BACTERIAL DECOMPOSITION OF GRASRUCTOSAN OF DIFFERENT DEGREES OF POLYMERIZATION

The bacterial decomposition of grass fructosans with different degrees of polymerization was monitored in vitro. The period required for the microbial decomposition of polymeric fructosans was directly related to the extent of polymerization. It was concluded that there might be a relationship between the digestibility of other organic nutrients of fodder plants and polymerization and that polymerization increases with maturity of the plant.     

合丰号大豆品种系谱分析

合丰号大豆 32个品种 84 .4 %来源于满仓金、荆山朴、丰收 6号×克山四粒黄、丰收 1号×蓑衣领四个族系。其基因库源于 33个祖先亲本。细胞核祖先亲本有 33个 ,细胞质祖先亲本有 8个。核遗传贡献率较大的祖先亲本为金元 (18.7% )、四粒黄 (18.3% )、白眉 (6 .9% )、十胜长叶 (5 .9% )、小粒豆九号 (5 .6 % )等。细胞质遗传贡献率最大的是四粒黄 (46 .7% ) ,其次是小粒豆九号(16 .7% )、白眉 (13.3% )。合丰号大豆直接利用亲本 36个。利用国内优良亲本克 4 430 - 2 0、合交80 0 9- 16 12等成功地育成了合丰 2 5号、合丰 35号等高产稳产大豆品种 ;利用国外抗病品种Ohio、Rampage、Wilkin直接作亲本育成高抗灰斑病品种 4个。合丰号大豆品种有 16个具有国外血缘 ,占品种总数的 5 0 %。随着年代的推移 ,合丰号大豆的细胞核、细胞质祖先亲本发生了变化。不同年代有其不同的主要贡献者 ,合丰号大豆遗传多样性是其成功的关键。制定一个祖先品种核质在新品种中达到新的更高水平协调的育种方案非常重要     

中国大豆种质资源对大豆孢囊线虫3号生理小种抗性鉴定研究

１９９１－１９９５年，应用田间自然病圆和病土盆栽鉴定方法，对安徽、河北、福建、山东等２４个省市保存的３３５５份栽培大豆种质资源和１８６份野生大豆种质资源分别进行大豆孢囊线虫３号生理小种的抗性鉴定。     

中国大豆种质资源抗大豆孢囊线虫5号生理小种鉴定研究

１９９２－１９９５年,应用田间自然病圃和病土盆栽鉴定方法,对黑龙江,河北,山东,安徽,福建和广东等２１个省市保存的３３９１份栽培大豆和１６９份野生大豆种质资源进行了抗大豆孢囊线虫５号生理小种的抗性鉴定。     

花生叶斑病流行预测研究

作者经1985—1992年的调查研究,确认河南省花生叶斑病主要有两种,即褐斑病和黑斑病。每年都有不同程度的发生,其年度流行程度取决于花生苗期的平均湿度、总降雨量及初始孢子量,初步确定了四者与病情指数之间的直线相关关系。     

《热带作物学报》文献引文分析

统计结果,1980—1990年《热带作物学报》平均每篇文献的引文量为7.27篇。引文中,期刊文献为52.58％,外文文献为51.96％,英文占外文的95.81％;《热带作物学报》等被引用10次以上的书刊种类数为被引用文献种类数的2.65％,被引次数为总引文量的3.078％;引文发表时间的跨度达87年,1975—1985年间发表的约为57.40％,历年有近2～6年内发表的文献的年被引用量,大于其它年发表的年被引用量的趋势;引文主要为生物科学和农业科学两大类。这对研究热带作物科技情报流向,提供情报服务,不失其参考价值。     

大豆对灰斑病7号生理小种的抗性遗传研究

以对大豆灰斑病７号生理小种表现抗感反应不同的５个亲本配制的４个杂交组合后代的接种鉴定分析，指明大豆对这个小种的抗性也是受一个的单显性基因控制。     

山西晋北三种类型大豆的核型分析

本文对山西省北部三种不同生态类型大豆（小黑豆、大黑豆、黄豆）进行了核型分析。结果表明：三种大豆体细胞染色体数均为２ｎ＝４０,主要由中间和亚中部着丝点染色体组成。三种大豆只有一对粒位于最长染色体上的随体,而且随体染色体形态相近,三种大豆的核型公式分别为：小黑豆２ｎ＝２ｘ＝４０＝２８ｍ＋１２ｓｍ（２ＳＡＴ）;大黑豆２ｎ＝２ｘ＝４０＝６Ｍ＋１８ｍ＋１２ｓｍ＋４ｓｔ（２ＳＡＴ）;黄豆２ｎ＝２ｘ＝４０＝２Ｍ     

大豆疫霉根腐病传播途径研究

对带菌土壤、病残体进行病试验,研究了人工接种条件下种子带菌条件及带菌种子传病情况,结果表明,带菌土壤和病残体无论是在当年还是越科后都可有效地传播大豆疫霉根霉是大豆疫霉根腐病的主要初侵染不原和传播途径。人工接种可以导致大豆种子力,但只在有病资助以豆荚才有这种结果,幼荚期接种豆荚可以使荚内的豆粒严重发病,豆粒被一层菌丝包裹,这些豆粒虽然本身不能萌发,但能作为接种体导致邻近的健康植株发病。作者通过大量的     

大豆主要农艺性状遗传的双列杂交图解分析

本文利用在主要农艺性状和形态上存在显著差异的六个大豆基因型间的双列杂交,对成熟期、株高、主茎节数、百粒重和单株粒重等性状的遗传进行了图解分析,并且利用这些性状的数据估算的阵列方差(V_r)和协方差(W_r)等统计量间的关系进行了遗传解释。结果表明成熟期的6×6完全双列群体符合双列分析的所有假设,直线回归系数b=0.7597,与W_r+V_r值的相关密切(r=0.7086),可见早熟基因倾向显性。株高的遗传并不完全趋于显性,很可能存在向高低两个相反方向发展的因素。与株高的遗传动态相仿,主茎节数和百粒重的遗传并不都是由显性基因控制。六个亲本在控制单株粒重的遗传中都存在上位性效应。维尔金带有较多的早熟性和单株粒重的显性基因;设交76—5184具有较多的控制株高和百粒重的显性基因,合丰22号控制主茎节数的显性基因较多。     

不同类型大豆杂交后代主要农艺性状相关分析

本文研究了不同类型大豆杂交后代主要农艺性状间及产量性状与主要发育阶段的关系。结果表明，不同类型大豆杂交后代主要农艺性状存在明显差异。含有秣食豆血缘的组合较栽培大豆品种间杂交组合，在植株形态性状上表现为植株高大繁茂、粒茎比小的特点，在产量性状上表现为单株荚数和单株粒数多及百粒重小的特点。由于秣食豆种质的导入，植株高大繁茂与小的粒茎比存在相关遗传。大豆主要产量因子，在主要发育阶段存在相互制约现象。大豆各生育阶段与蛋白质含量的相关，与各生育阶段与油分含量的相关方向始终相反。单株荚数、单株粒数等产量性状与蛋白质含量与各生育阶段的相关方向相同。     

COMPARATIVE PRODUCTIVITY OF 27 STRAINS OF GRASS IN THE WEST OF SCOTLAND

Seasonal productivity from plots of 27 strains of the principal grass species has been compared at Auchincruive over two seasons by a cutting technique. The following conclusions are reached:
Peak growth is limited to a short period before the first week in June. Extension at peak-growth level into the summer gap is not possible by the use of any of these grass strains grown alone.
The provision of grass for one cow per acre is possible for up to 142 days by the combination of strains.
Extension into the autumn can be achieved by conserving second-peak growth, which does not mature to the same extent as the first-peak growth.
In combining strains with advantageous growth periods due regard must be paid to their growth at other periods, which may be particularly low.
Combination of many strains is not likely to achieve as good a result as the use of 2, or at most 3, well chosen strains.     

THE EFFECT OF THE TIME AND LEVEL OF INJECTION OF ANHYDROUS AMMONIA ON THE PRODUCTIVITY OF GRASSLAND

Four levels of nitrogen, 188, 285, 358 and 392 kgJ.ha (150, 225, 285 and 350 units/ac) supplied as anhydrous ammonia were injected on each of four occasions, 18 Dec, 5 Feb., 12 Mar. and 16 Apr. DM and CP yields were estimated at each of three harvests taken on 4 June, 19 July and 28 Sept Total DM yields showed only a 10% difference between the highest yielding injection date, 12 Mar., which yielded 12270 kg/ha (10946 Ib/ac) and the lowest, 16 Apr., which yielded 11169 kgJ.ha (9963 Ib/ac). Early injection of ammonia promoted growth during the late spring and later injections resulted in increased yields at the two later harvests. The responses per kg fertilizer N were 11.9 kg DM (10.8 lb/unit) and 3.6 kg CP (3–3 Ib/unit). It was concluded that ammonia should be applied to grassland before April and, preferably, during March, for maximum yields of DM and CP.     

THE EFFECT OF METHOD OF DETERMINATION OF ACID-DETERGENT FIBRE ON ITS RELATIONSHIP WITH THE DIGESTIBILITY OF GRASSES

The acid-detergent fibre (ADF) contents of 50 grass samples of known in vivo and in vitro digestibility were determined by hydrolysing with acid for 1, 2, 3,4, 5, and 6 h. The 50 samples used consisted of 6 Lolium perenne, 9 Cenchrus ciliaris, 15 Chloris gayana, 10 Digitaria spp., and 10 Setaria spp. Regression and residual standard deviations (RSD) were calculated for each hydrolysis time for each grass and for all 50 samples. Increasing the hydrolysis time decreased the RSD for Lolium perenne and Setaria, had no effect on Chloris gayana and Digitaria and increased the RSD for Cenchrus ciliaris regressions. For regressions based on all 50 samples die RSD varied between ±4.8 and 5.0 digestibility units with only minor differences between hydrolysis times. Correcting the ADF for contaminating ash generally increased the RSD. Changing the acid strength from the 10 N recommended by van Soest (8) did not lead to any major improvement in the RSD for regressions based on Cenchrus ciliaris, but with Setaria the RSD was reduced from ±2.8 to 1.7 digestibility units when 2N acid was used and hydrolysis was extended to 2 h. It was concluded that unless the optimum conditions for determining ADF for each grass are known then the in vitro technique provides digestibility estimates with a lower error.     

THE EFFECTS OF TYPE OF CUTTER AND HEIGHT OF CUTTING ON THE RECOVERY OF FOUR GRASS VARIETIES

S23 and S24 Lolium perenne and S37 and S143 Dactylis glomerata were cut to heights of 1 1/2 and 4 1/2 in. in a replicated experiment, using: a flail harvester, a reciprocating mower, and a reciprocating mower followed by a flail harvester to collect the wilted grass.
At the short cutting height there was a marked depression of regrowth of all grasses following the use of the flail harvester (P<0.01), compared with the other mowing treatments. No such effect was observed at the higher level of cutting. Close cutting with a flail forage harvester was shown to be detrimental to regrowth, but the reasons for this effect are not clear.     

THE AFTER-EFFECTS OF VARYING RATES OF SPRING APPLICATION OF NITROGEN AND OF DATES OF FIRST DEFOLIATION ON THE YIELD AND BOTANICAL COMPOSITION OF A GRASS/CLOVER SWARD

Mid–season depression of grassland yield following spring application of N was found to be due almost entirely to clover depression, the grass fraction showing no after effects of the treatment. The effect became more marked and lasted longer in successive years. Varying the date of first defoliation in spring did not affect the clover depression significantly. Possible causes contributing to the depressing effect are discussed.     

大豆种粒斑驳的基本化学组成

本研究用ＴＬＣ技术结合紫外吸收光谱分析以及其它化学定性方法,分析大豆因感染ＳＭＶ产生物种粒斑驳的化学组成：有种粒斑驳的种皮和大豆健种皮含有花色素、黄酮、黄酮醇、二氢黄酮、二氢黄酮醇和它们的苷,也含有黄烷醇以及黄烷醇多聚物。种粒斑驳中的黄酮类化合物在含量和组成上都可显著地区别于健株种皮,其积累与感染ＳＭＶ相关。按种粒斑驳的颜色箱关的黄酮类化合物分类,斑驳可以分为有或无花色素苷两个类型。     

东北亚四国（地区）SMV株系毒力比较

将我国，韩国，日本及俄罗斯远东地区的ＳＭＶ株系与鉴别寄主交互接种测定其毒力。结果指出采用外国的株系鉴别寄坟难以区分我国株系毒力。同样，用我国鉴别寄坟也难以区分外国毒株的毒力，所测定的我国９个株系的１３个代表毒株全部能侵染最抗病的鉴别寄主韩国的Ｂｕｆｆａｌｏ和日本的Ｈａｒｏｊｏｙ。