Phenotypes Including Immunocompetence in Scavenging Local Chicken Ecotypes in Tanzania

A study was conducted to determine the variations in physical characters and immunocompetence among scavenging local chicken ecotypes in Tanzania. Eighty-four adult scavenging local chickens from four eco-climatic regions of Tanzania were studied. Measurements of adult body weight, body length, shank length and egg weight and observations of plumage colour and pattern, earlobe colour, skin colour and the shape of the comb were conducted. The antibody response to sheep red blood cells, serum haemolytic complement and the cutaneous response to phytohaemagglutinin-P were assessed. Five ecotypes were identified and named Mbeya, Morogoro-medium, Ching'wekwe, Kuchi and Singamagazi. Singamagazi and Kuchi were significantly heavier, with longer shanks and heavier eggs than the other ecotypes. The average adult body weight for males ranged from 1621 g (Mbeya) to 2915 g (Singamagazi). Average female weights ranged from 1108 g (Morogoro-medium) to 2020 g (Singamagazi). Mean egg weights ranged from 37.65 g (Ching'wekwe) to 45.61 (Singamagazi). The Kuchi had mostly rose and walnut combs, while the other ecotypes were mostly single combed. In each ecotype there were chickens with a high or low antibody response to red blood cells, but there was a significant difference between the ecotypes.     

I-69杨苗期生长及营养特性的研究

杨树是重要的速生树种,在我国长江中下游平原地区发展具有重要意义。1983年对杨树的黑杨派良种I-69杨(Populus deltoides cv.“Lux”)苗期生长与营养特性的研究,旨在培育和选择优质苗木,为杨树用材林定向培育的造林设计提供科学依据。     

桑青尺蠖的生物学特性研究

研究了桑树常见害虫桑青尺蠖的形态特征、继代繁殖等生物学特性 ,以及幼虫食叶量、寄生性天敌及温度对青尺蠖发育历期的影响。该虫在室温下全年可继代繁殖 5代 ,以蛹越冬。随着饲养温度的升高 ,其发育历期缩短。在 2 0 95、2 4 16和 2 9 70℃的温度下 ,全代历期分别为 5 8 1、43 9和 35 2d。幼虫多为 6龄 ,少数 5龄。平均每头幼虫全龄食叶量为 2 948 11mg ,其中第 5龄和第 6龄食叶量占全龄食叶量的 95 48%。     

大通县"西繁东育"项目实施情况调查

通过“西繁东育”项目的实施,大通县牛羊贩运育肥规模户由2001年的898户发展到2005年的4170户,贩运育肥出栏牛羊由2001年的12.12万头只增加到2005年的65万头只,纯收入由2001年的456.76万元增长到2005年的4548.97万元,逐步成为大通农民增收的主渠道。     

返青期休牧对退化高寒草甸植被生长及其优势植物垂穗披碱草光合作用的影响

返青期休牧为退化草地恢复中最经济可行的措施且已得到了较广泛的推广和应用,为探索返青期休牧对高寒草地植物生长及光合特性的影响,本研究于2015年开始在青海省祁连山区进行返青期休牧试验,于2018年和2019年调查并测定试验样地植物群落特征和光合生理指标。结果表明：返青期休牧4年后,草地总盖度、优势种牧草垂穗披碱草（Elymus nutans）高度、地上生物量和地下生物量较未休牧分别提高了35%,777%,1140%和217%,垂穗披碱草叶绿素含量和净光合速率分别增加了172%和146%;草地总盖度、地上生物量和垂穗披碱草叶绿素含量及净光合速率在休牧第4年和休牧第5年之间差异不显著。因此,在高寒草地实施返青期休牧可提高优势牧草光合作用、促进退化草地植被的恢复,且退化草地植被在休牧一定年限后趋于稳定。本研究为青藏高原推广实施返青期休牧这一措施来恢复退化草地植被提供了理论基础。     

棘托竹荪的生物学特征

棘托竹荪的生物学特征周崇莲（中国科学院沈阳应用生态研究所沈阳１１００１５）曾德容（湖南合同县政协会同４１８３００）关键词棘托竹荪，形态特征，生态习性，营养成份１９８５年对湖南会同县的竹荪进行野外调查时，采到一种不同于竹荪（Ｄｉｃｔｙｏｐｈｏｒａｉｎｄ...     

Morphological variation in the short-tailed fruit bat (Carollia) in Ecuador,with comments on the practical and philosophical aspects of boundaries among species

The mechanisms for the morphological delimitation of species in Carollia remain poorly understood. This is the first study to assess variation in size and shape from strictly geometric terms. Both factors are assessed by statistical perspectives of distribution, overlap and relative distances. Despite its overlap, the size of the skull seems to be the most influential character for the discrimination of species, with shape playing a much smaller role. The smallest species seems to be the most distinct in shape, not only in terms of distance among centroids in morphometric space, but also in the overall trend and direction of variation. Contrary to previous studies, sexual dimorphism is not given by size but by distinct shapes of the skull. Characters such as the shape of the maxilla, previously described qualitatively as discrete with sharp boundaries, appear to be truly continuous with fuzzy borders among species. Because morphometric space is a gamut of continuous variation and overlap, the taxonomic error rate for size characters seems to be substantial for the medium-sized species (Carollia brevicauda Schinz, 1821), with approximately 30–40% of individuals erroneously assigned to a different species after a jackknifed discriminant function. This taxonomic error is higher for shape characters. Morphological, systematic and ecological consequences of the observed patterns of shape and size variation are commented within the context of previously proposed arguments and hypotheses.     

中国假俭草种质资源主要性状变异及其形态类型

对中国59份假俭草的11个重要经济性状进行统计分析,并对其形态类型加以聚类分析。结果表明:1花序密度变异系数高达76.9%,是所测性状中变异范围最大者,叶长次之,变异系数为31.3%,结实率、草层高度以及生殖枝高度变异系数分别为23.0%、18.0%及22.1%,变异范围为25.0%～74.8%、14.3～33.2cm及5.8～17.0cm;百粒重、叶宽、花序长、花序小花数以及节间长度变异幅度相对较小,分别为15.1%、14.6%、12.5%、12.5%及11.4%,其中以节间直径最小,仅为4.7%;2生殖枝高度和花序密度随着纬度的增加,呈显著增高和极显著增加趋势,而其它性状未出现显著变异规律;3节间直径与叶宽呈极显著正相关;草层越高,生殖枝愈高,节间愈长愈粗,而生殖枝愈高,花序愈长,节间愈长,花序密度也愈大,结实率愈高;4在欧氏距离11.2处,可将供试草种分为营养繁殖型和种子繁殖型两大类型,前者花序密度低,结实率低,叶片较长,而后者花序密度高,结实率较高,叶片则较短。     

乳牛体型性状线性评定数学模型的指导和应用

本文说明了乳牛体型性状线性评定的常规方法,在此基础上推导出了该评定方法的数学模型。该模型的提出,极大地简化了常规评定方法的繁琐计算,值得在乳牛业生产实践中推广使用。     

结缕草属植物生殖性状的遗传分析

选用2份生殖性状存在差异的结缕草(Z136)和中华结缕草(Z039)相互杂交,获得正反交F₁分离群体,应用植物数量性状主基因+多基因混合遗传模型分析方法对F₁群体的花序密度、生殖枝高度、花序长度、每穗小穗数、小穗长度、小穗宽度、小穗长度/宽度进行遗传分析,以初步明确这些性状的遗传特性。结果表明,1)在调查的7个性状中,正反交杂交后代中每一个性状的变异范围均超出了双亲的变异范围,不同性状的变异系数差异较大,花序密度的变异系数最大,其次为生殖枝高度和每穗粒数,小穗长度和宽度的变异最小,花序长度的变异居中。2)花序密度、生殖枝高度、小穗长度和小穗长/宽正反交后代的观测值存在显著差异,可能有母体遗传效应,花序长度、每穗粒数和小穗宽度正反交后代间的观测值无显著差异。3)花序密度正反交后代群体的最佳遗传模型为存在2对主基因控制的遗传模型,生殖枝高度、花序长度和小穗宽度正反交后代群体的最佳遗传模型均为A-0模型,即无主基因模型。每穗粒数正交为1对主基因的遗传模型,反交为无主基因模型,小穗长度的正交为无主基因模型,反交为1对主基因模型。小穗长/宽正交的最适遗传模型为B-1模型,即2对主基因的加性-显性-上位性遗传模型,主基因遗传率为42.72%,反交群体的最适遗传模型为B-2模型,即2对主基因的加性-显性遗传模型,主基因遗传率为98.81%。