0 引言
【研究意义】收获期玉米籽粒含水率是影响机械粒收质量的关键指标[1,2,3,4],生理成熟前后籽粒含水率变化主要由水分散失速率主导,苞叶、籽粒、穗轴和穗柄等穗部性状与籽粒水分散失密切相关。通过研究穗部性状对籽粒脱水速率的影响,筛选能够用于适宜粒收品种选育的鉴定指标,对于选育籽粒脱水速率快、收获期含水率低的品种,推广机械粒收技术具有重要意义。【前人研究进展】前人研究了不同穗部性状对籽粒含水率变化的影响,主要结论有以下几点：（1）表征苞叶性状的指标中,大多****认为苞叶脱水速率快、层数少、长度短、宽度小、面积小、干重低、松紧程度低等有利于籽粒脱水[5,6,7,8,9,10];而张林等[11]研究认为,苞叶层数和厚度与收获期籽粒含水率没有显著相关性。（2）有关果穗形态的指标,多数研究认为穗轴脱水速率与籽粒脱水速率显著正相关[8],果穗长度、果穗直径、穗轴直径等与收获期籽粒含水率显著正相关,即果穗短、果穗细、穗轴细有利于籽粒脱水,收获期籽粒含水率低[11,12,13,14,15,16,17];而张春荣等[18]研究认为,穗轴直径与收获期籽粒含水率显著负相关,张立国等[19]研究表明,果穗直径大反而有利于生理成熟后籽粒脱水。（3）百粒重、穗行数、行粒数、籽粒宽度、籽粒长度等有关籽粒性状的指标与籽粒脱水速率显著相关,但是****之间的研究结果存在差异[8,11,14,16-17,19-20]。【本研究切入点】前人研究主要以亲本及杂交组合为供试材料,各****研究的穗部指标不尽相同,且多集中于测产考种项目,研究结果受所用材料、环境因素及分析方法等条件的限制,不同研究结论存在差异甚至矛盾。本研究以黄淮海夏玉米区当前生产中的主栽品种为试验材料,在相同栽培管理条件下,选用包含苞叶、籽粒、穗轴、穗柄等41个性状指标,系统分析不同穗部性状在品种间的差异及其与籽粒脱水速率之间的关系。【拟解决的关键问题】通过本研究,辨析影响籽粒脱水速率的主效因素,筛选能够用于选育和鉴定籽粒脱水特征的关键指标,为适宜机械粒收技术的品种选育和筛选提供理论支持。1 材料与方法
1.1 试验设计
试验于2015和2016年在中国农业科学院作物科学研究所新乡综合试验站（N 35°10′,E 113°47′）进行,2015年种植11个品种,6月16日播种;2016年种植17个品种,6月4日播种（表1）,2年共有6个品种为重复测定品种。所选品种为黄淮海夏玉米区应用面积较广的品种,大区种植,每区宽7.8 m、长18.0 m,面积140.1 m2,种植密度75 000株/hm2。播后浇蒙头水,以保证出苗整齐,生育期施肥、灌水、植保等管理措施同大田。各区选择无病虫害、长势均匀一致的植株200株进行标记,吐丝前对雌穗做套袋处理,吐丝后统一授粉,确保测定植株授粉日期一致。取样时以多株果穗为重复样本。Table 1
表1
表1玉米品种信息
Table 1Information of maize cultivars
| 序号 Number | 品种 Cultivar | 种植年度 Year | 亲本 Parent |
|---|---|---|---|
| 1 | 郑单958 ZD958 | 2015、2016 | 郑58×昌7-2 Zheng58×Chang7-2 |
| 2 | 先玉335 XY335 | 2015、2016 | PH6WC×PH4CV |
| 3 | 农华101 NH101 | 2015、2016 | NH60×S121 |
| 4 | 农华816 NH816 | 2015、2016 | 7P402×B8328 |
| 5 | 京农科728 JNK728 | 2015、2016 | 京MC01×京2416 Jing MC01×Jing 2416 |
| 6 | 中单909 ZD909 | 2015、2016 | 郑58×HD586 Zheng58×HD586 |
| 7 | 裕丰303 YF303 | 2015 | CT1669×CT3354 |
| 8 | 联创808 LC808 | 2015 | CT3566×CT3354 |
| 9 | 中科玉505 ZKY505 | 2015 | CT1668×CT3354 |
| 10 | 禾田1号 HT1H | 2015 | B10194×合344 B10194×He344 |
| 11 | 宁玉721 NY721 | 2015 | 宁晨26×宁晨137 Ningchen26×Ningchen137 |
| 12 | 华美1号 HM1H | 2016 | HF12202×HM12111 |
| 13 | 真金323 ZJ323 | 2016 | H351×Z962 |
| 14 | 新单58 XD58 | 2016 | 新09美×新3782 Xin09mei×Xin3782 |
| 15 | 新单65 XD65 | 2016 | 新026×新3782 Xin026×Xin3782 |
| 16 | 辽单575 LD575 | 2016 | 辽3358×辽3258 Liao3358×Liao3258 |
| 17 | 锦华318 JH318 | 2016 | 7P402×L9097 |
| 18 | 锦华207 JH207 | 2016 | 京X005×京147 Jing X005×Jing147 |
| 19 | 金通152 JT152 | 2016 | NY60×B8328 |
| 20 | 迪卡517 DK517 | 2016 | D1798Z×HCL645 |
| 21 | 陕单636 SD636 | 2016 | KA103×KB043 |
| 22 | 丰垦139 FK139 | 2016 | K334×K454 |
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1.2 籽粒、苞叶、穗轴和穗柄含水率动态测定及脱水速率计算
选择有标记植株,取包含穗柄和苞叶的完整果穗,将果穗分为苞叶、穗柄、穗轴、中部百粒和剩余籽粒5部分,分别称量鲜重,然后在烘箱中85℃烘干至恒重后,称量各部分干重。以乳线消失、黑层完全形成为生理成熟的判定依据,记录各取样植株的生理成熟日期。生理成熟前每5 d取一次样,接近生理成熟期取样间隔缩短至1—3 d,生理成熟后恢复为每5 d取一次样,遇降水天气取样延后1 d。2015年从授粉后26 d开始取样,每次取9个果穗,至11月14日止;2016年从授粉后11 d开始取样,每次取5个果穗,至10月17日止,测定籽粒、苞叶、穗轴和穗柄含水率动态变化。为避免品种熟期不同造成的含水率差异,本研究将各品种生理成熟后第N天（第10—15 天中某一测试当天）规定为其收获期。含水率计算公式为：
\[含水率(\%)= \frac {鲜重（g）-干重（g）}{鲜重}×100\]
籽粒脱水速率：以单位积温含水率降低值表示,
单位为%·(℃·d)-1,生理成熟前籽粒平均脱水速率、生理成熟后籽粒平均脱水速率和籽粒总脱水速率的计算公式参！！！考！！！文！！！献[21]。
穗轴脱水速率：以穗轴最大含水率与收获期穗轴含水率的差值除以二者之间的积温计算。
穗柄脱水速率：以穗柄最大含水率与收获期穗柄含水率的差值除以二者之间的积温计算。
苞叶脱水速率：苞叶含水率随着授粉后积温的动态变化用分段函数模型拟合,公式如下：
式中,MC为因变量,表示含水率,%;T为自变量,表示授粉后积温,℃·d;n1、n2分别为模型自变量的分段点;a、b、k、c均为模型参数,a代表苞叶最大含水率,c代表苞叶最小含水率,k代表苞叶脱水速率。2016年,17个品种拟合的R2值均在0.970—0.996;由于2015年取样起始日期较晚,苞叶含水率动态变化未用此模型拟合。
1.3 穗部其他性状测定方法
苞叶层数：采用从外至内逐层数计的方法,苞叶内层包裹不足半圈的不计为1层。于2015年10月26日,每个品种取连续10株的果穗,数计苞叶层数。于2016年8月5日至9月20日,每隔5 d左右测定一次,每品种每次取5个果穗,数计苞叶层数。苞叶厚度：每个果穗从外至内逐层取下约1 cm×2 cm大小的苞叶,叠加后,用电子游标卡尺测叠加部分的厚度,作为该果穗的苞叶厚度。于2016年8月5日至9月20日,每隔5 d左右测定一次,每个品种每次取5个果穗,测定苞叶厚度动态变化。文中苞叶最大厚度和最小厚度均以实测值表示。
苞叶面积：以苞叶长度、宽度和苞叶面积系数的乘积计算苞叶面积。苞叶长度和宽度的测定以每张苞叶的最长和最宽值为标准。于2015年10月26日每个品种取连续10株的果穗,2016年10月15日每个品种取连续5株的果穗,用刻度尺分别测量每张苞叶的长度和宽度。苞叶面积系数的确定参考叶面积系数的计算方法[22],于2016年完成各品种苞叶长度和宽度测量后,使用UNIS-B600扫描仪逐层扫描相应苞叶,获得单层苞叶图像,使用ImageKS1.0.0.0对扫描后的图像进行识别,获取每张图像的苞叶面积,累加后计算整个果穗的苞叶面积,将图像识别得到的果穗苞叶面积与相应果穗的长度与宽度乘积之和相除,得到比值,即为苞叶面积系数。经计算,苞叶面积系数为0.65 ± 0.04,用该值计算苞叶面积：
苞叶面积(m2)=苞叶长度(m)×苞叶宽度(m)×0.65
比苞叶重：参考比叶重[23]计算方法,以单位面积苞叶干重表示比苞叶重,g·m-2。于2015年10月26日,每个品种取连续10株果穗,2016年10月15日每个品种取连续5株果穗,将每个果穗的苞叶在烘箱中85℃烘干至恒重后称重,用相应的苞叶面积计算比苞叶重。
苞叶蓬松度：在大田自然状态下,用电子游标卡尺测定果穗外层苞叶的最大距离（苞叶松散状态下）,然后将游标卡尺拉紧,使苞叶收缩,记录苞叶被卡紧后的数值,二者的比值为苞叶蓬松度。于2015年10月22日,在田间各个品种选择连续10株果穗,测定苞叶蓬松度。
果穗夹角：在大田自然状态下,用电子量角器测定各个品种连续10株的果穗与茎秆之间的夹角,平均值计为该品种的果穗夹角。于2015年10月22日、2016年9月19日测定。
果穗长度、果穗直径、穗轴直径、穗粒数、穗行数、穗柄长度：于2015年10月26日,2016年10月13日,每个品种选择10个代表性果穗,用刻度尺分别量取每穗的穗长,用电子游标卡尺测定果穗和穗轴直径,记录每穗的穗行数和行粒数,计算穗粒数。其中,2015年用刻度尺测定了每个品种的穗柄长度。
籽粒长度：籽粒长度以中部果穗直径与穗轴直径的差值表示。
果穗、穗轴体积：将果穗、穗轴近似为圆柱体,计算体积：
单粒所占空间：单个籽粒拥有的空间大小：
\[单粒所占空间(cm^3)= \frac {果穗体积（cm^3）-穗轴体积（cm^3）}{穗粒数}\]
本文采用的穗部指标见表2。
Table 2
表2
表2穗部指标及其简称
Table 2Ear parameters and their abbreviations
| 序号 Ordinal number | 指标 Parameter | 简称 Abbreviation |
|---|---|---|
| 1 | 苞叶层数Bract number | BN |
| 2 | 苞叶最大厚度Max thickness of bract (mm) | BTmax |
| 3 | 苞叶最小厚度Min thickness of bract (mm) | BTmin |
| 4 | 苞叶面积Bract area (m2) | BA |
| 5 | 苞叶面积/果穗表面积 Bract area/ear area | BA/EA |
| 6 | 苞叶长度Bract length (cm) | BL |
| 7 | 苞叶长度/果穗长度 Bract length/ear length | BL/EL |
| 8 | 比苞叶重Bract relative weight (g·m-2) | BRW |
| 9 | 苞叶蓬松度 Fluffy degree of bract | BFD |
| 10 | 苞叶生理成熟期干重Bract dry weight at physiological maturity (g) | BDWpm |
| 11 | 苞叶生理成熟期鲜重Bract fresh weight at physiological maturity (g) | BFWpm |
| 12 | 苞叶生理成熟期含水率Bract moisture content at physiological maturity (%) | BMCpm |
| 13 | 苞叶生理成熟期含水量Bract moisture at physiological maturity (g) | BMpm |
| 14 | 苞叶最大鲜重Max fresh weight of bract (g) | BFWmax |
| 15 | 苞叶最大含水量Max moisture of bract (g) | BMmax |
| 16 | 苞叶最大含水率Max moisture content of bract (%) | BMCmax |
| 17 | 苞叶最小含水率Min moisture content of bract (%) | BMCmin |
| 18 | 苞叶脱水速率Dehydration rate of bract (%·(℃·d)-1) | BDR |
| 19 | 果穗长度Ear length (cm) | EL |
| 20 | 果穗直径Ear diameter (cm) | ED |
| 21 | 穗轴直径Cob diameter (cm) | CD |
| 22 | 果穗夹角Ear angle (°) | EA |
| 23 | 果穗体积Ear volume (cm3) | EV |
| 24 | 穗轴体积Cob volume (cm3) | CV |
| 25 | 穗轴最大含水量Max moisture of cob (g) | CMmax |
| 26 | 穗轴最大含水率Max moisture content of cob (%) | CMCmax |
| 27 | 穗轴生理成熟期含水量Cob moisture at physiological maturity (g) | CMpm |
| 28 | 穗轴生理成熟期含水率Cob moisture content at physiological maturity (%) | CMCpm |
| 29 | 穗轴脱水速率Dehydration rate of cob (%·(℃·d)-1) | CDR |
| 30 | 穗柄长度Ear-pedicel length (cm) | EPL |
| 31 | 穗柄最大含水率Max moisture content of ear-pedicel (%) | EPMCmax |
| 32 | 穗柄生理成熟期含水量Ear-pedicel moisture at physiological maturity (g) | EPMpm |
| 33 | 穗柄生理成熟期含水率Ear-pedicel moisture content at physiological maturity (%) | EPMCpm |
| 34 | 穗柄脱水速率Dehydration rate of ear-pedicel (%·(℃·d)-1) | EPDR |
| 35 | 穗粒数 Grain number per ear | GNPE |
| 36 | 穗行数 Rows per ear | RPE |
| 37 | 籽粒长度Grain length (mm) | GL |
| 38 | 果穗周长/穗行数Ear perimeter/ rows per ear (mm) | EP/RPE |
| 39 | 果穗长度/行粒数Ear length/grain number per row (mm) | EL/GNPR |
| 40 | 单粒所占空间Space of single grain (cm3) | SSG |
| 41 | 生理成熟期百粒干重100-grain dry weight at physiological maturity (g) | 100GDWpm |
| 42 | 生理成熟期籽粒含水率Grain moisture content at physiological maturity (%) | GMCpm |
| 43 | 收获期籽粒含水率Grain moisture content at harvest (%) | GMCh |
| 44 | 生理成熟前籽粒脱水速率Grain dehydration rate before physiological maturity (%·(℃·d)-1) | GDRbpm |
| 45 | 生理成熟后籽粒脱水速率Grain dehydration rate after physiological maturity (%·(℃·d)-1) | GDRapm |
| 46 | 籽粒总脱水速率Total dehydration rate of grain (%·(℃·d)-1) | GTDR |
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1.4 数据处理
用Excel 2007和SPSS 16.0进行数据整理和分析,相关分析结果用Pearson相关系数表示,显著性检验采用Two-tailed检验;方差分析采用Duncan的SSR法检验差异显著性。本研究气象资料下载自中国气象数据共享服务网[24]发布的中国地面气候资料日值数据集（V3.0）,采用距试验点直线距离24.5 km的新乡站（53986）数据。
2 结果
2.1 不同品种穗部性状
调查范围内,表征苞叶特性的18个指标在品种间均有极显著差异（表3）。2年供试品种的苞叶层数在8—11层之间;“苞叶面积/果穗表面积”的变化范围为3.8—8.2;“苞叶长度/果穗长度”的变化范围为1.2—1.7;生理成熟期苞叶含水率为6.34%—31.56%;2016年苞叶脱水速率为0.069—0.128 %·(℃·d)-1。表征果穗性状的11个指标和表征穗柄性状的5个指标在品种间均有极显著差异（表4）。其中,供试品种生理成熟后果穗夹角的变化范围为14.2°—30.7°;穗轴生理成熟期含水率为50.12%—65.67%;穗柄生理成熟期含水率为75.80%—83.65%;2016年穗轴脱水速率变化范围为0.017—0.033%·(℃·d)-1,穗柄脱水速率为0.003—0.011%·(℃·d)-1。
表征籽粒性状的指标在品种间也存在极显著差异（表5）。其中,籽粒长度的变化范围为16.3— 27.4 mm;生理成熟期籽粒含水率为21.54%—33.05%;收获期籽粒含水率为15.65%—26.29%;籽粒总脱水速率为0.037—0.050 %·(℃·d)-1。
Table 3
表3
表3不同品种苞叶性状
Table 3Bract characters of cultivars
| 品种 | 年份 | 苞叶层数 | 苞叶最大厚度 | 苞叶最小厚度 | 苞叶面积 | 苞叶面积/果穗 | 苞叶长 | 苞叶长度/果穗长度 | 苞叶 | 比苞叶重 | 苞叶生理成熟期 | 苞叶生理成熟期 | 苞叶生理成熟期 | 苞叶生理成熟期 | 苞叶最大鲜重 | 苞叶最大含水量 | 苞叶最大含水率 | 苞叶最小含水率 | 苞叶脱水 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cultivar | Year | BN | BTmax (mm) | BTmin (mm) | BA | 表面积 | BL | BL/EL | 蓬松度 | BRW (g·m-2) | 干重 | 鲜重 | 含水率 | 含水量 | BFWmax (g) | BMmax (g) | BMCmax | BMCmin | 速率 |
| (m2) | BA/EA | (cm) | FD | BDWpm (g) | BFWpm (g) | BMCpm (%) | BMpm (g) | (%) | (%) | BDR (%·(℃·d)-1) | |||||||||
| XY335 | ### | 10±0.7 | 0.15±2.1 | 5.2±0.5 | 22.3±1.1 | 1.2±0.1 | 1.44±0.1 | 70.6±5.7 | 12.63±1.5 | 13.90±1.2 | 9.33±4.7 | 1.27±0.5 | |||||||
| ZD958 | ### | 9±0.9 | 0.17±2.5 | 6.2±0.7 | 25.0±1.2 | 1.5±0.1 | 1.20±0.1 | 49.8±6.0 | 8.93±2.1 | 9.52±2.2 | 6.34±1.7 | 0.59±0.2 | |||||||
| NH101 | ### | 9±0.9 | 0.15±3.0 | 4.7±0.9 | 23.7±1.2 | 1.3±0.1 | 1.60±0.2 | 62.8±4.5 | 10.36±1.9 | 11.55±1.8 | 11.57±3.9 | 1.32±0.5 | |||||||
| JNK728 | ### | 9±1.2 | 0.19±9.5 | 6.9±3.5 | 24.2±0.8 | 1.4±0.1 | 1.33±0.2 | 60.5±2.7 | 11.40±1.0 | 13.44±1.4 | 14.95±5.2 | 2.04±0.8 | |||||||
| NH816 | ### | 10±0.6 | 0.17±2.0 | 5.4±0.5 | 26.0±1.3 | 1.3±0.1 | 1.44±0.2 | 60.2±5.2 | 10.21±1.0 | 14.69±2.0 | 30.12±4.9 | 4.48±1.3 | |||||||
| ZD909 | ### | 8±0.7 | 0.13±1.9 | 4.2±0.4 | 25.4±1.5 | 1.3±0.1 | 1.29±0.1 | 69.3±8.5 | 8.96±1.7 | 9.71±1.9 | 7.56±2.3 | 0.74±0.3 | |||||||
| YF303 | ### | 11±1.1 | 0.20±3.3 | 6.4±0.6 | 25.0±1.6 | 1.3±0.1 | 1.45±0.1 | 76.6±13.5 | 16.21±2.6 | 20.41±2.8 | 19.24±3.7 | 4.20±1.2 | |||||||
| LC808 | ### | 10±1.0 | 0.15±3.0 | 4.9±0.7 | 24.1±1.9 | 1.3±0.1 | 1.41±0.2 | 64.7±6.0 | 14.33±4.0 | 16.45±4.8 | 12.66±2.1 | 2.12±1.0 | |||||||
| ZKY505 | ### | 11±0.7 | 0.18±2.7 | 5.8±0.6 | 22.8±1.7 | 1.2±0.1 | 1.34±0.1 | 72.4±8.6 | 10.66±2.6 | 11.71±3.0 | 8.75±1.7 | 1.05±0.4 | |||||||
| HT1H | ### | 10±1.7 | 0.12±1.1 | 4.8±0.6 | 21.6±1.1 | 1.2±0.1 | 1.48±0.1 | 69.6±8.4 | 9.69±2.0 | 12.45±2.7 | 20.78±3.1 | 2.76±0.9 | |||||||
| NY721 | ### | 8±0.6 | 0.12±2.0 | 3.8±0.4 | 23.7±1.6 | 1.3±0.1 | 1.44±0.2 | 83.3±9.6 | 9.99±1.3 | 12.15±1.4 | 17.78±4.4 | 2.16±0.6 | |||||||
| XY335 | ### | 9±0.8 | 3.62±0.6 | 1.55±0.4 | 0.17±2.6 | 6.5±1.0 | 24.5±1.0 | 1.4±0.2 | 77.8±12.4 | 10.77±1.6 | 14.41±2.0 | 25.29±3.7 | 3.65±0.7 | 67.70±9.9 | 53.75±8.0 | 79 | 14 | 0.074 | |
| ZD958 | ### | 9±0.8 | 3.86±0.2 | 0.92±0.2 | 0.18±2.3 | 7.0±0.7 | 25.4±0.2 | 1.5±0.1 | 63.1±12.0 | 8.83±1.6 | 10.30±1.3 | 14.34±2.5 | 1.47±0.3 | 72.20±10.7 | 59.61±8.6 | 81 | 16 | 0.109 | |
| NH101 | ### | 10±0.8 | 4.19±0.7 | 1.34±0.3 | 0.15±1.6 | 5.6±0.3 | 24.9±0.9 | 1.4±0.1 | 63.9±9.1 | 9.53±1.3 | 13.90±1.1 | 31.56±5.6 | 4.37±0.7 | 80.19±16.6 | 64.19±12.9 | 79 | 16 | 0.085 | |
| JNK728 | ### | 10±0.7 | 4.55±0.2 | 1.56±0.3 | 0.16±1.8 | 7.7±0.5 | 25.2±1.3 | 1.7±0.1 | 58.2±4.0 | 9.79±1.3 | 11.18±1.4 | 12.44±0.6 | 1.39±0.2 | 89.09±5.9 | 74.07±6.0 | 80 | 13 | 0.128 | |
| NH816 | ### | 10±0.6 | 4.40±0.3 | 1.69±0.2 | 0.17±2.5 | 6.1±0.4 | 27.2±0.8 | 1.4±0.1 | 66.5±6.3 | 9.29±2.6 | 12.58±4.7 | 24.37±6.8 | 3.28±2.3 | 75.58±7.0 | 61.75±5.6 | 82 | 16 | 0.082 | |
| ZD909 | ### | 9±0.8 | 3.84±0.6 | 0.99±0.1 | 0.13±2.3 | 4.8±0.8 | 24.9±1.0 | 1.4±0.1 | 59.8±5.7 | 7.92±0.6 | 9.74±1.1 | 18.24±5.5 | 1.82±0.7 | 67.94±8.4 | 55.20±6.9 | 80 | 18 | 0.099 | |
| XD58 | ### | 11±0.7 | 5.32±0.9 | 1.38±0.1 | 0.13±2.1 | 5.8±0.5 | 24.2±1.3 | 1.5±0.1 | 59.2±7.6 | 8.14±0.8 | 11.51±1.2 | 29.16±4.0 | 3.37±0.7 | 81.78±9.6 | 67.10±7.4 | 80 | 15 | 0.093 | |
| XD65 | ### | 10±0.9 | 4.58±0.2 | 1.61±0.1 | 0.14±1.5 | 7.1±0.9 | 23.4±0.6 | 1.6±0.2 | 65.9±6.6 | 9.46±0.6 | 11.36±1.2 | 16.32±6.3 | 1.90±0.9 | 86.17±5.9 | 70.21±5.2 | 80 | 15 | 0.105 | |
| FK139 | ### | 11±1.2 | 4.37±0.1 | 1.46±0.3 | 0.16±4.0 | 8.2±1.1 | 26.3±1.2 | 1.7±0.2 | 77.3±9.6 | 10.32±1.3 | 14.79±2.6 | 29.73±4.2 | 4.48±1.5 | 65.54±8.6 | 51.46±5.7 | 77 | 15 | 0.094 | |
| DK517 | ### | 9±0.7 | 3.23±0.1 | 1.04±0.1 | 0.13±2.3 | 5.0±0.4 | 23.9±1.6 | 1.3±0.1 | 52.4±3.5 | 6.33±0.9 | 7.96±1.2 | 20.49±2.2 | 1.63±0.3 | 51.13±2.1 | 41.45±1.8 | 79 | 16 | 0.088 | |
| SD636 | ### | 10±0.8 | 4.53±0.4 | 1.53±0.3 | 0.14±1.9 | 6.0±0.5 | 25.9±1.5 | 1.5±0.1 | 75.6±14.6 | 8.66±1.4 | 10.19±1.6 | 15.08±2.2 | 1.54±0.3 | 71.66±10.3 | 59.92±7.5 | 81 | 16 | 0.091 | |
| JH207 | ### | 10±1.0 | 4.25±0.7 | 1.53±0.1 | 0.13±2.0 | 5.5±0.5 | 23.8±1.1 | 1.4±0.2 | 63.8±6.9 | 8.36±0.7 | 10.17±0.9 | 17.84±1.2 | 1.82±0.2 | 77.78±13.5 | 61.40±10.6 | 79 | 16 | 0.071 | |
| LD575 | ### | 11±1.0 | 4.97±0.4 | 1.93±0.2 | 0.17±1.5 | 7.0±0.5 | 24.9±0.9 | 1.6±0.1 | 71.7±9.9 | 12.32±2.1 | 15.22±4.5 | 16.59±11.0 | 2.90±2.8 | 87.82±11.9 | 70.81±9.6 | 78 | 16 | 0.081 | |
| HM1H | ### | 9±0.7 | 4.41±0.7 | 1.45±0.2 | 0.12±1.4 | 4.8±0.4 | 25.9±0.7 | 1.5±0.1 | 68.6±3.6 | 10.56±2.8 | 15.84±6.8 | 29.73±10.6 | 5.27±4.0 | 66.10±4.0 | 53.39±3.3 | 79 | 14 | 0.08 | |
| JH318 | ### | 10±0.6 | 4.00±0.4 | 1.44±0.2 | 0.12±0.9 | 5.3±0.8 | 22.3±0.7 | 1.4±0.2 | 67.9±3.7 | 8.28±0.8 | 11.70±1.6 | 28.96±2.7 | 3.42±0.7 | 57.56±4.8 | 44.88±7.3 | 78 | 19 | 0.069 | |
| JT152 | ### | 11±0.8 | 4.80±0.2 | 1.52±0.1 | 0.15±2.7 | 6.0±0.4 | 26.9±0.9 | 1.5±0.1 | 59.2±7.5 | 11.50±1.8 | 14.33±2.7 | 19.47±2.5 | 2.84±0.9 | 82.91±3.7 | 66.77±2.6 | 81 | 17 | 0.072 | |
| ZJ323 | ### | 8±0.7 | 4.29±0.2 | 1.32±0.2 | 0.12±2.2 | 4.6±0.4 | 27.0±2.1 | 1.5±0.1 | 72.0±4.5 | 7.72±1.2 | 8.28±1.3 | 6.82±0.7 | 0.56±0.1 | 74.57±8.8 | 59.01±7.2 | 80 | 15 | 0.075 | |
| 变化范围 | #### | 3.23-5.32 | 0.92-1.93 | 0.12-0.20 | 3.8-8.2 | 21.6-27.2 | 1.2-1.7 | 1.20-1.60 | 49.8-83.3 | 6.33-14.33 | 7.96-20.41 | 6.34-31.56 | 0.56-5.27 | 51.13-89.09 | 41.45-74.07 | 77.09-81.35 | 12.90-18.65 | 0.069-0.128 | |
| Variation range | |||||||||||||||||||
| 样本量(n) | 1 000 | 85 | 85 | 195 | 280 | 195 | 280 | 110 | 195 | 184 | 184 | 184 | 184 | 85 | 85 | ||||
| Sample number | |||||||||||||||||||
| F值 F value | 37.49** | 5.76** | 7.92** | 3.98** | 14.09** | 8.83** | 15.61** | 5.28** | 7.47** | 8.72** | 7.91** | 20.53** | 9.04** | 6.69** | 7.44** | ||||
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为了比较不同年份环境条件对测定指标的影响,选择两年共有品种和29个共同测定指标进行年际间方差分析,结果显示,苞叶长度、果穗长度、果穗直径等指标在年际间差异显著;苞叶面积、比苞叶重、穗行数、穗粒数等指标在年际间差异不显著（表6）。以上表明两年环境条件对部分穗部性状有一定影响,但不影响玉米正常生长成熟。
Table 6
表6
表6不同性状年际间方差分析F值
Table 6F value in variance analysis of different characters in years
| 序号 Ordinal number | 指标 Parameter | 年份 Year | 品种 Cultivar | 年份×品种 Year×cultivar | 样本量(n) Sample number |
|---|---|---|---|---|---|
| 1 | 苞叶层数BN | 15.23** | 25.37** | 10.59** | 365 |
| 2 | 苞叶面积BA | 0.02 | 3.08* | 0.50 | 90 |
| 3 | 苞叶面积/果穗表面积 BA/EA | 15.10** | 14.32** | 0.25 | 120 |
| 4 | 苞叶长度BL | 13.51** | 12.59** | 2.18 | 90 |
| 5 | 苞叶长度/果穗长度 BL/EL | 45.02** | 19.18** | 4.35** | 120 |
| 6 | 比苞叶重BRW | 3.13 | 10.49** | 4.65** | 90 |
| 7 | 苞叶生理成熟期干重BDWpm | 8.77** | 7.19** | 0.50 | 84 |
| 8 | 苞叶生理成熟期鲜重BFWpm | 0.07 | 11.54** | 2.62* | 84 |
| 9 | 苞叶生理成熟期含水率BMCpm | 64.94** | 28.69** | 18.60** | 84 |
| 10 | 苞叶生理成熟期含水量BMpm | 23.27** | 20.98** | 12.43** | 84 |
| 11 | 果穗长度EL | 10.89** | 14.96** | 1.63 | 120 |
| 12 | 果穗直径ED | 83.59** | 7.29** | 1.77 | 120 |
| 13 | 穗轴直径CD | 28.69** | 31.29** | 0.79 | 120 |
| 14 | 果穗夹角EA | 15.96** | 13.27** | 3.06* | 120 |
| 15 | 果穗体积EV | 63.55** | 6.39** | 1.48 | 120 |
| 16 | 穗轴体积CV | 5.94* | 15.13** | 0.97 | 120 |
| 17 | 穗轴生理成熟期含水量CMpm | 2.13 | 14.48** | 4.30** | 84 |
| 18 | 穗轴生理成熟期含水率CMCpm | 6.87* | 30.87** | 1.42 | 84 |
| 19 | 穗柄生理成熟期含水量EPMpm | 5.09* | 22.09** | 1.93 | 84 |
| 20 | 穗柄生理成熟期含水率EPMCpm | 14.38** | 5.01** | 0.69 | 84 |
| 21 | 穗粒数 GNPE | 3.51 | 16.66** | 5.01** | 240 |
| 22 | 穗行数 RPE | 0.24 | 8.07** | 1.07 | 240 |
| 23 | 籽粒长度GL | 139.72** | 3.69** | 2.35* | 120 |
| 24 | 果穗周长/穗行数EP/RPE | 28.94** | 8.87** | 1.35 | 120 |
| 25 | 果穗长度/行粒数EL/GNPR | 0.27 | 8.78** | 3.08* | 120 |
| 26 | 单粒所占空间SSG | 76.5** | 1.86 | 0.82 | 120 |
| 27 | 生理成熟期百粒干重100GDWpm | 0.86 | 5.68** | 1.52 | 84 |
| 28 | 生理成熟期籽粒含水率GMCpm | 0.94 | 7.76** | 9.7** | 84 |
| 29 | 收获期籽粒含水率GMCh | 2.63 | 31.68** | 2.71* | 84 |
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2.2 穗部性状与籽粒脱水的关系
将生理成熟期籽粒含水率、收获期籽粒含水率、生理成熟前籽粒脱水速率、生理成熟后籽粒脱水速率和籽粒总脱水速率共5个籽粒脱水特征参数与各穗部性状间进行相关分析,相关矩阵利用热力图表示（图1）。苞叶长度（BL）与生理成熟后籽粒脱水速率（GDRapm）显著负相关（r=-0.454*）,与收获期籽粒含水率（GMCh）显著正相关（r=0.452*）;“苞叶长度/果穗长度”（BL/EL）与生理成熟后籽粒脱水速率显著负相关（r=-0.394*）。果穗夹角（EA）与籽粒总脱水速率（GTDR）显著正相关（r=0.429*）;穗轴生理成熟期含水率（CMCpm）与籽粒生理成熟期含水率（GMCpm）（r=0.628**）及收获期含水率（r=0.671**）均呈极显著正相关。穗粒数（GNPE）与生理成熟前籽粒脱水速率（GDRbpm）（r=-0.507**）、总脱水速率（r=-0.459*）呈负相关,分别达到极显著、显著水平;“果穗长度/行粒数”（EL/GNPR）与籽粒生理成熟前（r=0.382*）、后（r=0.460*）和总脱水速率（r=0.483**）分别呈显著或极显著正相关,与收获期籽粒含水率（r=-0.477*）显著负相关;生理成熟期百粒干重（100GDWpm）与生理成熟期籽粒含水率显著负相关（r=-0.441*）。在本研究中,穗部其他性状与籽粒脱水速率、生理成熟期和收获期籽粒含水率的相关均未达到显著水平。
显示原图|下载原图ZIP|生成PPT图1玉米穗部性状与籽粒脱水相关分析
-->Fig. 1Correlation analysis of ear characters and dehydration parameters in maize
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3 讨论
玉米果穗由籽粒、苞叶、穗轴和穗柄等不同部位组成,这些部位又包括各自不同的调查性状。前人在研究穗部农艺性状与籽粒脱水关系时,由于研究目标和测试手段的不同,多针对几个或十几个指标进行分析[8,12,15-20],且多集中于苞叶长度、果穗长度、果穗直径、穗轴直径等指标,有一定的局限性,限制了对果穗性状与籽粒脱水关系的系统理解。本研究将苞叶、籽粒、穗轴和穗柄等4个部分细分出41个不同的测试指标（表2）,不仅囊括了前人研究所涉及的指标,而且增加了一些新的指标,如“苞叶面积/果穗表面积”、“苞叶长度/果穗长度”、果穗夹角、单粒所占空间等,能够较为系统、完整地表征玉米穗部性状。此外,前人相关研究所用的试验材料多为自主选配的杂交组合,如闫淑琴等[8]用9份自交系组配了36个杂交组合;张林等[11]和张立国等[19]分别用10份自交系组配了90个杂交组合;张春荣等[18]用了4个黄淮海区主推品种和13个自选的杂交组合;孙生林等[14]对600个玉米单交、三交组合进行研究。由于研究目的不同、掌握的材料不同,不同研究者选用的自交系遗传背景差异较大,其研究结果难以进行简单的比较;而自选的杂交组合又存在遗传背景相对简单的问题,有可能掩盖或者夸大不同穗部性状与籽粒脱水特征的关系,影响测试分析结果。本研究以当前生产上的主推品种为供试对象,遗传基础广泛,研究结果能够反映当前品种遗传基础的现状,对今后适合籽粒收获玉米品种的选育或筛选更具参考价值。本研究表征苞叶性状的指标中,只有苞叶长度、“苞叶长度/果穗长度”与生理成熟后籽粒脱水速率显著负相关,表明较短的苞叶有利于生理成熟后籽粒脱水。表征果穗的指标中,生理成熟期穗轴含水率与籽粒含水率显著正相关,反映出穗轴与籽粒含水率的变化具有一定的同步性[25];果穗夹角与籽粒总脱水速率显著正相关,表明增大果穗夹角有利于籽粒脱水。表征穗柄的5个性状均与籽粒脱水无显著相关性,穗柄是果穗与茎秆的连接器官,承担着物质运输功能[26],穗柄含水率在籽粒发育和干燥过程中相对稳定[25],对籽粒脱水影响不大。表征籽粒的性状中,穗粒数与籽粒脱水速率显著负相关,“果穗长度/行粒数”与籽粒脱水速率显著正相关,表明较少的穗粒数、较小的籽粒有利于籽粒脱水,这与大穗高产并不矛盾。一般而言早熟品种脱水速率快,同时也具有穗粒数少、籽粒小的特点,当前欧美一些国家推广的适合粒收的品种多为中小穗型耐密植品种。本研究结果与前人的差异之处主要在于前人认为的一些与籽粒脱水速率显著相关的指标,比如苞叶层数、苞叶面积、果穗长度、果穗直径、穗轴直径、籽粒长度等[5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20],在本研究中影响并未达到显著水平,这与参试品种的综合性状表现和测试指标的变化范围有关。以苞叶层数为例,本研究中所采用的当前主栽品种苞叶层数在8—11层之间,该指标自身的变化范围较小,加上穗部其他指标也作用于籽粒脱水,不同指标对籽粒脱水的综合作用可能会削弱苞叶层数的效应,这也是造成不同****之间结果不一致的原因。
长期以来,我国玉米选育目标一直以产量性状为主,没有特别关注籽粒脱水特征并按照提高籽粒脱水速率、降低成熟期籽粒含水率的目标开展种质资源的系统筛选与育种工作。本研究收集了当前生产上主要种植的品种,这些品种的产量水平和生态适应性都通过了品种审定的考验,研究结果表明,穗部特征和籽粒脱水性状方面仍存在较大差异,这一方面表明我国玉米育种在选育籽粒快速脱水性状方面还存在较大的差距,也从另一个侧面提示我们,目前的育种材料存在实现产量与脱水性状共同提高的遗传资源,可以选出产量高、脱水快的品种。
4 结论
2015—2016年研究调查的22个品种的41个穗部性状表明,不同品种的穗部性状具有显著差异,其中苞叶短、穗轴生理成熟期含水率低、果穗夹角大、穗粒数少、“果穗长度/行粒数”小有利于籽粒脱水,其他穗部性状对籽粒脱水的影响未达到显著水平,可供适宜机械粒收品种的选育和种质资源的鉴定参考应用。The authors have declared that no competing interests exist.
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| [1] | . 机械粒收是玉米收获技术发展的方向,是玉米实现全程机械化、转变生产方式的关键。当前,籽粒收获过程中破碎率高的问题不仅降低玉米等级和销售价格,而且导致收获产量下降,并增大烘干成本、增加安全贮藏的难度,是推广机械粒收技术面临的重要问题。玉米不同基因型间籽粒破碎率存在显著差异,抗破碎特性是可遗传的性状,可通过育种培育抗破碎率的品种;不同收获机械和作业参数对籽粒破碎率有显著影响,选择轴流式收获机,并根据玉米生长、成熟和籽粒含水率状况及时检查与调试收获机参数是保证低破碎率的有效措施;生态环境因素对破碎率也有显著的影响,籽粒形成、自然干燥和收获期的光照、温度、湿度等因素均会影响到籽粒硬度、容重、含水率和质地等与籽粒破碎相关的特性;种植密度、水肥管理、收获时期等栽培管理措施对籽粒破碎率也会产生明显的影响。因此,针对不同区域生态环境条件,应选择适宜生育期内能与当地光温资源匹配的品种以及确定品种适宜的种植区域。合理种植密度、优化氮肥管理和适量灌溉有利于降低破碎率,而选择在最佳收获期收获是降低籽粒破碎率的最有效措施。 . 机械粒收是玉米收获技术发展的方向,是玉米实现全程机械化、转变生产方式的关键。当前,籽粒收获过程中破碎率高的问题不仅降低玉米等级和销售价格,而且导致收获产量下降,并增大烘干成本、增加安全贮藏的难度,是推广机械粒收技术面临的重要问题。玉米不同基因型间籽粒破碎率存在显著差异,抗破碎特性是可遗传的性状,可通过育种培育抗破碎率的品种;不同收获机械和作业参数对籽粒破碎率有显著影响,选择轴流式收获机,并根据玉米生长、成熟和籽粒含水率状况及时检查与调试收获机参数是保证低破碎率的有效措施;生态环境因素对破碎率也有显著的影响,籽粒形成、自然干燥和收获期的光照、温度、湿度等因素均会影响到籽粒硬度、容重、含水率和质地等与籽粒破碎相关的特性;种植密度、水肥管理、收获时期等栽培管理措施对籽粒破碎率也会产生明显的影响。因此,针对不同区域生态环境条件,应选择适宜生育期内能与当地光温资源匹配的品种以及确定品种适宜的种植区域。合理种植密度、优化氮肥管理和适量灌溉有利于降低破碎率,而选择在最佳收获期收获是降低籽粒破碎率的最有效措施。 |
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| [4] | . 【目的】机械粒收是玉米生产的发展方向,收获质量是影响其推广应用的主要因素。中国玉米机械粒收还处于起步阶段,目前在西北和东北等春播玉米区推广应用面积较大,黄淮海夏播玉米区正在积极开展试验示范。本研究通过分析黄淮海夏玉米机械粒收质量及其影响因素,为该技术的推广应用提供支持。【方法】2013—2015年累计选用了23个玉米品种,在黄淮海典型代表区河南新乡开展试验研究。2013年和2015年在收获期分别进行2次机械收获,2014年1次机械收获。收获当天测定各个品种的收获前籽粒含水率,并调查测产。机械收获后从机仓随机取一定量籽粒样品,立即测定收获后籽粒含水率,然后手工分拣样品,测定籽粒破碎率和杂质率;收获后,在田间选取3个代表性样区,调查落穗损失和落粒损失。【结果】2013—2015年,籽粒破碎率共调查131个样点,结果显示,收获时玉米籽粒含水率在20.80%—41.08%,籽粒破碎率变幅为4.98%—41.36%,籽粒破碎率随着籽粒含水率的提高明显升高;破碎率低于8%的有38个样点,占比29.01%,籽粒含水率低于26.92%时,收获的玉米籽粒能够满足破碎率8%以下的要求。机收杂质率共调查134个样点,杂质率0.37%—5.28%,杂质率低于3%的样点有107个,占比79.85%,杂质率也随着籽粒含水率的升高而增加;2013—2014年,籽粒含水率低于28.27%时,杂质率能够低于3%的国家标准;2015年收获时籽粒含水率虽然较高,但杂质率均在3%以下。田间损失率共调查108个样点,变幅为0.18%—2.85%（落穗率和落粒率）,均能满足国家标准,损失率不是影响机械收获质量的限制因素。在本试验条件下,籽粒含水率低于26.92%时,破碎率和杂质率分别低于8%和3%,田间损失率也符合国家标准,能够满足机械粒收质量要求。研究还发现,籽粒含水率相近的不同品种之间,机械收获的破碎率和杂质率也存在显著差异,17 . 【目的】机械粒收是玉米生产的发展方向,收获质量是影响其推广应用的主要因素。中国玉米机械粒收还处于起步阶段,目前在西北和东北等春播玉米区推广应用面积较大,黄淮海夏播玉米区正在积极开展试验示范。本研究通过分析黄淮海夏玉米机械粒收质量及其影响因素,为该技术的推广应用提供支持。【方法】2013—2015年累计选用了23个玉米品种,在黄淮海典型代表区河南新乡开展试验研究。2013年和2015年在收获期分别进行2次机械收获,2014年1次机械收获。收获当天测定各个品种的收获前籽粒含水率,并调查测产。机械收获后从机仓随机取一定量籽粒样品,立即测定收获后籽粒含水率,然后手工分拣样品,测定籽粒破碎率和杂质率;收获后,在田间选取3个代表性样区,调查落穗损失和落粒损失。【结果】2013—2015年,籽粒破碎率共调查131个样点,结果显示,收获时玉米籽粒含水率在20.80%—41.08%,籽粒破碎率变幅为4.98%—41.36%,籽粒破碎率随着籽粒含水率的提高明显升高;破碎率低于8%的有38个样点,占比29.01%,籽粒含水率低于26.92%时,收获的玉米籽粒能够满足破碎率8%以下的要求。机收杂质率共调查134个样点,杂质率0.37%—5.28%,杂质率低于3%的样点有107个,占比79.85%,杂质率也随着籽粒含水率的升高而增加;2013—2014年,籽粒含水率低于28.27%时,杂质率能够低于3%的国家标准;2015年收获时籽粒含水率虽然较高,但杂质率均在3%以下。田间损失率共调查108个样点,变幅为0.18%—2.85%（落穗率和落粒率）,均能满足国家标准,损失率不是影响机械收获质量的限制因素。在本试验条件下,籽粒含水率低于26.92%时,破碎率和杂质率分别低于8%和3%,田间损失率也符合国家标准,能够满足机械粒收质量要求。研究还发现,籽粒含水率相近的不同品种之间,机械收获的破碎率和杂质率也存在显著差异,17 |
| [5] | . Study of historically important cultivars may provide information on physiological traits that have been changed during selection for yield. Traits related to grain filling and drying were studied in commercially important maize (L.) hybrids sold over the past 50 years. Hybrid studied were of approximately the same relative maturity and adapted to central Iowa. The duration of the grain filling period increased with year of release while grain filling rate was unchanged. The increase in grain filling duration was the result of later physiological maturity (black layer formation) rather than a change in flowering date. Late season plant health was improved in newer hybrids, which may have provided more viable leaf area to support prolonged grain filling. Grain drying rates were calculated by regression of water content路kernelon heat units. Slopes of water loss were the same in the 2 years despite very different environmental conditions in the two seasons. Heat unit intercepts were different in the 2 years, with grain drying earlier in the hot, dry year of 1983. Grain water content at physiological maturity was correlated with year of release in 1983, but not in 1982. Several traits previously proposed to be associated with drying rate (husk number, date of husk death, ear angle, and number of kernel rows) were correlated with year of hybrid release. Correlation with drying rates over the season was significant for date of husk death in 1983. |
| [6] | . Maize ( Zea mays L.) hybrids with fast grain-drying capabilities are needed especially because of the use of costly, non-renewable fossil fuel for drying grain artificially. The objectives of this study were to examine grain-moisture reduction during the grain-filling period and its relationship with rate of fill, and to determine factors affecting these two traits. Ten-ear samples per plot from each of ten commercial and two public hybrids were taken on each of three sampling dates, beginning 28 days after mid-silking and at 10-day intervals thereafter during the grain-filling period. A most significant finding was that rate of grain fill had a direct positive effect on grain-moisture reduction per growing degree day (GDD) during the grain-filling period, suggesting that the hybrids with relatively higher grain moisture reduction would also be fast fillers. GDD to black layer and GDD to mid-silk had direct positive effects on rate of fill. Grain yield and percentage ear moisture were negatively correlated at the three sampling dates ( r = 610.84 6565). Husk weight showed a small positive correlation with grain yield during the filling period, suggesting that husks probably contribute some photosynthate to developing kernels. Husk weight showed an undesirable, positive correlation with percentage ear moisture. |
| [7] | . The effects on germination and early seedling growth of presowing true potato seed in water or gibberellic acid (GA) at 1500 ppm and of priming in -1.0, -1.25 and -1.5 MPa solutions of KNO3 + K3PO4 were studied using 30, 18, 6 and 3/4 month-old seed. The influence of light during presowing on the effectiveness of treatments was also investigated. Overall, priming in the light at -1.0 MPa was the most, and GA the least successful treatment for enhancing emergence and subsequent seedling growth. Though GA increased final emergence from about 20 to 70 % in the most recently harvested lot (3/4 mo), the rate and extent of final germination or emergence in this dormant seed was still much lower than that of the nondormant lots (6-30 mo), especially when the latter were primed. For all lots, dry weight per seedling was 40 % lower in dormant than in nondormant seed, and 20 % higher when seeds were primed at -1.0 MPa than when GA treated. In conclusion, the use of nondormant seed may be a requirement for both effective priming and sowing of potato crops via true seed. |
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| [9] | . Synopsis: Husk and shank characteristics and shape or size of ear were not found to be major factors associated with differing rates of drying among strains of corn. |
| [10] | . react-text: 412 Foliar application of dinoseb (2-sec-butyl-4-.6-dinitro phenol) has been reported to increase the grain yield of corn (Zea mays L.) The objective of our work was to evaluate the response of dent corn hybrids adapted to the northern region of the Corn Belt to foliar applications of dinoseb. Several rates of dinoseb were evaluated on corn grown at two locations for 4 years. Dinoseb with a... /react-text react-text: 413 /react-text [Show full abstract] |
| [11] | . 以黑龙江省第一积温带10份熟期相近而收获期含水量差异较大的优 良自交系为试验材料,采用完全双列杂交设计配制杂交组合,对田间自然脱水速率、苞叶长等农艺性状与玉米收获期籽粒含水量进行遗传相关和通径分析.相关分析 表明,田间自然脱水速率与收获期籽粒含水量表现为极显著负相关(R=0.4508),苞叶长、粒宽等性状与收获期籽粒含水量表现为极显著正相关;通径分析 表明,苞叶长、粒宽等性状对收获期含水量的直接通径系数均为正值,穗长、田间自然脱水速率对收获期含水量的直接通径系数为负值.为选育低收获期含水量的玉 米品种,应着重选育田间自然脱水速率快、苞叶长较果穗长略短、穗位稍低、轴细、籽粒偏窄及百粒重稍低的基因型. . 以黑龙江省第一积温带10份熟期相近而收获期含水量差异较大的优 良自交系为试验材料,采用完全双列杂交设计配制杂交组合,对田间自然脱水速率、苞叶长等农艺性状与玉米收获期籽粒含水量进行遗传相关和通径分析.相关分析 表明,田间自然脱水速率与收获期籽粒含水量表现为极显著负相关(R=0.4508),苞叶长、粒宽等性状与收获期籽粒含水量表现为极显著正相关;通径分析 表明,苞叶长、粒宽等性状对收获期含水量的直接通径系数均为正值,穗长、田间自然脱水速率对收获期含水量的直接通径系数为负值.为选育低收获期含水量的玉 米品种,应着重选育田间自然脱水速率快、苞叶长较果穗长略短、穗位稍低、轴细、籽粒偏窄及百粒重稍低的基因型. |
| [12] | Three “fast” drying and three “slow” drying corn inbreds, whose hybrids demonstrate various rates of drying after physiological maturity, were used to study the genetics controlling differential drying rates among hybrids. Drying rate was estimated by the moisture loss from husked ears in a forced-air dryer at 38 C for 18 hours. Initial moisture range was 30 to 40% while dried ears had a range of 20 to 30%. |
| [13] | . Responses and limits to selection are found to differ invarious maize (Zea mays L.) populations and traits. Twenty-four cycles of recurrent selection for high oil concentration have been completed in maize population Alexho Synthetic. The objectives of this study were to determine the response of oil concentration to direct selection and correlated responses of fatty acid concentration, grain yield, and other agronomic traits. Cycles 0, 3, 5, 9, 11, 15, 18, 21, and 24 per se, the same cycles crossed to inbreds B73 and R802A, and hybrid check B73 X Mo17, were evaluated in six environments at Yugoslavia and at Urbana, IL in 1985 and 1986. Selection was effective in increasing oil concentration. Total oil concentration increased by 118, 51, and 57 g kg-1 of dry matter in cycles per se B73 and R802A testcrosses, respectively. The rate of response in oil concentration was 4.9, 2.1, and 2.4 g kg-1 cycle-1 for the cycles per se for B73 and R802A testcrosses, respectively. The quadratic response was significant in testcrosses, but not in cycles per se. Thus, oil concentrations has not yet shown evidence of plateauing. Oleic and linoleic acid concentration changed with selection for oil concentration in cycles per se -1.39 and 1.39 g kg-1 cycle-1, respectively. Total grain yield of the cycles per se decreased by 1718 kg ha-1, which corresponds to a response of -71.6 kg ha-1 cycle-1. Yield of the testcrosses to inbreds B73 and R802 decreased 19.7 and 15.2 kg ha-1 cycle-1, respectively. Plant height, ear height, 500 kernel weight, ear length, and lodging decreased, while grain moisture and ear row number increased with selection for oil concentration. No change was found in days to silk. |
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| [16] | . 本文主要分析了玉米收获前 (吐丝后 6 0d)子粒水分与品种生育日数、百粒重、轴粗、穗粗等性状的相关性及脱水速度与粒型的关系。结果表明 :影响子粒水分相关程度的顺序是生育日数 轴粗 百粒重 穗粗。齿型品种脱水速度快于硬粒型品种。因此在解决“水苞米”问题时 ,首要考虑的是选用合适熟期的品种 ;其次熟期相近的品种 ,要选穗轴较细、粒重偏低的品种 ,这样有利于降低子粒水分 ,提高品质。 . 本文主要分析了玉米收获前 (吐丝后 6 0d)子粒水分与品种生育日数、百粒重、轴粗、穗粗等性状的相关性及脱水速度与粒型的关系。结果表明 :影响子粒水分相关程度的顺序是生育日数 轴粗 百粒重 穗粗。齿型品种脱水速度快于硬粒型品种。因此在解决“水苞米”问题时 ,首要考虑的是选用合适熟期的品种 ;其次熟期相近的品种 ,要选穗轴较细、粒重偏低的品种 ,这样有利于降低子粒水分 ,提高品质。 |
| [17] | . 20 hybrids derived from incomplete diallel cross and their parents were used as materials to analyze the correlation between the traits of plant ear and the ear moisture loss rate of maize.The results showed that there were significant differences between varieties in the ear moisture loss rate,so varieties with high ear moisture loss rate could be selected through genetic improvement in breeding process.Because its heritability was lower,it could not be directly selected in earlier generation. The ear moisture loss rate in the field was mainly affected by the plant traits.The genotypes with lower plant height,higher ear height,more green leaves in flowering time,higher water content in stalk and lower water content in leaves would redound to the loss of ear moisture.The results also indicated that there were some correlation between ear moisture loss rate in harvest and some traits related ear,for example,negative correlation with ear diameter and rows number per ear,positive correlation between ear diameter and rows per ear.Therefore ,the ears with fewer row numbers per ear were thinner in ear diameter and could increase its loss of ear moisture. . 20 hybrids derived from incomplete diallel cross and their parents were used as materials to analyze the correlation between the traits of plant ear and the ear moisture loss rate of maize.The results showed that there were significant differences between varieties in the ear moisture loss rate,so varieties with high ear moisture loss rate could be selected through genetic improvement in breeding process.Because its heritability was lower,it could not be directly selected in earlier generation. The ear moisture loss rate in the field was mainly affected by the plant traits.The genotypes with lower plant height,higher ear height,more green leaves in flowering time,higher water content in stalk and lower water content in leaves would redound to the loss of ear moisture.The results also indicated that there were some correlation between ear moisture loss rate in harvest and some traits related ear,for example,negative correlation with ear diameter and rows number per ear,positive correlation between ear diameter and rows per ear.Therefore ,the ears with fewer row numbers per ear were thinner in ear diameter and could increase its loss of ear moisture. |
| [18] | . . |
| [19] | . 为选育脱水速率快的玉米新品 种,以黑龙江省10个熟期相近而脱水速率差异较大的优良玉米自交系为试验材料,采用完全双列杂交设计配置杂交组合,对玉米的百粒重、穗粗等12个农艺性状 与玉米生理成熟后籽粒脱水速率进行遗传相关和通径分析。结果表明:穗粗、穗行数、粒宽和胚重/胚乳重与玉米生理成熟后籽粒脱水速率之间均表现为显著或极显 著正向相关;百粒重、穗长、胚占籽粒体积比和果皮厚度与玉米生理成熟后籽粒脱水速率之间均表现为极显著负向相关。通径分析结果表明:穗粗、穗行数、粒宽和 胚重/胚乳重与玉米生理成熟后籽粒脱水速率直接通径系数为正值,百粒重、穗长、胚占籽粒体积比和果皮厚度与玉米生理成熟后籽粒脱水速率直接通径系数为负 值。为获取脱水速率快的玉米,应主要选育果穗短粗、籽粒宽度较大、果皮薄和百粒重小的基因型的玉米杂交种。 . 为选育脱水速率快的玉米新品 种,以黑龙江省10个熟期相近而脱水速率差异较大的优良玉米自交系为试验材料,采用完全双列杂交设计配置杂交组合,对玉米的百粒重、穗粗等12个农艺性状 与玉米生理成熟后籽粒脱水速率进行遗传相关和通径分析。结果表明:穗粗、穗行数、粒宽和胚重/胚乳重与玉米生理成熟后籽粒脱水速率之间均表现为显著或极显 著正向相关;百粒重、穗长、胚占籽粒体积比和果皮厚度与玉米生理成熟后籽粒脱水速率之间均表现为极显著负向相关。通径分析结果表明:穗粗、穗行数、粒宽和 胚重/胚乳重与玉米生理成熟后籽粒脱水速率直接通径系数为正值,百粒重、穗长、胚占籽粒体积比和果皮厚度与玉米生理成熟后籽粒脱水速率直接通径系数为负 值。为获取脱水速率快的玉米,应主要选育果穗短粗、籽粒宽度较大、果皮薄和百粒重小的基因型的玉米杂交种。 |
| [20] | . A selection procedure to change the drying rates of maize ( Zea mays L.) ears was developed and tested. Results indicated that drying rates were affected by hybrid genotype, ear maturity at harvest, number of kernels per row, ear diameter, and moisture content at harvest.Mass selection was initiated in an early synthetic, NDSG, in an attempt to produce both fast and slow drying strains. After two cycles resultant substrains were evaluated in the laboratory for direct and in the field for correlated selection responses. Laboratory results indicated that selection effectively changed moisture loss rates in NDSG, and confirmed earlier observations that an ear's moisture content at harvest affects its drying rate.Data from field experiments grown at five locations in 1980 revealed that each of two selection cycles for slow laboratory drying rate significantly reduced ear moisture content at harvest, in the field. This lower harvest moisture content appeared to result from a lower moisture content at physiological maturity rather than a faster drying rate. Other correlated selection responses included lowered yield, plant height, and ear weight due to selection for fast laboratory drying, and lowered plant height and ear weight from selection for slow drying.Data indicated that this selection procedure can be used to change moisture loss rate and ear moisture content at harvest. Results also contributed to understanding of factors involved in ear drying rates which may lead to more effective selection procedures. |
| [21] | . . |
| [22] | |
| [23] | . 该研究以冬小麦为对象，对叶面积指数测量的几种方法（比叶重法、照相法及SUNSCAN测量法）从测量难易程度、误差来源、适宜条件等方面做了比较分析与评价。研究表明比叶重法及照相法在整个生育期间均可使用，而基于SUNSCAN的仪器测量法在冬小麦封垄前的测量还需进一步研究。对SUNSCAN一天内不同时间测量的结果进行了比较，得出最适宜测量时间为13:00－15:00。照相法的测量精度最高，比叶重法次之，SUNSCAN测量需要根据作物生长特点做参数修正。针对SUNSCAN测量LAI提出了一种对叶倾角分布参数进行修正的方法，对3种冬小麦株型品种3个不同生育期进行了参数修正。该研究有助于地面测量叶面积指数的方法选择，同时对提高SUNSCAN测量精度具有参考意义。 . 该研究以冬小麦为对象，对叶面积指数测量的几种方法（比叶重法、照相法及SUNSCAN测量法）从测量难易程度、误差来源、适宜条件等方面做了比较分析与评价。研究表明比叶重法及照相法在整个生育期间均可使用，而基于SUNSCAN的仪器测量法在冬小麦封垄前的测量还需进一步研究。对SUNSCAN一天内不同时间测量的结果进行了比较，得出最适宜测量时间为13:00－15:00。照相法的测量精度最高，比叶重法次之，SUNSCAN测量需要根据作物生长特点做参数修正。针对SUNSCAN测量LAI提出了一种对叶倾角分布参数进行修正的方法，对3种冬小麦株型品种3个不同生育期进行了参数修正。该研究有助于地面测量叶面积指数的方法选择，同时对提高SUNSCAN测量精度具有参考意义。 |
| [24] | |
| [25] | . . |
| [26] | . In recent years, most works about grain yield forming focused on sink-source relationship, and set up a series of theory and technique of high yield using in crop production. There were few studies on sink-flow, which is important for grain yield forming. The spike vascular bundle is an essential or In recent years, most works about grain yield forming focused on sink-source relationship, and set up a series of theory and technique of high yield using in crop production. There were few studies on sink-flow, which is important for grain yield forming. The spike vascular bundle is an essential or |
