偏型、粘型和易型小麦雄性不育系的初步研究

调查了10种不同山羊草(Aegilops)细胞质的异质小麦品种 Chris 与1B /1R 小黑麦易位系77(2)杂交 F_1及回交后代的育性表现,结果表明:1.在同核背景下,山羊草不同种的细胞质在对77(2)的育性反应上明显不同,依此差异进行特定的质核组配,能得到更宜于培育杂种小麦的新型不育系;2.不同的不育胞质在同核背景下虽都能产生雄性不育,但     

Preliminary Diallel Analysis of Anther Culture Response in Wheat (Triticum aestivum L.)

A four-parent complete dialleld mating-set of three Triticum aestivum L. cultivars ‘Edwall’, ‘Chris’ and ‘Spillman’, and an alloplasmic line of ‘Selkirk’ in Aegilops variabilis Eig. cytoplasm was used. Genetic components among total variation for callus induction, green plant percentage and green plant yield werr 92%, 80% and 77%, respectively, but lower (36%) for plant regeneration. General combining ability (GCA) variance components and narrow-sense heritabilities estimated for callus induction, green plant pereentnge and green plant yield were 74%, 66%, and 53%, and 0.68, 0.54 and 0.43. respectively. Specific combining ability (SCA) variancw was calculated as 85%) of total genctie variation for plant regeneration. Significant reciprocal effects for callus induction. green plant percentage and green plant yield were observed.     

普通玉米3个籽粒品质性状的配合力分析

以10个普通玉米自交系及其90个杂交组合在北京和山西2个地点的试验数据,分析了蛋白质、淀粉和油分含量的配合力效应。结果表明：(1) 各性状的一般配合力(GCA和特殊配合力(SCA) 均方极显著,且GCA均方大于SCA均方,说明它们在遗传上主要受加性基因效应的影响。(2) 杂交种的3个品质性状与亲本GCA平均值和SCA极显著正相关,但与亲本GCA均值间的相关性相对较强,其相关系数(r)分别为0.708**(蛋白质)、0.756**(淀粉)和0.772**(油分),表明提高亲本GCA对改良杂交种品质具有更大的作用。(3) 自交系BT1和E28的蛋白质含量GCA较高,掖478、昌7-2、掖107和48-2的淀粉含量GCA较高,E28、黄C和P138的油分含量GCA较高。     

Inheritance of threshing percentage in pearl millet

Summary The threshing percentage (TH%) has been suggested as a selection criterion to identify the pearl millet (Pennisetum glaucum (L.) R.Br.) lines with improved ability to fill and set grains under water limiting conditions. In this study, eight genetically diverse pearl millet inbreds and their 28 crosses produced by half diallel crossing design were used to examine range in TH%, to evaluate general combining ability (GCA) of parents and specific combining ability (SCA) effects of crosses. The results showed significant variation among parental lines for TH%. The inbreds differed for their GCA effects and crosses for their SCA effects. Parents with high TH% and positive GCA effects were identified. The results of the study revealed that both additive and dominance components, with the preponderance of later, were important in the inheritance of TH%. Heritability in narrow sense was moderate (55%) indicating that selection for high TH% might be effective.     

Combining ability of low phytic acid (<Emphasis Type="Italic">lpa1</Emphasis>-<Emphasis Type="Italic">1</Emphasis>) and quality protein maize (QPM) lines for seed germination and vigour under stress and non-stress conditions

Grain yield is more likely to be compromised by poor seed germination and vigour in low phytic acid (LPA) and quality protein maize (QPM) than normal maize (Nm), especially when grown under stressful tropical environmental conditions. The objectives of this study were to determine the effect of stress conditions on seed germination and vigour traits (percentage germination, seedling dry weight, average root and shoot length and vigour index) and to determine the GCA effects of the parental lines and SCA effects of the crosses. A ten parent half diallel (LPA, Nm, QPM lines) was subjected to the standard germination (non-stress) and accelerated aging (AA) (stress) tests. All seed lots were at the same physiological age and produced under the same season and conditions. Genotypic and group differences were investigated. General combining ability (GCA) and specific combining ability (SCA) effects were significant (P ≤ 0.001) for all traits under both stress and non-stress conditions indicating that both additive and non-additive gene effects were significant. Generally SCA effects were superior for all traits. The LPA lines displayed 61 % reduction in germination and 23–52 % reduction in vigour under stress conditions thereby underscoring challenges that are expected in deploying LPA maize in stress conditions. However, LPA line CM 31 exhibited large positive and mostly significant GCA effects, while two LPA × LPA crosses showed significant positive SCA effects. Results indicate breeding is required to improve both germination and vigour of the LPA lines to adapt them to tropical conditions that are generally stress-prone.     

玉米人工合成群体配合力效应及遗传潜势研究

选用6个自交系为测验种, 采用NCII遗传交配设计, 对以我国西南地区优良玉米地方种质巫溪14, 兰花早和北美, 热、 亚热带种质为主体的人工合成群体LBM、 WBM、 LLS、 WLS和两个美国优良群体BSSSR、 BS16等6个群体的配合力效应及遗传潜势进行了系统评估。 两年两地(武汉、 安阳)的研究结果表明： LBM、 WBM、 WLS群体的单株     

Responses to selection and changes in combining ability after three cycles of a modified reciprocal recurrent selection in maize

This research reports responses to selection and changes in general (GCA) and specific (SCA) combining abilities after three cycles of a modified reciprocal recurrent selection procedure (MRRS) in EPB-4 and EPB-5 maize populations. In the MRRS procedure a cycle can be completed in 1 or 2 years depending on the availability of winter breeding nurseries. The original and the three selection cycles of the two populations per se (eight entries) and the partial diallel developed from the crosses between them (16 entries) were evaluated in six environments. Realized response to selection on the population cross was 7.25% cycle⁻¹ for grain yield, −13.63% cycle⁻¹ for plant lodging, and 11.93% cyle⁻¹ for prolificacy, whereas plant and ear heights remained unchanged. GCA estimates increased with selection cycles for both populations for grain yield and prolificacy, and decreased for plant lodging, indicating that the frequency of favorable alleles with additive effects for these traits increased with the MRRS cycles in both populations. SCA estimates increased for grain yield and prolificacy indicating that the frequency of favorable complementary alleles at loci with non-additive effects in the reciprocal populations increased with the MRRS cycles. For grain yield, SCA effects increased more than GCA effects with selection cycles, indicating that MRRS exploited more the non-additive effects than the additive effects for the improvement of this trait. The overall results showed that the MRRS procedure was highly effective in improving the population cross, exploiting both GCA and SCA effects.     

粘类小麦雄性不育系F_1结实性状的遗传分析

采用MINQUE统计方法、加性-显性(AD)及其与环境互作的遗传模型,对粘类小麦雄性不育系和恢复系杂交F1小穗两边结实数、中间结实数等结实性状进行了分析。结果表明,粘类小麦雄性不育系育性恢复性主要以加性效应为主,其次是显性效应,加性方差占表现型方差的比例变幅为38%~48%;不育系(V)-90-110、(Ven)-90-110、(K)-224、(V)-224所配制的组合,在2个结实性状上,包括国内法、国际法,平均结实率均具有正向显著或极显著的加性效应,亲本5253、02-7-215、00-6-247、M8003具有使不育系恢复度提高的加性效应;双亲加性效应高的组合多数表现出其显性效应比较差;国际法恢复度高的组合(K-224×5253),究其原因是双亲国际法恢复度的加性效应高,尤其亲本5253国际法恢复度的加性效应在供试材料中是最高的,其显性效应也较高(36.14%);粘类小麦雄性不育系杂交结实率的高低与环境的互作相对较小,育性恢复性在年份间的表现比较稳定。     

Genetic analysis of resistance to nematodes in inbred maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) and maize hybrids

Nematodes cause substantial grain yield loss in susceptible maize (Zea mays L.) cultivars. This study was conducted to estimate general combining ability (GCA), specific combining ability (SCA) and genetic effects associated with nematode resistance in maize. The 30 F ₁ hybrids generated from a 6 × 6 diallel and two local checks were evaluated in 2009 at three sites in Uganda. A split plot design was used with nematode treatments serving as whole plots and the hybrids as subplots but arranged in an 8 × 4 spatially adjusted alpha-lattice design. The experiment was replicated three times. Results showed GCA to be important for the reduction of P. zeae and Meloidogyne spp. densities and increase of root mass, with a contribution of 72 to 93% of the phenotypic variance. Inbreds MP709 and CML206 had the highest GCA for Pratylenchus zeae resistance, whereas for grain yield, it was CML444, CML312 and CML395 that were outstanding. The SCA influenced plant height and grain yield under nematode infestation, contributing 43 and 58% of the phenotypic variance, respectively. Observed reciprocal differences due to maternal effects also played a role in influencing the grain yield under nematode infestation. Overdominance genetic effects explained the non-additive variance recorded for the plant height, grain yield, number of root lesions, and P. zeae and Meloidogyne spp. densities under nematode infestation. The parents MP709, CML206, 5057, and CML444 contributed most of the dominant genes for the P. zeae resistance in all their crosses. The parent CML444 contributed most of the dominant genes for improved grain yield in all of its crosses. The high GCA effects among some parents support their utility in breeding of widely adapted nematode-resistant cultivars. The dominant genes and SCA effects would favour pedigree and various sib tests to improve grain yield under nematode pressure.     

A diallel analysis of various traits in winter triticale

In triticale, preharvest sprouting tolerance is important for yield stability and quality of the grain. Therefore, an experiment was conducted to estimate quantitative genetic parameters of preharvest sprouting tolerance in triticale using a diallel of eight modern triticale cultivars and breeding lines. The 28 F₁‐hybrids and the parents were planted in the breeding nurseries in 2001 and 2002 at four locations. Heading, plant height, falling numbers of two harvest dates, thousand kernel weight (TKW) and preharvest sprouting (Spr) were measured. The heritabilities for plant height and TKW were the highest with 0.91 and 0.85, respectively. Falling number and sprouting showed heritabilities between 0.66 and 0.83. Mid‐parent heterosis (MPHET) was negative for heading, indicating a non‐significant earlier heading of the F₁‐hybrids. In plant height and TKW the heterosis was positive with 4.7% and 6.3% MPHET. Both falling numbers displayed a negative MPHET of nearly −15%. In contrast to falling numbers, the preharvest sprouting of hybrids was slightly reduced in comparison with the parents. In all traits analysed, general combining ability (GCA)‐variances were greater than specific combining ability (SCA)‐variances.     

Combining ability for seed yield traits of Chenopodium quinoa breeding lines

For a better understanding of the inheritance of seed yield traits in Quinoa (Chenopodium quinoa) Willd., a half-diallelic crossing experiment with six diverse but uniform breeding lines was conducted. True hybrid plants were detected by means of differences in panicle colour in 14 out of the 15 crosses performed. The agronomic performance of 14 F₂ populations and six parental lines was evaluated in field trials on fertile clay soil. General and specific combining ability of the lines (GCA and SCA) were estimated. Highly significant differences in GCA effects were found between the lines for plant height at maturity, early flowering, early maturity, seed yield and thousand seed weight. Significant SCA effects were only found for plant height at maturity. However, SCA effects were rather small and accounted for 7% of the total variance. The finding of large GCA effects and low SCA effects suggests that best selection results could be expected from crosses between the agronomic best performing genotypes. This revised version was published online in August 2006 with corrections to the Cover Date.     

小麦杂种后代籽粒蛋白质含量的配合力研究

选用６个蛋白质含是高低不同的亲本，采用Ｇｒｉｆｆｉｎｇ双列杂交方法二，对亲本在Ｆ１－Ｆ３的蛋白质含量配合力作了研究。结果表明，蛋白质含量的ＧＣＡ与ＳＣＡ方差均极显著，表明在要试验中基因加性效应和非加性效应均起重要作用。但由于三个世代ｇｃａＭｓ／ｓｃａＭｓ值均极显著，且随着世代的推进这一比值又逐渐增加，因此蛋白质含量在杂种后代的表现主要还是由基因加性效应决定，随着世代的推进，基因加性效应越显重要，在     

CIMMYT新型人工合成小麦Pina和Pinb基因等位变异

六倍体人工合成小麦由硬粒小麦（Triticum turgidum subsp. durum）与粗山羊草（Aegilops tauschii Coss.）杂交产生,是研究小麦进化过程中基因变异的重要材料。以国际玉米小麦改良中心（CIMMYT）提供的57份由野生二粒小麦（T. turgidum subsp. dicoccoides）与粗山羊草杂交产生的新型人工合成六倍体小麦为材料，用单籽粒特性测定仪和Pina、Pinb特异性PCR引物对其籽粒硬度变异以及控制籽粒硬度的主效基因Pina和Pinb的分布情况进行了研究。结果表明，这些材料的SKCS硬度值变异较大，从10.5到42.6，其中15~30的占78%。共有Pina-D1a、Pina-D1c、Pinb-D1h和Pinb-D1j 4种等位变异型，基因型为Pina-D1a/Pinb-D1j的8个，占14%；基因型为Pina-D1c/Pinb-D1h的49个，占86%。方差分析表明，基因型Pina-D1a/Pinb-D1j与Pina-D1c/Pinb-D1h对籽粒硬度的影响差异不显著，但父本粗山羊草和母本野生二粒小麦以及二者间的互作对籽粒硬度有显著影响，说明除Pina和Pinb外，还有其他微效基因影响籽粒硬度的形成。     

高赖氨酸玉米主要品质性状的配合力分析

用4个软质胚乳和4个硬质（或半硬质）胚乳的高赖氨酸玉米自交系，进行8×8完全双列杂交试验，分析了后代籽粒品质性状的遗传表现和配合力。软质胚乳亲本和硬质胚乳亲本杂交时，当代F1籽粒的胚乳硬质度表现出显著的正反交差异，以硬质亲本作母本时F1籽粒硬质度较高，但F2籽粒的硬质度无显著的正反交差异。硬×硬类型杂交后代的     

Combining ability under drought stress relative to SSR diversity in common wheat

Eight-parental diallel cross and SSR molecular markers were used to determine the combining ability of common wheat lines grown under well-watered (WW) and water-stress (WS) conditions. Analysis of variance of yield indicated highly significant differences among the progenies. General combining ability (GCA) determined most of the differences among the crosses. Specific combing ability (SCA) was also significant but less important. The estimates of GCA effects indicated that one line was the best general combiner for grain yield under drought. Neis genetic distance, measured using SSR markers, differed from 0.20 to 0.48 among the eight genotypes. The correlation of Neis genetic distance with SCA for grain yield and heterosis ranged from 0.4 to 0.5. These results indicate that the level of SCA and heterosis depends on the level of genetic diversity between the wheat genotypes examined. Microsatellite markers were effective in predicting the mean and the variance of SCA in various cultivars combinations. However, selection of crosses solely on microsatellite data would miss superior combinations.     

Genetics of resistance to kernel infection by Aspergillus flavus in maize *

Although kernel infection by Aspergillus flavus Link ex Fries and subsequent pre-harvest aflatoxin contamination of maize (Zea mays L.) grain are major production problems in the south-eastern United States and elsewhere in the world, limited progress has been made in developing and identifying sources for resistance. Genetics of kernel infection by A. flavus remains poorly understood. A 10-parent diallel experiment was conducted in 1992 and 1994 to study the genetic nature of percentage kernel infection (PKI) by A. flavus. General combining ability (GCA), specific combining ability (SCA), and reciprocal mean squares for PKI were significant. The GCA and SCA sums of squares were about equal. The GCA, SCA, and reciprocal effects varied across years, which implied that percentage kernel infection was greatly influenced by environments. The percentage kernel infection was always greater when Mo 17 was the male parent in a cross than when it was the female parent. The percentage kernel infection mean for female Mo 17 was 38.5% lower than that for male Mol7. Similarly, percentage kernel infection mean for female L668 was 23.7% lower than that for male L668. The use of inbred lines L729 and B73 as female parents should be avoided, as they showed significant, positive maternal reciprocal effects.     

冬小麦若干品质性状遗传及相关的研究

F_1的沉淀值、伯尔辛克值介于双亲之间,前者以正向部分显性为主,后者以负向部分显性为主,与中亲值相关显蔟,遗传力高,表明这两个性状在杂交后代易于获得遗传进展。相反,蛋白含量在 F_1出现了各种类型的表现,很难指出以哪种遗传形式为主,与中亲值无显著相关,遗传力低,表明高蛋白育种较难。但在 F_2、F_3中各组合都出现了蛋白含     

Heterosis and combining ability for grain yield and other agronomic traits in winter triticale

Hybrid breeding is a widely discussed alternative for triticale. Heterosis as well as general (GCA) and specific combining ability (SCA) effects were estimated for eight agronomic traits. The experiment comprised 24 F₁ hybrids, produced by a chemical hybridizing agent, together with their six female and four male parents, grown in drilled plots in two locations. In comparison with the mid‐parent values, hybrids averaged a 6.4 dt/ha (10.1%) higher grain yield, 8.4% more kernels per spike, a 6.8% higher 1000‐kernel weight, 9.7% lower falling number (FN) and 4.4% greater plant height. SCA effects for grain yield were significant and ranged from 4.5 to 6.9 dt/ha for grain yield. Together with GCA x location interactions, they explained most of the variation. For 1000‐kernel weight, GCA effects were predominant. SCA and interactions with location accounted for most of the variation in FN, whereas interactions were negligible for plant height. Correlations between mid‐parent and hybrid performance and between GCA and per se performance of parents were tight for all traits except grain yield, which allows for pre‐selection of parental lines. Although the amount of heterosis in triticale at present is closer to wheat than to rye, by selecting parents for combining ability and identifying heterotic patterns, grain yield heterosis of up to 20% appears sufficiently encouraging to embark on hybrid breeding.     

Analysis of diallel crosses between wheat genotypes with genetically different resistance to Pseudocercosporella herpotrichoides (Fron) Deighton

Two diallels were analysed for general combining ability (GCA) and specific combining ability (SCA) to study the resistance of crosses‐between wheat genotypes, advanced to the F₅ generation, to Pseudocer‐cosporella herpotrichoides. The parents either carried the resistance‐gene Pch‐1 or had different levels of quantitative resistance, one genotype was susceptible. At medium milk‐ripening, significant effects were‐found for GCA and SCA. GCA effects were the more important. Diallel crosses between genotypes, all carrying Pch‐1, revealed interactions‐of the gene with the genotypic background. Some combinations had a‐higher level of resistance than the best parent. In these populations'CH‐75417’ was involved as a parent. Both ‘CH‐75417’ and ‘F–210.13.4.42’ had significant GCA effects. Crosses between quantitatively resistant parents yielded populations that transgressed both parents. The increased resistance level was associated with ‘Cappelle‐Desprez’, distinguished by its high GCA. In some crosses SCA contributed significantly to an increase in resistance level. Selection for resistance within the best advanced populations is recommended since it‐takes advantage of additive gene action and the high heritability estimates based on ELISA values in plant progenies.     

Combining ability analysis for harvest index in winter wheat

Summary Cereal breeders have used harvest index (HI) as a selection criterion in segregating generations to identify physiologically superior lines with improved partitioning of total assimilate into grain. Information on combining ability for HI of the hard red winter wheat (Triticum aestivum L.) cultivars of the Southern Great Plains is not available. A study was undertaken to examine HI of seven genetically diverse winter wheat parents, evaluate their general combining ability (GCA) and specific combining ability (SCA) effects, and study correlations of HI with several agronomic traits. The seven parents were crossed in a half-diallel mating design to produce 21 crosses. The F₁'s, their F₂ progenies, and the parents were evaluated in replicated field tests at Stillwater and at Lahoma, OK. The combining ability analysis was performed using Griffing's Method 4, Model 1. The results showed significant variation among parents for HI. The GCA and the SCA effects were mostly inconsistent between generations and between environments. However, parents with consistently high HI and positive GCA estimates were identified. The progeny with high HI mostly resulted from parents with high GCA estimates. The correlations between HI and agronomic traits indicated that improvement in HI should also result in high grain yield, early maturity, and short plant height.