长江中下游地区不同穗型中籼杂交稻高产群体农艺特征

探明长江中下游地区不同穗型中籼杂交稻产量成因及高产品种群体共性特征。以120个中籼杂交稻为材料,于2019—2020年在安徽舒城农科所开展品种评比试验,并根据每穗粒数排序将供试品种均分为大穗型(193～270)、中穗型(167～191)和小穗型(108～166) 3类,比较不同穗型中籼杂交稻的产量及构成、生育进程、日产量、叶面积指数、生物量和穗型结构的差异。结果表明,各穗型下水稻产量变幅均较大,通过聚类分析可进一步分别分为高产、中产和低产3种类型。高日产量是不同穗型品种高产共性指标,其中大穗型与增加叶面积指数有关,而中、小穗型可能与促进光能转化效率有关。除日产量外,不同穗型品种高产形成极具差异。从产量构成来看,大穗型品种主要依靠有效穗数、每穗粒数和千粒重来增产;中穗型品种为有效穗数和结实率;而小穗型品种为有效穗数、每穗粒数和结实率,这种穗型间的差异与分类方法和大穗型水稻灌浆障碍有关。从物质积累来看,与小穗型高产品种较高的收获指数不同,大、中穗型水稻要依靠生物量增加来提高产量。各穗型下不同产量水平的穗位枝梗分布与穗长均无显著差异。主成分分析发现,大穗型高产品种主要表现为日产量高、生物量大...     

品种类型与营养生长积温对小麦穗部性状的影响

大穗型，中间型和多穗型品种具有各自不同的穗、粒、重间的协调平衡关系。以高产为目标，最适穗容量平衡点呈多穗型＞中间型＞大穗型。营养生长基础对群体穗粒重的效应为多穗型＞大穗型＞中间型。穗粒数的增加是提高穗粒得的有效途径，增加小穗数／穗对高结实率品种 有效，减少不孕小穗数／穗对环境敏感型品种效应显著。     

云南籼稻每公顷15吨高产的产量及其结构分析

本文利用ＩＲ７２汕优６３等材料,在云南永胜县涛源乡高产环境下,对高产品种的产量及其构成因素分析研究表明,高产品种的结实率与产量呈极显著的正相关,相关系数为０．８１８１;有效穗与穗粒数呈显著负相关,有效穗、穗粒数、结实率和千粒重对产量的直接效应均为正值,其中以结实率的影响力最大,直接通径系数为０．７９７９。穗数、大穗型和中间型的品种（组合）均能获得１５t/hm^2的产量,但穗粒协调的中间型品种更易获得１５t/hm^2的高产。云南涛源获得每公顷１５t以上产量就在于高水平的穗数群体下,仍能协调与穗粒数及产量的关系。使得粒数和粒重达到相当的水平,１９９６年汕优６３获得１５t/hm^2产量的产量结构为,每平方米穗数489,每穗实粒数101．4千粒克30．7g;桂朝2获15．18t/hm^2的产量结构为每平方米穗数433,每穗实粒数126．2,千粒重27．3g。     

大穗型小麦穗粒重分布规律及相互关系探讨

通过分析大穗型小麦穗粒重分布特征及粒数与粒重之间的关系,表明:(1)大穗条件下穗粒数和粒重之间呈二次曲线关系,与单穗重呈极显著正相关关系,不同年度之间极值相近;(2)随着每小穗结实粒数增加,每小穗平均粒重增加,二者呈极显著线性正相关,但不同花位粒重变异幅度增大,籽粒整齐度变小;(3)不同结实粒数的小穗每花位籽粒重表现出一定的规律:当每小穗结实粒数为2时,以第1粒粒重最大,当每小穗结实粒数为3、4、5时,以第2粒粒重最大,当每小穗结实粒数为6、7时,以第3粒粒重最大,当每小穗结实粒数为8时,以第4粒粒重最大.     

河南小麦品种穗粒数性状的动态变化及全基因组关联分析

穗粒数是小麦产量构成的重要因子,研究小麦穗粒数及其相关性状的变化规律与遗传机制对于高产育种具有指导意义。以198份河南种植或审定的小麦品种(系)为材料,在4个环境下鉴定穗粒数相关性状表现,选用660K SNP芯片检测材料的基因型并进行全基因组关联分析。发现穗粒数存在着广泛的变异,穗粒数、穗长、总小穗数、可育小穗数和不育小穗数的广义遗传力分别为77.43%、87.54%、85.45%、79.70%和68.08%,2002年以前、2003-2008年、2009-2014年和2015年以来育成品种的平均穗粒数分别为35.71个、36.85个、37.40个和37.98个,随着育种时期的推进总小穗数和可育小穗数也表现出逐渐提高的趋势。共发现41个和穗粒数等性状相关联的位点,分布在除了1D、3A、3D、4B和4D的16条染色体上,单个关联位点的表型变异贡献率(R2)范围为6.19%~20.83%,其中10个位点至少在2个环境中稳定表达。对关联位点进一步分析发掘了多个与穗粒数性状相关的优异等位变异,如7A上AX-109368219(A)能增加穗粒数1.86粒,2A上AX-111674224(C)能提高总小穗数0.96个,2D上AX-111582877(G)能提高可育小穗数0.73个。研究揭示近五十年河南小麦穗粒数性状的动态变化及其规律,获得了多个和穗粒数等性状关联位点及等位变异,为小麦产量性状的遗传改良及分子设计育种提供了技术支持和基因资源。     

冬小麦边际效应研究Ⅰ.品种与小麦边际效应相关规律

该研究在高产田条件下，选择了产量潜力高但植株性状及产量构成显著不同的少穗大穗型核生2号、多穗小穗型烟农15及中间类型的泰876161品系，进行了品种-空背宽度-边际效应相关规律的研究，结果表明：（l）在间套行较窄的情况下，选择多穗小穗型品种有利于发挥边行增产作用，在间套行较宽的情况下，选择中穗或大穗型品种则更有利于发挥边行小麦的增产效果；（2）边行小麦增产，大穗型核生2号以增加穗数为主要特征，小穗型烟农15以增加穗数和穗粒数为主要特征，中间型的泰876161则是相对的穗数、粒数与粒重协调增加；（3）随空背宽度加宽，边行增产幅度提高，大穗型核生2号是增穗为主，穗粒数比重不变，粒重比重下降；小穗型烟农15是穗粒数比重提高，穗数比重持平，粒重比重下降，中间型泰87616正则是穗数、粒数比重协调增加，粒重比重下降；（4）边2行小麦的增产作用与品种和边1行的增产幅度相关，40cm空背下，少穗大穗型核生2号边2行增产幅度最高，其次是中间型泰876161，多穗小重型烟在15几乎无增产效果，空背加宽，边1行增产幅度提高，使边2行的增产幅度下降，甚至减产，100cm空背下，大穗型核生2号边2行较内行稍有增产，而小穗型烟农15和中间型泰876161则边2行出现减产，以边1行增产幅度最大的泰8761     

小麦产量及其构成因素的育种分析

本文介绍了１９９４年１９９５年两年的研究结果；小麦产量构成因素为穗数，千粒重和穗粒重，而粒数又受有效小穗数的多少和每小穗粒数所制的，其中穗数多少，又与有效分蘖存在密切关系。有效分蘖数与有效穗数呈极显著正相关，粒数与千粒重呈负相关，穗数与粒数呈显著负相关。通过北项研究在小麦育种中合理地协调产量三要素的关系，选育高产品种提供依据。     

洛旱2号的丰产性、稳产性、抗旱性及产量结构分析

对1997-2000的区试试验和品种比较试验结果进行统计分析，结果表明小麦品种洛旱2号丰产性好，稳产性突出，抗旱性明显优于对照豫一等奖号，是一个产量高而稳、抗旱性突出的旱地小麦新品种。通过对不同产量水平下的产量结构进行分析，得出洛旱2号的产量构成最佳模式为：公顷穗数525-600万/hm^2，穗粒数30-32粒，千粒重37-40克。对其产量构成要素与产量的通径分析表明：洛旱2号的高产栽培技术途径是在保证足够穗数的基础上，提高小穗结实率，增加穗粒数，稳定千粒重，充分发挥其丰产性。     

沿江双季稻北缘区晚稻适宜品种类型及高产群体特征

研究沿江双季稻北缘区晚季籼稻和粳稻产量差异,明确适宜类型品种及高产形成机制。试验于2018—2019年在安徽庐江进行,以当地常规种植的17个籼稻和17个粳稻优质品种(系)为研究对象,比较和分析籼稻和粳稻在产量及构成、物质积累和生育进程方面的差异。结果表明,粳稻与籼稻总体上产量水平相当,但粳稻产量限制因子少,安全齐穗性有优势,具有更高的产量稳产性和生态安全性。高产粳稻主要是通过增加移栽–抽穗期干重来增加总干物质积累,以提高总颖花量和产量。不同穗型粳稻品种生育前中期不同阶段的干物质积累对总颖花量的影响差异较大,其中大穗型(每穗粒数102.3～112.0)和小穗型粳稻(每穗粒数52.0～99.7)干物质优势积累期分别为移栽–穗分化期和穗分化期–抽穗期,与总颖花量的相关系数达到0.709和0.829。进一步分析发现,大穗型粳稻品种移栽–穗分化期干物质积累受穗分化期分蘖数显著影响,而小穗型粳稻品种穗分化–抽穗期干物质积累由抽穗期分蘖数和单茎干重共同影响。综上所述,本研究认为粳稻是沿江双季稻北缘区适宜的双季晚稻品种类型,高产粳稻群体颖花量为33.8×10~3～41.0×10~3 m^–2<...     

新型斐特有机肥在小麦上的应用效果研究

研究表明：各试验处理的产量差异较大。（1）浇水条件下施25kg/667m2生物肥＋2/3传统施肥的产量最高,为345.3kg/667m2,较对照增产6.5%,达显著水平,其成产三因素较为协调。（2）不浇水条件下施25kg/667m2生物肥＋2/3传统施肥的产量最高,为338.5kg/667m2,较对照增产5.9%,达显著水平,其穗数为45.4万/667m2,穗粒数为24.9个/穗,千粒重较大,为36.9g,成产结构较为协调。（3）浇水处理的株高、穗长和小穗数明显高于不浇水处理,不孕小穗数差异不明显。处理W6和W5,5和6的株高、不孕小穗数较其它处理低,小穗数个数较其它处理高,穗长差异不明显。浇水处理利于冬小麦生长。     

北京地区冬小麦品种冠层结构的研究

1983～85年对本地区22个冬小麦品种的产量及其构成因素与上部三个节的茎、叶和穗部性状的关系进行了研究。结果表明,在产量水平为5～6吨/公顷时,决定产量的主导因素是穗粒重,其中千粒重和穗粒数的贡献大体相同。上部三个叶片性状有较大的一致性,旗叶宽、面积、绿色面积持续期对穗粒数、粒重、穗粒重有中度正相关,其中叶宽影响较大;但与穗数/米~2呈中度负相关,因而与产量表现为一定程度的正相关。茎、鞘直径与产量构成因素关系比长度密切,上部茎节直径影响也比下部大。逐步回归分析表明决定产量的还是产量构成因素本身,旗叶性状居从属地位,其中开张角、基角和叶宽对千粒重的影响较大。将产量居前五名品种的主要性状平均值与由曲线回归方程计算而得的“最优值”相比较,二者基本一致。据此提出选育产量潜力为6吨/公顷上下品种时可加考虑的冠层性状指标。     

北方冬麦区高肥区域试验品种产量性状分析与探讨

对北方冬麦区1983～1988年高肥区域试验的80个参试品种的产量性状进行相关与通径分析。结果表明,北部冬麦区和黄淮麦区北片参试品种的增产因素主要是穗粒重,其次是亩穗数;黄淮南片参试品种的穗粒重与亩穗数对产量的贡献几乎相等,亩穗数稍大于穗粒重。鉴于直线相关是有一定范围的,结合各片的生态条件及育种实践,认为培育400公     

绵麦系列小麦品种（系）的农艺性状和品质性状分析

为利用好小麦资源材料,对19份绵麦系列小麦品种（系）的农艺性状和品质性状等15个性状进行分析。结果表明,农艺性状与品质性状间有着复杂的相关关系,有13对性状表现为显著或极显著相关,有23对性状表现为显著或极显著偏相关。产量与8个农艺性状的关联系数的序次为：基本苗>千粒重>穗粒数>容重>株高>最高苗>生育期>有效穗;产量与6个品质性状的关联系数的序次为：稳定时间>最大阻力>籽粒蛋白>面积>吸水率>湿面筋;蛋白质与9个农艺性状的关联系数的序次为：最高苗>有效穗>基本苗>穗粒数>产量>容重>千粒重>株高>生育期;稳定时间与9个农艺性状的关联系数的序次为：容重>最高苗>产量>生育期>有效穗>千粒重>株高>基本苗>穗粒数;面积与9个农艺性状的关联系数的序次为：基本苗>穗粒数>千粒重>产量>株高>最高苗>有效穗>生育期>容重。供试材料从农艺性状和品质性状可被聚为三类,第Ⅰ_2、Ⅰ_3、Ⅰ₄类育种时可以作为高产材料加以应用,同时Ⅰ₃和Ⅰ₄类群育种时可以作矮杆材料加以运用;Ⅰ₁和Ⅰ₄类群育种时可以作为优质品质材料加以运用。第Ⅱ类育种时可从粒重方面加以应用;第Ⅲ类从优质矮杆材料加以应用。     

The stability of the number of tillers of barley varieties and its relation with consistency of performance under semi-arid conditions

Summary In 1981/82 60 barleys varieties were grown at 18 environments (three locations, three seed rates, two soil fertility regimes) and in 1982/83 22 varieties were grown again at 21 environments (seven locations, three seed rates). Grain yield was recorded only in the second year. The estimates of variances s_x ² (untransformed data) and s² _logx (transformed data) for number of tillers and grain yield varied significantly among varieties. When untransformed data were used, high tillering varieties had a higher variance for number of tillers per unit area than low tillering varieties. When the variation was measured by CV of untransformed data or by s² _logx on transformed data a reverse relation occurred, i.e. the correlation coefficient between number of tillers and the variation of number of tillers was negative.High grain yielding varieties had a high mean number of tillers and a low variance for number of tillers per unit area when transformed data were used to compute variances. All interactions between variety, seed rate and location for grain yield were significant. The regression analysis of variety grain yield (Y) on environment mean grain yield (X) gave regression coefficients, b, ranging from 0.51 to 1.69. There was no significant correlation between regression coefficient and grain yield. The highest yielding varieties had b values around 1.0. High grain yielding varieties had low variance of yield over environments and low values for deviations from the regression when transformed data were used. However, the correlations between mean yield and variance for yield or mean yield and deviations from regression were positive when untransformed data were used.From this study it is concluded that high mean number of tillers per unit area and low variance for number of tillers could be used in selecting varieties with consistently high yield at varying environments. Techniques are proposed for application early in the breeding programme, i.e. in segregating population or in nurseries.     

杂交水稻籽粒比重与产量品质性状相关分析及其在育种中的应用

为了探究杂交水稻籽粒的比重与产量因素及品质因素相关性,以高产优质品种天优华占为对照,对7个三系不育系与5个自选恢复系进行杂交配组后得到组合的单株穗数、每穗总粒数、籽粒体积、比重、充实度、千粒重等进行研究。结果发现,千粒重是影响产量的最大因素,其次是单株穗数；籽粒比重的提高可以提高整精米率和降低垩白度,从而改善水稻的产量和品质。研究认为,杂交稻水稻的选育中,籽粒较大的情况下兼顾单株穗数和充实度,且单方面强调通过增加粒重去提高产量会导致整精米率降低,因此为兼顾产量与品质,籽粒比重适中为宜。     

Yield and Agronomic Characters of Tropical Maize (Zea mays L.) Cultivars under Different Irrigation Regimes

Drought spells are unpredictable under tropical conditions and can occur at every growth stage of the maize plants. Little is known about the reactions of tropical maize cultivars to water shortage. A set of Thai cultivars was examined in the field during the dry season. Three stress situations were imposed: prolonged stress throughout the growing season, pre- and post-anthesis stress. Pre-anthesis water stress delayed flowering and especially the data of silking. Thus, the anthesis-silking interval was wider. Prolonged water stress decreased grain yield mainly due to a low number of kernels and/or thousand kernel weight (TKW). Post-anthesis stress mainly reduced TKW grain set per ear. Relief from pre-anthesis stress increased grain yield by a grater number of kernels and higher TKW as compared to prolonged stress. Genotypic differences were high for the anthesis-silking interval following pre-anthesis stress. Low yielding, early but generally drought-stable cultivars existed as well as cultivars which were generally high yielding even under water stress because of a good residual yield. Some cultivars were resistant to pre-anthesis stress but not to post-anthesis stress and vice versa. It can be concluded that ample genotypic variability exists for adaptation to varying situations of pre-and post-anthesis stress within tropical maize cultivars.     

Genetic variation,heritability and path-analysis in landraces of bread wheat from southwestern Iran

Summary Nine pure lines of bread wheat collected from landraces of southwestern Iran and one local Iranian cultivar from the same area were used to estimate genetic variation and heritability for 12 developmental and yield component characters. Path-analysis was used to partition the genetic correlations between some of the characters into direct and indirect effects. Mean values for these lines were also compared with those of five improved cultivars from Iran and California. The goal of the experiment is to breed improved landraces and/or modern cultivars for areas of low input agriculture in southern California, southwestern Iran, and regions with similar environmental and agronomic conditions.Moderate genetic variation was displayed by the number of effective heads per plant, number of grains per head, and grain weight in the landrace genotypes. The heritability estimates ranged from 43 to 97%. Expected genetic advance with selection of the highest 5%, expressed as percent of the mean, was around 20% for number of heads per plant, number of grains per head, and 1000-grain weight.Days to booting, to heading, and to anthesis were positively correlated but none of them were significantly associated with days to maturity. Plant height had a negative genetic correlation with number of grains per head, 1000-grain weight, grain yield, and harvest index. The genetic correlation between number of heads per plant and number of grains per head, 1000-grain weight, and harvest index was also significantly negative. Harvest index had a negative genetic correlation with days to booting, to maturity, plant height, number of heads per plant, and straw yield and a positive correlation with number of grains per head, 1000-grain weight, and grain yield.Days to maturity, plant height, number of heads per plant, number of grains per head, 1000-grain weight, and harvest index each had a positive direct effect on grain yield. The first two characters exhibited the highest and lowest direct effects, respectively. The positive direct effects of days to maturity, plant height, and number of heads per plant, however, were partially or completely counter-balanced by their strong negative indirect effects through number of grains per head, 1000-grain weight, and harvest index. Pathanalysis indicated that late and tall landrace genotypes tend to produce more heads per plant, but with fewer number of grains per head, smaller grains, and lower harvest index.Comparisons between the local lines and the improved cultivars revealed that, in general, the former were much taller and produced a larger number of non-effective tillers. Mean number of grains per head, grain weight, harvest index, and grain yield of local lines were smaller than those of improved cultivars.Our observations indicate that the landraces could be improved by selecting for shorter genotypes with smaller numbers of tillers per plant, but with larger numbers of grains per head and heavier grains.     

山西省近年审定小麦品种的综合性状分析

为给小麦育种和生产提供借鉴,对2013-2017年山西省审定的41个小麦品种进行产量、品质与抗病性分析。结果表明,各麦区审定小麦品种平均产量年度间虽有波动,但总体均呈逐步上升趋势。南部水地和中部水地审定小麦品种产量三因素中穗数变异系数均为最大,南部旱地和中部旱地审定品种则是穗粒数变异系数均为最大,因此,水地小麦育种应在提高穗数的基础上,协调提高穗粒数和千粒重;旱地小麦育种应在提高穗粒数的基础上,提高穗数和千粒重。从品质类型看,强筋和中强筋小麦比例很少,中筋小麦比例较多,区组间品质差别较大,达标品种（包括强筋、中强筋和中筋）比例由高到低的顺序依次为南部水地>南部旱地>中部水地>中部旱地。审定品种的蛋白质和湿面筋含量指标均相对较高,但有61.0%的品种面团稳定时间较短,低于中筋小麦标准,故应把提高面团稳定时间作为品质育种的主攻方向。山西省近年审定品种总体的抗病性较差,没有兼抗两种病害的品种,条锈病、叶锈病和白粉病抗病品种占审定品种比例分别为2.4%、0和12.2%。需要引进抗病资源,同步提高产量和品质水平,培育优质、高产、多抗的小麦新品种。     

CIMMYT 145份小麦种质资源的鉴定及杂交利用

为了拓宽和丰富小麦种质资源遗传多样性,提高小麦产量和品质,在大田对国外引进的145份小麦种质资源进行了农艺性状和品质性状的鉴定和评价。结果表明,这些材料基本属弱春性类型。在山西南部麦区,可推迟播期于10月下旬种植,作为育种材料利用。主要农艺性状的单株穗数、穗粒数、千粒重和产量变异系数分别为15.7%、16.03%、12.23%和23.96%,多数材料籽粒综合品质较好,尤其面筋品质好,筋力强。这些材料的农艺性状和品质性状具有丰富的遗传多样性。株高和千粒重与产量的相关系数最大,分别为0.5032和0.4178,达极显著水平,是提高产量的关键因素。综合3年试验结果,筛选出产量超过3750 kg/hm2有32份,鉴选出8个组合的相应强筋力品系和35个综合性状表现较优异品系,其突出优异性状表现植株穗大,小穗结实好,穗粒多,可作为小麦育种的重点种质材料利用。通过播期调节花期,利用CIMMYT材料合理杂交配组,已选育至F3代、BC2F1代和BC1F1代,有望育成优质大穗丰产抗旱创新材料及新品系。