白三叶对黑麦草、弯叶画眉草的化感作用初探

针对白三叶Trifolium repens与黑麦草Lotium perenne、弯叶画眉草Eragrostis curvula混播时导致后2种植物数量减少甚至消失的现象,通过白三叶的根部、地上部和植株水提液对黑麦草和弯叶画眉草种子进行发芽实验,以及白三叶与黑麦草、白三叶与弯叶画眉草种子混播进行实验,研究表明:白三叶(幼苗、2年生植株根及茎叶)的水提取液在原液以及稀释20倍时对受体植物的胚根和胚芽的生长均产生明显的抑制作用,而在100倍稀释液时表现出一定的促进作用;白三叶与黑麦草及白三叶与弯叶画眉草种子混播实验,表明5∶1的比例为最佳混播比例.     

基于PLC的苔麸播种机设计与试验

设计了一种基于PLC的苔麸施肥播种机。该播种机主要由排种器、开沟器和PLC控制器等关键部件组成,通过转速传感器测量播种速度,建立播种速度和伺服电动机转速之间的对应关系,通过控制伺服电动机转速实现不同播种速度下单位面积播种量一致。在播种量4、5、6kg/hm2,播种速度3、4、5km/h条件下,进行了排种器性能测试,播种量5kg/hm2条件下,得到各行排种量一致性变异系数5.02%,总排种量稳定性变系数0.89%,种子破损率0.1%,试验零水平时排种均匀性变异系数18.9%,满足标准要求;田间试验结果表明播种均匀性变异系数20.4%,满足苔麸农艺要求。     

Plant growth and survival of five introduced and two native/naturalized perennial grass genotypes exposed to two defoliation managements in arid Argentina

The field performance of the native Pappophorum vaginatum, the naturalized Eragrostis curvula and various cultivars of the introduced Achnatherum hymenoides and Leymus cinereus was evaluated as potential forage resources in rangelands of arid Argentina during the warm seasons of 2007/2008 and 2008/2009. Plants of these grass species, obtained from seeds, were transplanted to the field in 2006, when they were 1 year old. During the study years, there were two defoliation managements: plants of all study genotypes either remained undefoliated (controls) or were defoliated twice a year during spring at 5 cm stubble height. Despite tiller number being lower (P < 0·05) on defoliated than on undefoliated plants, and total leaf length per unit basal area being similar (P > 0·05) between defoliation managements by mid‐spring, there were no differences (P > 0·05) in dry weight production between defoliated and undefoliated plants in all genotypes at the end of the second growing season. Plants of one or more of the introduced genotypes showed a similar (P > 0·05) or greater (P < 0·05), but not lower, tiller number per plant and per square centimetre, daughter tiller production, total leaf length and dry weight production per unit basal area than the native species at the end of the first and/or second growing seasons. These morphological variables were similar (P > 0·05) or greater (P < 0·05) in the native than in the naturalized genotype. Plant survival, however, was lower (P < 0·05, overall mean = 20%) in the introduced than in the native (>70%) or naturalized (>39%) genotypes at the end of the first or second growing seasons.     

两种优良野生草坪植物生态生物学特性分析

通过 1 998～ 2 0 0 0年对野生宿根画眉草和鼠尾粟观察 ,对其形态特征和生物学特性进行了鉴定分析 ,从草坪和水土保持植物利用的角度对其进行建坪试验和水土保持试验 ,发现其具有优良坪用性状和水土保持效果。并对其特性作了综合性描述。     

Heritability and genetic advance in recombinant inbred lines of tef (Eragrostis tef)

Recombinant inbred lines (RILs) of the tef cross Kaye Murri × Fesho were evaluated for nine quantitative traits at three locations in the central highlands of Ethiopia during the 1998/99 main season in order to estimate the genetic coefficient of variation (GCV), heritability and genetic advance expected from selection. Highly significant differences were obtained among the RILs for all traits studied. Grain yield, panicle weight and yield per panicle showed a relatively high GCV (12–16%). A comparatively high heritability was obtained from days to heading (31%) followed by panicle length (25%) and grain yield (23%). Moderate amounts of heritability values were obtained for panicle weight and yield per panicle. High genetic advance as percent of the mean were obtained from grain yield (16%), yield per panicle (12%) and panicle weight (10%) at5% selection intensity, which indicated the possibility of improving these traits. Several RILs were identified that have exceeded the better yielding parent at all locations. Grain yield showed a strong positive association (r = 0.26–0.70) with shoot biomass, lodging index, panicle length, plant height, panicle weight and yield per panicle. Overall, the present results showed a) the availability of genetic variance for some useful traits in the RILs for exploitation through selection, b) the existence of significant genotype × location interaction that indicated the need to test inbred populations in more environments, and c)the availability of superior inbred lines for further breeding work. This revised version was published online in August 2006 with corrections to the Cover Date.     

4个画眉草品种在云南嵩明地区的比较

通过对4种画眉草的种植以及调查研究,对它们的种子形状特征与发芽率、牧草生长情况、种子产量构成要素、叶片特征、产草量及营养器官物质分配以及营养成分进行了测定并比较分析.结果表明,4种画眉草均能在嵩明地区较好的生长,引进品种弯叶画眉草Eragrostis curvula和野生种嵩明画眉草E.songmingensis各方面性状较优,能够在该地区进一步推广应用.     

Diversity among germplasm lines of the Ethiopian cereal tef [ Eragrostis tef (Zucc.) Trotter]

Three hundred twenty germplasm lines of the major Ethiopian cereal, tef, [ Eragrostis tef (Zucc.) Trotter], were evaluated for 20 morphological, phenological and agronomic characters in two-replicated randomized complete blocks at Debre Zeit and Melkassa Agricultural Research Centers in Ethiopia during the 1995 main season. The objectives were to assess the diversity of the lines, and to estimate the broad sense heritability (H) and genetic advance (GA) of the various characters. The mean squares of genotypes were highly significant (p ≤ 0.001) for all the traits. The phenotypic and genotypic coefficients of variation ranged in that order from about 6–40% and 3–23% for days to maturity and grain yield/plant, and days to maturity and number of spikelets/main shoot panicle, respectively. The cluster analysis grouped the genotypes into 14 major complexes consisting of one to 183 lines. Of the 19 principal components involved in explaining the entire variation among the genotypes the first five which had eigenvalues of more than one explained about 73.8%. The first principal component which accounted for about 34% of the total variance was due chiefly to plant height, culm and panicle length, diameters of the two basal culm internodes, main shoot panicle mass and grain yield, number of main shoot panicle branches and spikelets, and days to panicle emergence and maturity. Estimates of H varied from about 22% for length of the lowest main shoot stem internode to 74% for number of main shoot panicle branches. Values of GA (expected from selection of the superior 5% of the lines and expressed relative to the means) ranged from about 3% for days to maturity to 36% for number of spikelets/main shoot panicle. Overall, the study indicated the existence of trait diversity in tef germplasm and this can be exploited in the genetic improvement of the crop through hybridization and selection. This revised version was published online in July 2006 with corrections to the Cover Date.     

Gene action controlling yield and yield‐related traits among tef (Eragrostis tef [Zucc.] Trotter) populations under drought‐stressed and nonstressed conditions

This study was aimed to determine gene action for grain yield and yield‐related traits of newly developed tef populations under drought‐stressed and nonstressed conditions to improve drought tolerance. Ten crosses, along with the parents, were evaluated in the F₂ generation under drought‐stressed conditions at Hastebo and Adigdad sites in 2015 and Dura site in 2016 and under nonstressed conditions at Dura site in 2016. Additive gene action predominantly controlled the inheritance of the grain yield and majority of the yield‐related traits under drought‐stressed and nonstressed conditions. Under both test conditions, the genotypes DZ‐Cr‐387 and 9415 were the best general combiners for increased grain yield and morphological traits. Conversely, genotype 222076 was the best general combiner for reduced maturity period only. The selected parents are novel genetic materials for tef breeding programmes to improve grain yield and morphological traits with reduced days to maturity for drought tolerance breeding. The family of the cross DZ‐Cr‐387 × 222076 was selected for high grain yield and early maturity in both the drought‐stressed and nonstressed environments.     

干旱胁迫下黑穗画眉草的生理响应

[目的]探讨云南昆明周边黑穗画眉草(Eragrostis nigra)的抗旱生理特性。[方法]以采自云南3个不同地方的黑穗画眉草为试验材料(编号为H_1、H_2、H_3),采用不同浓度的聚乙二醇(PEG 6000)模拟干旱胁迫,研究在不同胁迫情况下抗氧化酶、叶绿素含量、可溶性总糖含量及光合参数的变化。[结果]H_1、H_2、H_3的过氧化物酶(POD)活性、抗坏血酸过氧化物酶(APX)活性、过氧化氢酶(CAT)活性、可溶性总糖含量和丙二醛含量均与胁迫强度和处理时间呈正相关,叶绿素含量与胁迫强度和处理时间呈负相关。3个材料的净光合速率(Pn)、蒸腾速率(Tr)、胞间CO_2浓度(Ci)和H_1的气孔导度(Gs)均与处理时间和胁迫强度呈负相关。H_2和H_3干旱胁迫时Gs随处理时间的延长先增加后减小,轻度胁迫时有最大值。[结论]3种黑穗画眉草均有一定的抗干旱胁迫能力,H_1抗旱能力高于其他2种,更能适应干旱缺水的环境。