北方杂交粳稻核心亲本的播始历期及其稳定性的分析

对于亲本播始历期的准确把握是确保杂交稻制种父母本花期相遇的根本。然而由于水稻的光温敏感性,其播始历期受环境影响较大,而且品种间也存在很大差异,很难做一般性的把握。作者从杂交稻的育种实践出发,采用在不同年份和地点进行分期播种和插秧的方法,对北方杂交粳稻核心亲本的播始历期及其稳定性进行研究。结果表明:(1)多数不育系与保持系播始历期差异不明显;(2)核心亲本105A,91A,95A,99A,02A,屉A,C52,C258,C01,C418的基本播始历期分别为104.7,105,104.8,107.7。106.8,106.9,105.7,111,107.1,115.6d;(3)播始历期具有明显的年份、地点、播期和秧龄效应及其间互作效应;(4)总体上105A、C258,C01,91A,C418的播始历期稳定性较差,而C52,99A,TA,02A,95A稳定性较好。     

地膜小麦不同覆盖方式及播量试验

小麦全生育期地膜覆盖栽培是小麦生产中的一项显著增产技术。通过在膜上打孔穴播和垄盖膜际精播的不同覆盖方式、不同带距、不同播量的试验研究,证明在高水肥栽培条件下,两种模式均可获得高产,每公顷产量可达9000kg以上。在不同带距高产栽培中,窄行匀播比宽行播种增产潜力大,产量高;在不同播量中,以每公顷播种105kg产量最高,增产幅度最大。     

Influence of Anthesis Date and Boll Branch Position on Qualities and Super-molecular Structure of Cotton Fiber

The influences of the anthesis date and the fruiting branch positions on parameters of cotton fiber quality and super-molecular structure were studied. Fiber quality parameters, such as cotton fiber length, micronair, maturity and fiber strength deteriorated with postponing the anthesis date and decreasing temperature. When anthesis happened on the same date, the fruiting branch positions affected the fiber quality parameters, and the fiber quality parameters of the lower portion turned out to be higher than that of the upper portion, although the difference was insignificant. The super-molecular structure of the lower portion turned out to be superior to that of the upper portion at the early anthesis date and high temperature, which is in accordance with what was mentioned above, but the fruiting branch positions did not affect the impact of the anthesis date on the super-molecular structure.     

Calving date and its variability as a potential trait in the breeding objective to account for reproductive seasonality in alpacas

The low fertility and offspring survival indicators in alpacas can be partially due to their particularity seasonal reproduction that reduces the opportunities of the females to become pregnant within a season, with the survival of the offspring concerned by the availability of food and exposure to diseases that depends on the calving date. Optimizing the date of delivery and reducing its variability are shown as eligible criteria that could be used as selection criteria within the genetic improvement programmes in alpacas, the calving date being a much more appropriate trait to measure and optimize fertility unlike of age at first calving and the calving interval, this due to the reproductive seasonality in camelids. For this study, 6,533 birth date records were taken between 2001 and 2018 of Peruvian alpacas, to estimate the genetic parameters. Models assuming heterogeneity in the residuals were fitted besides classical homogeneous models to address, not only the possibility of forwarding or delaying the calving date, but also the trend to have parturitions in similar dates. The heritability and repeatability ranged from 0.07 to 0.20 for a homogeneity model and from 0.08 to 0.23 for a heterogeneity model, and suggest the possibility of advancing or delaying the calving date. It should be taken into account that the gestation length of camelids makes it difficult to adapt many reproductive traits, and trying to centre the calving date could delay it. It was concluded the feasibility to genetically select the calving date, also in the production of camels and dromedaries, which have the same reproductive characteristics as alpacas. This selection can be combined with other traits. The heterogeneity model was shown to provide a better fit.     

冬小麦北移栽培的施肥量、播种量和播期的组配效应研究

对米808和京冬1号两种类型的冬小麦品种进行了比较研究，分析了在冬麦北移栽培中，施肥量、播种量和播期三因素对小麦生长发育和产量的影响，并制定出不同的优化栽培方案。     

基于多因素模型重构陕西苹果主要物候数据序列

苹果生长发育受气象因素影响较大,陕西高低温灾害发生频率的增加对苹果的产量和品质有很大影响。物候期的确定是指导果业生产、进行灾害风险管理的重要依据。目前,物候期观测数据十分匮乏,通过构建物候模型可对历史物候期进行重构。在陕西的四个果区,分别选取物候资料记录相对全面的两个代表站点,礼泉和凤翔（关中果区）、旬邑和长武（渭北西部果区）、铜川和白水（渭北东部果区）、延长和洛川（延安果区）。在各果区的两个代表站点中,选取历史物候期记录时间序列更长的站点,利用SPSS软件对该站点物候期日序与所选气象指标进行逐步回归分析,建立多个单项或多项物候期预测模型,再通过回代检验和预测检验两种方法选取最优模型。采用平均绝对误差（MAE）、物候期模拟值与实际值相差0～3d的相对准确率（RA）评估检验结果,并选择最优模型。结果表明：（1）萌芽期模型MAE为0.8～2.4d,RA为84.6%～100%;花期模型MAE为2.5～3.4d,RA为55.6%～75%;果实发育期模型MAE为0.9～2.8d,RA为63.2%～100%;成熟期模型MAE为2.2～3.2d,RA为69.2%～72.2%;模型模拟效果由好到差依次为萌芽期、果实发育期、成熟期和花期。（2）重构1981−2019年延安果区、渭北东部果区、渭北西部果区和关中果区苹果萌芽期年日序分别为72−98、70−88、73−98和71−85,花期年日序分别为102−116、86−107、100−125和84−115;1981−2019年延安果区、渭北东部果区和关中果区苹果果实发育期年日序分别为114−122、89−118和87−117,成熟期年日序为260−301、276−297和224−348。（3）重构物候期的空间分布,1981−2019年延安果区和渭北东部果区萌芽期由东南向西北逐渐推迟,关中果区和渭北西部果区自西向东推迟;花期整体自南向北越来越晚;果实发育期从南向北逐步推迟;延安果区和渭北东部果区成熟期从东向西逐步推迟,关中果区和渭北西部果区自西向东逐步推迟。本研究构建的物候模型的模拟效果总体较好,所重构的苹果物候期数据序列可为苹果生产管理和灾害风险防范提供基础性支撑,对果树物候期模型的研发具有借鉴意义。     

播期对浙东南地区直播晚粳稻产量、生育期及温光利用的影响

为筛选适宜在浙东南地区作受灾补播的直播晚粳稻品种,选用3个籼粳杂交稻(甬优1540、甬优7850、嘉优中科3号)和2个常规粳稻(秀水519、秀水417),开展大田分期直播试验,研究不同播期对水稻产量及产量构成因素、生育期和温光资源利用的影响。结果表明,水稻产量表现为籼粳杂交稻>常规粳稻,具体为甬优1540>甬优7850>嘉优中科3号>秀水519>秀水417,随着播期的推迟,产量均呈下降趋势,下降幅度为籼粳杂交稻>常规粳稻,播期每推迟5 d,籼粳杂交稻平均产量下降0.71 t·hm^-2,常规粳稻下降0.30 t·hm^-2,主要与每穗粒数和结实率显著降低有关;水稻生育时期随播期推迟而相应顺延,且播种-齐穗期、齐穗-成熟期等生育阶段缩短,籼粳杂交稻全生育期缩短幅度大于常规粳稻;水稻全生育期的有效积温、日照时数及其利用率和有效积温生产效率随播期推迟基本呈下降趋势,同一播期内,籼粳杂交稻有效积温生产效率高于常规粳稻。产量与齐穗-成熟期的温光资源呈显著或极显著正相关。救灾品种若在7月15日前补播,籼粳杂交稻首选甬优1540,其次为甬优7850,而常规粳稻宜选用秀水519,且播期可推迟至7月20日。本研究结果可为浙东南地区受灾后,采用直播技术选择适宜救灾补播品种提供实践指导与科学依据。     

北京房山区山地景观荞麦适宜播期研究

为更好地发挥荞麦在房山区景观营造中的作用,开展了荞麦播期试验,研究播期对荞麦观赏期和株高的影响。结果表明,房山区荞麦春播适宜播期为4月5 — 16日,花期为70 d左右,初花至倒伏亦为70 d左右,封行至倒伏为60 d左右,盛花至倒伏可以持续60 d左右,观赏持续期最长;夏秋播适宜播期为7月20日至8月25日,植株不易发生倒伏,花期在34~57 d,其中7月20日左右播种最佳,花期达57 d;5月7日至6月9日也可播种,初花至倒伏在21~49 d;6月25日至7月5日不适合播种。     

麦套花生套期与密度优化配置研究

采用二次饱和D-最优设计建立了小麦行距为30cm的麦套花生套期和密度与产量的数学模型.进一步分析表明,花生套期和密度对花生产量作用显著,且密度效应大于套期.套种花生最适播期为麦收前22d,与其相配套的最适密度为15.55×104穴/hm2,最高产量可达到4 679.4kg/hm2.适期过后,套期每推迟5d,花生平均减产187.2kg/hm2.花生产量在3 500kg/hm2以上的优化措施组合为:5月10日～5月29日套种,密度14.66×104～20.72×104穴/hm2.     

Survival and prognostic indicators for cycad intoxication in dogs

Background: Cycad palms are commonly used in landscaping and ingestion by dogs can cause disease or death. Objectives: Determine the morbidity and case fatality of cycad palm toxicosis in dogs from Louisiana, and examine putative prognostic factors. Animals: Thirty‐four client‐owned dogs with confirmed cycad palm toxicosis between 2003 and 2010. Methods: Retrospective cohort study. Search of all medical records for animals with cycad palm toxicosis. Results: Seventeen of 34 (50%) dogs died or were euthanized as a direct consequence of cycad intoxication. There were no differences in presenting signs and physical examination findings between survivors and nonsurvivors. Nonsurvivors had higher serum alanine transaminase activity (median 196 U/L; range 16–4,123 versus 113.5; 48–1,530) and total bilirubin concentration (0.5 mg/dL; 0.1–6.2 versus 0.25; 0–1.7) upon presentation, and their initial serum concentrations of albumin (2.9 g/dL; 1.4–4.1 versus 3.3; 2.2–3.9) were lower than those of survivors. Nadir serum albumin concentration was also lower in nonsurvivors (1.9; 1.4–3.7 versus 3.2; 1.8–3.5). A higher proportion of nonsurvivors had prolonged coagulation times, prothrombin time. and partial thromboplastin time. In a multivariate model, administration of charcoal at initial presentation was associated with longer survival (heart rate [HR] 0.019, 95% CI 0.001–0.644), while high serum aspartate aminotransferase activity was a negative prognostic factor (HR 118.2, 95% CI 2.89–4,826). Conclusions and Clinical Importance: Cycad intoxication is associated with a higher case fatality than previously published. Several laboratory parameters might help differentiating potential nonsurvivors from survivors. Administration of charcoal as part of the emergency treatment appears to have a protective effect.