共查询到20条相似文献，搜索用时 31 毫秒
1.
A. M. Abu-Awwad 《Journal of Agronomy and Crop Science》1999,183(1):1-7
Caused by the necessarily imperfect seed placement accuracy of sowing machines and, additionally, caused by many other biotic and abiotic factors, the resulting plant stands exhibit nonregular spatial distributions of its plants. Based on several simplifying assumptions, a stochastic approach is developed which allows an estimation of the effects of nonregular spatial patterns on yield per area. In this approach, two random variables are attached to each plant: single plant yield E and individual space A . The latter is estimated by the area of Thiessen polygons. Yield per area, calculated by the expectation of the ratio E/A , can be approximately expressed dependent on the means ( Ē and Ā ) and coefficients of variation ( v E and v A ) of E and A and their correlation ( r EA ). In relation to the commonly used estimate Ē/Ā for yield per area, one obtains yield decreases if v A / v E < r EA . This inequality, however, will be usually valid in the field of applications. The theoretical approaches and results were applied to three experimental data sets for drilled seeds of winter oilseed rape ( Brassica napus L.) (plant density: 60 plants m−2 , row distance: 10 cm). These data sets are characterized by different accuracies of longitudinal distributions within rows (58 %, 101 %, 150 %): yield depression increases with an increasing variability of plant distances within rows. 相似文献
2.
M. Hühn 《Journal of Agronomy and Crop Science》2000,184(2):133-136
Based on several simplifying assumptions, a previously developed stochastic approach allows an estimation of the effects of non-regular spatial patterns of the distribution of individual plants on yield per area (F). In this approach, two random variables were attached to each plant: single plant yield (E) and individual space per plant (A). The latter was estimated by the area of Thiessen-polygons. Yield per area was calculated theoretically by the expectation of the ratio E/A. Based on a logarithmic relationship between E and A the expectation of E/A can be expressed by an approximation which depends on the mean and on the variance of the individual plant spaces. An improvement of this approximation can be easily obtained by including skewness and kurtosis of the distribution of individual plant areas. Finally, all theoretical concepts and results were applied to an experimental data set of winter oilseed rape ( Brassica napus L.). 相似文献
3.
M. Hühn 《Journal of Agronomy and Crop Science》1999,182(2):89-98
Based on several simplifying assumptions, a stochastic approach was developed which allows an estimation of the effects of nonregular spatial patterns of the distribution of individual plants on yield per area (F). In this approach, two random variables were attached to each plant: single plant yield (E) and individual space per plant (A). The latter was estimated by the area of Thiessen polygons. Yield per area was calculated theoretically by the expectation of the ratio E / A. Appropriate approximations of this expectation depend on the means (ē and ā), coefficients of variation (vE and vA) of E and A and their correlation (rEA). Yield per area can be decomposed into two additive terms: the first term gives the commonly used estimate ē/ā— or h(ā)/ā if a functional relationship between E and A is assumed: E = h(A). In this study, the two relationships E = k1 + k2 · ln A and E = A/(k3 + k4A) were used (with appropriately chosen constants k1, k2, k3, and k4). The second term in the decomposition of F can be interpreted as the effect of variable individual plant spaces on yield per area. In this paper, all theoretical concepts and results were applied to 17 experimental data sets of three cultivars of winter oilseed rape (Brassica napus L.). Single plant yields (E) and individual plant areas (A) were positively correlated with correlation coefficients from 0.64 up to 0.91. The ranges for both coefficients of variation were similar: 0.27 ≤ vE ≤ 0.65 and 0.28 ≤ vA ≤ 0.59. One obtains no significant differences in the goodness-of-fit for both tested relationships between E and A although the logarithmic relationship seems to be slightly superior. For only three data sets one obtains negative values for the percentage of the second term in the decomposition of F. This indicates an overestimation of yield per area by the commonly used estimates h(ā)/ā and ē/ā, respectively. These overestimations, however, are less than 5 %. In all other cases with positive values for the second term the yield per area is underestimated by the common estimates. For almost all data sets, however, the percentages of F which are explained by the common estimates are much larger than 90 %. 相似文献
4.
M. Hühn 《Journal of Agronomy and Crop Science》2001,187(4):241-250
In this study a stochastic approach, based on several simplifying assumptions, is developed that allows an estimation of the effects of nonregular spatial patterns of the distribution of individual plants on yield per area. In this approach, two random variables were attached to each individual plant: single plant yield and individual space per plant. The latter can be estimated, for example, by the area of Thiessen polygons. Yield per area is calculated theoretically by the expectation (=mean) of the ratio between individual yield and area. Based on the logarithmic relationship between single plant yield and individual space per plant, yield per area can be broken down into three additive terms: the first term depends only on the mean of individual plant areas, while the second depends on their mean and variance simultaneously. This second term is the product of the variance and a factor which depends only on the mean. The third term is a function of the mean and of higher order (≥ 3) central moments of a fractional linear transformation of individual plant area. Finally, these theoretical concepts were applied to 17 experimental data sets of three cultivars of winter oilseed rape (Brassica napus L.) with measurements for single plant yields and individual areas for the Thiessen polygon tesselations. Since yield per area is theoretically defined by the expectation of the ratio between individual yield and area, it is estimated by the arithmetic mean of the individual yield/area‐ratios. The agreement between this estimate and the sum of the estimated terms from the aforementioned additive decomposition of yield per area is particularly good. For the 17 data sets, percentages for these additive terms of approximately 71.4 % up to 98.4 % (mean: 89.0 %) for the first term, 1.6 % up to 20.0 % (mean: 9.8 %) for the second term and 0 % up to 8.7 % (mean: 1.2 %) for the third term are obtained. As a consequence it may be concluded, that yield per area can be explained mainly by dependencies on the means of individual plant areas while the variance of individual plant spaces is of only minor importance. The effect of the third term is insignificant. These results clearly indicate an answer to the main issue raised in the paper, namely the importance of seeding density as opposed to seeding accuracy/uniformity: nonuniformity is of limited influence and seeding density is the main correlate of yield/area. Seed placement accuracy of seeding technology therefore plays an only minor role. 相似文献
5.
向日葵单株幼苗活力对产量形成的影响 总被引：1，自引：0，他引：1
1990～1991年以出苗期为指标.着重研究了单株幼苗活力对向日葵植株籽粒产量的影响.旨在改进Wade等(1988)提出的向日葵苗期估产数学模型.结果表明.向日葵单株葵盘重量与单株籽粒产量之间呈极显著的回归关系(R~2=0.97～0.99),由前者预测后者非常可靠.可作为成熟期测产的参考.在苗期根据向日葵苗情预测收获时的籽粒产量.尽管Wade等模型有效.但加入单株幼苗活力这个因素后.整个多元回归模型的可信度大为提高.原模型中的预测因子仅包括单株面积印株距变异系数时.多元回归方程的决定系数R~2为0.25;当模型中再加入单株幼苗活力指标后,R~2增加到0.44.而且,单株面积与株距变异系数之间和单株面积与单株幼苗活力之间的互作也达到显著水平.改良模型中影响单株籽粒产量的各因素间,以单株面积和单株幼苗活力最为重要. 相似文献
6.
M. Hühn 《Journal of Agronomy and Crop Science》1987,159(2):73-81
The yield F per area can be expressed multiplicatively by using yield components. For the most simple case of including only two yield components one obtains: F = X1 − X2 with X1 = number of plants per area (= plant density) and X2 = mean yield per plant.
For normal variables X1 and X2 the phenotypic yield stability of F, which has been measured quantitatively by the variance V(F) of F, can be explicitly expressed dependent on 1) the component means, 2) the component variances and 3) the correlation between the two components. V(F), therefore, depends on 5 parameters.
For many applications the use of the coefficient of variation v of F instead of the variance itself may be advantageous, v can be explicitly expressed dependent on 1) the coefficients of variation of the yield components and 2) the correlation between the components, v, therefore, depends on 3 parameters.
The different conditions leading to the same phenotypic yield stability can be investigated by using these explicit expressions for V(F) and v.
The main purpose of the present paper is the application of these theoretical models and results to the data of an extensive field trial with winter-rape, which has been performed for 5 years with 4 plant densities and 3 row distances.
For the lowest plant density (40 plants/m2 ) there results a very good agreement between the theoretically expected and the experimentally obtained values for the phenotypic stability of yield per area. But, for the higher plant densities this result don't hold true. Possible causes and explanations are discussed in detail. 相似文献
For normal variables X
For many applications the use of the coefficient of variation v of F instead of the variance itself may be advantageous, v can be explicitly expressed dependent on 1) the coefficients of variation of the yield components and 2) the correlation between the components, v, therefore, depends on 3 parameters.
The different conditions leading to the same phenotypic yield stability can be investigated by using these explicit expressions for V(F) and v.
The main purpose of the present paper is the application of these theoretical models and results to the data of an extensive field trial with winter-rape, which has been performed for 5 years with 4 plant densities and 3 row distances.
For the lowest plant density (40 plants/m
7.
G. Geisler S. A. Shrief A. F. Ibrahim R. Shabana 《Journal of Agronomy and Crop Science》1992,168(1):20-33
Investigations on the effect of competition on stand structure of spring oilseed rape
On the basis of a field experiment with spring oilseed rape, frequency distributions of plant dry matter and plant height were investigated. Samples were taken at four developmental stages: rosette, begin of flowering, end of flowering, ripeness (harvest). To understand the effect of competition in a plant population on frequency distribution, distance of rows (16 cm, 32 cm) and number of plants (60, 90 and 120 plants/m2 ) were varied. Differences in frequency distribution were estimated by skewness and kurtosis.
The results show that with age of the plant population the skewness of the plant character dry matter decreases from a high positive value till ripeness to a low positive value; kurtosis also decreases during development and tends to a value of 0 at ripeness. The effect of competition as produced by number of plants for area is mirrored by a positive skewness increasing with increasing number of plants per area. The value for kurtosis also increases with the stronger competition as consequence of plant density. Row distance did not show specific effects of frequency distribution. Plant height did, generally speaking, not react to competition. 相似文献
On the basis of a field experiment with spring oilseed rape, frequency distributions of plant dry matter and plant height were investigated. Samples were taken at four developmental stages: rosette, begin of flowering, end of flowering, ripeness (harvest). To understand the effect of competition in a plant population on frequency distribution, distance of rows (16 cm, 32 cm) and number of plants (60, 90 and 120 plants/m
The results show that with age of the plant population the skewness of the plant character dry matter decreases from a high positive value till ripeness to a low positive value; kurtosis also decreases during development and tends to a value of 0 at ripeness. The effect of competition as produced by number of plants for area is mirrored by a positive skewness increasing with increasing number of plants per area. The value for kurtosis also increases with the stronger competition as consequence of plant density. Row distance did not show specific effects of frequency distribution. Plant height did, generally speaking, not react to competition. 相似文献
8.
以不同粒重的花生种子为试材,采用不同播种方式,研究粒重大小和播种方式对花生生长发育、光合特性及产量的影响。结果表明,单粒精播处理可使产量增加,与传统双粒穴播相比,在一垄两行播种方式下,相对大粒种子和相对小粒种子分别增产9.77%、4.19%;一垄单行种植方式下分别增产3.44%和2.77%。无论种子粒重大小,单粒精播处理的主茎高、侧枝长和地上部干物质积累量均显著高于双粒穴播,但其荚果干重、净光合速率和单株叶面积与双粒穴播间均无显著差异。相关分析表明,叶片干重、茎柄干重与单株叶面积间呈极显著相关关系;饱果成熟期与结荚期地上部干物重之差与产量间呈显著相关关系。采用垄作双行单粒精播模式,选用饱满粒重较小的种子,可达节本降耗、明显提高经济效益的目的。 相似文献
9.
Investigations on the effect of number of plants/area on the yield potential of rapeseed plants (Brassica napus L. var. napus) Based on field experiments with winter rapeseed, the effect of number of plants per area on yield potential and components of yield were investigated. The dependence of yield from number of plants per area before and after winter was analyzed by manipulating the number of plants immediately after sowing and in spring before beginning of growth. The number of plants per area was varied between 10 plants/m2 till 185 plants/m2. The results show that the yield potential is partly dependend on the growing conditions before winter as influenced by the number of plants per area; the yield potential declines with increasing number of plants/area before winter; affected are the number of siliquae producing lateral shoots, the number of siliquae per shoot and seeds per siliqua. The growing conditions before winter, in this way control the capacity of the rapeseed plant to utilize environmental factors in the main growing period. 50–100 plants/m2 before winter and 45–90 plants/m2 after winter are within the compensation capacity of rapeseed plants. 相似文献
10.
为探索南方机械化作业条件下大豆高产高效栽培技术,以‘湘春豆V8’为材料,通过大田大区试验研究了播种量和施肥量对春大豆农艺性状、产量及产量构成以及机收质量的影响。结果表明：（1）大豆株高、底荚高度、倒伏率随着播种量和施肥量的增加而增大,大豆出苗率、成株率则随着播种量的增加而降低。（2）大豆单位面积株数随着播种量的增大而增多,而每株有效荚数则反之;施肥量的增加能有效提高每荚果粒数;均数间两两比较表明,S2F2（播种量75 kg/hm2+复混肥量90 kg/hm2）处理可获得最高产量2834.91 kg/hm2。（3）播种量和施肥量对机收损失率均无显著影响,且不存在交互效应,总体机收损失率在5.39%~6.21%之间。相关性分析表明,播种量主要通过单位面积株数、成株率、株高、倒伏率来影响机收含杂率,主要通过单位面积株数、成株率来影响机收损伤率;而施肥量主要通过株高、底荚高度和倒伏率来影响机收含杂率。播种量对机械收获质量,特别是机收含杂率和损伤率影响较施肥量更为广泛。综合考虑大豆产量及机械收获质量等因素,认为采用播种量75 kg/hm2+复混肥量90 kg/hm2可获最高产量2834.91 kg/hm2（机收2731.88 kg/hm2）,且能有效降低机收含杂率和机收损伤率至6.82%和11.38%。 相似文献
11.
B. Märländer 《Journal of Agronomy and Crop Science》1990,164(2):120-130
Influence of Plant Density on Yield and Quality and Possible Causes of Competition in Sugar Beet Crops
In trials conducted over 9 years at 1 location plant densities ranged from 35,000 to 110,000 plants/ha. Root yield, sugar yield and white sugar yield reached maximum values at 92,700, 94,700 and 96,000 plants/ha, respectively. The decrease in yield per 1,000 plants/ha was greater as the plant density fell. The quality criteria (sugar concentration, white sugar concentration and sugar gain) were at their maxima at 107,000, 104,600 and 100,000 plants/ha, respectively, and they decreased at an almost constant rate as plant density declined. The concentrations of potassium, sodium and amino-N, the main factors which determine quality in Germany, as well as the sugar loss were all minimized at about 110,000 plants/ha and they increased at a progressively-greater rate per 1,000 plants/ha as plant density declined. The maximum differences between large and small plant densities were: root yield 13.6%, sugar yield 16.7%, white sugar yield 18.6%, sugar concentration 3.7%, white sugar concentration 5.3%, sugar gain 1.7%, sugar loss 9.3%, potassium concentration 8.4%, sodium concentration 30.5% and amino-N concentration 25.4%. As well as a comparison of the yield and quality criteria, the paper considers competition within the foliage, particularly when different amounts of nitrogen are available, as the main cause for yield differences between sugar beet crops. 相似文献
In trials conducted over 9 years at 1 location plant densities ranged from 35,000 to 110,000 plants/ha. Root yield, sugar yield and white sugar yield reached maximum values at 92,700, 94,700 and 96,000 plants/ha, respectively. The decrease in yield per 1,000 plants/ha was greater as the plant density fell. The quality criteria (sugar concentration, white sugar concentration and sugar gain) were at their maxima at 107,000, 104,600 and 100,000 plants/ha, respectively, and they decreased at an almost constant rate as plant density declined. The concentrations of potassium, sodium and amino-N, the main factors which determine quality in Germany, as well as the sugar loss were all minimized at about 110,000 plants/ha and they increased at a progressively-greater rate per 1,000 plants/ha as plant density declined. The maximum differences between large and small plant densities were: root yield 13.6%, sugar yield 16.7%, white sugar yield 18.6%, sugar concentration 3.7%, white sugar concentration 5.3%, sugar gain 1.7%, sugar loss 9.3%, potassium concentration 8.4%, sodium concentration 30.5% and amino-N concentration 25.4%. As well as a comparison of the yield and quality criteria, the paper considers competition within the foliage, particularly when different amounts of nitrogen are available, as the main cause for yield differences between sugar beet crops. 相似文献
12.
密度与播期对晋西旱作玉米农艺性状及产量的影响 总被引：1，自引：0，他引：1
为了研究不同玉米品种在晋西旱作条件下的最佳栽培模式,采用3因素随机区组设计,对3个耐密型品种在4个种植密度和3个播期下的农艺性状及产量的数值差异进行比较研究。结果表明,密度对3个品种的最大叶面积指数、穗粒数、千粒重、产量的影响达显著或极显著水平,对株高、穗位高的影响不显著;播期对株高、穗位高、最大叶面积指数、穗粒数、千粒重、产量的影响达显著或极显著水平,主要农艺性状之间的交互作用共同影响并且决定了玉米产量。综合分析可知‘：先玉335’和‘大丰30’在67500株/hm2和5月中旬处理组合下产量最高,分别为13914.17kg/hm2、13487.67kg/hm2‘;福盛园55’在75000株/hm2和4月下旬处理组合下,产量最高为16114.37kg/hm2,本研究为3个玉米品种在本地区获得高产提供了一定的技术支撑。 相似文献
13.
为了探索油菜新品种（组合）98P37-21高产、高效栽培技术,在稻板田中开展不同播种量和移栽密度试验,研究其对油菜生长发育、主要经济性状、产量及其构成因素的影响,并对直播和移栽油菜效益进行了比较。结果表明：直播油菜4.5~7.5 kg/hm2播种量范围内（密度27.3万株/hm2~38.7万株/hm2）,产量随着播种量的增加呈先增后减的趋势;移栽油菜9.0万株/hm2~15.0万株/hm2密度范围内,产量随着移栽密度的增加而增加,直播油菜以6.0 kg/hm2产量最高,移栽油菜以15.0万株/hm2产量最高,但高密度增产优势不明显,表明密度过大也不利于高产,甚至可能降低产量。随着播种量或移栽密度的增加,主茎总叶数、绿叶数、根颈粗、叶面积、一次有效分枝数、全株角果数、每角粒数、千粒重、单株地上部干重、单株产量呈现下降的趋势,而株高、分枝高度变高,叶面积指数变大。移栽油菜主要经济性状指标优于直播油菜,直播油菜产量和产值明显要低,但直播油菜节省劳力和减少投入,净收入却比移栽油菜多1735.7元/hm2,效益明显要高。 相似文献
14.
氮肥与密度互作对单粒精播花生根系形态、植株性状及产量的影响 总被引：1，自引：0，他引：1
Jun-Hua LIU Zheng-Feng WU Pu SHEN Tian-Yi YU Yong-Mei ZHENG Xue-Wu SUN Lin LI Dian-Xu CHEN Cai-Bin WANG Shu-Bo WAN 《作物学报》2020,46(10):1605-1616
为明确花生单粒精播适宜的氮肥水平和种植密度,本研究于2018年和2019年以‘花育22’为供试花生品种,设置3个氮肥水平(0 kg hm~(–2), N0; 60 kg hm~(–2), N1; 120 kg hm~(–2), N2), 3个种植密度(7.93万株hm~(–2), D1; 15.86万株hm~(–2),D2; 23.79万株hm~(–2), D3),采用二因素裂区试验设计,研究氮肥、密度及其互作对单粒精播花生根系形态、植株性状及产量的影响。氮肥对花生根长、根表面积、根体积、根干重的影响不显著,而密度的影响显著。单株根长、根表面积、根体积及根系干重随密度的增加而降低, D1显著高于D2和D3, D2、D3处理间差异不显著;单位面积根长、根表面积、根体积及根系干重随密度的增加而增加, D1显著低于D2和D3, D2、D3处理间差异不显著。氮肥和密度互作对2019年收获期单位面积根长、根表面积的影响显著,与D1相比, N1处理下D3的增幅显著高于N0和N2处理。氮肥及氮肥与密度互作对植株性状的影响存在年度和时期间的差异,主茎叶片数、侧枝数和主茎第一节间粗随密度增加有降低趋势。氮肥对荚果产量的影响不显著,荚果产量随密度的增加呈增加的趋势。产量与根体积、根干重、主茎叶片数、主茎高及侧枝长呈显著正相关。综上所述,在本试验条件下,花生单粒精播适宜的氮肥(N)水平为60 kg hm~(-2),种植密度为18.8万株hm~(-2)。 相似文献
15.
四川地区影响脱毒马铃薯原原种单株产量因素研究 总被引：1，自引：1，他引：0
为了提高马铃薯原原种单株产量,降低原原种生产成本,实现工厂化生产,就栽种密度、栽种时间、苗源3个主要因素对原原种单株产量进行研究。结果表明：不同扦插密度对原原种单株产量影响很大,方差分析结果达极显著,栽种密度为400苗/m2时单株产量最高,平均达到2.5粒,栽种密度过低或过高单株产量都会明显降低。不同栽种时间对原原种单株产量的影响也很大,四川地区最适栽种时间为3月15日至4月1日,过早或过迟栽种单株产量都会降低。试管苗和扦插苗的原原种单株产量相当,试管薯效果最好,平均单株产量达到3.5粒。大规模生产脱毒马铃薯原原种企业综合使用合适的栽种密度,掌握栽种时间,使用适当的苗源,是提高原原种总产量的基础。 相似文献
16.
Growth and yield responses to plant density (6.75 × 104 , 9.75 × 104 and 12.75 × 104 plants ha–1 ) and stage of transplanting (30, 35 and 40 days after sowing) of winter oilseed rape cultivar HO 605 were investigated in two field trials in the 1996/97 and 1997/98 growing seasons at Zhejiang University Farm, Huajiachi Campus, China. Results revealed a progressive decrease in leaf area per plant in response to increasing plant density and delayed transplanting, though leaf area m–2 and leaf area index were higher in high-density plants. Number of effective branches and pod per branch decreased with increasing plant density and delayed transplanting. There were no significant differences in the mean seed weight among treatments. Although the average number of seeds per pod was significantly lower for high-density plants and delayed transplanting, the economically highest seed yields were realized in relatively high-density plants. Seed oil content was negatively affected by increasing plant density, but no significant differences were observed with delayed transplanting. The highest seed yields of 1730.7 and 1748.1 kg ha–1 with no significant differences were observed for plant densities of 9.75 × 104 and 12.75 × 104 plants ha–1 , respectively, transplanted at 35 and 30 days after sowing. 相似文献
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为了研究单粒播种条件下不同种植密度对花生植株农艺性状、光合特性、产量及品质的影响,以高产、优质、适应性广的花生新品种‘泉花551’为材料,采用大田试验方法筛选其最优种植密度,为推广应用提供依据。在单粒播种条件下,花生株高、干物质积累、叶面积指数及光合势与种植密度呈正相关态势;单株分枝数、结果枝数、荚果数、单株生产力和叶绿素含量与种植密度呈负相关态势。在本试验设置的播种密度范围内产量随密度的增加呈先增加后降低的变化,以处理R4产量最高,与对照相比增产达显著水平,其较高的产量与其合理的干物质分配和较强的光合能力等有关。不同密度处理对花生籽仁品质影响较少。各处理以R4处理最适宜,既可促进单株健壮发育,充分发挥单株增产潜力,同时能协调个体与群体的发展,促进群体荚果产量的提高,实现花生的增产增效。 相似文献
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An attempt was made to assess possible constraints to higher production, with respect to partitioning of total dry matter to reproductive sinks in early pigeonpea. Growth, dry matter accumulation and yield components were determined in four diverse genotypes under four dates of sowing and different plant densities. Data on growth characteristics, dry matter accumulation (vegetative and reproductive) were obtained for three sowings, while the data on yield components were obtained for two dates of sowing. Growth analysis showed that the total dry matter was low upto 30 days after sowing and increased linearly upto 120 days. Coversely, LAD was high for the first 30 days and reduced at later stages of growth. The mean LAI of genotypes did not very much at initial stage of growth. However, it has given interesting picture during 70 to 90 days of growth. The higher biological yield and seed yield were attributable to high LAI and LAD coupled with thick stem, more effective branches, more pods per plant and larger raceme length. Harvest index was the maximum with increased plant populations in all sowings. Indeterminate varieties under high plant density and narrow row spacing (50 cm) developed a large leaf area and were presumably able to make better use of light. Growth and branching of individual plants were reduced at the higher plant population, but on per unit basis more dry matter was produced. It is suggested that breeding should be concentrated to improve an inability to accumulate adequate vegetative dry matter for the maintenance and filling of pods, may force the plant to continue vegetative production into the reproductive dry matter to support production of ultimate seed yield. 相似文献
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Subapical ears are largely responsible for grain yield variations in prolific maize (Zea mays L.) grown under conditions favourable for the expression of prolificacy trait, but limited information exists on yield components contributing to yield responses. A field experiment was conducted to determine the yield components of apical and subapical ear in prolific maize after various pollination treatments at two plant populations. Hybrid Pioneer 3733 was grown in the perfect stands of 71 428 and 35 714 plants ha?1. Three pollination treatments were carried out: (i) free pollination; (ii) subapical earshoots were covered to prevent pollination; and (iii) apical earshoots were covered to prevent pollination. Grain yields of free pollinated plants were by 50.1 % larger at low plant population (265 g per plant) than at high plant population (177 g per plant) due to a 45.3 % increase in kernels per plant, whereas 1000‐kernel weight slightly increased by 3.3 %. These increased kernels per plant at low plant population were, in part, the result of kernel increments on apical ear (10.1 %), and mainly associated with kernels from subapical ears that did not occur at high plant population. At low plant population, the total grain yield per plant was reduced by 94 g (35.5 %) after the apical ear was bagged to prevent pollination, but only 52 g (19.6 %) when the subapical ear was bagged. When subapical ear development was stopped at low plant population, grain yield on apical ears increased by only 3.9 % as a result of heavier 1000‐kernel weights, clearly demonstrating limitations in kernel set and size. After grain development on apical ear was prevented, subapical ear enlarged to 80.3 % of maximum apical ear yield because the former had, on average, 2.5 % lighter 1000‐kernel weight and 17.5 % fewer kernels than the latter. Ears did not differ in row number when only apical or subapical ear was developed on plant, whereas subapical ears tended to have fewer rows than apical ears when both were present on the same plant. Our results showed that: (i) plant population affected all yield components on both apical and subapical ear except row number; (ii) the occurrence of subapical ear is triggered by achieving maximum potential kernel set on apical ear; and (iii) subapical ear is inferior in potential grain yield to apical one even when the latter was prevented from pollination. 相似文献