共查询到20条相似文献，搜索用时 187 毫秒
1.
玉米人工合成群体产量相关性状选择潜势及杂种优势模式分析 总被引：5，自引：2，他引：5
采用NCⅡ遗传交配设计 ,以分属于不同杂种优势群的 6个自交系做测验种 ,与 6个合成群体组配成 36个组合。结果表明 :单株产量的GCA以LBM最高 ,其次为WBM ,从株型、穗型性状的SCA分析合成群体与自交系组成了 9个优良杂种优势模式。单株产量最高的组合为HZ85×WBM ,其均值为 10 8 75g。通过对优良杂优模式内的变异参数估计 ,在群体内有丰富的变异个体 ,具有很强的选择潜势。组合内个体产量分布以及出现的频率对选系和轮回选择具有明确的指导意义。人工合成群体具有丰富的遗传变异 ,分属于不同的杂种优势类群 ,具有多元种质的特性。作为选系和轮回选择群体 ,具有明显的选择潜势 相似文献
2.
水稻显性早熟基因Ehd的SSR标记定位 总被引：1，自引：0，他引：1
以籼稻品种广陆矮4和粳稻品种台中65为亲本构建高世代回交分离群体,选用分布于水稻全基因组的145个SSR标记对亲本及抽穗期早熟基因进行分析.结果表明,114个标记在亲本间具有多态性,多态率78.6%;在BC3F1群体中,检测到10个标记的基因型来源于供体亲本广陆矮4号;在BC3F2定位群体中,早熟植株数与晚熟植株数的分离比例为3:1,早熟植株平均比晚熟植株提早抽穗21 d;通过SSR标记与抽穗期共分离分析将显性早熟基因Ehd界定在分子标记RM271和RM258之间;Ehd与标记RM184和RM271紧密连锁,遗传距离分别为2.6 cM和2.1 cM,此结果为该基因分子标记辅助选择奠定了基础. 相似文献
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大白菜叶片毛刺基因BrLt的EST-SSR定位 总被引：2，自引：0，他引：2
本研究以叶面光滑无毛刺大白菜‘501’为母本,叶面有毛刺‘601’为父本构建了F2代作图群体及其F3家系,其表型鉴定结果表明,大白菜叶片毛刺性状是由单显性基因(BrLt)控制的(χ2=3.86,P0.05)。通过分离群体分组分析(BSA)法,筛选出与BrLt基因连锁的1个SSR标记cnu_m400a,以及基于表达序列标签(EST)序列的2个EST-SSR标记,sau_um072和sau_um160。以139株F2个体为作图群体,并以cnu_m400a为锚定标记,将BrLt基因定位于芸薹种A6连锁群。sau_um072、sau_um160和cnu_m400a位于BrLt基因的同一侧,遗传距离分别为2.7cM、3.3cM和7.2cM。BrLt基因的定位将为图位克隆该基因以及研究大白菜叶片毛刺的形成机理奠定基础。 相似文献
5.
本研究利用在固体培养基上长期保存的杂交鹅掌楸胚性愈伤为外植体,对杂交鹅掌楸进行了遗传转化的研究.对于影响转化效果的众多影响因素,本研究主要讨论了乙酰丁香酮、菌液浓度、侵染时间对杂交鹅掌楸转化结果的影响.试验结果表明,在预培养阶段,乙酰丁香酮的使用有利于转化效率的提高,最佳条件时浓度100 mg/L,预培养4 d.而在共培养阶段,乙酰丁香酮的使用和延长共培养时间并不能显著提高杂交鹅掌楸的遗传转化效率.同时,在侵染时,不同菌液浓度和不同侵染时间对转化结果的影响也无显著的差异.通过PCR检测经过筛选培养获得的阳性植株,初步验证了外源基因已经整合到杂交鹅掌楸基因组中. 相似文献
6.
用SSR标记分析豫综5号和金皇后综合种的遗传变异 总被引：1，自引：0，他引：1
利用40对SSR标记引物分析了豫综5号和金皇后综合种的遗传变异.结果表明:40对引物在两群体中都扩增出115个多态位点;累加40对引物扩增的基因型种类,豫综5号196种,金皇后194种;豫综5号的平均遗传距离为0.383 4,金皇后综合种为0.339 7;豫综5号的平均观察杂合度是0.382 6,平均期望杂合度是0.474 7;金皇后综合种的平均观察杂合度是0.329 2,平均期望杂合度是0.414 3.从以上结果来看,豫综5号的遗传变异较丰富. 相似文献
7.
研究玉米自交系繁殖过程中保种圃建立的理论和株系性状的选择依据对自交系性状的保持、保纯以及杂交种特性保持具有重要意义。利用3个不同纯度水平玉米自交系连续自交3代,在SSR水平上和SNP水平上检测玉米纯合度,并在S2和S3调查田间性状。利用不同初始纯合度的自交系建立保种圃应自交的代数。不同株系在SSR分子检测具有一致性的前提下,在SNP水平上仍然存在较高的杂合度,随初始纯合度升高自交纯合的效率减低,选择初始纯度高的材料有利于后代遗传位点的快速纯合。在田间选择自交系时,根据性状稳定性并结合自交代数依次进行。首先依据较易稳定纯合的群体目测性状;其次,数量性状中,果穗长、果穗直径、雄穗一级侧枝数、穗行数等可作为第二类依据的性状;最后,在自交高代选择穗位高/株高、行粒数、叶长、叶宽等较难稳定的性状。 相似文献
8.
宁麦13选系的遗传多样性及品质差异 总被引：4，自引：0，他引：4
系统选择是新品种选育的有效方法, 也是修饰育种的重要途径, 群体内剩余变异和天然杂交是系统选择的来源基础。为探讨其分子生物学基础, 利用25对SSR引物对宁麦13的65个选系进行了位点多态性分析。结果表明, 每位点的遗传多样性指数为0~0.57, 平均遗传多样性指数为0.08, 仅有9对引物呈现多态性, 从基因型水平为系统选择提供了理论依据。对宁麦13的9个选系的分析表明, 硬度基因型全部表现为Pina-D1a/Pinb-D1b, Pinb-D1b可能来源于天然异交。角质度受环境影响大, 遗传力较低, 应结合角质度和硬度基因标记辅助选择提高籽粒品质的早代选择效率。系统选择可对重要农艺或品质性状进行改良。 相似文献
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为了明确不同地理位置杂草稻群体的遗传多样性现状、遗传分化水平以及杂草稻群体之间的基因流。本研究利用24对SSR引物对来自黑龙江、吉林、辽宁、江苏和广东共17个杂草稻群体的469份杂草稻样本进行的遗传多样性及遗传分化分析。结果表明杂草稻群体的总体遗传多样性较为丰富(I=0.36, He=0.23),不同杂草稻群体间的遗传多样性指数差异较大,He在0.07～0.35之间。AMOVA分析结果表明,杂草稻群体70%的变异来源于群体间,30%的变异来源于群体内。聚类分析显示,相邻地区的种群间相似性较高,江苏省杂草稻的不同种群间存在较高遗传分化;遗传分化与基因流结果表明,17个杂草稻种群间总的Nm值为0.117,总Fst值为0.694。地理位置较近的种群间Nm普遍较高,Fst较低;而地理位置较远的种群间Nm普遍较低,Fst较高。总之,本实验中的杂草稻群体总体的遗传多样性水平较高,群体之间的遗传多样性指数差异较大;杂草稻群体间的遗传分化显著大于群体内的分化,符合遗传距离的空间隔离模型;杂草稻群体间和地区间有一定水平的基因流,本研究对理解杂草稻在农田生态系统中的适应性进化及制定杂草稻控制策略具有重要意义。 相似文献
11.
天山蒲公英(Taraxacum tianschanicum)具有有性和无融合两种生殖方式,为了解两种生殖方式个体的性细胞分化的异同点,本研究采用常规石蜡切片法,对天山蒲公英两种生殖方式个体的大、小孢子发生及雌、雄配子体分化进行了对比观察。结果表明,无融合生殖个体与有性生殖个体的小孢子分化阶段无明显区别,四分体分化期之后,两性生殖个体的雄配子体依次分化形成单核、二核、三核花粉,而无融合生殖个体进入了雄配子体败育期;与两性生殖个体的大孢子和雌配子体分化过程相比,无融合生殖个体的大孢子母细胞不经过四分体分化期,二分体的合点端大孢子发育成胚囊,卵细胞不通过受精作用就发育成心形胚。无融合生殖个体雄配子体败育可能是胼胝质不分解或绒毡层结构发生异常所致;兼性无融合生殖特性的出现可能是该植物适应多变气候特征的进化对策。本研究可为蒲公英植物的分类和植物无融合生殖发生机理提供胚胎学参考依据。 相似文献
12.
干旱胁迫对杂种马褂木形态特征的影响 总被引：1，自引：1，他引：0
杂种马褂木(Liriodendron chinense×L. tulipifera)是一种生长快、材质好、树形美、观赏价值高的优良树种,现已广泛应用于园林绿化和用材林培育。为了了解杂种马褂木的抗旱性,笔者对南京市8年生的杂种马褂木在夏季干旱条件下的生长情况进行了调查研究。结果表明,杂种马褂木具有较强的抗旱性,但是在严重的干旱胁迫下,杂种马褂木叶片含水率和叶绿素含量明显降低,叶片发生黄化和脱落。在下蜀黄土上,如果土壤含水率低于12%,杂种马褂木会出现明显的叶片黄化和脱落现象,故在土壤含水率降低到12%之前有必要补充水分。 相似文献
13.
F. Pank F. Matzk U. Kästner W.D. Blüthner E. Foltys de Garcia A. Meister U. Ryschka G. Schumann 《Euphytica》2003,134(1):77-84
St. John's wort (Hypericum perforatumL.) is a medicinal crop plant that reproduces by apomixis. To study the reproductive diversity within the initial breeding
material, 656 plants from 92 accessions of the species were analysed by flow cytometric seed screening (FCSS) and compared
to 66 plants of cv. ‘Topaz’ as a control. Among plants from the 92 accessions, 16 were obligate sexuals, nine were obligate
apomicts and all remaining ones were facultative apomicts. Among controls, there were six obligate and 60 facultative apomicts.
Tests of reproductive pathways indicated that, in the investigated collection, all apomictic plants were tetraploid and all
sexual plants were diploid. A strategy for a cross breeding program in St. John's wort is illustrated by crossing one diploid
obligately sexual mother plant with six tetraploid facultative apomicts. All 91 F1 progeny obtained were triploid with 58% being obligate sexuals and 42%
facultative apomicts. To quantify the different routes of seed formation within facultatively apomictic individuals, the reproductive
pathways were reconstructed from about 30 single seeds from each of five tetraploid and two triploid plants using FCSS. The
frequency of seed formed by apomixis ranged from 54% to 67% among four tetraploid genotypes. One triploid and two tetraploids
formed 23% to 73% of the so-called BIII hybrids (fertilization of unreduced eggs) and one triploid was obligately sexual. The results show that while the mode of
reproduction in H. perforatum is highly variable, tetraploid obligate apomicts as well as diploid and triploid obligate sexuals can be selected as starting
material for breeding purposes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Genetic Variation for Agronomic Characters in a Burley Tobacco Synthetic Following Recurrent Selection for Increased Black Shank Resistance 总被引：1，自引：0，他引：1
Black shank, a fuagal disease caused by Phytophthora parasitica var. nicotianae, is a major hazard in the production of burley tobacco (Nicotiutta tubacum L.). Moderate levels of resistance have been bred into cultivars, but little success has been achieved in utilizing high levels of resistance found in the cigar line. Beinhart 1000-1. Beinhirt 1000-1 and seven burley cultivars were combined into a synthetic population and three cycles of selection for increased black slunk resistance were conducted. The objectives of this study were (i) t0 estimate genetic variability for agronomic traits in the original base population (Co) and die three selection cycles and (ii) to characterize the effects of selection for black shank resistance on the agronomic traits. Fifty selfed lines From the base population and each of three selection cycles were evaluated in replicated field trials at Lexington and Princeton, KY. Differences among cycle means for six agronomic traits were not statistically significant. Genetic variation for the six traits among lines within cycles was highly significant and did not change during selection. The results indicated that previously assumed associations between black shank resistance in Beinhart 1000-1 and undesirable agronomic traits were due to chromosomal linkages which were apparently broken by intercrossing. The C3 population would be a useful base population for selection to improve agronomic performance in black shank resistant genotypes. 相似文献
15.
采用胡萝卜片培养短体线虫技术,测试不同培养时间和接种密度对咖啡短体线虫(Pratylenchus coffeae)繁殖和形态的影响。结果表明,在25℃培养条件下,每片胡萝卜(厚10 mm,直径3 cm)接种25头线虫雌虫,线虫的数量随培养时间的延长而增加,前3周线虫的繁殖系数为6.24,线虫的群体数量增长缓慢;第3~6周线虫的繁殖系数略有增高,为8.99;第6~9周其繁殖系数高达17.88,线虫群体数量快速增长;之后,线虫群体数量增速下降,其繁殖系数降为1.42。在接种不同密度线虫的实验中,线虫的群体数量均显著增长,其繁殖系数在不同接种密度处理中差异不显著;随机挑取10头雄虫与雌虫,比较不同线虫密度对线虫形态特征的影响,结果表明,线虫密度除对雌虫的b值(体长/头顶至食道腺与肠连接处长)有显著影响外,对雄虫和雌虫的其他形态特征测量值均无显著影响。 相似文献
16.
高山姬鼠种群繁殖参数的变化 总被引：1，自引：1，他引：0
对1996-2008年贵州省大方县高山姬鼠种群繁殖参数的变化规律研究结果表明,高山姬鼠种群繁殖具有明显的季节周期性波动,主要繁殖期在4～9月,一年中在春季4～5月和秋季8～9月出现2次妊娠高峰期。研究期间共解剖标本1080只, 雌鼠556只,雄鼠524只,种群性比为1.06,10年平均怀孕率为20.63%,平均胎仔数为5.92只,平均繁殖指数为0.67,平均睾丸下降率为72.05%,雄鼠睾丸下降率季节变化与雌鼠怀孕率季节变化呈同步变动趋势。不同年度、不同月份、不同季节种群繁殖参数存在一定差异。不同年龄组之间种群繁殖参数存在显著差异,随着种群年龄的增长,种群繁殖力不断增加。种群繁殖参数具有明显的地理差异。 相似文献
17.
Common bean (Phaseolus vulgaris L.) is grown in regions where water deficits during reproductive development significantly
reduce yield. The purpose of this study was to evaluate the association of specific phenological and physiological traits
with drought resistance in common bean. Five genotypes were grown under and near a rain shelter in 1988, and an additional
16 progeny lines were included in 1990. Drought stress determined by the drought intensity index was severe (0.78) in 1988
and more moderate (0.63) in 1990. Water stress reduced the expression of most traits with the exception of days to flower
and leaf moisture retention capacity. Seed yield among genotypes was reduced from 22 to 71% due to drought. Yield under stress
was correlated with yield under nonstress in 1990 and negatively correlated with the drought susceptibility index in 1988.
Yield components which exhibited the largest differential genotypic responses to stress were pod and seed number, whereas
seed size was more stable. Genotypic variation was detected in all the partitioning indexes, chiefly harvest index and relative
sink strength, and the heritability estimates for these traits were high. The limited genetic variability observed among water
relations traits and their role in water conservation would restrict their potential use in the selection for drought resistance
in common bean. The differential correlations between phenological, biomass and partitioning traits and the indexes for yield
and drought susceptibility would suggest that the most effective approach in breeding for drought resistance in common bean
would be based first on selection for high geometric yield followed by selection among the high-yielding individuals for low
to moderate levels of the drought susceptibility index.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
小麦冬春轮回选择育种方法研究进展 总被引：2，自引：2，他引：0
江苏淮安地处中国南北气候分界线上(33°33′ N),冬季低于5℃的天数达112天,所有冬小麦都能通过春化,1月（最冷）平均气温在0.2℃以上,春小麦也可以安全越冬。经过多年研究与实践,利用中国独有的太谷核不育小麦、矮败小麦以及冬春性小麦品种在淮安地区开展冬春轮回选择育种,把轮回选择交配圃中生产的具有很高潜在育种价值的材料向全国更多地方的小麦育种单位提供,建立供种与优良材料部分返还制度,把冬春杂交、轮回选择和穿梭育种的优越性相结合,形成了一个投入小,效益高的小麦育种体系,并成功培育出了一系列小麦新品种,为提高小麦育种成效、丰富小麦育种手段开辟了新途径。总结了国内外轮回选择育种方法研究所取得的进展,并将以解决淮北地区小麦迟播、早熟、高产间矛盾;构建抗赤霉病轮回群体,创造出优异的赤霉病抗源;以轮回群体为材料诱导小麦单倍体育种;加强同国外科研单位的合作,引入国外优良种质资源,丰富群体的遗传变异;加强与矮败小麦育种体系单位的协作等方面的研究作为今后工作的重点,以期培育出适应性广、综合性状优良的小麦新品种。 相似文献
19.
黑线姬鼠不同体重种群繁殖力变化 总被引：1，自引：1，他引：0
对贵州省余庆县1987~2007年2563只黑线姬鼠体重统计分析,结果表明：黑线姬鼠体重最低5.36g,最高53.41g,平均体重为26.31±8.14g,其个体体重主要分布在15.01~35.00g之间,占总鼠数的79.01%,是活动能力较强的个体。黑线姬鼠怀孕鼠最低体重为17.61g,睾丸下降鼠最低体重为16.50g,体重达16.0g以上时开始繁殖,随着体重的增加,种群繁殖力不断增加,体重达24.0g以上时,种群繁殖力迅速增加,怀孕率、睾丸下降率分别达31.82%、67.02%,接近雌鼠总怀孕率30.06%和雄鼠总睾丸下降率52.67%,繁殖指数达0.7138,亦接近总繁殖指数0.7599。黑线姬鼠不同年龄组种群繁殖力存在显著差异,随着种群年龄的增长,雌鼠怀孕率、胎仔数、雄鼠睾丸下降率、繁殖指数不断增加,成年Ⅰ组、成年Ⅱ组、老年组是黑线姬鼠种群的繁殖群体,因此,它们在种群中所占比例的多少与种群数量消长关系密切,可以作为预测黑线姬鼠种群数量的重要依据。 相似文献
20.
Fertility (number of strobili) was investigated in six natural populations over three ranges of altitudes (215–960 m) in Brutian pine (Pinus brutia Ten.) for two consecutive years. The fertility and fertility variation varied among populations and years. The average of strobilus production varied between 173 and 269 in female, and between 533 and 1,060 in male, respectively. The fertility variation did not seem closely related to the altitude, and it was not consistently dependent on the richness of strobilus production. Positive significant correlations were found between female and male strobilus production for all populations and years. Coefficient of variation in strobilus production among individual trees varied between 0.638 and 0.838 for female; and between 0.603 and 0.809 for male when flowering assessments were combined. The clone fertility variations among trees were slightly different among all six stands (sibling coefficient ranged from 1.354 to 1.525) and it is unlikely that trees in typical stands vary extremely in reproductive success. 相似文献