不同生育时期施氮对冬小麦氮素分配及叶片代谢的影响

通过＾１５Ｎ示踪结合叶片代谢变化研究二棱期,雌雄蕊原基形成期和四分体期分别施氮对冬小麦籽粒产量和蛋白质含量的影响机理。结果表明：四分体形成期和雌雄蕊原基形成期施氮处理,收获期营养器官中＾１５Ｎ原子百分超显著降低,籽粒中＾１５Ｎ原子百分超明显增加,并提高了开花后叶片硝酸还原酶活性和叶片衰老后期的光合作用速率,显著增加了籽粒产量和籽粒蛋白质含量。     

鲁笋玉1 号专用型笋玉米特征及高产栽培技术

1 选育方法 父本无棣白自交系:基础材料是从山东无棣县引进的单株结穗4～5个,籽粒为白色爆裂型的无棣白品种,自1985年始经过连续的大田、海南、温室种植的多代自交分离选育而成,其主要特点是,单株结穗4～5个,籽粒为白色爆裂型;母本多7自交系:基础材料是从本所保存的品种资源中,经过田间种植观察筛选出的单株结穗3～4个的地方品种,后经大田、海南、温室种植的多代自交分离选育而成,其主要特点是单株结穗3～4个,籽粒为白色硬粒型,产量较高.1987年用多7作母本,无棣白作父本杂交育成专用型笋玉米品种.     

玉米品种耐旱性评价及相关鉴定指标的研究

耐旱性鉴定和评价是培育优良耐旱玉米杂交种品种的基础。本研究通过对一组杂交种进行耐旱性指标评价分析发现,产量仍是衡量耐旱性强弱最重要的指标,而开花吐丝间隔期、株高等农艺指标在评价品种耐旱性时也具有重要的参考价值。产量指标中,种质耐旱指数（DTIg）也可用于评价品种耐旱性。根据DTIg对参试品种进行了五级耐旱性评价。     

千斤高粱干物质积累分配与产量形成

1979～1982年对两个杂交种亩产千斤水平的干物质积累、分配及其对籽粒产量的影响进行了研究。发现高梁总干物质生产中开花前约占43%,开花后约占57%。籽粒产量主要依赖开花后光合作用的净同化率所同化,开花前提供约12～33%。同时观察到高梁生长后期茎叶干重多有回升。群体生长率的动态变化呈双峰曲线,其消长过程与产量形成关系     

小麦白穗的防治

小麦白穗常造成结穗不实,籽粒不饱满,千粒重下降,影响小麦产量和品质。一般减产10％～20％,严重的减产50％以上,成为小麦生产中不可忽视的减产因素。     

玉米机械化籽粒收获组合鉴定与主成分分析

玉米机械化籽粒收获是未来玉米发展的方向。以16份玉米杂交组合为材料,测定产量性状（产量、穗长、穗粗、百粒重）、农艺性状（株高、穗位高）、机收性状（籽粒含水率、籽粒破碎率、杂质率）共9个指标,并进行相关性分析。结果表明,产量与穗长、穗粗、百粒重之间呈极显著正相关,株高与穗位高之间呈极显著正相关,籽粒含水率与籽粒破碎率之间呈显著正相关。对产量及产量相关性状、籽粒含水率、籽粒破碎率、杂质率等指标进行主成分分析,通过对16份杂交组合的玉米机械化籽粒收获适宜性综合评价,结合机械籽粒收获与人工收获的产量差异比较,表明新单65、新单58、新单68和新单88均适宜机械化籽粒收获。     

关中小麦品种同化物积累分配特性与源库构成遗传改良的研究

对陕西关中小麦品种同化物积累分配特性及源库构成的遗传改良进行了分析。结果表明,在关中小麦品种更换中生物学产量的提高主要是开花前生物学产量的显著提高,品种演变中开花前积累的干物质在开花后的输出率显著增加,这对籽粒产量的提高有十分重要的作用。源库构成的分析表明,关中小麦品种在源库性状上存在着较大的遗传差     

大豆生育性状与产量因子对不同土壤干旱等级的响应

干旱是黑龙江省最主要的农业气象灾害之一。为明确大豆对干旱的响应机制,利用田间控水试验,研究播种出苗期和开花结荚期大豆在各干旱胁迫等级下各性状的生育特点。结果表明,播种出苗期大豆在干旱胁迫下,出苗缓慢;株高和地上、地下干物质、株荚数、株籽粒重明显偏低,空荚率偏高,其中重度胁迫空荚率比无胁迫大豆高99%;开花结荚阶段大豆遭遇中度以上干旱,光合量减少,植株相对矮小,而空荚率高,其中重度胁迫比无胁迫高81%以上;大豆花荚期是水分的敏感期,即轻度干旱也会造成较差的产量表现。大豆播种出苗期遭遇干旱胁迫后产量偏低,主因是出苗率低、生育期短,株籽粒重低和空荚率高是次要原因;光合量少、株荚数与株籽粒重下降,且空荚率高是开花结荚期产量低的综合结果。     

不同绿豆品种花后干物质积累与转运特性

以夏播区高产绿豆品种冀绿2号、安9910和低产品种赤峰绿豆、泰来绿豆为材料,对开花至成熟期间植株茎秆、叶片、豆荚、籽粒等地上部各器官的干物质积累、分配与转运规律进行了研究。结果表明,绿豆开花后,植株地上部总干物质积累和籽粒干物质积累均呈近“S”型增长趋势,花后16~31 d是生物产量和籽粒产量形成的关键时期;主茎开花节位叶片是籽粒充实的主要源器官,对籽粒产量的贡献率最大。不同绿豆品种间差异显著,高产品种冀绿2号和安9910各器官干物质积累和转运能力强,尤其是主茎开花节位叶片干物质合成和积累较多,具有较充足的源,加之其单株结荚数多,具有较大的库容,最终获得了较高的收获指数和籽粒产量。因此,绿豆生产中,选用库容大的多荚、大粒型品种,抓好花后田间管理,延缓主茎开花节位叶片衰老,同时采用去除无效分枝等措施增强源库间的物质运输与分配是提高籽粒产量的关键。     

不同行距配置对玉米雌雄开花间隔和产量的影响

以大丰30为实验材料,在同一密度下(67500株/ hm2)设置5种不同行距配置(60cm*60cm,50cm*70cm、40cm*80cm、30cm*90cm和20cm*100cm),研究不同行距配置对雌雄穗开花间隔(ASI)、千粒重、穗粒数、总穗数和产量的影响。结果表明,不同行距配置下,产量、千粒重、穗粒数和总穗数的变异系数均在5%以下,ASI的变异系数在4.33%-12.50%。各处理的ASI、穗粒数和产量差异呈极显著水平,但千粒重和总穗数差异不显著。多重比较的结果表明行距配置为40cm*80cm时雌雄穗开花间隔时间较短,穗粒数较多,产量又达到了最高水平,为最佳行距配置。     

玉米抗甘蔗花叶病毒资源的遗传多样性研究

利用人工接毒方法对46份我国主要玉米自交系进行了两年抗甘蔗花叶病毒鉴定,筛选出高抗系8份(K22、CN962、P138、齐318、中自01、金黄96B、齐319、Pa405),抗病系7份(旱21、中自03、旱23、农大178、获白、K12、黄早四).用SSR标记研究了46份自交系的遗传多样性.49对引物共检测出168个等位基因变异,每对引物检测等位基因2～10个,     

玉米雌雄穗开花间隔与产量关系研究

以2个热带玉米群体Pool 16、 Pool 18的不同世代种质为材料, 分别种植在开花期充足灌水、中度水分胁迫和严重水分胁迫3种水分梯度条件下, 研究玉米的雌雄穗开花间隔(ASI)与产量及其其它性状间的关系. 研究表明, 随水分胁迫程度的加强, 产量与ASI间的相关性增强. 在严重胁迫条件下, 二者的相关系数r=-0.529**; 在胁迫条件下,     

Genetic Variation for Maize Epicuticular Wax Response to Drought Stress at Flowering

Drought stress is thought to promote epicuticular wax accumulation on maize leaves, which reduces plant water loss. We evaluated 62 maize inbred lines and their hybrid testcross progeny for epicuticular wax accumulation on flag leaves at flowering under full and limited irrigation regimes. Extracted wax was measured as a percentage of wax weight to leaf weight (WLW) and leaf area (WLA). Eleven genotypes had above average WLW as both inbred lines and hybrid testcrosses. Thirteen genotypes had above average WLA as either inbred lines or hybrid testcrosses. The drought treatment did not significantly alter WLW or WLA. Heritability of WLW was 0.17 (inbred lines) and 0.58 (hybrid testcrosses). Heritability of WLA was 0.41 (inbred lines) and 0.59 (hybrid testcrosses), suggesting it is a better trait than WLW for epicuticular wax screening. Correlations (r) between inbred lines and their testcross progeny were 0.44 and 0.18, for WLW and WLA, respectively. Heritability of grain weight per ear and plot yield was highest in hybrid testcrosses, with no correlation between inbred and hybrid germplasm. It is not warranted to evaluate epicuticular wax accumulation as the sole drought tolerance mechanism. However, it may be a good secondary trait to observe in relation to grain yield production in hybrids tested under water‐limiting conditions.     

水分胁迫对甜玉米主要农艺性状及产量的影响

在大棚内采用人工供水的方法,研究不同水分胁迫下甜玉米品种主要农艺性状与产量的关系。结果表明,轻度干旱胁迫下可用株高、茎粗、散粉至吐丝间隔期(ASI)、穗粗、每穗粒数、千粒重等6个性状耐旱系数作为品种耐旱性鉴定的指标,而中度干旱胁迫下可用穗位叶面积、散粉至吐丝间隔期(ASI)、穗粗、每穗粒数、出籽率、千粒重这6个性状耐旱系数预测品种产量的耐旱系数。在不同程度水分胁迫下,散粉至吐丝间隔期(ASI)、穗粗、每穗粒数、千粒重等4个性状耐旱系数是不同品种耐旱性鉴定的重要指标,除此之外,株高、茎粗、穗位叶面积等决定植株形态的性状指标也对甜玉米耐旱性起一定作用。     

Combining ability and testcross performance of drought‐tolerant maize inbred lines under stress and non‐stress environments in Kenya

Drought and poor soil fertility are among the major abiotic stresses affecting maize productivity in sub‐Saharan Africa. Maize breeding efforts at the International Maize and Wheat Improvement Center (CIMMYT) have focused on incorporating drought stress tolerance and nitrogen‐use efficiency (NUE) into tropical maize germplasm. The objectives of this study were to estimate the general combining ability (GCA) and specific combining ability (SCA) of selected maize inbred lines under drought stress (DS), low‐nitrogen (LN) and optimum moisture and nitrogen (optimum) conditions, and to assess the yield potential and stability of experimental hybrids under these management conditions. Forty‐nine experimental three‐way cross hybrids, generated from a 7 × 7 line by tester crosses, and six commercial checks were evaluated across 11 optimum, DS and LN sites in Kenya in 2014 using an alpha lattice design with two replicates per entry at each site. DS reduced both grain yield (GY) and plant height (PH), while anthesis–silking interval (ASI) increased under both DS and LN. Hybrids ‘L4/T2’ and ‘L4/T1’ were found to be superior and stable, while inbreds ‘L4’ and ‘L6’ were good combiners for GY and other secondary traits across sites. Additive variance played a greater role for most traits under the three management conditions, suggesting that further progress in the improvement of these traits should be possible. GY under optimum conditions was positively correlated with GY under both DS and LN conditions, but GY under DS and LN was not correlated. Our results suggest the feasibility for simultaneous improvement in grain yield performance of genotypes under optimum, DS and LN conditions.     

Large-scale screening maize germplasm for low-phosphorus tolerance using multiple selection criteria

Phosphorus (P) deficiency is one of the major limiting factors in maize production in many developing countries. This experiment was conducted to evaluate multiple low-P tolerance criteria and identify the suitable maize germplasm for our future low-P tolerance breeding. A total of 456 diverse maize inbreds were evaluated for low-P tolerance at seedling stage using four shoot-related traits and six root-related traits measured under applied phosphorus (AP) and non-applied phosphorus (NAP) conditions. Analysis of variance revealed significant genetic variation among genotypes for all tested traits. Medium-to-high heritability estimates were obtained for most traits. Total dry weight (DW) was highly inheritable while the widely used root/shoot ratio had only an intermediate level of heritability. Based on the synthetic index (SI), the tested inbreds were classified into three groups representing low, moderate and high tolerance to low-P stress. Regression model built based on selection criteria for low-P tolerance explained 67.8 and 76.8 % of variation for DW under NAP and AP conditions, respectively. Using low-P tolerance index for DW and SI as selection criteria, 23 and 109 maize inbreds were identified as germplasm resources that were extremely tolerant and sensitive to low-P stress, respectively, which could be further used for genetic improvement of low-P tolerance.     

Phenotypic characterization and validation of provitamin A functional genes in early maturing provitamin A-quality protein maize (Zea mays) inbred lines

The number of drought and low-N tolerant hybrids with elevated levels of provitamin A (PVA) in sub-Saharan Africa could increase when PVA genes are optimized and validated for developed drought and low-N tolerant inbred lines. This study aimed to (a) determine the levels of drought and low-N tolerance, and PVA concentrations in early maturing PVA-quality protein maize (QPM) inbred lines, and (b) identify lines harbouring the crtRB1 and LcyE genes as sources of favourable alleles of PVA. Seventy early maturing PVA-QPM inbreds were evaluated under drought, low-N and optimal environments in Nigeria for two years. The inbreds were assayed for PVA levels and the presence of PVA genes using allele-specific PCR markers. Moderate range of PVA contents was observed for the inbreds. Nonetheless, TZEIORQ 55 combined high PVA concentration with drought and low-N tolerance. The crtRB1-3′TE primer and the KASP SNP (snpZM0015) consistently identified nine inbreds including TZEIORQ 55 harbouring the favourable alleles of the crtRB1 gene. These inbreds could serve as donor parents of the favourable crtRB1-3′TE allele for PVA breeding in maize.     

Genetic analysis of drought-adaptive traits at seedling stage in early-maturing maize inbred lines and field performance under stress conditions

Maize hybrids that are tolerant to drought at the seedling stage are needed to boost productivity in the rainforest agro-ecology of West Africa. Genetics of tolerance of maize seedling to drought stress is not well understood and is poorly documented. The objectives of this study were to screen early-maturing maize lines for seedling drought tolerance, determine the inheritance and the combining ability of selected inbred lines, and evaluate the performance of seedling drought-tolerant hybrids under field conditions. Forty-nine early maize lines were screened for drought tolerance at the seedling stage. Ten drought-tolerant and two susceptible inbred lines were selected and used in diallel crosses to generate 66 hybrids. The twelve inbred lines and their hybrids were evaluated under induced drought at seedling stage in the screen house and under marginal growing conditions on the field for two seasons. Data collected were subjected to analysis of variance using the DIALLEL-SAS program. Mean squares for both GCA and SCA were significant for most traits in all research environments, indicating that additive and non-additive gene actions are controlling seedling traits under stress conditions. However, for most traits, SCA was preponderant over GCA in all environments, indicating overdominating effect of non-additive gene action. Which in turn implied that the best improvement method for the traits is hybridization. Inbred TZEI 7 had the best GCA effect for seedling traits under screenhouse conditions and for grain yield and other agronomic traits under drought conditions in the field. Hybrids TZEI 357?×?TZEI 411 and TZEI 380?×?TZEI 410 showed superior SCA effects under screen house conditions. In conclusion, the study established wide genetic variability for drought tolerance at seedling stage among tropical early-maturing maize germplasm however, the non-additive gene action was more important for most seedling traits.     

37个玉米新品种（组合）耐旱性评价

为评价37个玉米新品种（组合）的耐旱性潜力,采用4种控水处理对玉米植株性状和产量性状进行了分析评价。结果表明,水分胁迫对穗长、秃尖长、行粒数、百粒重、ASI和单株产量6个性状有显著或极显著影响。水分胁迫使玉米品种抽丝散粉间隔期延长,秃尖变长,结实率降低,行粒数减少,籽粒变小,百粒重下降,单株产量降低。应用模糊数学隶属函数法综合评价分析,‘帮豪玉509’、‘忠玉9号’、D36、BH0310和D30综合耐旱性较强,D23、D3、D26和BH3404综合耐旱性较差。     

Genetic variation among European maize inbreds for resistance to the European corn borer and relation to agronomic traits

The univoltine European corn borer (ECB) has become a major limiting factor for maize (Zea mays L.) production in central Europe. The objective of this study was to survey the genetic variation for ECB resistance in European elite maize germplasm. Eighteen flint and 23 dent inbreds were screened under artificial ECB infestation at two locations in 1993 and 1994. Resistance was assessed by damage rating of broken plants, measurement of tunnel length in dissected stalks, and yield reduction in infested plots relative to insecticide-protected control plots. Flint lines showed significantly greater means for damage rating than dent lines with grain yield reduction of 35% and 24%, respectively. Significant genotypic variances among lines and high heritabilities were found for agronomic traits and damage rating. Heritabilities were intermediate for tunnel length and relative grain yield. Significant associations of days to silking, ear dry matter content, and dry matter yield of the whole plant with damage rating and tunnel length suggested a better resistance in late-maturing, high-yielding inbreds. Genotypic correlations of relative grain yield with tunnel length and damage rating ranged between ?0.46 and ?0.72. Partial correlations, eliminating the effect of flowering time, confirmed these associations. Damage rating of stalks is the most suitable trait for evaluation of ECB damage owing to its high heritability and easy recording. Tunnel length below the primary ear is a useful trait for assessing antibiosis because it is not correlated with days to silking. Inbreds with extreme resistance and susceptibility were identified which can be used as parents for establishing breeding and QTL mapping populations.