四个不同节气对哈巴特肉仔鸡血糖值的影响

[摘要]为比较哈巴特肉仔鸡在春分、夏至、秋分和冬至四个不同节气时的血糖值,分别在同一年度的春分、夏至、秋分和冬至的当天测定12日龄哈巴特肉仔鸡的空腹血糖值。结果表明：哈巴特肉仔鸡的血糖值在夏至时为最低,冬至时为最高,且冬至时极显著地高于春分和夏至（P〈0．01）,秋分时极显著地高于夏至（P〈0．01）,而血糖值春分和秋分之间无显著性差异（P〉0．05）。可见,随着季节的变换,哈巴特肉仔鸡的血糖值也发生相应变化。     

墨西哥春小麦品种熟期与穗部经济性状的遗传通径分析

对３５份墨西哥春小麦品种的拔节期、抽穗期、开花期、成熟期和穗粒数、千粒重、穗粒重及小区产量等８个性状的遗传相关和通径关系进行分析研究,结果表明：（１）黑西哥小麦品种的抽穗期、开花期与成熟期呈极显著表型正相关（ｒ＝０．５９和０．５６９）和遗传正相关（ｒ＝０．６７和０．７１２）;（２）抽穗期、开花期和成熟期与穗粒数呈显著遗传正相关（ｒ＝０．３８９、０．４４２ｔ ０．４１８）;（３）拔节期、抽穗期、开花     

An autumn profile of growth regulatory hormones in chinook salmon (Oncorhynchus tshawytscha)

We examined trends in the growth regulatory hormones growth hormone (GH) and insulin-like growth factor-I (IGF-I) from August to December in chinook salmon. Fish on 100% (ad libitum) and 64% rations of a low fat high protein diet, and a 64% ration of commercial feed (BioOregon-grower) were sampled twice a month. Fish were kept on simulated natural photoperiod at constant temperature. GH declined in late August and early September, consistent with photoperiodic regulation. No effects of ration or diet composition on GH were found. IGF-I increased to a peak on 4 October 1998 and declined thereafter. High dietary ration and the higher fat commercial diet increased IGF-I. Fish length and IGF-I level were positively correlated. This study shows that a peak in IGF-I may occur in the fall in chinook salmon. This revised version was published online in August 2006 with corrections to the Cover Date.     

小春作物多样性控制病虫害试验研究初探

 为探索小春作物多样性对病虫害的持续控制规律及增产增收效果,2000～2001年在云南玉溪市峨山、澄江和红塔区共设6组小春作物多样性混种大区同田对比试验及18.7 hm²典型大田示范进行调查分析研究。结果表明,麦类与蚕豆混种或油菜与蚕豆混种不仅能有效地持续控制、减少病虫为害,减少农药、化肥施用,保护农田生态环境,而且能增产、增收;此外,混种引起了油菜、麦类及蚕豆主要经济性状和蚕豆根瘤生物量不同程度的变化,预示出小春作物油//豆或麦//豆间存在的相生相克规律,初步搭配的几个优化混种组合可供生产应用。     

春油菜蚜虫的为害及防治指标的研究

蚜虫是造成春油菜减产的重要因素之一,1991～1992年作者研究了春油菜不同生育阶段受蚜虫为害损失及防治指标。结果表明,不同生育阶段的油菜植株受蚜虫为害时,导致株高下降、有效角果数减少、单株产量下降。油菜苗期、苔花期、角果期的临界为害量分别为12～15、50～100、90～100(头/株)。根据虫量与产量损失预测模型,结合春油菜价格、产量水平、防治费用、经济效益及天敌各防治风险等因素,本文提出了每hm~2产1050kg的油菜田,防治指标为12头/株。