小麦早熟高产品种子粒灌浆特性分析

以中、晚熟小麦品种（系）为对照，对早熟高产小麦灌浆期干物质积累和子粒灌浆过程进行了研究。结果表明，早熟、高产小麦品种在子粒灌浆期较多地利用了花前贮藏的营养物质，对同化物的利用较协调；灌浆高峰来得迟，高峰峰值高；高峰出现后，灌浆速率下降稍快于中、晚熟类型小麦品种（系），但在花后35d内，灌浆速率仍显著高于中、晚熟类型小麦品种。     

玉米自交系中高CO_2交换率的选择

设计提高玉米潜在产量的选择计划中,光合作用是一个改良的主要特性。过去的研究中已提出,在自交亲本中选择高CO_2交换率(CER)常是有效的。对玉米自交系中高CER选择效果的评价,我们进行了试验。对自交系的一个选择周期,在营养生长期和中部籽粒灌浆期实际提高各是每平方分米每小时2.5mg(4.7%)和2.3mg(5.7%)CO_2。营养生长期和籽粒灌浆期CER实得遗传力是0.33和0.26。设计提高玉米潜在产量的选择计划中,光合作用是一个改良的主要特性。过去的一项研究中,在从来自衣阿华硬秆玉米综合群体的64个随机自交系的选择中,我们发现了提高CO_2交换率(CER)(从14%增加到20%)的良好预示(Cro-Sbie等,1977)。营养生长期和籽粒灌浆生长期两者CER的高度遗传型相关(r=0.90),表明营养生长期可以实施选择,并且多种选择配合,每年可以完成一个选择周期。在一次营养生长期和灌浆期4个低CER自交系和4个高CER自交系间的双列杂交试验中,Crosbie等(1978年)对CER的遗传作了进一步研究。结果表明:在两个生长期:(1)CER主要受核基因累加效应的控制;(2)若干个杂交表现出CER有效的杂种优势;(3)高CER自交系对它们的杂交表现了一般配合力的正效应和高CER传递;(4)低CER自交系对它们的杂交表现了一般配合力的负效应和传递低CER;(5)中亲值是F_1表现的合适的良好预测者。这些结果表明育种计划中,在自交系亲本中选择常是有效的。这项研究工作的目的是评价玉米自交系间高CER一个选择周期的效果。     

不同玉米自交系子粒脱水速率及其与主要影响性状的相关分析

为了明确不同群体玉米自交系子粒脱水特征差异和影响玉米脱水速率的主要性状与子粒脱水间的关系,以陕A群、陕B群选育的8份玉米自交系和2份骨干自交系（昌7-2和PH4CV）为试验材料,分析了不同玉米自交系的子粒脱水速率、收获期子粒含水率、子粒灌浆速率、苞叶性状、果穗性状、叶面积、叶绿素含量、株高、穗位高及产量构成等变化特征及其与子粒脱水间的相互关系。结果表明：不同玉米自交系子粒脱水速率呈现“快–慢–较快–慢–较快–慢”的变化趋势。子粒脱水速率与收获期子粒含水率、苞叶平均含水率、苞叶层数、苞叶长度、穗粗、粒长、粒宽、叶面积、SPAD值、子粒灌浆天数等性状呈显著负相关关系,与苞叶脱水速率存在显著正相关关系,与株高、穗位高和子粒产量间相关性不显著。不同自交系间的子粒脱水速率、收获期子粒含水率、苞叶含水率、苞叶脱水速率等指标差异明显,KB043、KA105和KB024自交系的子粒脱水速率快、产量较高,可在宜机收品种选育时作为快速脱水材料加以考虑。     

高产中早熟玉米杂交种选育探讨

通过对玉米高产构成因素分析,结合育种实践,着重探讨了高产、高配合力中早熟玉米自交系选育问题,明确指出：（1）玉米种质基础的拓宽是玉米选系材料创新的基础;（2）籽粒排列紧密程度是选育高配合力自交系的关键;（3）组配组合时,结合杂优模式,不为杂种优势模式所束缚,广配组合,进行杂交种产量比较观察,多点鉴定,慎重“破格升级”,缩短育种年限。     

小麦早熟高产品种光合生理特性分析

对陕西关中地区当前推广的早、中、晚三种熟性8个高产小麦品种的光合生理特性进行了研究，以探明参试的早熟小麦品种高产的光合生理机能和进一步提高早熟小麦品种产量潜力的性状改良途径，结果表明，参试早熟高产小麦品种的光合生理物性是：1．灌浆高峰期蒸腾速率高；2．花期至灌浆高峰期有持续稳定的高净光合速率；3．花前同化产物对子粒干物质累积贡献潜势大；4．花后单株生物增长量远高于中、晚熟品种；5．花前同化产物转流系数高，花后干特质增长系数高，光合产物分配性能好，收获指数高。同时也进一步明确早熟高产小麦品种的生物学产量低于中、晚熟品种，其原因主要在于拔节期至开花期的生物学增长量少。进一步提高早熟小麦品种产量潜力的途径是保持或提高收获指数的同时，较大幅度地提高花期的生物学产量。     

玉米生理成熟后子粒脱水速率的配合力分析

选用10个熟期相近而子粒脱水速率差异较大的玉米自交系为试验材料，采用完全双列杂交设计配制杂交组合，对玉米生理成熟后子粒脱水速率进行配合力分析。结果表明，供试10份玉米自交系生理成熟后子粒脱水速率一般配合力方差达到极显著水平，5份自交系表现为正效应。90个杂交组合的特殊配合力方差达到极显著水平，玉米生理成熟后子粒脱水速率正反交效应存在极显著差异。遗传参数估计表明，玉米生理成熟后子粒脱水速率的广义遗传力和狭义遗传力均较高，分别达到81．45％和61．71％，在后代的遗传中加性基因占主导地位。     

玉米杂交种及其亲本子粒脱水速率初步研究

以辽宁省推广面积较大的6个玉米杂交种及其12个玉米亲本自交系为供试材料,采用随机区组设计,系统分析了玉米子粒脱水速率和收获时子粒含水量变化规律及脱水速率与主要性状的相关性。结果表明：杂交种和自交系的子粒鲜重在灌浆中前期呈上升趋势,灌浆后期略有降低;杂交种和自交系的子粒脱水速率在整个灌浆期逐渐下降,下降速率逐渐变小,最后趋近于零;杂交种和自交系的子粒脱水速率在不同灌浆时期和品种间差异显著;杂交种和自交系子粒的自然脱水速率和收获时子粒含水量在不同品种间差异显著,不同密度间差异不显著。子粒脱水速率与灌浆日数呈显著负相关,灌浆时间越长,脱水速率越慢;自然脱水速率与收获时子粒含水量、穗行数和百粒鲜重呈显著负相关。     

冬小麦粒充实度及灌浆模式的研究

通过对小麦子粒灌浆及发育的研究分析，提出了子粒充实度的概念及计算公式，并据此对河南省小麦子粒灌浆模式进行了研究，结果表明，品种间的子粒充实度存在着显著差异，它可以较好地反映子粒生长潜力的发挥程度。河南省的高产小麦品种可以划分为中种灌浆模式：－①高灌浆速度与短灌浆持续期相结合类型；②长灌浆持续期与早开花相结合类型；③长灌浆持续期与晚开花相结合类型；④低灌浆速度与长灌浆持续期相结合类型。其中，①②模式     

5003自交系旱地覆膜繁殖制种高产技术

５００３自交系旱地覆膜繁殖制种高产技术山西省农科院谷子研究所（长治０４６０００）王斌５００３自交系配合力高，秆低，茎粗壮，配出的杂交种叶片上冲、大穗、抗倒伏、抗病，表现出良好的高产、抗病、抗倒伏性和较强的适应性，在生产和科研上被广泛采用。但由于５００...     

春玉米主要产量性状的遗传分析

利用12个玉米自交系，按双列杂交模式设计组配66个杂交组合．分析了8个穗部性状的配合力和遗传参数。试验表明一般配合力在亲本间存在显著差异，各自交系的特殊配合力，在同一性状不同组合间及同一组合不同性状间也有显著差异，穗粗、容重、子粒行数等性状主要受加性效应控制，遗传力较高，可以在早代选择．而单穗粒重、产量、每行粒数等性状则遗传力较低。     

籼、粳超级稻光合物质生产与转运特征的差异研究

为阐明籼、粳超级稻干物质积累及光合生产特征的差异,以江苏地区大面积推广种植的5个超级杂交籼稻组合和5个常规粳型超级稻品种为试验材料,对稻麦两熟制条件下籼、粳超级稻干物质积累、分配、运转及叶面积、光合势、群体生长率、净同化率、秧苗素质、叶型等方面进行了系统的比较研究。结果表明,粳稻生育前期(移栽至拔节期)干物质积累量、光合势、群体生长率、净同化率及上三叶叶长、叶基角、叶开角、披垂度和叶面积衰减率、收获指数均小于籼稻,而生育中后期(拔节至成熟期)干物质积累量、光合势、群体生长率、净同化率及有效叶面积率、高效叶面积率、粒叶比(颖花/叶、实粒/叶、粒重/叶)、最大叶面积指数、总充实量、实收产量、生物产量、茎鞘最大输出量和表观输出量及比率均大于籼稻,差异显著或极显著。虽然粳稻主要生育期单茎干物重均不及籼稻,但群体数量优势保证粳稻具有较高的群体干物质积累量和叶面积,且随着生长发育的持续,群体光合物质生产优势不断加大,群体干物质积累量于抽穗后25 d前后超过籼稻。粳稻灌浆后期(乳熟至成熟期)仍保持强劲生长优势,而灌浆初期(抽穗至乳熟期)茎鞘贮存物质合理输出,有效保障了高效光合层的安全支撑及高积累产量库的流畅充实。高生物学产量的稳定形成和叶面积“稳升缓降”态势以及拔节至成熟期较强的高效光合物质生产,是粳稻光合系统高效持续产出、灌浆充实多及高产形成的重要特征和原因。     

AB型增粒剂在杂交稻制繁中的应用效应研究

“AB型增粒剂”应用于杂交稻制种、繁殖，能够显著改善不育系的异交性能，提高异交结实率和产量。该剂应用后对于减轻不育系包颈、调节穗层结构、提早花时，提高柱头外露率以及柱头生活力等方面具有特殊功效。根据多年来各地制、繁种生产上研究和应用结果，一般可提高异交结实率20％-30％，增产20％-25％。     

The Influence of Plant Water Stress on Net Photosynthesis and Yield of Sunflower (Helianthus annuus L.)

The effect of plant water stress on net photosynthesis, leaf growth, yield and yield-related components were investigated in a single experiment in order to determine in which way water deficits affect sunflower yields.
Sunflower plants, grown under controlled temperature regimes, were stressed during budding, anthesis and seed filling by withholding water until the leaf water potential reached -1600 and -2000 kPa. Leaf area of unstressed plants significantly exceeded that of plants under severe stress during all growth stages investigated. The CO₂ uptake rate per unit leaf area as well as the total uptake rate per plant, significantly diminished with stress, while this effect drastically increased during the reproductive phase of the plant. Although this resulted in significantly smaller heads and kernels, it did not affect the number of seeds borne in the inflorescence. Severe stress during anthesis and seed filling resulted in more empty kernels. Moderate and severe stress during budding significantly lowered both grain and oil yields while plants that experienced moderate stress during anthesis and seed filling significantly outyielded those under severe stress.     

Relationships between seed yield and growth characters,yield components,seed quality of summer-type oilseed rape (Brassica napus L.)

Summary Five genotypes of rapeseed were observed in the field on a single plant and plot basis to evaluate growth characteristics, yield, yield components and seed quality. Observations were made in two years at two locations on three seeding date and three seeding rate treatments. Correlation of seed yield with growth characters demonstrated no consistent trend, indicating that an early maturity and high seed yield should be possible. Harvest index was strongly correlated with seed yield. Percent seed oil and protein were not directly related to seed yield.     

Diallel analysis of sugar composition of 10 vegetable soybean lines

Few studies have evaluated vegetable soybean for sugar content at the green pod stage. Information on combining ability and type of gene action that governs inheritance of seed traits can help breeders to select suitable parents and devise an appropriate breeding strategy. Ten vegetable soybean accessions were crossed in a complete diallel mating design. Parent lines and F₂ and F₃ progenies were evaluated for two nutritional components. In this study, both general and specific combining ability and reciprocal effects were significant for sucrose and total sugar. Cultivars 'Kanrich', 'Pella', 'Verde' and V81-1603 had good general combining ability for high sucrose. In general, high sucrose content was observed in progeny of the early maturity group genotypes 'Kanrich', 'Pella' and 'Verde'. The best combiners for high total sugar content were 'Verde', V81-1603 and PI 399055. These genotypes could serve as genetic sources in a vegetable soybean breeding programme.     

直播种植模式下水稻剑叶光合、强弱势籽粒灌浆特性及产量的氮素调控

为探讨不同施氮水平对水稻剑叶光合、籽粒灌浆特性和产量的影响。以生育期较短的‘新稻567’、‘新稻568’和‘新科稻31’为试验材料,在直播种植模式下,设置3个施氮水平0、255、300 kg/hm²,分别测定抽穗后剑叶光合速率、强弱势籽粒灌浆速率和产量等指标,研究氮肥调控水稻产量的生理机制。结果表明,随着施氮量的增加,3个品种产量均呈先增加后降低的趋势;高效叶面积率和粒叶比表现为中氮水平较高,高氮水平较低。灌浆期剑叶光合速率呈先增加后降低趋势,不同氮肥处理间基本表现为中氮处理高于高氮处理;强弱势籽粒灌浆速率在整个灌浆期内呈开口向下的抛物线趋势,不同氮肥处理间的差异在灌浆盛期至灌浆中后期较大,表现为无氮和中氮处理高于高氮处理,灌浆末期处理间差异较小。产量与灌浆期剑叶光合速率呈正相关关系,与强弱势籽粒灌浆速率在灌浆初期呈负相关在灌浆中后期呈正相关关系。适度的氮肥施用量有利于提高直播水稻高效叶面积率、粒叶比,增加剑叶光合速率、强弱势籽粒灌浆速率,从而促进水稻高产。     

郑单958与先玉335黄淮海北部物候期特点分析

【研究目的】为了实时掌握夏玉米在黄淮海北部生长发育进程,综合评价环境因素对玉米生长发育的影响,调查分析了郑单958与先玉335在北纬37°53′、东经115°42′的物候期特征。夏播玉米郑单958与先玉335播种后6d出苗,生育期间为111d,灌浆期持续66d,叶片展开速率和灌浆速率随温度升高而加速,收获前6d（10月5-11日期间）,郑单958与先玉335产量贡献率分别达6.61%和4.20%。【结论】分析结果认为,黄淮海区域属于一年两熟种植模式,黄淮海北部夏玉米一般不能达到完熟收获。选用中早熟品种,及早抢播、适时晚收,保证玉米充足的有效积温和授粉后充足的灌浆时间可以显著提高玉米产量。     

Breeding for yield in dry bean (Phaseolus vulgaris L.)

Strategies employed by dry bean breeders to improve yield include early generation testing, ideotype breeding, selection for physiological efficiency, and selection based on genotypic performance and combining ability across gene pools of Phaseolus vulgaris. Ideotype breeding has been successfully deployed to improve yield in navy, pinto and great northern seed types. The ideotype method is based on an ideal plant architecture to which breeders target their selection. Breeding for physiological efficiency is important in combining increased biomass, high growth rates and efficient partitioning. Genotypic performance and combining ability are also critical for yield improvement, since crosses between gene pools can exhibit negative combining ability and problems with lethality, whereas interracial crosses within the same gene pool exhibit the greatest potential. Breeders must work within specific constraints for growth habit, maturity, seed quality and disease resistance. A three-tiered pyramidal breeding strategy is proposed to facilitate yield improvement in dry bean. Breeding of elite, agronomically acceptable germplasm within the same market class is restricted to the apex of the pyramid. The intermediate level has fewer constraints and greater access to diverse germplasm. Interracial crosses within the same gene pool are utilized to exploit genetic differences within adapted material. Extracting genetic diversity from unadapted sources, including wild germplasm and other Phaseolus species, is conducted at the base of the pyramid. The objective of this breeding strategy is the movement of improved germplasm towards the apex, using different breeding procedures to optimize improvement at each tier of the breeding pyramid. This revised version was published online in July 2006 with corrections to the Cover Date.     

Heterosis in yield,fiber quality,and photosynthesis of okra leaf oriented hybrid cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.)

Leaf shape is an important factor affecting canopy structure, photosynthetic characteristics, and yield. Introducing okra leaf shape is considered an important strategy in cotton heterosis breeding. The objective of the study was to evaluate the heterosis in okra leaf cotton hybrid F₁s, which were developed by crossing two sterile near isolines and three restorer near isolines. A normal leaf check hybrid F₁, Zhongza 29, and four newly developed okra leaf oriented hybrid F₁s, including the super-okra (severely cleft and narrowly lobed leaf), okra (deeply cleft and narrowly lobed leaf), semi-okra (intermediate leaf lobe), and sub-okra (large leaf lobe) hybrids were selected in this experiment. Okra leaf oriented cotton hybrids significantly reduced leaf area index (LAI) (P < 0.0001), thus more light penetrated into the lower canopy. The LAIs for the super-okra and okra hybrids, however, were too small to supply adequate photosynthate, thus resulting in early maturity, short boll filling period, and low yield. As the LAI increases, the semi-okra and sub-okra hybrids showed certain heterosis. The semi-okra hybrid showed 7–12% heterosis over the check hybrid in lint percent, 6–11% in boll weight, 2–147% in canopy light intensity, 1–10% in net photosynthetic rate (Pn), and −3 to 3% in lint yield. As well, all tested okra leaf hybrids improved fiber quality such as micronaire compared with the normal leaf check hybrid. The results suggested that adopting okra leaf parental lines in cotton breeding provided potentials in increasing fiber quality with comparable lint yield.     

Influence of Solar Radiation and Vapour Pressure Deficit on Transpiration Efficiency of Rainfed Sorghum

Besides assimilation, plant water relations are important aspects of physiological basis of productivity of crops in water limited environment. The relationships of photosynthesis rate, transpiration rate, leaf water potential and stomatal conductance with photosynthetically active radiation (PAR) and vapour pressure deficit (VPD) during pre-flowering (panicle initiation to ear emergence) and grain filling (from anthesis to maturity) stages of a sorghum hybrid (cv. CSH-6 ) grown under rainfed conditions were studied. Photosynthesis rate declined when PAR was above 1300 μmol m⁻² s⁻¹. during both the growth stages. Higher transpiration rate during grain filling stage at higher PAR caused the transpiration efficiency to be lower than during pre-flowering stage when PAR was above 1200 μmol m⁻²s⁻¹.Leaf water potential and stomatal conductance decreased with increase in PAR. Leaf water potential was higher during pre-flowering than during grain filling stage but maximum photosynthesis rate was similar during both the growth stages. Changes in VPD did not qualitatively alter the relationships of the physiological variables with PAR.
Decreasing photosynthesis rate and LWP at high PAR suggest that photosynthesis rate was limited by low leaf water potential when PAR was optimal, and by low PAR even when leaf water potential was high in rainfed sorghum during rainy season.