陕西退耕还林工程对农业经济的驱动分析

根据1990~2004年陕西统计资料,通过对比来揭示退耕还林工程的实施,对农村劳动力结构、农业产业结构和农户收入水平的巨大影响力;构建农户收入水平的模型,并加以分析,得出结论:退耕还林工程的实施,明显地提高了农户收入,促进了农村劳动力结构和农业产业结构的转变.发现农户经济收入趋势线正处在朱格拉经济周期内,并根据趋势方程对未来5a的发展状况做出预测.     

60Co-γ照射对唐菖蒲“江山美人”品质及生物学特性的影响

为进一步了解辐射在唐菖蒲育种中对唐菖蒲主要品质指标和生物学特性的影响,取6组唐菖蒲“江山美人”品种种球分别经过0、25、50、75、100、150GY剂量60Co—γ射线照射后,植入大田,进行形态指标测定。结果显示唐菖蒲各主要品质指标均受到辐射的影响产生不同程度的变异,大体趋势为随着辐射剂量的增大各指标相映降低,但是低剂量辐射对某些指标产生了促进作用。如在发芽时间上25~100GY各组均比对照有所提前;株高方面25GY组平均株高略高于对照组;25GY和75GY两组叶片数多于对照;50、75、100GY三组花序长明显高于对照。表明低剂量辐射促进了植株株高、花序长等生长指标;辐射剂量在75GY左右,辐射变异率较高;在辐射剂量高于100~150GY时各指标均产生明显下降趋势。75GY左右是唐菖蒲育种适宜的辐射剂量。     

Improvement of penetrability of sugi wood by impregnation of bacteria using sap-flow method

The sap flow method of wood impregnation was conducted to aid the movement of bacteria through the living tree, thereby accelerating their distribution through wood within a short time. When log-pond water containing mixed species of bacteria were introduced in the living trees by butt-end dipping and then laid horizontally for 6 months, bacteria could be delivered by sap flow vertically through the sapwood tracheids up to the high portions from the butt-end of trees; they could be detected in the ray parenchymal cells. The sap-flow method was assumed to deliver the bacteria to sapwood and heartwood at high levels of standing sugi (Cryptomeria japonica D. Don) trees. Degradation of the pit membranes was observed even at more than 3 m upward from the butt-end after the treatment in sapwood, as well as around the butt-end of the trees. The uptake of the aqueous dye solutions in sapwood of the treated logs were about eight times more than those of control specimens after 8h.Part of this report was presented at the 40^th annual meeting of the Japan Wood Research Society, Tsukuba, April 1990; the 41^st annual meeting of Japan Wood Research Society, Matsue, April 1991; and the IUFRO 4^th international conference on wood drying, Rotorua, New Zealand, August 1994     

Assessing the suitability of stress tolerant early-maturing maize (Zea mays) inbred lines for hybrid development using combining ability effects and DArTseq markers

Identification of hybrids for commercialization is crucial for sustainable maize production in sub-Saharan Africa (SSA). One hundred and ninety test crosses, 10 tester × tester crosses + 10 hybrid checks were evaluated across 11 environments, 2017 to 2019. Inheritance of grain yield under Striga infestation, optimal and across environments was influenced by additive genetic action, but there was greater influence of nonadditive gene action under drought stress conditions. Nine, seven and two inbreds had significant and positive general combining ability (GCA) effects for grain yield under Striga-infested, optimal and drought stress environments, respectively, and would contribute high grain yield to their progenies. Heterotic grouping methods based on specific and GCA, GCA effects of multiple traits and DArTseq markers classified the inbreds into five, three and two heterotic groups, respectively, across research conditions. The DArTseq markers method that classified the inbred lines into two major heterotic groups and was one of the most efficient methods should be adopted for practical purposes in maize breeding programmes in SSA. Hybrids TZEI 7 × TZdEI 352, TZEI 1238 × TZEI 7 and TZEI 1252 × TZEI 7 had outstanding grain yield under contrasting environments and should be tested on-farm for commercialization in SSA.     

陕西省旬阳县狮头柑生产存在的问题与解决途径

针对旬阳县狮头柑生产中存在实生繁殖,后代良莠混杂;立地条件差,管理粗放;病虫害严重等问题提出推广实行嫁接技术,改善立地条件,加强病虫害防治等解决途径。     

Mandel方差分析法在基因型X环境互作研究中的应用初探

本文系统地介绍了Mandel二因子互作方差分析法的原理与方法,并应用1990年西南玉米区域试验资料详细说明共分析、计算方法。得到了一个估计试验资料的理论方程,用其估计的理论值与实际资料的吻合程度极高,是一种值得在G×E互作分析中广泛采用的分析方法。     

菜蛾绒茧蜂的人工繁殖与田间放蜂

介绍2种繁殖菜蛾绒茧蜂 Apanteles plutellae 的方法.以灯管繁蜂优于大棚繁蜂,其寄生率比大棚繁蜂高1倍多:田间3次放蜂,以第1次效果较好,寄生率达44%,与自然寄生率相同;在8℃下贮藏蜂茧的时间以15d 左右较适合,羽化率达86%.     

变质量高阶非线性非完整系统的Mic'evic' Duan—Rusov Lazar方程

本文利用变量力学系统的万有 D'Alembert 原理导出变质量高阶非线性非完整系统的 Mic'evic' Duan—Rusov Lazar 方程。     

Ca~(2+)GA混合液对水分胁迫下棉花幼苗生长的影响

通过测定水分胁迫下棉花幼苗长度、根系活力、过氧化物酶 (POD)活性、过氧化氢酶(CAT)活性、脯氨酸 (Pro)含量等指标 ,研究了Ca2 +和GA浸种对水分胁迫下棉花幼苗生长的影响 ,结果表明 :Ca2 +和GA混合后对水分胁迫下棉花幼苗长度、根系活力、POD活性、CAT活性及Pro含量均有显著影响 ,其中 5mmol/LCaCl2 与 1mg/LGA混合效果最佳 ,而Ca2 +和GA单独处理对这些指标的影响效果弱于其互作效应。     

三种长效磺胺药在水牛体内的代谢动力学

<正> 磺胺—5,6—二甲氧嘧啶(SDM')为人用的周效磺胺。在奶山羊体内的代谢动力学已进行了研究。磺胺—5—甲氧嘧啶(SMD)和磺胺—6—甲氧嘧啶(SMM、DS—36)亦为人用长效磺胺。SMM在鸡体内的分布、在牛、猪的血中浓度、血浆蛋白结合率如乙酰化率、对马和奶山羊体内的代谢动力学已进行了研究。