播种期对芝麻生育期及产量性状的影响

从4月30日到7月29日设立10个播种期,研究不同播种期对芝麻生育期及产量性状的影响。结果表明：播种期对芝麻生育期影响明显,呈先升后降,然后小幅上升的趋势;随着播种期推迟,芝麻株高、始蒴高度和单株产量表现为先升后降趋势,其中单株产量于5月21日播种达最大值;蒴节数、每蒴粒数和千粒重呈不断下降趋势;蒴果长和蒴果宽变化不明显;空稍尖长度变化的规律性不明显,于第6期（6月9日播种）和第7期（6月19日播种）达最大值;播种期之间的小区产量差异达显著或极显著水平。因此,播种期对芝麻生育期和产量性状影响明显,适宜播期为5月上旬到7月中旬,其中5月下旬播种产量最高。     

多小叶源对大豆光合特性和产量的影响

以多小叶大豆品系牡5796-3为材料,设置在不同生育时期摘除多的2片小叶,共5个处理,研究了多小叶源对大豆光合特性和产量的影响.结果表明:各处理R6期的叶绿素含量差异不显著;全生育期不摘叶处理的光合速率、单株叶面积、叶面积指数、单株荚数、单株粒数和百粒重均明显高于全生育期摘除多的2片叶的对照处理,因此,产量明显高于对照.总之,由于多小叶大豆品系具有良好的农艺性状和产量表现,可做育种亲本加以利用.     

夏芝麻促控栽培技术

1985年,分析了大面积生产调查和高产试验示范结果,发现夏芝麻单位面积经济产量同生物学产量相关程度较低。许多田块芝麻植株虽然高大,但是始蒴部位太高,植株果轴短,蒴果稀,蒴果少,经济产量低。尤其夏播芝麻,生育季节短,前中期因高温高湿,植株生长发育快,后期又易受低温阴雨影响,植株中上部蒴果质量差,产量低。因此,1985—1986年,我们从播期、密度、施肥量、施肥方法、防病保叶和植物生长调节剂等方面研究芝麻群体的调控方法和效果,形成了配套的芝麻促控栽培技术。1987—1988年在试验示范的基础上,又进行芝麻库源关系的研究,进一步明确了促控能培条件下芝麻的形态指标及生理参数。     

芝麻花期叶片光合产物的 运输分配及对产量的影响

在芝麻有效开花结蒴期,对当天见花节位进行不同比例、不同部位剪叶处理,以不剪叶和全剪叶植株为 对照,研究了留叶部位功能叶光合产物的运输分配方向及在不同剪叶部位籽粒中的积累。结果表明:芝麻籽粒产 量全部来源于开花后功能叶的光合产物,剪叶比例越高减产越明显。叶片光合产物的运输分配量的大小顺序为: 向同侧蒴果分配最多,侧向分配次之,横向运输分配极少。     

烯效唑和胺鲜酯对大豆叶片光合特性与碳代谢的调控效应

为探究化控技术对大豆盛花、盛荚和鼓粒期光合特性与碳代谢的调控效果,采用大田试验,于垦丰41初花期叶面喷施烯效唑(S_(3307))和胺鲜酯(DTA-6),以喷施清水作为对照,测定各生育时期光合参数、碳代谢产物及其相关酶、干物质和产量构成因素。结果表明:烯效唑和胺鲜酯能显著提高各生育时期的水分利用效率、净光合速率、SPAD、蔗糖与淀粉含量、及盛花期和盛荚期的气孔导度和蒸腾速率。胺鲜酯显著降低各生育时期转化酶活性,提高蔗糖合成酶与蔗糖磷酸合成酶活性,在盛荚期效果尤为显著,烯效唑可提高各生育时期蔗糖合成酶与蔗糖磷酸合成酶活性并降低花期转化酶活性。与对照相比,胺鲜酯和烯效唑提高盛花期叶和茎分配率,降低叶柄分配率,胺鲜酯显著提高各生育时期的单株干物质积累并降低盛荚期叶分配率,烯效唑显著提高盛花期单株干物质积累和盛荚期荚分配率。胺鲜酯和烯效唑可不同程度调控单株荚数、单株粒数和百粒重,提高产量,胺鲜酯和烯效唑的增产率分别达到8.78%和7.16%。说明烯效唑和胺鲜酯能够有效提高大豆各生育时期光合作用能力,促进碳代谢产物及相关酶的合成,有利于提高产量,且胺鲜酯作用效果最佳,增产率最高。     

不同生育期大豆去叶对生长发育的影响

通过对大豆不同生育时期摘除不同量叶片的研究表明：整个生育时期随着叶面积的损失量增大，大豆的单株有效荚数，有效粒数，籽粒增长强度及百粒重降低就越明显，在盛花期以前损失30%-50%的叶面积，对产量无明显影响，鼓粒期叶面积稍有损失，大豆产量就会明显降低。     

芝麻主要性状的遗传力分析

本文以9个芝麻品种(系)为试验材料,估算了10个性状的遗传力,遗传变异系数、遗传进度和遗传相关。结果表明千粒重和每蒴粒数的遗传力高,株高和分枝部位的遗传力低;单株蒴果数和单株产量的遗传变异系数和遗传进度大,株高、分枝数和千粒重遗传变异系数和遗传进度小;单株蒴果数、每蒴粒数、千粒重与单株产量的相关都达到显著水平,但三者之间存在不同程度的负相关。     

长春地区芝麻播种期与磷肥用量研究

通过不同播期和磷肥施用量对芝麻生育和产量性状的影响进行了比较研究,结果表明：不同播期对芝麻生育性状无显著差异,对产量性状影响不大,说明在长春地区4月下旬—5月上旬均可播种芝麻,适播期较长;而在同一播期不同磷肥施用量对生育性状和产量性状有极显著影响,在吉林省中部草甸黑土上种植芝麻,磷肥施用量50kg/hm2 和75kg/hm2有显著差异, 50kg/hm2 和100kg/hm2有极显著差异。因此,适宜的磷肥施用量为 75—100kg/hm2。     

芝麻单株叶蒴比与蒴果发育

本研究表明,芝麻终花期单株叶蒴比对蒴果干物质积累、水分含量、种子发育和脂肪、蛋白质累积均有较大影响。对蒴果形态发育影响较小。叶蒴比反应植株源库关系协调性,是高产栽培的重要生理指标。     

氮肥用量和基追肥比例对密植秋芝麻产量和冠层结构的影响

为了探索红壤旱地密植秋芝麻的节氮高产栽培技术,以品种金黄麻为材料,采用裂区设计,2016和2017年在江西省进贤县研究氮肥用量[即N_1(105kg/hm^2)和N_2(75kg/hm^2)]和基追肥比例[即Z_1(7∶3)、Z_2(6∶4)、Z_3(5∶5)、Z_4(4∶6)、Z_5(3∶7)]对芝麻产量和冠层结构的影响。结果表明,在N_1条件下,2016年Z_3的单株蒴果数较Z_2显著增加25.36%,Z_4的每蒴粒数和Z_2的千粒重较Z_1的分别显著增加19.96%和13.62%;不同的是,2017年Z_2的每蒴粒数较Z_3显著增加22.84%,对单株蒴果数和千粒重无显著影响。在N_2条件下,2016年Z_3的千粒重较Z_4显著增加6.42%,其它处理间的单株蒴果数、每蒴粒数、千粒重都无显著差异;N_2的平均产量(879.0kg/hm^2)较N_1显著增加22.3%;但是2017年N_1的平均产量(1 080.7kg/hm^2)较N_2增加8.1%。相同的是,两年的结果都表现为Z_2处理平均产量最高。芝麻产量表现为随着基肥的比例减少而先增后减。不同时期N_1的光能截获率和叶面积指数都显著高于N_2,且随生长发育进程而先增后减。不同位置的芝麻冠层光能截获率和叶面积指数都有显著差异,且随着测定位置的不断升高而降低。因此,氮肥用量为75kg/hm^2和基追肥比例为6∶4,有利于协调密植秋芝麻的群体冠层结构,保持秋芝麻的高产。     

密度和施肥水平对双低油菜苏油1号产量及分枝习性的影响

密度和施肥水平两因子对苏油1号产量及分枝习性影响的研究结果表明：（1）移栽11．25万株/hm2，施纯氮270kg/hm2是适宜苏油1号的种植密度和施肥处理，产量达到3452.0kg/hm2.(2)产量结构因子以单位面积有效角果数对产量的影响较大，其次为千粒重和每角粒数。（3）随密度和施氮量增加，单位面积有效果数呈先增后减的趋势，千粒重与施氮量关系密切，但过量施氮则降低千粒重，（4）单位面积为枝数多，分枝角果数多和分枝籽粒多是苏油1号的高产表现。     

芝麻产量性状与品质性状的典型相关分析

以15个芝麻品种(品系)为材料,根据生物学意义将15个性状归纳为4个性状组,对性状和性状组基因 型值进行相关分析和典型相关分析,并建立了由多个农艺性状间接改良品质性状的综合选择指数。结果表明:对 单株产量影响最大的因素是农艺性状(株高、果轴长、始蒴部位)和产量构成因子(蒴粒数、千粒重) ,而且农艺性状 与产量构成因子以正相关为主,因此可以同步改良农艺性状和产量构成因子以进一步提高产量潜力;含油量与主 要农艺性状、产量构成因子以及种子容重呈正相关,而与粒宽和蛋白质含量呈显著负相关,因此含油量和产量可以 协调发展,同步提高,而且可以通过籽粒性状间接辅助选择高产、高含油量的芝麻新品种。     

芝麻花期叶绿素含量变化及其与产量性状的相关分析

以110份芝麻栽培品种和5份野生资源种为研究材料，分析了芝麻花期叶绿素含量的变化规律及其与产量性状的相关性。结果表明：不同品种间的叶绿素含量差异较大；野生芝麻的叶绿素含量显著高于栽培品种；各种材料叶绿素含量从初花期到终花期不断升高；不同阶段的叶绿素含量相关显著；叶绿素含量与株高、果轴长度和千粒重呈显著正相关，而与单株产量仅呈中等强度的正相关。在分组方差分析中，高叶绿素含量品种组与低叶绿素含量品种组之间的单株产量差异显著，表明通过选育高叶绿素含量的芝麻新品种来实现增产是可行的。     

Alfalfa (Medicago sativa L.) seed yield and quality under different forage management systems and irrigation treatments in a Mediterranean environment

Alfalfa (Medicago sativa L.) is widely grown as a forage crop due to its good quality characteristics and high adaptability. However, seed yield is generally considered to be of secondary importance and is characterized by fluctuating yields with often poor seed quality. A field experiment using five alfalfa cultivars (Equipe, Iside, Lodi, Robot, Romagnola) was carried out in 1995, 1996 and 1997 at Foggia (southern Italy) to evaluate the effects of four defoliation practices (H1: crop mown during early plant growth; H2: plant desiccation by chemical agent at the end of February; H3: crop mown at early flowering; H4: never cut) and two irrigation treatments (I: irrigation applied from April to beginning of seed filling; NI: non-irrigated control) on seed yield, seed yield components and seed quality (as determined by seed germination with and without accelerated ageing (AA)). The relationships between yield components (stems per m², pods per stem, seeds per pod, 1000-seed weight) were determined by path-coefficient analysis. Irrigation significantly increased seed yield; on average doubling the control yield over the three seasons. However, the potential seed yield (calculated from seed yield components) was, on average, five times the actual seed yield. The two mowing treatments produced consistently higher seed yields than either desiccated or untreated swards. Cultivar differences were evident for seed yield, with Equipe having the highest value (40% higher than the mean of the other cultivars). Irrigation improved the yield primarily because it led on average a greater than four fold increase in the density of stems (the most influential yield component). By contrast, seeds per pod and 1000-seed weight increased in the absence of irrigation. Defoliation treatments had little effect on stems per m², seeds per pod and seed weight, whereas pods per stem were reduced by desiccation. Path analyses calculated across irrigation treatments and years revealed that stems per m² had the largest positive direct effect on alfalfa seed yield under each harvest management (path-coefficient values ≥0.89), and its indirect effects on seed yield via other traits were negligible. Seed quality, as measured by germination percentage both before and after AA, remained relatively consistent across both defoliation and irrigation treatments and cultivars, but was anomalously low in the 1997 irrigated crops. Overall, the highest seed yields were obtained under irrigated conditions when crops were mown during early growth or at early flowering. The potential seed yield of alfalfa varieties is sufficient to guarantee a profitable seed harvest. However, the harvest efficiency of the combine-harvester was low (20% of the potential seed yield); thus, more appropriate harvest techniques should be used.     

山东间作大豆产量与主要农艺性状关联分析

为明确间作大豆的性状表现,筛选适宜间作的高产、稳产性大豆品种,本研究在玉米大豆间作模式下,对50份大豆材料在两年的产量与11个主要农艺性状进行相关性及灰色关联度分析,并采用GGE双标图法进行品种适应性及稳产性分析。结果表明：50份材料的主要农艺及产量性状的变异系数在6.87%~77.32%,广义遗传力为0.62~0.97,且生育期、营养生长期、百粒重等9个性状的广义遗传力均大于0.8;相关性分析表明,单株产量与茎粗(0.75**)、生育期(0.76**)呈极显著正相关,其次为株高、主茎节数、分枝数、底荚高、营养生长期、百粒重、单株荚数、单株粒数;灰色关联度分析表明,单株产量与各农艺性状的关联顺序为茎粗>生育期>营养生长期>单株荚数>百粒重>底荚高>单株粒数>分枝数>主茎节数>株高>生殖生长期;GGE双标图法表明汾豆79、中作J7018和皖豆30为适宜间作的高产、稳产性较好的品种。     

芝麻干物质积累和分配研究初报

豫芝4号芝麻现蕾前积蓄的光合产物对产量贡献很小。现蕾至终花约40天内是芝麻产量形成的关键时期。这一时期营养生长和生殖生长竞争激烈,对外界环境敏感,栽培措施应以调节干物质分配流向为主,争取早发、稳长。封顶后,全株及蒴果干物质积累仍维持较高水平,延长后期光合器官功能,防止早衰,将有利于减少秕粒,提高千粒重。     

Late defoliation and wheat yield: Little evidence of post-anthesis source limitation

The effect of source reduction on yield and protein content of bread wheat under well-watered and mild drought stress condition in a semi-arid climate was studied. Field experiments were conducted at the Tehran University research farm during 2003–2004 and 2004–2005 growing seasons. Mild drought stress was imposed when plants were at the second node stage by repeatedly withholding watering and re-irrigating when they showed symptoms of wilting or leaf rolling. Partial defoliations (all leaf lamina other than flag leaves were removed) were imposed at booting and anthesis; complete defoliation was imposed at anthesis (defoliation treatments were applied to all plants of each plot). Drought stress caused a significant increase in the remobilization of pre-anthesis reserves to the grain. Defoliation did not significantly affect remobilization. Grain yield and 1000-grain weight was reduced slightly by drought stress, but in most cases it was not significantly reduced by defoliation. Significant changes were not observed for grain protein content between defoliated and control plots. The results suggested that grain yield of the cultivar used under the condition tested is more controlled by sink than source strength.     

Seed production in white clover (Trifolium repens L.). II. Effect of autumn defoliation on potential seed yield and seed yield components

A field experiment was conducted to assess the effect of autumn defoliation treatments on inflorescence production, potential seed yield and yield components of white clover cv Makibashiro. Between 10 July and 10 October 1992, white clover swards were subjected to one of three treatments: monthly cutting to 3–4 cm (4DEF), cutting to 3–4 cm on 10 August and 10 October (2DEF), and no cutting (control). The total numbers of inflorescences and the proportion of inflorescences in different development categories were counted throughout the period of seed crop development to determine the pattern of inflorescence development and optimum harvest date. There were consistent significant differences in inflorescence density between treatments. Plots which received the 2DEF treatment produced significantly more inflorescences than did the no-defoliation (control) and 4DEF-treatment plots. In this particular year the optimum harvest date (date at which the proportion of ripe inflorescences and potential seed yield was highest) was 26 July, approximately 30 d after peak flowering. Defoliation treatments had no effect on optimum harvest date. However, treatments differed in potential seed yield and ripe inflorescences on this date. The 2DEF treatment gave the highest potential seed yield because there were significantly more ripe inflorescences than either the contol or 4DEF plots. Control plots produced inflorescences with more florets than the other two defoliation treatments, but the differences were not always significant. Seed number per pod was higher in inflorescences obtained from previously defoliated plots than from control plots. The 1000-seed weight was significantly lower in inflorescences developed in 4DEF plots than those developed in 2DEF and control plots. The results are discussed in relation to the management of white clover seed crops and the importance of canopy structure and light intensity for seed production.     

Spring defoliation of white clover seed crops. 2. Potential harvestable seed yield and seed yield components of contrasting white clover cultivars

The effects of different spring defoliation managements on potential harvestable seed yield and seed yield components of three contrasting white clover cultivars were assessed. The small-leaved cv. S184 produced more but smaller inflorescences than the large-leaved cv. Olwen and Menna, a medium-leaved cultivar. Cultivar Olwen, however, produced more ripe and brown (nearly ripe) inflorescences with more florets, seeds per floret and a higher seed yield per ten inflorescences than the other cultivars. Potential harvestable seed yield and individual seed yield components were only influenced by defoliation after bud emergence, as defoliation before bud emergence had no effect on seed yield components. Defoliation after bud emergence had a similar effect on all cultivars: the number of ripe inflorescences was unaffected by defoliation but the number of brown and therefore harvestable (ripe + brown) inflorescences was highest following defoliation three weeks after bud emergence. Florets per inflorescence, seed per floret, 1000 seed weight, seed yield per ten inflorescences and potential harvestable seed yield were not influenced by defoliation after bud emergence. Season had a significant effect on seed yield components and influenced the effect of defoliation treatments, emphasizing the importance of climate in white clover seed production. The results are discussed in relation to the spring defoliation of white clover seed crops, harvesting techniques and the provision of guidelines for optimizing seed yield.