天农青饲一号高粱-苏丹草杂交种栽培与应用

介绍了天农青饲一号高粱—苏丹草杂交种的特征特性、栽培要点、利用方式、饲用技术及开发应用前景。     

高丹草（高梁×苏丹草）产量及其构成因素的QTL定位与分析

利用分子标记技术，在许多作物上已获得了高密度的分子遗传图谱，并定位了许多主要农艺性状的QTL，而在牧草上这方面的研究尚属空白。为提高育种中对牧草产量性状优良基因型选择的效率，对高丹草的单株产量及其构成因素（株高、分蘖数、叶片数）进行QTL定位，确定其在染色体的位置及其遗传效应，探讨其杂种优势产生原因。在以高粱413A和棕壳苏丹草杂交获得的248个F2：3家系构建的作图群体中，应用AFLP和RAPD两种标记技术构建了高丹草（Sorghum×Sudangrass）的遗传连锁图谱。共包含168个标记，分布于10个连锁群，图谱总长度为836cM，标记间平均图距为4．98cM。采用Joinmap／QTL4．0对高丹草单株产量及其三大构成因素进行QTL定位。共检测到QTLM9个，分布在8个连锁群上，其中，第1和3连锁群最多，各为4个和3个。单个QTL解释性状表型变异的5．20％．51．50％。检测到的19个QTL中，表现加性效应的有1个，占5．26％，部分显性效应的有3个，占15．79％，显性效应的有6个，占31．58％，超显性效应的有9个，占47．36％。超显性效应和显性效应在高丹草杂种优势的遗传基础中占主导地位。     

Genotypic Variability in Adaptation Responses of Selected Clones of Cassava to Drought Stress in the Sudan Savanna Zone of Nigeria

Identification of drought‐tolerant and ‐resistant varieties of cassava is of paramount importance for the maximization of productivity potential in drought‐prone areas. Nine improved cassava varieties developed in humid and subhumid agro‐ecologies were evaluated for their growth responses and adaptability in the dry savannas of Nigeria. Field trials were set up in two cropping seasons at three different locations. Parameters evaluated included fresh root yield (FRY), fresh shoot yield (FSY), cumulative leaves formed (CLF), cumulative leaf scars (CLS), root dry‐matter content (DMC), harvest index (HI), and root cyanogenic potential (CNp). Results demonstrated that varietal response differed with water table site, implying different adaptation responses of varieties to the water regime. Variations in all characters studied were significantly (P<0.05) influenced by genotype, suggesting a strong genetic basis for the phenotypic differences amongst varieties. Compared with variation attributable to location, the genotypic components were strong for FRY, FSY, CLF, CLS, HI and DMC. HI and DMC were not significantly affected by location. CNp tended to increase with increasing drought stress. The significance of genotype × environment effects for FRY suggested that genotypes may be selected for specific adaptation for drought‐prone environments. The poor adaptability responses of the majority of the varieties implied that an agro‐ecologically targeted breeding scheme for the dry savanna would be a more appropriate approach for the development of drought‐tolerant varieties.     

杂交苏丹草镉的吸收与分布规律研究

随着土壤中添加镉量的增加,杂交苏丹草的株高明显降低,生物量显著下降。镉添加量为40mg kg土的处理,杂交苏丹草株高和地上部的生物量分别只有对照的48%和8.4%。不加镉的对照,杂交苏丹草根、茎、叶的含镉量分别为3.2,2.7,3.2μg g-1,各部位含镉量没有显著差异;而在添加镉的土壤中,则呈现出根>茎>叶的变化规律;土壤添加镉的量越大,杂交苏丹草各部位含镉量越高,当镉添加量为40mg kg-1土时,根、茎、叶的含镉量分别为451.9,132.5,79.4μg g-1。杂交苏丹草植株中镉含量与土壤中镉的添加量呈现为显著的直线正相关,镉的累积量呈现为先上升后下降的规律。     

新鲜苏丹草压缩过程中压缩力变化规律的研究

[目的]推进草物料压缩设备的发展应用。[方法]用液压高密度压捆机压缩,设计新鲜苏丹草的喂入量为5、6、7、8 kg,研究喂入量相同条件下压缩力与压缩密度之间的关系以及相同压缩密度条件下喂入量对压缩力的影响。[结果]在新鲜苏丹草的喂入量相同条件下,压缩力随压缩密度的增加而增加,且压缩力与压缩密度呈三次多项式关系。相同压缩密度条件下,新鲜苏丹草的喂入量为5、6 kg时,其压缩力比较接近,6 kg之后随喂入量的增加,压缩力降低,且降低的幅度较大,压缩力与喂入量呈二次多项式的关系。[结论]该研究为压缩设备的优化设计提供了理论依据。     

一种快速筛选产聚羟基烷酸细菌方法的建立

为了从土壤微生物中快速分离纯化得到产聚β-羟基脂肪酸(PHAs)的微生物菌株,研究比较了几种聚羟基烷酸产生菌筛选方法.结果表明,尼罗蓝染色法优于苏丹黑染色法,而且0.1%的尼罗蓝丙酮染液55℃染色细菌菌落10min,紫外灯下观察菌落,能合成聚羟基烷酸的菌落具有明显的荧光现象.进而推出对于产生物降解塑料菌株的染色,尼罗蓝...     

苏丹红Ⅲ对泥鳅的急性毒性、遗传毒性及生理毒性研究

以苏丹红Ⅲ为诱变剂,研究了其对泥鳅(Misgurnus anguillicandatus)的急性毒性效应,在此基础上研究了苏丹红Ⅲ在不同浓度和染毒时间对泥鳅红细胞微核率及其肝脏中谷草转氨酶(GOT)和谷丙转氨酶(GPT)活性的影响.试验表明,苏丹红Ⅲ对泥鳅的24h半致死浓度为1.020 g/L,48 h半致死浓度为0.740 g/L,48 h安全浓度为0.117 g/L.染毒一段时间后,泥鳅红细胞的微核率与对照组比较均显著升高,达最高值后趋于平缓;随着苏丹红Ⅲ浓度的升高,泥鳅红细胞微核率与对照组相比出现极显著差异的时间相应提前.染毒后各组的谷草转氨酶和谷丙转氨酶活性呈下降趋势,达到峰值后趋于平缓;染毒时间越长,酶活下降的幅度越大.泥鳅红细胞的微核率及其肝脏中的GOT和GPT活性均与苏丹红Ⅲ有明显的剂量-时间效应,研究结果为进一步明确苏丹红Ⅲ的危害提供了试验数据.     

苏丹草品种间的RAPD分析

为评价苏丹草品种间的遗传多样性,用RAPD标记对14个苏丹草品种进行了遗传多样性分析.从100条RAPD引物中筛选出20条多态性明显、反应稳定的引物.14个品种共扩增出260条谱带,平均每条引物扩增出11.6条带,多态性比率达88.5％.聚类分析结果表明:苏丹草品种间遗传多样性丰富,材料间遗传相似系数分布在0.586 ～0.831;14个品种分为两大类,来自美国的“伊诺”和“布鲁赛”聚为一类;第Ⅱ类把高大型和低矮型聚为两类.结果显示出:聚类结果与形态特征有一定的对应关系,这为苏丹草种质资源的保存、利用和新品种选育提供了依据.     

高丹草遗传效应与杂种表现预测模型

以5个高粱不育系材料为母本, 18个优质苏丹草材料为父本, 按照遗传交配设计(NCII)配制成90个杂交组合。分别在内蒙呼市和包头两地, 利用与高丹草产量相关的QTL位点标记检测亲本间的遗传差异, 并将F₁的8个性状表型值对亲本材料进行标记位点的筛选, 建立标记效应和标记型值估算体系。估算特异性位点对性状表现的效应及杂种标记型值, 进而分析杂种标记型值与杂种表现的相关性, 应用逐步回归分析法建立8个性状杂种表现的预测模型, 并通过Jackknife抽样技术检测模型的精确度和稳定性。结果显示, 在分别考虑显性、加性作用下8个性状的标记型值与表型值的相关系数平均为0.65, 各性状的可决系数较大(0.51~0.88), 而且两地结果趋势一致, 表明该预测模型稳定性强, 精确度较高。该模型对高丹草的杂种表现预测以及亲本选配都具有一定的指导意义。     

Degradation and abandonment of mechanized rain‐fed agricultural land in the Southern Gadarif region,Sudan: the local farmers' perception

In the Gadarif Region of Sudan, destruction of the natural vegetation for agricultural expansion is one of the major causes of the degradation of renewable resources and the environment. This study identifies and analyses the farmers' attitudes and perceptions towards agricultural land degradation and abandonment. The cross‐sectional data collected from ten key informants and 41 large‐scale farmers focussed on the degradation and abandonment of mechanized agricultural land. The results of the study show that the respondents are well aware that soil degradation is in various forms are taking place on their cultivated agricultural land. This is based on their perception and interpretation of indicators such as weed infestation, poor soil fertility and soil compaction. Continuous cropping, mono‐cropping, rainfall shortage and the use of inferior seeds are the main reasons of land degradation as indicated by farmers. The main measures acknowledged to maintain and improve land productivity are repeated soil ploughing, abandonment/fallow periods and crop rotation. The study adduces evidence of widespread land degradation. The mitigation measures followed by the farmers may though not be sufficient to restore the soil fertility. The application of appropriate chemical fertilizers, sound crop rotation and long fallow periods can be recommended. Any management and research intervention regarding the problem of land degradation should; however, be concerted with the farmers' knowledge. Copyright © 2009 John Wiley & Sons, Ltd.