小麦细胞膜热稳定性的配合力与杂种优势分析

细胞膜热稳定性是较好地反映小麦品种耐热性大小的重要生理指标.本文利用冬、春小麦各6个亲本分别组配的6×6完全双列杂交(包括反交),对该性状(以相对热损伤率RI%表示)进行了配合力和杂种优势分析.结果表明:(1)该性状的一般配合力效应(GCA)、特殊配合力效应(SCA)和反交效应(R)均达极显著水平.上述三因素相对作用大小冬、春小麦分别为3.9:1:1.6和2.1:1:0.5,说明该性状的遗传虽以加性基因效应占一定优势,非加性基因效应和反交效应也起重要的作用.(2)该性状受质核互作和(或)细胞质的明显影响.(3)一些杂种F_1的细胞膜热稳定性具有明显的杂种优势,并存在超亲遗传现象.这将对小麦的耐热性遗传改良和杂种优势利用提供理论指导和依据.     

冬小麦品种籽粒平均灌浆速率的遗传机制研究

研究采用Griffing方法Ⅰ,利用6×6完全双列杂交,对6个冬小麦品种的籽粒平均灌浆速率的遗传机制进行了初步探讨.结果表明平均灌浆速率的一般配合力(GCA)效应、特殊配合力(SCA)效应和反交(R)效应均不同程度的达到显著和极显著水平,其均方比1.4268∶1.6839∶1;平均灌浆速率遗传以非加性基因效应占优势,加性基因效应次之;其广义遗传力为60.67%,狭义遗传力为78.69%.以综合性状评价河农2552品种为好.     

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。     

印水型杂交粳稻产量及产量构成因素的配合力分析

为确定新育成印水型杂交粳稻亲本的潜力,并为印水型杂交粳稻育种提供理论基础,本研究以4个不育系和4 个恢复系为亲本进行不完全双列杂交,研究产量及其构成因素的配合力。结果表明：产量性状一般配合力(GCA)方差均达到极显著水平,除结实率外,父本的一般配合力方差大于母本,单株产量、有效穗和结实率的特殊配合力(SCA)方差达到显著或极显著水平。139A和晚轮422 的GCA效应较高,产量性状以Ⅱ类为主,139A×晚轮422 和辽粳10A×晚轮422 的单株产量水平及组合SCA效应较高。父本GCA效应和组合SCA效应对产量性状的影响较大,母本GCA效应对产量性状的影响相对较小。本研究中,父本的遗传差异大于母本,对产量性状的影响也大于母本,139A和晚轮422 有较大的应用潜力。     

玉米穗部产量性状配合力和遗传参数分析

利用13份玉米自交系按不完全双列杂交组配成40个组合,对其穗部产量性状的一般配合力(GCA)、特殊配合力(SCA)和遗传变量进行估算分析。结果表明,除出子率外,所考察性状的GCA和SCA都达到极显著差异。R258和H24综合性状较优,是可用来组配强优势杂交组合的优良自交系。     

玉米和紫苜蓿配合力的稳定性分析

分析了玉米和紫苜蓿的五个双列杂交试验,结果表明,在采用稳定材料进行两种配合力的研究中,除个别性状外.其余各性状均表现GCA(一般配合力)×环境互作大于SCA(特殊配合力)×环境互作而SCA的SSs/(SSs+SSsc)×100比值小于GCA的SSg/(ssg+SSgc)×100,说明在不同环境中GCA较SCA稳定.但两种配合力与环境互作同相应主效的比值表现出SCA大于GCA的趋势.放在不同环境中应着重测定GCA,而在特定环境中则不能忽视SCA的测定.GCA与环境的工作主要是不同环境中方差值的变化所致,其本质则是生态因素对性状影响的差异.     

大麦花药培养力的遗传模式分析

用轮回式部分双列杂交法对大麦花药离体培养力进行基因型差异及配合力分析。结果表明, 花药愈伤组织诱导率的基因型差异显著;一般配合力(GCA)和特殊配合力（SCA）是相互独立的, 且其方差均达极显著水平;遗传的差异既包含加性效应,也包括显性效应,但加性效应更为重要。因而针对花药愈伤组织诱导率而言,GCA效应是首要的,在GCA效应高的基础上,选配SCA效应高的组合,通过杂交可以选育出花药愈伤组织诱导率高的基因型。     

玉米高赖氨酸和糯性基因聚合材料品质性状的配合力分析

为了解玉米高赖氨酸和糯性基因聚合材料品质性状的配合力效应,以优质基因聚合系及其亲本和常用玉米骨干自交系为材料,按9×15不完全双列杂交设计,进行品质性状的配合力研究。结果表明:5个品质性状的GCA和SCA均存在显著差异;各性状的GCA方差均大于SCA方差,GCA方差占基因型方差比例的大小顺序是含油量淀粉蛋白质谷氨酸赖氨酸;综合品质性状表现,三基因聚合材料QCL 8002-11(o2o16wx)和QCL 8006-2(o2o16wx)分别在增加赖氨酸含量和含油量方面有比较好的利用潜力,两基因聚合材料QCL 8009-5(o16wx)对增加谷氨酸和蛋白质含量、QCL 8003-2(o2o16)和QCL 8001-10(o2o16)对增加总淀粉含量有较好的利用潜力。     

棉花复合杂交育成亲本主要产量性状的杂种优势及配合力分析

为测定利用复合杂交育成的5个亲本的育种应用潜力,将5个亲本与4个推广品种采用不完全双列杂交设计配制20个组合,对组合的产量及相关性状的杂种优势进行分析,并对5个亲本的产量及相关性状进行配合力分析.结果:铃数对产量的贡献最大;A1亲本在铃数,A2亲本在衣分,A3亲本在铃重,A 5亲本在铃重、衣分性状上一般配合力(GCA)为正,A 5亲本是一个较理想的亲本;具有较高特殊配合力效应(SCA)的组合有A5×B3、A2×B2、A3×B1.结论:利用复合杂交培育高配合力亲本是可行的;但不同来源的亲本在同一性状,同一亲本的不同性状间一般配合力(GCA)是不同的;同一性状的不同组合间,同一组合的不同性状间特殊配合力(SCA)效应也都存在大小或方向上的差异.     

水稻抗性淀粉含量性状的配合力分析

抗性淀粉对人体具有多种重要的生理功能,为了获得具有高抗性淀粉含量的水稻杂交后代,选用6个抗性淀粉含量具有显著差异的水稻品种按Griffing双列杂交设计配置成杂交组合,及正反交F1为材料研究了水稻籽粒抗性淀粉含量性状的遗传规律。结果表明,水稻抗性淀粉含量在参试组合中加性效应起主要的作用,同时受非加性效应以及细胞质效应的影响。一般配合力(GCA)效应在各亲本间存在明显差异,‘降糖稻1号’和‘丙9331’亲本均表现很高的正向一般配合力(GCA)效应值,其一般配合力效应值分别为0.303和0.101。其他品种均表现负向一般配合力(GCA)效应值。亲本本身的抗性淀粉含量与一般配合力的表现趋势一致,与相应的特殊配合力(SCA)有明显的相关性,与杂种一代表现有显著的相关性,表明利用亲本表型值对于预测组合的杂种优势具有一定的意义。     

籼型染色体置换片段在杂交粳稻中的配合力分析

利用10个以粳稻为遗传背景、籼稻为供体的染色体片段置换系(CSSL)及6个粳稻测验种, 按NCII设计, 分析了籼粳亚种间杂种在10个染色体区段上的配合力效应及遗传力等参数。结果表明, 除千粒重外, 各置换系主要产量构成性状的GCA值均高于背景亲本Asominori, 其中带有第12、第4、第1和第11染色体片段的AIS84、AIS27、AIS3、AIS80和AIS76置换系产量相关性状的GCA综合表现最好。说明在染色体片段水平上, 水稻籼粳亚种主要产量构成性状的杂种优势都大于粳亚种内的杂种优势, 对粳稻基因组导入籼稻X24-2~R367 (Chr.12)、R1854~R288 (Chr.4)、C970~C955 (Chr.1)、C1350~R257 (Chr.11)和X52~R2913 (Chr.11)染色体片段, 可显著提高杂交粳稻的产量水平。同一亲本所配的不同组合及同一组合在不同性状间的特殊配合力差异较大, 最高或最低SCA的组合可来自不同GCA的亲本组合类型, 表明在一般配合力与特殊配合力间不存在必然的联系。在双亲一般配合力均高的前提下结合较高的特殊配合力是超高产杂交稻育种中亲本选择的基本原则。     

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.     

Genetic analysis of mechanisms associated with inheritance of resistance to sheath rot of rice

Understanding genetic mechanisms controlling inheritance of disease resistance traits is essential in breeding investigations targeting development of resistant genotypes. Using North Carolina design II, 32 F₁ hybrids were generated by crossing eight susceptible to four resistant parents and submitted for field evaluation. The analysis of general and specific combining ability (GCA and SCA) indicated involvement of additive and non‐additive gene action controlling inheritance of horizontal resistance to sheath rot of rice. High GCA/SCA ratio and high heritability estimates revealed additive effects and were more predominant than none additive ones. The level of dominance indicated dominant genes was more important than recessive genes. Estimates of GCA and SCA analysis suggested that crop improvement programmes should be directed towards selection of superior parents or good combiners, emphasizing on GCA. As far as source of resistance is concerned, most promising genotypes were Cyicaro, Yunertian and Yunkeng. The predominance of additive genetic effects together with the relevance of dominant genes suggested possibilities of improving the resistance by introgression of resistance genes through recurrent selection coupled with phenotypic selection.     

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.     

Genetic control of seedling tolerance to aluminum toxicity in rice

An uncomplete diallel analysis was conducted for 56 F1 progenies derived from 8 male × 7 female parents with differential Al tolerance based on root tolerance index (RTI) in a solution culture with Al concentration of 1 mM Al. Remarkable variation in RTI among the parents was observed after 6 weeks in culture. Significant (P < 0.001) general combine ability (GCA) variance for both male and female parents and specific combine ability (SCA) variance were observed. The variance of GCA was much higher than that of SCA, indicating greater additive expression of the tolerant trait. Higher narrow-sense heritability (48%) was detected, indicating the possibility of a genetic gain in selection for Al tolerance based on RTI. The tolerant performance of F1 progenies appeared to be influenced by the susceptible genotype. suggesting the inconsistent dominance effect. The possible mechanisms of the apparent inconsistent dominance was discussed in terms of the genetic background in wheat. Two restore lines, Pedel and 02428, and one sterile variety, XieqinzaoA, were found to be high in the GCA effect and SCA variance in this case. These genotypes may be useful in development of hybrid rice production on acid soils. This revised version was published online in July 2006 with corrections to the Cover Date.     

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.     

Response to selection, combining ability and heritability of coleoptile length in winter wheat

Selection of winter wheat cultivars with long coleoptiles is an important component of improving emergence, weed suppression and grain yield in low rainfall regions of the world. Seven winter wheat cultivars were hybridized in a Griffing’s half-diallel mating design, method 2 (reciprocals excluded, parents included), model 1 (fixed), and the progeny analyzed for coleoptile length in the F₁ through F₄ for response to selection, general combining ability (GCA), specific combining ability (SCA) and heritability. Highly significant differences existed for GCA among progeny in each generation. SCA was highly significant in the F₁, F₂ and F₄, although SCA estimates were inconsistent among generations in each progeny population. The SCA/GCA ratio was 0.15, 0.11, 0.06 and 0.04 in the F₁ through the F₄, respectively, indicating that additive effects increased with homozygosity. Broad-sense heritability for coleoptile length was estimated at 0.86, 0.76, 0.60 and 0.78 for the F₁ through the F₄, respectively. Realized heritabilities ranged from −0.16 to 0.85 with a mean of 0.32 in the F₃ and ranged from −0.68 to 0.68 with a mean of 0.13 in the F₄. Spearman’s rank correlation coefficients (R_S) were significant for all generation comparisons except the F₁:F₂, indicating that changes in rank for coleoptile length were insignificant. Cultivars with long coleoptiles and high GCA were the best parents for improving coleoptile length. Sustained selection over generations for coleoptile length was more effective than one generation of selection for genotypes both with and without reduced height genes.     

水稻广亲和品种农艺性状的配合力分析

用９个水稻不育系与３个广亲和品种进行不完全双列杂交，对其杂交组合１０个性状的配合力效应分析结果表明，就杂种Ｆ１主要农艺性状而言，亲本的一般配合力效应比组合特殊配合力效应更为重要；株高、单株有效穗数、穗长、每穗实粒数、结实率、单株粒重、千粒重等性状，以一般配合力作用为主，而每穗总粒数、生育期、着粒密度等性状虽以一般配合力作用为主，但特殊配合力的作用也不可忽视；株高、单株有效穗数、穗长、每穗实粒数。结实率、单株粒重等性状以广亲和品种的一般配合力作用为主；生育期、每穗总粒数、千粒重、着粒密度等性状以不育系的一般配合力作用为主。     

Cytoplasmic effects on quality traits of bread wheat (Triticum aestivum L.)

The inheritances of thousand kernel weight (TKW), protein percentage, protein quality and grain hardness were studied through an 11 x 11 complete diallel set of bread wheat genotypes consisting of four alloplasmic lines of Selkirk, two alloplasmic lines of Siete Cerros 66, and five commercial cultivars. Genetic components accounted for 93%, 90%, 78%, and 92% of total variation for TKW, protein percentage, protein quality, and grain hardness, respectively. General combining ability (GCA) effects were dominant for TKW (48% GCA, 38% SCA [specific combining ability], and 7% reciprocal effects [RE]), protein percentage (70% GCA, 10% SCA, and 10% RE), and grain hardness (59% GCA, 29% SCA, and 4% RE). However, SCA effects dominated for protein quality (30% GCA, 43% SCA, and 5% RE). Broad- and narrow-sense heritabilities were estimated at 0.95 and 0.65 for TKW, 0.94 and 0.82 for protein percentage, 0.83 and 0.47 for protein quality, and 0.95 and 0.74 for grain hardness. Reciprocal effects were highly significant for all quality traits, but less effective than additive and non-additive gene effects. Aegilops cylindrica, Ae. ventricosa, and Triticum turgidum cytoplasms showed positive effects on TKW in some crosses. Ae. cylindrica, Ae. variabilis, and Ae. uniaristata cytoplasms seemed to have potential for improving protein percentage. T. aestivum cytoplasms were superior to alien cytoplasms for protein quality. Bolal 2973, Kiraç 66 and Bezostaja 1 cytoplasms increased protein quality in some crosses. Ae. cylindrica, Ae. variabilis, Ae. ventricosa and Ae. uniaristata cytoplasms had significant effects on grain hardness. The cytoplasmic variation in B type T. aestivum cytoplasm was found to be significant for all traits.