黑杨派南方型无性系引种及选择的研究

对黑杨派南方型８个无性系的引种试验进行了总结。主要考察了高，径，材积冠幅和抗病能力，应用方差分析和系统聚类分析，将参试无性系划为３个等级，确定了适宜江西省江，湖冲积滩地推广的优良无性系，处于第１级的Ｓ１－８和７２５，其材积生长量分别比１－７２杨提高３２．６％和３０．２％，且有较好的抗病性能，处于第２级的５０、７１０、５５／５６和Ｓ１－６，它们的材积生长量比Ｉ－７２杨提高１７．６％￣２１．７％。     

农户经济增长与发展稳定性研究

通过大量长期跟踪观察的农户资料对农户纱济增长与发展进行了实证分析，揭示出农记脓庭经济增长与发展的稳定性是有条件的，在一定家庭生命周期段农户经济可以持续增长，当家庭生命周期运行到一定程度，农户经济增长必然出现衰退。     

四川盆地丘陵区坡地农林复合系统林带类型、农作物复种方式的选择

针对四川盆地丘陵区农、林业生产特点和坡地农林复合系统特征，运用层次分析法（ＡＨＰ），从结构、功能，效益方面设置评价指标，分别对系统中的６种林带类型和１０种农作物复种方式进行综合评价，结果提出了３种较好的林带类型（即桤、柏混交和栎，柏混交－灌－草结构的林分以及桤木－草结构的林分）和４种较好的农作物复种方式（即小麦－花生、小麦／西瓜／蔬菜，蚕豆／玉米／红薯和蚕豆／西瓜／红薯等）；为该区坡地农林复合系统     

家蚕丝质性状选择效果研究

本文采用系统选择、杂交改良等方法。对解舒、净度、强伸力、茧丝长等家蚕主要丝质性状进行了研究。结果表明,解舒、净度、茧丝长系统选择与杂交改良是有效的;对解舒率和茧丝长进行严格综合系统选择,在一定程度上能克服解舒率与茧丝长的负相关关系;系统选择法所建立的解舒好系与解舒差系能稳定遗传;解舒率与强力、伸长度成正相关,但相关程度很低,一代杂种的强力高于原种。     

北方林区运材汽车选型的实验研究

本文依据北方林区汽车运材的工况条件和各种运材汽车的使用情况,结合我国汽车工业的发展规划,确定了CA141K_2型和CA150K_2型运材汽车总布置参数及其主挂车的匹配设计;简述了CA141K_2型和CA150K_2型运材汽车的研制过程、林区使用实验、性能检测、整车技术鉴定及其推广应用等情况。     

高阶时滞神经网络模型的全局指数稳定性

对具有时滞的二阶Hopfield型神经网络平衡点的全局渐近稳定性问题进行了研究.在不要求连接权矩阵的对称性和输入输出函数的可微性与单调性,只要求系统的参数满足是一个M矩阵的情况下,利用推广的Hanalay不等式和上右导数导得系统全局指数稳定性的若干充分条件.为二阶时滞神经网络稳定性的新方法、新结论.     

应用SSR分子标记分析国外种质对我国小麦品种的遗传贡献

利用363对SSR标记分析了在我国小麦生产和育种中发挥了重要作用的11份国外引进品种和33份选育品种的遗传组成,旨在揭示国外种质对我国小麦品种改良的遗传贡献,指导种质资源引进和利用。国外种质包含了选育品种所发现等位变异的76.3%。与不同时期小麦品种等位基因多样性比较发现,国外种质的平均等位变异数最多(3.92),20世纪60年代(2.86)和70年代(3.01)基本一致,80年代有所升高(3.46)。品种间遗传距离比较与品种等位基因多样性结果相吻合。比较引进和选育品种在SSR位点的等位变异频率变化,发现至少在33个SSR位点,国外种质等位变异在我国小麦育种中被优先选择(该等位变异在引进和选育品种的分布频率均高于70%),其中一些位点已知与产量、生育期和抗病等性状密切相关。表明引进品种在以上基因组区域对我国小麦品种具有非常高的遗传贡献。     

Selection for a qualitative trait in an autotetraploid crop

Summary A procedure for a programme of repeated backcrossing of autotetraploid crops is outlined. It aims at minimizing the numbers of plants needed for the backcross generations and for the identification of the desired quadruplex plants. Also the danger of inbreeding depression, especially with cross-fertilizing crops, is taken into consideration.     

Effects of high- vs. low-yield environments on selection for increased biomass yield in switchgrass

No information is available on the effects of different biomass yield environments on selection efficiency in switchgrass (Panicum virgatum L.) breeding improvement. This study was conducted to assess the effects of high- and low-biomass yield environments (HYE and LYE, respectively) on recurrent selection for general combining ability (RSGCA) in a lowland population of switchgrass (NL-94). The top 14 of 65 NL-94 C₀ parent plants were selected based on biomass yield of half-sib (HS) progeny tested for one post-establishment year under HYE and LYE conditions. Nine of the 14 C₀ parent plants were the same based on HS performance under HYE and LYE. Selected plants were intercrossed to produce NL-94 HYE and NL-94 LYE C₁ populations. One hundred and twenty-five HS C₁ progeny families (60 NL-94 HYE and 65 NL-94 LYE) were evaluated for biomass yield for 3 years (2002–2004) under HYE and LYE conditions. The HYE produced about 2.5 times higher biomass yields than the LYE in both C₀ and C₁ HS progeny tests. Estimated additive genetic variance and predicted gains from selection (ΔG) were high in the C₁ populations indicating that RSGCA should achieve higher biomass yields. Mean biomass yields of C₁ HS families originating from the LYE protocol were significantly higher than those of families originating from the HYE protocol in both HYE and LYE performance tests, suggesting greater selection response under LYE in the C₀ population. The estimates of narrow-sense heritability ( ) and ΔG from the C₁ populations indicate that positive response to selection for biomass yield is possible in subsequent cycles of selection under either HYE or LYE, with a possible small advantage for HYE.     

不同栽培条件对小麦杂种后代性状表现的影响

采用4种不同的栽培方式,探讨了杂种F_2代的性状分离和选择效果。结果表明,适当地增加种植密度和改善肥水条件,有助于抗性和丰产性诸性状的遗传变异更好的得以表达,进而达到提高性状鉴定和选择效果之目的。本文结合有关育种理论,对如何创造有效的性状鉴定条件和多种杂交后代处理办法的结合作了讨论。