高粱航天新不育系与恢复系的配合力分析

为了尽快鉴定高粱航天新恢复系和不育系的配合力和遗传力,采用双列不完全杂交法分析了高粱新选航天新不育系与恢复系的配合力。结果表明,不育系中产量、穗粒重的一般配合力较高的有52A和55A,恢复系中一般配合力较高的有sp42和sp46。在穗粒重性状上特殊配合力最高的组合是52A×sp46。加性方差与基因型方差的比值依次之顺序是穗粒重>株高>穗粒数>产量>千粒重>穗长。杂交种产量的髙低取决于双亲一般配合力和特殊配合力效应较高的组合,试验中52A×sp46,52A×sp42是两个较优的杂交组合。     

Selective logging and fire as drivers of alien grass invasion in a Bolivian tropical dry forest

Logging is an integral component of most conceptual models that relate human land-use and climate change to tropical deforestation via positive-feedbacks involving fire. Given that grass invasions can substantially alter fire regimes, we studied grass distributions in a tropical dry forest 1–5 yr after selective logging, and experimentally tested the effect of forest fire on populations of invasive grasses. In unlogged forests and in microhabitats created by selective logging we found a total of four alien and 16 native grass species. Grasses covered 2% of unlogged and 4% of logged forest, with grass cover in logged forest concentrated in areas directly disturbed by logging; log landings and roads had relatively greater grass cover (37% and 17%, respectively) than did skid trails (10%) and felling gaps (8%). Total grass cover and grass species richness increased with canopy openness and were greatest in sites most severely disturbed by logging. The grass flora of these disturbed areas was composed mostly of native ruderal species (e.g., Digitaria insularis, Leptochloa virgata), a native bamboo (Guadua paniculata), and Urochloa (Panicum) maxima, a caespitose C₄ pasture grass introduced from Africa. Urochloa maxima formed monodominant stands (up to 91% cover and 2–3 m tall) and grew on 69% of log landings and 38% of roads. To better understand the potentially synergistic effects of logging and fire on the early stages of grass invasion, we tested the effect of a 12-ha experimental fire on U. maxima populations in a selectively logged forest. Three years after the fire, the area covered by alien grass in burned forest increased fourfold from 400 m² (pre-fire) to 1660 m²; over the same period in a logged but unburned (control) area, U. maxima cover decreased from 398 m² to 276 m². Increased canopy openness due to fire-induced tree mortality corresponded with the greater magnitude of grass invasion following fire. Selective logging of this dry forest on the southern edge of the Amazon Basin promotes alien grass invasion; when coupled with fire, the rate of invasion substantially increased. Recognition of the grass-promoting potential of selective logging is important for understanding the possible fates of tropical forests in fire-prone regions.     

高粱丝黑穗病研究综述

丝黑穗病是遍布全世界的重要高粱病害,是影响我国高粱生产发展的主要病害之一,在高粱产区每年都有发生,发病率有时高达70%,给生产造成很大损失。综述了高粱丝黑穗病对高粱生产的影响、病原菌及其生理分化、我国抗病杂交种选育历程、抗性遗传机制及抗病育种策略等方面的研究,以期为选育抗病品种并在生产上应用提供参考。     

高粱籽粒总蛋白及其4种组分含量的遗传效应分析

依据1989年（4×4）和1990年（6×6）两套双列杂交试验资料用Hayman方法对高粱籽粒总蛋白及其4种组分含量进行了遗传效应分析。结果表明,总蛋白、清蛋白、谷蛋白和醇溶谷蛋白含量两年试验结果均符合加性-显性模型,球蛋白含量在1989年符合加性 - 显性模型。加性效应和显性效应对各性状均有重要影响,但也存在一定差别：总蛋白和清蛋白含量为加性效应 > 显性效应,为部分显性;球蛋白含量加性效应与显性效应相当,属完全显性;谷蛋白和醇溶谷蛋白含量两年结果不一致,谷蛋白含量在1989年,醇溶谷蛋白含量在1990年为加性效应 > 显性效应,呈部分显性,但二者分别在1990年和1989年又为显性效应 > 加性效应,呈超显性。除醇溶谷蛋白含量显性方向指向增效外,其余4个性状的显性方向均指向减效。清蛋白和球蛋白含量正负基因频率分布在两年均呈对称性,而总蛋白、谷蛋白和醇溶谷蛋白含量的正负基因频率分布在1989年和1990年分别表现为对称和不对称性。各性状的显性控 制基因组数均为1组,狭义遗传力均较低。     

Sensitivity Analysis of the ALMANAC Model‘s Input Variables

Crop models often require extensive input data sets to realistically simulate crop growth. Development of such input data sets can be difficult for some model users. The objective of this study was to evaluate the importance of variables in input data sets for crop modeling. Based on published hybrid performance trials in eight Texas counties, we developed standard data sets of 10-year simulations of maize and sorghum for these eight counties with the ALMANAC (Agricultural Land Management Alternatives with Numerical Assessment Criteria) model. The simulation results were close to the measured county yields with relative error only 2.6%for maize, and - 0.6% for sorghum. We then analyzed the sensitivity of grain yield to solar radiation, rainfall, soil depth, soil plant available water, and runoff curve number, comparing simulated yields to those with the original, standard data sets. Runoff curve number changes had the greatest impact on simulated maize and sorghum yields for all the counties. The next most critical input was rainfall, and then solar radiation for both maize and sorghum, especially for the dryland condition. For irrigated sorghum, solar radiation was the second most critical input instead of rainfall. The degree of sensitivity of yield to all variables for maize was larger than for sorghum except for solar radiation. Many models use a USDA curve number approach to represent soil water redistribution, so it will be important to have accurate curve numbers, rainfall, and soil depth to realistically simulate yields.     

盐碱胁迫对甜高粱种子萌发及幼苗生长的影响

为探讨甜高粱在黄河三角洲滨海盐碱环境下的适应能力,将NaCl、Na2SO4和NaHCO3按不同比例混合模拟出不同盐度和碱度的盐碱条件,对甜高粱种子萌发期进行处理,研究了混合盐胁迫对其萌发率,萌发指数,相对盐害率,幼根、幼芽生长情况的影响。结果表明,随着盐浓度和pH值的增加,甜高粱种子的萌发率、萌发指数均显著下降,且在蒸馏水中达到最大萌发率(97%),当pH值为7.08、盐浓度低于300 mmol.L-1时甜高粱的萌发率、相对盐害率与对照无显著性差异,说明甜高粱能够耐受一定浓度的中性盐胁迫,而随着pH值的增加,相对盐害率随浓度显著增加;随着盐浓度和pH值的升高,幼根、幼芽长度,幼苗的鲜、干质量均显著降低。通过盐度、pH值及两者相互作用的双因素分析表明盐度对甜高粱萌发率、萌发指数、相对盐害率影响最为显著;盐度与pH值两者的相互作用对幼芽、幼根长的影响最为显著。     

高粱遗传图谱构建及分子标记研究进展

文章概述了高粱遗传图谱构建和图谱构建过程中所运用的分子标记两方面的研究进展,比较了不同作图群体和不同分子标记在高粱遗传图谱构建中的发展过程及差异,展望了高粱遗传图谱的发展方向及重要作用。     

高粱──苏丹草杂交种的选育和利用

利用高粱、苏丹草强大的杂种优势，选育的高粱──苏丹草杂交种经试验、示范，不仅单株优势明显、单位面积产量高，而且品质也十分优良，用于养鱼和养牛，均获得成功。     

施氮量对高粱产量、品质及氮利用效率的影响

为了更好地对高粱进行氮素管理,采用盆栽试验研究了施氮量对高粱生长、籽粒产量及品质、氮素累积及转运利用的影响。选取肥力较低的土壤,设6个氮水平：0（N0）、0.05（N1）、0.1（N2）、0.2（N3）、0.4（N4）和0.6g/kg（N5）（风干土）。结果表明,N3处理干物质累积量、叶片SPAD值、籽粒产量、穗粒数及收获指数均显著高于N0和N5处理;N3处理籽粒淀粉含量低于N1处理,但淀粉产量最高;随施氮量的增加籽粒单宁含量降低,蛋白质含量增加,蛋白质总产量以N3和N4最高。随施氮量的增加叶鞘中NO₃^--N含量增加,N3处理挑旗期和穗花期叶鞘中NO₃^--N含量明显高于N0、N1和N2,但在灌浆期N0~N3处理间硝态氮含量没有显著差异;N3处理从茎叶向籽粒的转运率最高,达到76.76%。综上,适宜的施氮量有利于高粱生长及产量的提高,且在生长前期提高了叶鞘中硝态氮累积,能协调籽粒产量和功能成分的关系,获得较高的淀粉和蛋白总产量。     

苏丹草在塔里木河下游地区的栽培试验

2002-2003年在地处塔里木河下游的新疆生产建设兵团农二师33团五里村试验区,对苏丹草(Sorghumsudanense)进行了栽培试验。结果表明,苏丹草种子对Na2SO4,NaCl的耐盐性高于苜蓿;每年可刈割4-5茬,年产鲜草91 369.85-138 506.90 kg／hm2,生育期比新疆北部地区栽培提前了22-25 d,产草量提高了7 059.85-54 196.90 kg／hm2;在4种不同的微肥处理下,施用万物春效果最佳,可大大提高苏丹草的产草量。