苏丹草、甜高粱与高粱雄性不育系杂交父本生产性能的初步评价

试验选用苏丹草、甜高粱品种(系)与高粱雄性不育系进行杂交,选育优势杂交组合。共参试15个品种(系)。为避免后续杂交育种工作中选择亲本的盲目性,使针对性更强,首先,通过8个农艺性状指标和两个产量指标先对15个父本进行选择,以减轻工作量,为日后选育高产草量、高产籽量和适中含糖量的杂交育种工作提供理论性依据。最后,共选择了7个父本:W010、T03、N0601、06-071⑤、DxK、B8①和B9⑤。在这7个入选的父本中,同等种植密度下,B8①为籽粒产量高的苏丹草品种,而鲜草产量偏低;甜高粱DxK的籽粒产量最低,鲜草产量较高;其余5个父本的籽粒产量和鲜草产量兼得,是理想的父本材料。     

Revisiting development potential of riverain sunt (Acacia nilotica) forest reserves ¨C A case study in Sinnar State, Suda

The present study is an attempt to find a solution for the forest management conflicts existing between local people and the central authoritarian forest services in Sinnar State,Sudan.Sinnar was purposely selected as a study area because 9%(496.4×103 ha)of the forest reserve area of the entire country is located in this state.A comprehensive survey consisting of field observations, questionnaires and interviews was carried out specifically in the Alsabonabi area for its heterogeneous local community.The results show that the existing management system of the sunt forest reserve(the Alumbwa forest)has failed to support the local people, both residents and semi-nomads.Hence,the present study proposes a series of strategic and organizational changes in order to help in showing the way for integrated and participatory forest resource management and improving the welfare of all impoverished rural communities.     

高效液相色谱法测定苏丹红的研究

建立了一种简单、快速的基于高效液相色谱分离的测定苏丹红的方法.探讨了流动相组成、流速、柱温等对苏丹红分离的影响,优化后的苏丹红分离条件为:流动相为100%甲醇,流速为1.0mL/min,柱温为30℃.测定苏丹红Ⅰ～Ⅳ的线性范围为0.01～40mg/L,相对标准偏差均小于5%,检出限在0.01～0.02mg/L之间.用于实际水样和食品中苏丹红的分析获得满意结果.     

比色法测定鸡蛋中苏丹红残留的研究

通过试验研究,建立了鸡蛋中苏丹红Ⅰ～Ⅳ残留的快速测定方法(比色法):将鲜鸡蛋样品用乙腈反复提取,分别在491(苏丹红Ⅰ)、513(苏丹红Ⅱ)、348(苏丹红Ⅲ)、478(苏丹红Ⅳ)nm下用紫外分光光度计测定吸光度,再根据所建立的苏丹红Ⅰ～Ⅳ的标准回归方程,即可计算出样品中苏丹红的残留量。本方法的回收率为88.5%～92.3%,相对标准偏差0.8%～2.6%,最低检测限为1μg/mL。     

苏丹红I对泥鳅红细胞微核率和组织磷酸酶活性的影响

[目的]为明确苏丹红Ⅰ的危害提供试验依据。[方法]用不同浓度(0.312 5、0.625、1.25、2.50和5.00 mg/L)苏丹红Ⅰ处理泥鳅后8、162、4、32和40 h,观察带有微核的红细胞数,并测定肝脏、肌肉和肾脏组织中磷酸酶活性,研究苏丹红Ⅰ对泥鳅红细胞微核率和不同组织中磷酸酶活性的影响。[结果]泥鳅红细胞微核的自然发生率为1.128 3‰。经不同浓度苏丹红处理一定的时间后,泥鳅红细胞微核率较对照组均显著提高,最高达6.063 6‰。随着苏丹红Ⅰ浓度的提高,泥鳅红细胞微核率出现最高峰的时间也相应提前。染毒后各组织的酸性磷酸酶(ACP)活性迅速上升,而碱性磷酸酶(ALP)活性迅速下降。[结论]泥鳅红细胞微核率与苏丹红Ⅰ浓度大体上呈正相关,同时也有一定的时间效应。     

Soil nutrient harvesting in indigenous teras water harvesting in eastern Sudan

The indigenous teras water harvesting system offers greater production security, but its major benefit is that it raises the nutrient-limited yield from some 150–250 kg ha⁻¹ to some 650 kg ha⁻¹ through its nutrient harvesting effects. Soil fertility was found to be two to four times higher inside the teras field. Calculated nutrient-limited yields are considerably higher than real yields, which points at other yield-limiting factors such as labour and water availability. The example of the teras system shows that nutrient harvesting may in some cases be a viable alternative to application of mineral fertilizers. This implies that indigenous technologies can be sustainable and should be thoroughly examined before they are complemented by external inputs. © 1998 John Wiley & Sons, Ltd.     

Economic incentives for abandoning or expanding gum arabic production in Sudan

In this paper we use a real options approach to analyze farmers' economic incentives to abandon gum production or expand by creating new plantations. Our results indicate that agricultural crops currently provide higher economic benefits as compared to gum agroforestry. However, we show that the incentives for gum producers to abandon gum production is low, because (i) land is abundant, (ii) gum arabic is produced during the dry season and agricultural crops mainly during the wet season, and (iii) the dry season opportunity cost of labor is low. Hence, an increase in deforestation in the near future is not expected. The analysis further shows that an increase in the prices of gum arabic of about 315% is needed to induce an expansion of gum agroforestry and a shift in land use system from continuous agricultural production to gum agroforestry system. Hence, also an expansion of gum forests and/or agroforests in the near future is not expected. Price policies to improve incentives for expanding gum forests are discussed.     

Acacia albida and other multipurpose trees on the fur farmlands in the Jebel Marra highlands,Western Darfur,Sudan

This paper describes the traditional agroforestry systems based on Acacia albida and other multipurpose trees as practised by the sedentary Fur people on the lower slopes and highlands of the Jebel Marra massif, Sudan. The basic agrosilvopastoral system consists of terraced village fields, where semipermanent rainfed cropping of staple millet and other subsistence crops takes place under stands of multipurpose trees dominated by Acacia albida, Cordia abyssinica and Ziziphus spina-christi. Trees have been retained primarily for food, wood and fodder. Thorn from cut and browsed branches makes a good fencing materal.This system has been able to sustain self-sufficiency of a densely settled population over centuries. However, recent out-migration of people from the montane dry-farming areas has caused gradual return to shifting cultivation. As a consequence, the present-day subsistence farming in the region is characterized by a general level of carelessness and exploitative management and this is reflected in a successive decrease of the tree cover.The evaluation of the AF practices described includes a discussion on their regional importance and extrapolability within the framework of similar situations, especially in Africa, emphasis being given to mountain and highland conditions. The outstanding potential for Acacia albida-based AF systems to be sustained and spread almost all over semiarid to semihumid Africa is highlighted by illustrating its ecologic and economic variability. Extrapolation of such examples, however, is not feasible, without thorough feasibility studies concerning the ecologic, ethnologic and socio- economic conditions in the respective project areas. Basic research needs for improving and extending the system are also indicated.     

Plant Protection in India: Problems and Prospects

Abstract

Agricultural productivity in India has hardly increased in the past 25 years. Inefficient plant protection services are held responsible to some extent by the author. Suggestions for improvements in surveillance and diagnosis and emphasis on cultural control and safe storage are made with an example from the Saharanpur District.