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1.
控制双亲混合选择对不同玉米合成群体的改良效应 总被引：4，自引：0，他引：4
基于田间试验的统计分析和SSR分子标记的遗传参数评估,分析了3个玉米人工合成群体GP3、GP4和GP5经4轮控制双亲混合选择的改良效应。结果表明,多数性状在不同群体及不同轮回间存在真实的遗传差异,粒深遗传增益以GP4＞GP5＞GP3,穗行遗传增益以GP3＞GP5＞GP4,各个群体C4的粒深、穗行均值都显著或极显著大于C0,直接选择效应显著;株高和穗位高随选择周期增加呈明显增加趋势,且GP4的增幅显著大于GP3和GP5,单株产量及穗粗的遗传增益以GP4大于GP3和GP5,各群体多数产量性状的均值以C4显著大于C0,相关选择效应显著;除株高、穗位高外,其他性状GCA变异群体间差异达显著或极显著水平,GP5多数产量性状的GCA优于GP3和GP4,各群体多数产量性状的GCA效应值随改良进展呈增加趋势,对照优势大于8%的大部分测交组合均为各群体C4所配组合,间接选择效应显著;随改良世代进行,群体部分性状的表型变异系数虽有所减小,但变化幅度不大;基于SSR分子标记估算的群体内遗传相似系数,GP3和GP4改良后代呈略增趋势,GP5变化不大,对于群体基因型数,GP3和GP4随改良代数增加呈略减趋势,GP5呈略增趋势。上述结果说明,适度控制双亲混合选择在有效改良群体的同时,还能较好地保持群体的遗传多样性,但不同基础群体及不同性状间,其改良效应存在一定的差异。 相似文献
2.
两种轮回选择方法对玉米群体主要性状的改良效果 总被引：2，自引：0，他引：2
研究了控制双亲混合选择和半同胞-S2:3(HS-S2:3)轮回选择对2个玉米基础群体P_4C_0和P_5C_0主要性状的改良效果.结果表明,对于基础群体P_4C_0,其改良群体P_4HSC_1、P_4MSC_1和P_4MSC_2的单株产量分别比P_4C_0提高21.64%,10.29%和8.70%,达显著或极显著水平;对于基础群体P_5C_0,其改良群体P_5HSC_1的单株产量比P_5C_0降低7.53%,达显著水平;改良群体P_5MSC_1和P_5MSC_2平均单株产量变化与P_5C_0相比,分别降低和提高了2.67%和3.65%,均未达到显著水平.控制双亲混合选择改良群体,其产量的显著改进伴随着株高和穗位高的显著增加;HS-S2:3轮回选择改良群体,不同基础群体,其产量和株高、穗位高的改良效果不同.两种选择方法改良群体,多数性状的表型变异系数随着选择的进行有所下降,但也有部分性状变异系数变化较小或有所增大,群体内仍保持了较丰富的遗传变异,且以控制双亲混合选择保持群体遗传多样性的效果更好. 相似文献
3.
运轮1号玉米群体轮回选择改良效果 总被引：1，自引：1，他引：0
种质资源遗传基础狭窄是制约玉米育种的重要因素,而群体轮回选择是拓宽玉米资源遗传多样性的重要方法。以具有中国reid 血缘的8 个自交系组成的群体和美国坚秆种质群体BSSS 杂交后经过一轮混合授粉形成运轮1 号玉米群体。3 轮混合选择后,以昌7-2 为测验种分析了运轮1号群体的产量性状的配合力。结果表明,群体内单株间产量配合力差异显著,遗传变异较丰富。从138 个测交种中筛选出20 个较优良的对应自交单株作为新一轮轮回选择的亲本。预计新一轮合成群体产量配合力将提高11.6%,灌浆脱水速率较对照优越,其他农艺性状也得到相应改良。 相似文献
4.
轮回选择对豫综5号玉米群体产量性状配合力的改良效果 总被引：1，自引：0，他引：1
玉米群体遗传基础广泛、遗传变异丰富,是培育优良玉米自交系的源泉。玉米群体的改良研究对玉米种质资源创新、优良自交系选育具有重要的指导意义。本研究采用NC II遗传交配设计,以豫综5号5个轮次改良群体为父本,以黄早四、丹340、中综5号、齐319、掖478、Mo17为测验种配制成30个测交组合,通过一年两点的产量性状及其配合力评价试验,研究轮回选择对豫综5号群体的改良效果。结果表明,轮回选择对群体单株产量的改良是有效的,群体与各测验种间的杂交后代产量平均每轮提高3.57%。半姊妹轮回选择和相互半姊妹轮回选择在改良群体产量一般配合力方面, 均得到显著提高,呈逐轮上升的趋势;采用半姊妹轮回选择对豫综5号群体3轮的选择后,C3群体与C0相比,一般配合力效应值从–11.63增长到5.57,差异极显著;经1轮相互半姊妹轮回选择后,群体的一般配合力效应值从C3的5.57增加到C4的9.75。豫综5号改良群体与黄早四的特殊配合力得到一定的提高,逐轮朝着Reid×唐四平头杂优模式水平提高的方向稳定发展。 相似文献
5.
对ZZ4完成了4轮MS1-HS和MS1选择.结果表明,经4轮选择的群体,两种方法均有效地保留了各主要性状的遗传方差.MS1-HS选择的群体遗传方差下降速率更慢,C4群体的单株籽粒产量的遗传方差仅减少3.7%.穗长、穗粗、粒行数、行粒数、出籽率、百粒重的遗传方差的变化与单株籽粒产量一致,MS1C4的遗传方差减少了8%～15%,MS1-HSC4的遗传方差仅减少了4%～15%.株高、穗位高、抽丝期、植株保绿度、抗倒性等相关选择性状的遗传方差的变化与产量性状基本一致.MS1-HS法对改良玉米群体籽粒产量与测验种间的特殊配合力十分有效,呈逐轮上升的趋势;改良群体与测验种综系140间的杂交后代产量平均每轮提高6%,杂种优势平均每轮提高6.9%.两种方法在改良群体产量性状一般配合力方面,均得到了良好的效果.同时,穗部性状及株高、穗位、抽丝期、散粉期、抗性等田间农艺性状的一般配合力也获得了同步改良.通过ZZ4改良群体与6个测验种间杂交组合产量及杂种优势的比较研究,得出ZZ4与黄早四类种质为杂种优势模式对. 相似文献
6.
为了对玉米群体进行合理有效的改良利用,通过改良S1选择法对12个玉米群体改良一轮后进行效果比较分析。结果表明,穗行数、行粒数和百粒重是构成产量的三因素,遗传增益最大的群体为蒙群2,其他依次为蒙群4、蒙群1等7个群体,蒙群3及3个国外引进群体遗传增益为负值;玉米群体在穗部、植株性状以及遗传变异中均存在一定的变化。试验研究得出,蒙群2、蒙群4、中综7号、蒙C群、蒙A群产量遗传增益均较大,并在其他农艺性状中改良效果显著,可直接选择优株自交进行选系,而其余7个群体遗传增益小,改良利用潜力不大。 相似文献
7.
半姊妹轮回选择对玉米群体改良效果研究 总被引：4，自引：0，他引：4
用半姊妹轮回选择法完成了对中综2号三轮改良,结果表明：该法对群体产量和配合力均有显著的改良效果。经三轮选择后平均每周期获得量为7.4;一般配合力从C0的-10
081增长到C3的15.924。二者每周期的获得量与选择轮数之间均呈显著的正相关。本研究第一轮的选择用遗传基础广泛的非亲缘综合种做测验种,二、三轮的选择用自交系 相似文献
8.
玉米“黄金”群体产量等性状轮回选择改良效果评价研究 总被引：3，自引：0，他引：3
利用群体改良方法,充分挖掘地方优异种质的遗传潜力是玉米种质改良与创新的一个重要途径。本研究以黄金群5个轮次改良群体为材料,通过1年2点产量比较试验,分析了混合选择和相互半姊妹轮回选择方法对黄金群产量及穗部性状的改良效果。结果表明,两种选择方法对群体产量改良是有效的,随着改良轮次的增加,黄金群的单株产量逐轮提高,平均每轮提高3.78%,其中,混合选择改良的3轮群体平均每轮提高4.27%,相互半姊妹轮回选择的改良群体提高2.07%;虽然群体产量的变异系数从15.43%下降到12.80%,但群体内仍有较丰富的变异。通过改良群体穗部性状比较发现,穗长和行粒数改良效果显著,分别提高14.71%和17.62%,说明它们的提高是群体单株产量提高的主要因素。 相似文献
9.
17个玉米地方种质选系的配合力分析 总被引：3，自引：0，他引：3
分析玉米地方种质选系的配合力,可以为探明自交系的应用价值提供技术支撑。选用11个自交系为测验种,采用不完全双列杂交设计,对17个玉米地方种质新选的自交系的配合力、杂种优势以及主要性状遗传参数进行了分析。结果表明:单株产量GCA表现突出,且构成产量因子性状GCA表现也较好的新选自交系有P1-1、P1-16和P1-14;SCA值高、杂种优势强的组合是P2-4×P1-10;在株高、穗位高、穗行数等4个性状中,亲本的基因加性效应对F1性状形成起主导作用,而穗长、秃尖长、百粒质量等5个性状的遗传变异主要来自于基因非加性效应。因此,对于高产组合的选配,至少要选择1个GCA高的材料作亲本,并在此基础上兼顾SCA的选择,而利用地方种质选系则应根据性状遗传特性决定其选择时期和选择强度。 相似文献
10.
11.
Long-term selection experiments provide germplasm to study the effects of selection in a closed population. Recurrent selection
to enhance grain yield in oat has been ongoing at the University of Minnesota since 1968. The objectives of this study were:
(i) estimate the GCA and SCA effects for three agronomic traits in the seventh cycle of selection, (ii) assess the effect
of the current methods of selection on parental contribution and unselected traits, and (iii) determine the direct and indirect
responses to seven cycles of recurrent selection for grain yield. Progeny of the Cycle 6 parents and parents for Cycles 0
through 7 were grown in two separate tests. Grain yield, heading date and plant height were evaluated in each test. Grain
yield was increased by 21.7% after seven cycles of selection. Evaluation of Cycle 6 progeny showed that GCA effects were significant
for all three traits studied, and SCA effects were significant only for grain yield. Four Cycle 6 parents did not have any
progeny selected as Cycle 7 parents. Results from this study indicate that long term recurrent selection has continued to
increase grain yield. Alternative selection strategies may be necessary to maintain the genetic variability in this population,
particularly when improvement of secondary traits is required.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
Long-term continuous selection is essential for germplasm improvement. However, choice of germplasm for long-term genetic improvement might limit the success of germplasm enhancement programs. The objective of this research was to report the response to long-term selection in early maturing North Dakota (ND) synthetic varieties. We wanted to determine whether the performance of three ND maize synthetic varieties was improved by long-term mass selection (M) and if the performance of one of them was improved by long-term modified ear-to-row (MER) selection. The evaluation of long-term selection response was performed at two plant densities. An experiment in a randomized complete block design with split-plot arrangement was used to evaluate NDSM(M), NDSAB(M), NDSCD(M), and NDSAB(MER) under 75,000 and 42,500 plants per hectare across seven environments. Long-term mass selection for grain yield and stalk lodging resistance in NDSM(M), NDSAB(M), and NDSCD(M) was not successful, since there were no significant changes in grain yield or stalk lodging in these populations at either low or high densities. On the other hand, long-term modified ear-to-row selection was effective for grain yield improvement in NDSAB(MER). Grain yield increased non-linearly from 3.9 Mg ha−1 in cycle 0 to 5.0 Mg ha−1 in cycle 12 at a rate of 2.5% per cycle. Interaction between plant density and genotype was not detected even though selection was performed at relatively low densities (20,000 plants ha−1 for mass selection and 50,000 plants ha−1 for ear-to-row selection). The confirmation of a lack of interaction between plant density and genotype suggests that selection at low plant densities might still be able to provide high-density stress resistance through density-independent genotypes, allowing progeny testing across multiple locations with better accuracy and fewer resources. Selection methods that emphasize both additive and dominance effects such as full-sib recurrent selection are recommended to maximize genetic improvement of advanced population cycles of early maturing synthetics. 相似文献
13.
A program was initiated in 1994 to compare the efficiency of marker-assisted selection (MAS) and conventional phenotypic selection.
A population of 300 F3:4 families was generated from the cross between two maize inbred lines F2 and F252 and selected on an index combining grain yield and grain moisture at harvest. This population was characterised for 93 RFLP
markers and evaluated as testcrosses in a large range of environments. Three methods of selection were applied (i) two cycles
of conventional phenotypic selection; (ii) two cycles of MAS based on an index combining phenotypic values and QTL genetic
values and (iii) one cycle of combined MAS followed by two cycles of selection based only on the QTL effects estimated in
the first generation. The different populations were characterised for RFLP markers. The evolution of allele frequencies showed
that selection on only-markers was very efficient for fixing QTL alleles found favourable in the initial population. This
evolution was quite different from that observed for phenotypic selection or combined MAS. Genetic gain was evaluated and
found significant for each method of selection. Nevertheless, the difference between phenotypic selection and combined MAS
was not significant. The two additional cycles of MAS on only-markers did not improve significantly the genetic value of the
population. Moreover, the genetic variance of this population remained high, despite most of the QTL initially detected were
almost fixed. The results suggest that the QTL effects estimated in the initial population were not stable due to epistasis
and/or QTL by environment interactions.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Maksimir 3 Synthetic (M3S) maize population was developed at the Faculty of Agriculture University of Zagreb by intercrossing
inbred lines, whose origins trace back to several open-pollinated varieties and local populations from different regions of
the former Yugoslavia. The population was subjected to two cycles of selfed progeny recurrent selection for grain yield. The
objectives of this study were: (i) to determine genetic distances among the parental inbred lines of the M3S population (M3S
progenitors), the M3S population before and after two cycles of recurrent selection, and elite inbred lines representing the
BSSS and Lancaster heterotic group; and (ii) to examine the effect of two cycles of recurrent selection on allele frequency
changes in the population. Nine M3S progenitors, three BSSS lines, and three Lancaster lines were genotyped at 24 SSR loci,
out of which nine randomly chosen loci were used for genotyping 96 individuals from both C0 (the M3S population before selection)
and from C2 (M3S population after two cycles of selection). A total of 101 alleles were detected across 24 loci in the 15
lines, whereas 83 alleles were found in the nine M3S progenitors. Among the latter 83 alleles 31 were unique, i.e. found only
in one of the progenitors. Mean genetic distance among nine M3S progenitors was 0.61 indicating a broad genetic base of the
M3S population. High mean genetic distance was found between M3S progenitors and BSSS lines (0.69) and M3S progenitors and
Lancaster lines (0.71). This indicates that the M3S population represents a germplasm source unrelated to both the BSSS and
Lancaster germplasm. Mean genetic distance between the M3S population and BSSS as well as Lancaster lines decreased slightly
after two cycles of recurrent selection suggesting the need to introduce testers from both groups in future selection in the
M3S population in order to maintain heterotic complementarity of the M3S population to these groups. A test of selective neutrality
identified several non-neutral loci in the population whose allele frequency changes from the C0 to the C2 cannot be explained
by genetic drift. The majority of non-neutral alleles, whose frequency increased after two cycles of selection, were present
in at least one line from the BSSS or Lancaster heterotic group. 相似文献
15.
J.B. Holland Å. Bjørnstad K.J. Frey M. Gullord D.M. Wesenberg T. Buraas 《Euphytica》2000,113(3):195-205
In order to test if selection can improve a population's adaptation to diverse environments simultaneously, three cycles of
recurrent selection based on grain yield in Iowa, Idaho, and Norway were practiced in an oat (Avena sativaL.) population developed from North American, Scandinavian, and wild species (A. sterilis L.) germplasm sources. Specific objectives were to determine if selection: increased mean yields across environments and
within all environments; changed the genetic correlation of yields in different environments; and changed genetic variation
for yield within the population. We evaluated 100 to 210 randomly-chosen families from each cycle of selection at three Iowa
locations, in Idaho, and in Norway for two years. Grain yield within each location and mean yields across locations increased
significantly over cycles of selection. Mean yields across locations expressed as a percent of the original population mean
increased at a rate of 2.6% per year. Several families from the third cycle population exhibited both high mean yields across
locations and consistently high yields within all locations. Average genetic correlations of yield in different environments
were higher in the second cycle than in the original population. A trend of reduced genetic variation and heritability was
observed in Iowa only. These results suggest that we successfully improved mean population yield both within and across locations,
and yield stability across environments, and in developing families with outstanding adaptation to diverse environments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献