Mating system in an experimental garden composed of cassava (Manihot esculenta Crantz) ethnovarieties

Crossing patterns were investigated in an experimental garden of ethnovarieties ofManihot esculenta (Euphorbiaceae) inPiracicaba, São Paulo, Brazil. A model of evolutionary dynamics for cassava presupposes genetic recombination by means of crossing within cassava gardens as a source that amplifies genetic diversity. Quantitative analysis of mating system parameters was performed using progeny arrays assayed for eight allozyme markers. The multilocus outcrossing rate (t _m)estimate (0.915±0.04)revealed that outcrossing was prevalent, but that a low level of self-pollination also occurred. The multilocus outcrossing rate ranged from 0.69 to 1.00 among eight varieties. The high value found for the outcrossing rate indicates that the ethnovarieties studied are preferentially allogamous. Genetic recombination occurred through crossing within the cassava garden, in agreement with an assumption of the model of evolutionary dynamics for this species.     

Heredity of seventeen isozyme loci in cassava (Manihot esculenta Crantz)

Summary Starch gel electrophoresis was used to assess isozyme polymorphism in two Manihot species. Crude extracts were obtained from leaves and pollen. Ten enzymes were examined for their polymorphism in a germplasm collection of 365 cultivated plus 109 wild accessions, mainly from Africa. The inheritance of these enzymes was examined using 13 intra and interspecific progenies. Seventeen polymorphic loci were found for the ten enzyme systems, with 59 alleles. All the markers showed disomic heredity and three linkage groups were identified.     

木薯离体培养的研究

以本薯茎段作为外植体进行快速离体繁殖研究。于MS 6—BA0．05mg/L GA30．05mg／L NAA0．02mg/L中进行诱导腑芽的生长和继代培养，诱导和增殖效果较好，于MS 6—BA0．05mg／L NAA0．02mg／L MET4mg／L中进行生根培养，植株矮壮，根系发达。     

木薯块根淀粉积累分子机制综述

该文综述了相关的淀粉合成机理以及调控木薯淀粉合成关键酶的生化特性基因调控研究进展,认为人们对木薯淀粉的生物合成机理、关键酶的生化特性与表达调控等方面有了很大的突破。     

木薯外植体表面灭菌与增殖培养的研究

[目的]筛选出适合木薯组织培养的灭菌体系,为加快木薯组织快繁提供科学依据。[方法]以木薯品种GR891的腋芽为外植体,研究经甲基托布津杀菌剂处理和无处理外植体分别采用不同组合、不同处理时间对其表面灭菌的效果,同时研究6-BA和6-BA与NAA组合对丛芽诱导培养效果的影响。[结果]经甲基托布津杀菌剂处理后用体积分数75%乙醇消毒10 s＋质量分数0.1%升汞处理8 min效果最好,外植体存活率为61.3%;以MS＋6-BA 1.5 mg/L＋糖30 g/L＋琼脂6.5 g/L培养基诱导培养芽效果最好,有的丛芽能达到7～9株,丛芽生长速度快,健壮。[结论]建立了木薯GR891组织培养外植体灭菌与增殖培养体系。     

The origin of Manihot esculenta Crantz (Euphorbiaceae)

Summary Contrary to views that cassava (Manihot esculenta) is only known in cultivation an argument is made that wild accessions of the species grow over much of the American neotropics, in Brazil, Bolivia, Peru, Venezuela, Guyana, and Surinam. Three subspecies are recognized. M. esculenta subsp. esculenta is the domesticate and includes all cultivars known in cultivation. The wild M. esculenta subsp. peruviana occurs in eastern Peru and western Brazil. The wild M. esculenta subsp. flabellifolia shows a wider distribution and ranges from the central Brazilian state of Goiás northward to Venezuelan Amazonia. The large area of distribution of the two wild subspecies makes it difficult to assign a place of initial domestication.     

木薯酒精废水初沉物调理过滤脱水的研究

以木薯干片作原料的酒精废水初沉物为对象，研究了调理作用对木薯酒精废水初沉物过滤脱水的影响。实验表明：某一种聚丙烯酸胺(CPAM)作为调理剂对木薯酒精废水初沉物的过滤速率有较大的提高，并降低了滤饼含水率。在实验数据的基础上提出调理木薯酒精废水初沉物过滤脱水滤液量和时间关系的半经验方程。     

氧化木薯淀粉用量对脲醛树脂性能的影响

通过调节甲醛、尿素用量,控制脲醛树脂的物质的量比为1.0和1.5,并在脲醛树脂合成反应后期,加入不同比例的氧化木薯淀粉进行改性,考察不同氧化木薯淀粉添加量对不同物质的量比脲醛树脂基本性能、固化特征以及胶接性能的影响。结果表明：氧化木薯淀粉可以有效提升脲醛树脂的固体含量及粘度,而对树脂固化特征的影响随n_F : n_U和添加量的不同而表现不一;当n_F : n_U=1.0时,随着氧化木薯淀粉用量的增加,树脂的固化时间在逐渐缩短,用量在5%以内时,树脂的固化起始温度均低于未改性树脂,湿状胶接强度先增后降;当n_F : n_U=1.5时,树脂固化时间变化趋势同前,但固化起始温度均高于未改性树脂,干、湿状胶接强度随氧化淀粉用量的增加而提高;从树脂的综合性能考虑,n_F : n_U=1.0时,氧化木薯淀粉用量为尿素用量的3%时,综合效果最优,而n_F : n_U=1.5时,5%时综合效果最优。     

种子活力和作物产量

\t\t\t\t\t目的\t\t\t\t\t种茎质量是木薯增产的主要限制因素之一,研究筛选木薯种茎活力评价指标,可为木薯种茎处理技术提供理论依据。\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t选用华南8号和南植199木薯为材料,从植后150 d开始,每隔30 d采样1次种茎,共采集6次,分别在正常供水和干旱胁迫条件下,开展种茎发芽试验;同时测定发芽前的种茎生理生化指标。通过主成分分析得到不同采样期的种茎活力综合得分,并进行种茎生理生化指标与综合活力得分的相关性分析。\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t6次采样的种茎活力综合得分差异较大;华南8号种茎活力综合得分与丙二醛含量和含水量呈显著负相关(P<0.05),与淀粉含量呈极显著正相关(P<0.01),与可溶性蛋白和游离脯氨酸含量呈显著正相关(P<0.05);南植199种茎活力综合得分与丙二醛含量呈极显著负相关(P<0.01),与过氧化氢酶活性、淀粉含量、游离脯氨酸含量、含水量相关系数较高,但未达显著水平(P>0.05)。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t推荐种茎的丙二醛含量作为木薯种茎活力的评价指标。\t\t\t\t     

沼渣在棉花上的施用效果初探

通过田间试验,初步探讨了沼渣在山西省临猗县棉花上的肥效。结果表明:棉花基施沼渣、猪粪能够改善棉花的生物学性状,主要表现为叶片增厚增大、光合作用增强、脱铃率降低、铃重和衣分增加,为提高产量打下了基础。基施沼渣3.0万kg/hm2,比对照增产27.4%~27.9%;基施沼渣1.5万kg/hm2,比对照增产6.8%~10.4%。