zhang D  Zhang X 《Domestic animal endocrinology》2007,32(3):216-225

Ghrelin, acts as the endogenous ligand for growth hormone secretagogues receptor (GHS-R), is a novel growth hormone (GH) releasing peptide with reported effects on food intake in chickens. In this study, an 8 bp indel polymorphism in exon 1 of the chicken Ghrelin (cGHRL) gene was genotyped in a F(2) designed full-sib population to analyze its associations with chicken growth and carcass traits. Later, mRNA level in the proventriculus was determined by real-time PCR to reveal the expression feature of cGHRL gene. Result showed that this 8 bp indel was significantly associated with body weight at the age of 28 days (BW28) and 56 days (BW56), eviscerated weight (EW) and leg muscle weight (LMW) (P<0.05), highly significantly associated with hatch weight (HW), BW14, 21, 35, 42, 49, 90 and body length (BL), dressed weight (DW), eviscerated weight with giblet (EWG), wing weight (WW), breast muscle weight (BMW) and head and neck weight (HNW) (P<0.01). Meanwhile, A allele (with 'CTAACCTG') was positive for chicken growth as individuals with AA genotype had the highest value of all traits. Analysis on cGhrelin mRNA level revealed that it differed significantly among individuals with three genotypes (P<0.05). Individuals with AB genotype had the highest mRNA level, whereas that of AA had the lowest one. It was concluded that this 8 bp indel of cGHRL gene was significantly associated with most body weight and body composition traits, and negative effect of endogenous Ghrelin on chicken growth were indicated by this study.  相似文献   

陆地棉品种间杂种F_2代优势研究及经济农艺性状的通径分析   总被引：6，自引：0，他引：6  

李煦远  吴红星  董彩虹 《棉花学报》1996,(3)

用７个Ｆ１代具高竞争优势的陆地棉品种间杂种Ｆ＿２代和高产、优质、多抗的品种鄂棉１５（对照）为材料，研究了Ｆ＿２代及皮棉产量等经济性状的竞争优势，又对它们与株高等在艺性状进行了通径分析。结果表明：正确选配亲本，能将高产、优质、早熟综合于一体，多代利用陆地棉品种间杂种。３８４×３６１Ｆ＿２，鄂荆１号（３２４７）×３６１Ｆ２显著优于对照，分别增产１５．４９％、１２．１６％，且纤维长度、早熟性与对照相近，在生产上有很大的利用价值。决定Ｆ＿２代皮棉产量主要是单株铃数、衣分以及它们之间的互作。同一农艺性状对不同经济性状影响程度很不相同，每个经济性状一般都受１～３个主要农艺性状和它们之间，或它们与其他农艺性状互作所制约。在湖北生态条件下，高产、优质、早熟的陆地棉品种间杂种Ｆ＿２代应具备棉抹较高，果位适中而果高偏低，纵横比较大，果枝夹角较小及主茎节距较大等农艺性状  相似文献   

活塞组机械疲劳试验的有限元仿真     

刘永启  王延遐  门秀花  林风华  张运泰 《拖拉机与农用运输车》2006,33(4):20-22

对某铝合金活塞在机械疲劳试验机上做的疲劳试验进行有限元分析,为活塞的改进设计提供依据。采用装有活塞销的三维整体活塞有限元模型,应用接触单元模拟实际情况,对活塞在交变机械载荷作用下的应力和应变进行了计算,找出了危险点部位,计算结果与试验吻合。  相似文献   

莲子脱壳机设计与试验   总被引：13，自引：0，他引：13  

郑传祥 《农业机械学报》2003,34(5):106-108

设计了一种实用的高效莲子脱壳机，对传统手工脱壳工艺进行改进，利用高速刀具对莲子外壳进行切割和挤压使其脱壳，同时增加了脱壳切割的刀具数量，使其更适合机械化生产，将莲子按大小进行分类脱亮，使莲子脱壳实现机械化，试验证明该机器技术可行。  相似文献