Diallel analyses of soluble sugar content in cowpea (Vigna unguiculata L.Walp.)

The content of soluble sugar in cowpea(Vigna unguiculata L. Walp.) seeds is important for their acceptability to consumers. The objective of this study was to evaluate the genetic control of soluble sugar content in cowpea using diallel analysis. For this purpose,half-diallel crosses were made among seven diverse parents. The amount of total soluble sugar was estimated by the phenol sulfuric acid reagent method and reducing sugar were measured by the DNS(3,5-dinitrosalicylic acid) reagent method. The total soluble sugar ranged from 11.12(VYA) to 40.79 mg g^(-1)(IT93 K-693-2) with a mean of 22.31 mg g^(-1).Reducing soluble sugar showed a mean value of 9.11 mg g^(-1) and ranged from 13.61(TVx3236) to 4.98 mg g^(-1)(Lori niebe). Diallel analysis showed that both additive and non-additive gene effects were significant in the genetic control of these traits. However,dominance variance was greater than additive variance for soluble sugar. The traits were controlled mainly by an overdominance model, suggesting the advantage of delaying selection to later generations. Soluble sugar content was found to be highly heritable, with broad-sense heritability ranging from 0.987 to 0.976. Narrow-sense heritability ranged from0.154 to 0.422 and revealed the lower importance of additive variance. Parents and F_1 hybrids differed significantly on the basis of their general and specific combining abilities,respectively. Recessive alleles had positive effects on total soluble sugar and reducing soluble sugar. These results could help cowpea breeders improve the acceptability of cowpea seeds and cowpea-based foods by appropriate selection.

Combining ability and heterosis analysis over two environments in a diallel cross of three families of the clam Meretrix meretrix

A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix（P1, P2 and P3） was used to determine the combining ability of parental families and heterosis of F1 under indoor and openair environments for growth traits. Analysis of variance for shell length and whole body weight indicated highly significant cross effects, environment effects and the interaction of cross by environment. General combining ability（GCA） and specific combing ability exhibited great variation among crosses and between two environments. Pooled over environments, P2 was the top combiner among the three parental families for both traits studied. The cross of P1 and P3 had the highest SCA. Additionally, significant reciprocal effects were observed. For individual environment, about half of the crossbred combinations showed favorable Mid-parent heterosis（MPH）（〉1%） for the shell length and whole body weight. Our data has shown that non-additive genetic and reciprocal effects constituted the major sources of genetic variation for both shell length and whole body weight, which indicates that crossbreeding among selective families could further explore the heterotic effects.

Diallel Crossing Analyses of Resistance to Main Diseases in Pepper(Capsicum annuum L.)

Fifteen capsicum combinations were made with 6 parents by （1/2）n（n-1） diallel crossing. Genetic parameters in the resistance to TMV, CMV, phytophthora blight, bacterial spot of these combinations were studied by Hayman. The results indicated that the resistance to TMV, CMV and bacterial spot conformed genetically to the “additive-dominant” model but the resistance to phytophthora blight did not and significant epistatic dominance effect existed in it. F1 hybrid＇s resistance to CMV was controlled by homozygous dominant gene （s）, but resistance to bacterial spot by heterozygous one （s）. There were little, or no sum of dominant effect and genomes controlling the dominant expression of F1 hybrids in its phytophthora blight resistance.

Combining Ability and Parent-Offspring Correlation of Maize(Zea may L.) Grain β-Carotene Content with a Complete Diallel

Vitamin A deficiency has become a worldwide problem.Biofortified foods can potentially be an inexpensive,locally adaptable,and long-term solution to dietary-nutrient deficiency.In order to improve the β-carotene content in maize grain by breeding and minimize vitamin A deficiency,a complete diallel cross was designed with eight inbred lines of maize,and 64 combinations were obtained in this study.The experimental combinations were planted in Yunnan and Sichuan provinces,respectively,with a random complete block design.The β-carotene contents in the grains of the experimental materials were analyzed by high-performance liquid chromatography.Among the tested materials,the effect difference of general combining ability of the β-carotene content was significant;however,the effect difference of the special combining ability and the reciprocal effect were not significant.The β-carotene content of maize grain was not influenced significantly by the cross and the reciprocal cross.There was a significant correlation about the β-carotene content in the maize grains between the F 1 and their parents.The combinations with high β-carotene content were obviously influenced by the environment,and the mean value of β-carotene content for the experimental materials planted in Ya＇an of Sichuan was higher than that planted in Yuanjiang of Yunnan,with the results being significant at the 0.01 level.

Diallel Analysis for Lycopene Content in the Hybrids Derived from Different Colored Parents in Tomato

Lycopene is a red pigment in tomato with purported antioxidant properties. As the amount of lycopene has been reported to differ in different colored tomatoes or even absent in non-red tomatoes, the objective of this study was to investigate the inheritance of lycopene content and the color parameters of hybrids using a 10 parent diallel excluding reciprocals. Parents differed in general combining ability (GCA) for lycopene and color parameters. “Chocolate Stripe” (purple and brown striped) had the highest lycopene content followed by NC 1CS (red colored with the crimson gene) with the best general combining ability among parental lines. Hybrids differed in lycopene content and color parameters across two summer and greenhouse experiments, with no interaction between experiments indicating that the lycopene content was consistent. Narrow-sense heritability for lycopene was only 9% whereas broad-sense heritability was estimated to be 25%. The order of dominance for lycopene content was found as purple-brown > red > blue > yellow > green. Heritability estimates for color parameters were close to those for lycopene. This information may be useful in developing specialty type tomatoes or increasing lycopene content in tomatoes.

Gene Action Studies in the Inheritance of Economic Traits in Diallel Cross of Lentil (Lens culinaris Medik)

The present study was conducted in 4 × 4 half diallel cross fashion using the genotypes named as NL-2002, NL-2006, Punjab Masoor-2009 and Markaz-2009 for the evaluation of gene action in the inheritance of economic traits of lentil by following the Griffing (1956) Method of analysis. Minirap 13.1 Copyright© 2000, Minitab inc. Method II, Model I was used for the analysis and gene action was computed by variance component analysis using Mixed Model with GLM (general linear model) procedure. The F1 direct crosses along with the parental genotypes were then evaluated by framing the experiment in RCBD in 3 replications. The data were recorded for the characters which are under the study are, plant height (cm), number of primary branches, number of secondary branches, number of pods per plant, number of seed per pod, seed yield per plant, biomass (gram), 100 seeds weight (gram), harvest index (%), yield per plant. The simple ANOVA for all the characters revealed that difference among genotypes was highly significant. As significant differences were present between the genotypes, it permitted subsequent analysis of the data. The Combining Ability (CA) results showed that value of variance for GCA (General Combining Ability) was significantly higher than that of those of the values of variance of SCA (Specific Combining Ability). Hence current results clearly depicted the role of additive type of gene action governing the characters under study.

基于虾夷扇贝自交家系的双列杂交配合力分析

为评估“先纯后杂”种质改良技术在虾夷扇贝中的应用效果,利用3个自交F_(1)家系(21#、12#、16#)的子代,采用3×3完全双列杂交构建包含亲本正反交的9种组合,统计幼虫期和成体期的成活率性状并开展配合力分析。试验结果显示:自幼虫期3日龄起,各阶段存活率均有显著差异(P<0.05);3组亲本的一般配合力的大小和方向均不相同,在27、140、200、440日龄一般配合力差异显著(P<0.05),尤其在140日龄差异极显著(P<0.01),效应值为-6.88~8.25;在幼虫期,不同交配组合中62.96%的特殊配合力与其反交组合是相反的方向,16#×12#展现出较高的特殊配合力,最高值达18.33;在成体期特殊配合力的大小和方向也不同,从幼虫到成体的转换期(27~140日龄)多数组合出现了效应值下降趋势。21#×12#、16#×12#组合在存活率上的杂种优势展现了合理运用“先纯后杂”的育种策略的有效性;同时21#×21#、12#×12#、16#×16#组合在存活率上的优势显示了虾夷扇贝具有较强的遗传负荷清除效率。试验结果可为虾夷扇贝遗传改良提供基础数据。

A new approach to dissecting complex traits by combining quantitative trait transcript (QTT) mapping and diallel cross analysis

A promising way to uncover the genetic architectures underlying complex traits may lie in the ability to recognize the genetic variants and expression transcripts that are responsible for the traits' inheritance.However,statistical methods capable of investigating the association between the inheritance of a quantitative trait and expression transcripts are still limited.In this study,we described a two-step approach that we developed to evaluate the contribution of expression transcripts to the inheritance of a complex trait.First,a mixed linear model approach was applied to detect significant trait-associated differentially expressed transcripts.Then,conditional analysis were used to predict the contribution of the differentially expressed genes to a target trait.Diallel cross data of cotton was used to test the application of the approach.We proposed that the detected differentially expressed transcripts with a strong impact on the target trait could be used as intermediates for screening lines to improve the traits in plant and animal breeding programs.It can benefit the discovery of the genetic mechanisms underlying complex traits.

加工型辣椒主要性状的遗传效应分析

为了提高加工型辣椒优势组合的选配概率,以5个不同来源的辣椒材料作为亲本(P_(1)~P_(5)),按照Griffing完全双列杂交[p(p+1)/2]组配杂交组合,对亲本和F1的9个主要农艺性状的杂种优势、配合力和遗传力进行分析。结果表明,单株结果数、单株产量、株高和株幅的杂种优势潜力较大。果肉厚度和茎粗的变异系数较大,分别为13.80%和12.25%。配合力分析表明,P_(4)可以作为培育出单株结果数较多品种的亲本;P_(5)可以作为培育出大果、高产品种的亲本;P_(1)×P_(2)为单果质量较大的杂交组合;P_(1)×P_(4)为株高和株幅较大、果肉厚度较小、单株结果数多的杂交组合。遗传力分析表明,单株产量和果实横径的狭义遗传力大于90%,受加性效应控制;株幅和茎粗的环境方差均大于遗传方差。遗传相关性分析表明,辣椒单株产量与果肉厚度、果实横径、单果质量、果实纵径呈极显著正相关。研究结果为加工型辣椒育种进程中的亲本选配和后代选择提供了一定的理论依据。

Combining ability and gene action studies for yield and fibre traits in Gossypium arboreum using Griffings numerical and Haymans graphical approach

Background For the purpose of utilising hybrid vigour to produce possible hybrids with a suitable level of stability,the knowledge of gene activity and combining ability is a crucial prerequisite before choosing desirable parents.The present study was carried out with six parents crossed in full diallel fashion and generated 30 F1 hybrids.These hybrids were evaluated in two replications in Randomized Block Design at Department of Cotton,TNAU for combining ability and gene action.Diallel analysis was carried out according to Griffing’s method-I(parents + F_(1) + reciprocals) and model-I and Hayman’s graphical approach by using INDOSTAT software.Results Analysis of variance for combining ability indicated that mean square values of GCA,SCA and reciprocals were highly significant for all the traits except for the uniformity index.RG763 and K12 showed highly positively significant GCA effects for most of the yield traits while PA838 and K12 for fibre quality traits,so they were found as best general combiners.PAIG379 × K12 and PDB29 × K12 for yield traits,and PDB29 × PA838,RG763 × PA838,and CNA1007 × RG763 cross combinations for fibre quality traits could be recommended for future breeding programms.Conclusion The results of both Griffing’s and Hayman’s approaches showed that non-additive gene action predominates as SCA variance was bigger than GCA variance,so heterosis breeding is thought to be a more fruitful option for enhancing GCA of many traits.

A novel procedure for identifying a hybrid QTL-allele system for hybrid-vigor improvement, with a case study in soybean(Glycine max)yield

“Breeding by design” for pure lines may be achieved by construction of an additive QTL-allele matrix in a germplasm panel or breeding population, but this option is not available for hybrids, where both additive and dominance QTL-allele matrices must be constructed. In this study, a hybrid-QTL identification approach, designated PLSRGA, using partial least squares regression(PLSR) for model fitting integrated with a genetic algorithm(GA) for variable selection based on a multi-locus, multi-allele model is described for additive and dominance QTL-allele detection in a diallel hybrid population(DHP). The PLSRGA was shown by simulation experiments to be superior to single-marker analysis and was then used for QTL-allele identification in a soybean DPH yield experiment with eight parents. Twenty-eight main-effect QTL with 138 alleles and nine QTL × environment QTL with 46 alleles were identified, with respective contributions of 61.8% and 23.5% of phenotypic variation. Main-effect additive and dominance QTL-allele matrices were established as a compact form of the DHP genetic structure. The mechanism of heterosis superior-to-parents(or superior-to-parents heterosis, SPH) was explored and might be explained by a complementary locus-set composed of OD+(showing positive over-dominance, most often), PD+(showing positive partial-to-complete dominance, less often) and HA+(showing positive homozygous additivity, occasionally) loci, depending on the parental materials. Any locus-type, whether OD+, PD + and HA+, could be the best genotype of a locus. All hybrids showed various numbers of better or best genotypes at many but not necessarily all loci, indicating further SPH improvement. Based on the additive/dominance QTL-allele matrices, the best hybrid genotype was predicted, and a hybrid improvement approach is suggested. PLSRGA is powerful for hybrid QTL-allele detection and cross-SPH improvement.

木荷全同胞家系生长与分枝性状的遗传变异及效应分析

【目的】揭示木荷Schima superba F1代全同胞家系的生长与分枝性状的遗传变异规律,为木荷科学育种提供依据。【方法】以2015年在浙江龙泉营建的4×4半双列交配设计的木荷全同胞家系测定林为研究对象,对木荷亲本组合生长与分枝性状的遗传变异参数、一般配合力(GCA)和特殊配合力(SCA)等进行分析。【结果】6年生木荷全同胞家系间的生长和分枝性状存在极显著差异(P<0.01)。生长和分枝性状的变异系数为20%~53%。木荷的生长和分枝性状受较强的遗传控制(全同胞遗传率为0.86~0.93),其中,生长性状的父本遗传率更高,受基因加性和显性效应共同控制;分枝性状的母本遗传率更高,受基因加性效应控制。相关分析表明:木荷全同胞子代生长和分枝性状存在极显著的表型相关(r=0.20~0.87,P<0.01),胸径生长与一级分枝数、枝下高呈极显著遗传相关(r=0.67~0.70,P<0.01)。生长和分枝性状的GCA和SCA效应均达到显著(P<0.05)和极显著(P<0.01)水平。根据GCA和SCA的结果,认为江西上犹和福建连城的优树为优良亲本,两者组合具有速生性状的特殊配合力效应,初选的6株优良全同胞子代可作为2代育种亲本材料。【结论】6年生木荷全同胞家系生长和分枝性状受较强遗传控制,生长性状父本控制力更强,分枝性状母本控制力更强。根据生长性状和分枝性状分别对亲本进行选配,可以得到速生优质的超级亲本组合。

茄子青枯病抗性遗传效应分析

【目的】解析茄子青枯病抗性遗传规律,为选育抗病杂交组合、优势育种及挖掘相关抗病基因提供理论支持与技术指导。【方法】以4份茄子种质(Y23、NO21、JA02和SG19)为亲本,通过Griffing完全双列杂交方法对各组合青枯病抗性进行配合力分析;分别构建2个杂交组合SG19×Y23和B1×BC03的6世代遗传群体(P_(1)、P_(2)、F_(1)、F_(2)、BC_(1)P_(1)和BC_(1)P_(2)),采用数量性状主基因+多基因世代联合分析法,对各世代青枯病抗性进行遗传模型分析。【结果】茄子青枯病抗性一般配合力远高于特殊配合力,说明抗性以加性效应为主,其次是非加性效应,受到细胞质基因遗传的影响较小;广义遗传力为69.8%,狭义遗传力为63.3%,说明茄子青枯病抗性的遗传不仅受遗传效应的影响,同时也受环境效应影响;抗青枯病的优良杂交组合为Y23×NO21和NO21×Y23;杂交组合SG19×Y23和B1×BC03的抗性均符合MX2-ADI-ADI遗传模型,即由2对加性—显性—上位性效应主基因+加性—显性—上位性效应多基因控制,以加性效应为主,感病表现为不完全显性,BC_(1)P_(2)群体和F_(2)群体以主基因遗传为主,主基因遗传率为77.112%~88.417%,BC1P1群体以多基因遗传为主,多基因遗传率为35.332%~75.050%。通过发病时期作为病情评价标准估算出的最优遗传模型与通过病级分布估算出的最优模型一致。【结论】在青枯病抗病育种过程中应注意加性效应的利用,尽可能选用青枯病抗性强的亲本进行杂交育种;在后续开展基因定位过程中,可利用2对主基因+多基因控制青枯病抗性的理论作为抗性基因定位的依据,避免抗性基因挖掘的盲目性。

DH血缘对玉米单倍体诱导率和自然加倍率的影响

通过对4份Lancaster种质进行双列杂交和统计分析,研究含有DH系的基础材料对单倍体诱导率、散粉率和自然加倍率的影响。结果表明,不同基因型材料的诱导率为3.6%~11.4%,散粉率为11.4%~40.0%,自然加倍结实率为3.4%~14.1%;来源不同的单倍体株系的诱导率、散粉率以及结实率均表现出相同的趋势,由高到低排序依次为双亲都为DH系的基础材料、双亲有1个为DH系的基础材料、双亲无DH系的基础材料。以含有DH系的基础材料具有较高的诱导率、散粉率和结实率。将优秀自交系与选育的DH系进行杂交,有助于提高诱导效率和加倍效率,使优良基因充分聚合,实现轮回上升式改良种质的目标,旨在为提高单倍体育种效率提供理论依据。

不完全双列杂交玉米组合抗倒伏综合评价

【目的】研究36份玉米杂交组合产量性状与茎秆力学倒伏综合评价,筛选出抗倒伏强的品种。【方法】以4份玉米自交系为测验种,9份玉米高代系为待测系,采用NCⅡ不完全双列杂交组配设计,对其茎秆性状及产量性状进行相关性、主成分、隶属函数、聚类分析,综合评价36个杂交组合的产量因子和茎秆性状。【结果】不同玉米杂交组合单株粒重与基部第3节穿刺强度、穗下第1节穿刺强度、基部第4节弯曲强度、穗下第1节弯曲强度和茎秆抗推力表现为极显著正相关,分别为0.451^(**)、0.588^(**)、0.459^(**)、0.422^(**)和0.490^(**);单株粒重与茎粗均表现为负相关;株高、行粒数、单株粒重与茎秆抗推力呈显著正相关关系,分别为0.388、0.387、0.490;穗高、秃尖、穗粗、轴粗、生育期与茎秆抗推力呈负相关关系;通过主成分分析,8个性状进行主成分分析,前5个主成分其累计贡献率达到了89.98%。【结论】结合隶属函数、贡献率计算权重、综合评价36个玉米杂交组合抗倒伏、宜机收能力的综合评价D值,并进行聚类分析,将其划分为三类,9个综合指标强的组合,14个综合指标弱的组合,13个综合指标中等的组合。

不同壳色菲律宾蛤仔品系间的双列杂交

于2006年秋,以"海洋红"(R)、白蛤(W)、斑马蛤(Z)为材料,开展了不同壳色菲律宾蛤仔品系间3×3的双列杂交。实验由3个自交组R×R、W×W、Z×Z和3个杂交组R×Z、W×Z、W×R,即6个正反交RZ、ZR、WZ、ZW、WR、RW组成,研究了子一代在不同阶段生长、变态、存活的杂种优势及壳色遗传机制。结果表明,在不同阶段,不同杂交组合的杂种优势表现程度不同。浮游期间,各杂交组幼虫生长优势(Hg)随着日龄而增大,存活优势(Hs)与日龄几乎无相关性,其值分别为Hg=6.20±2.43,Hs=14.83±0.28。W×Z杂交组合表现出明显的杂种优势,其值分别为Hg w×z=8.50±2.79,Hs w×z=20.59±0.98,与R×Z、W×R杂交组差异显著(P<0.05)。杂交有效地提高了变态率,缩短了变态时间;变态率的杂种优势为Hm=15.84,平均缩短变态时间2d。室内培育期间,刚刚完成变态的稚贝很快表现出生长优势,而后一段时间才表现出存活优势,其值分别为Hg=8.98±2.91,Hs=8.11±8.18;W×Z杂交组合的杂种优势为Hg w×z=15.93±6.47、Hs w×z=8.78±8.76,Hg w×z与R×Z、W×R杂交组差异显著(P<0.05),Hs w×z与W×R杂交组差异显著(P<0.05)。养成期间,幼贝的杂种优势分别为Hg=12.77±1.20,Hs=49.85±1.93;W×Z杂交组合的杂种优势分别为Hg w×z=20.92±1.98,Hs w×z=61.60±1.38,与其它杂交组的显著性差异程度与稚贝期相同。从总体水平上分析,幼虫、稚贝、幼贝生长速度的杂种优势分别为15.06、17.40、15.77,彼此间无显著性差异(P>0.05);综合各阶段的杂种优势,3个杂交组的杂种优势大小顺次为:W×Z>R×Z>W×R。R×Z、W×Z、W×R的子一代的壳色分别表现为:红斑马、白斑马(左壳背部有一条深色条带)、中红(左壳背部有一条深色条带),且正反交的壳色表现一致,说明壳色表现形式与性别无关,为非伴性遗传。

棉花耐盐性的双列杂交分析

根据Ｈａｙｍａｎ的方法，对６个耐盐性不同的棉花品种（系）及其１５个半双列杂交组合的Ｆ１、Ｆ２ 代的平均盐害级别进行了双列杂交分析，结果表明，耐盐和盐敏感品种的一般配合力效应差异达极显 著水平，耐盐×盐敏感组合的特殊配合力普遍低于盐敏感×盐敏感、耐盐×耐盐组合。因此，棉花耐 盐育种以配制耐盐×盐敏感组合为最佳。棉花耐盐遗传参数估计说明，棉花的耐盐性存在着加性和显 性效应，以加性效应为主，耐盐性呈不完全显性，受一对主效基因控制。Ｆ１和Ｆ２代的广义遗传力接 近，Ｆ２代的狭义遗传力高于Ｆ１代，且狭义遗传力较高。因而，在Ｆ２代选择改良棉花的耐盐性是可能 的。

马尾松纸浆材重要经济性状配合力及杂种优势分析

报道了马尾松不同种源优良无性系 6× 6全双列交配的 7a生遗传测定林的分析结果。研究发现 ,树高、胸径和材积生长、干物质积累及木材基本密度等纸浆材主要经济性状的一般配合力 (GCA)和特殊配合力 (SCA)效应极为显著 ,但显性基因效应起主导地位 ,加性基因效应次之。基因上位效应则因性状而异 ,仅对木材基本密度作用显著 ,而对树高、胸径、材积生长和干物质积累作用较小或可忽略。马尾松生长和材质材性指标的遗传控制模式不同于玉米、杉木等研究结果 ,这可能与交配亲本来源于不同地理种源及经过一般配合力间接选择有关。马尾松生长性状普遍存在自交衰退现象 ,一般配合力小的亲本自交衰退程度有增加的倾向。马尾松不同交配组合间的杂种优势差异巨大 ,正反交杂种优势在总体上大致相似。研究虽然发现一般配合力较高的亲本间杂交在材积增加和干物质积累等性状上会产生强杂种优势的倾向 ,却无明显的规律可寻。以干物质指数作为主要筛选指标 ,初选出

能源甘蔗主要经济和光合性状的遗传分析

以 4× 5不完全双列杂交 (NcII)衍生的 2 0个家系实生苗为材料 ,对其主要经济和光合性状的遗传力和配合力进行分析 .结果表明 :(1)锤度、株高和茎径的遗传主要由加性基因效应引起 ,而丛有效茎数、丛重、锤重和地上部鲜重的遗传主要由非加性基因效应引起 ;(2 )配合力分析表明 ,CP84 / 1198、CP74 / 383、崖 90 / 3、桂 73/ 16 7和科 5各性状 gca较大 ,是较好的高生物量高光效亲本 ,CP84 / 1198×Ya 90 / 3、CP85 / 14 32×桂 73/ 16 7、CP74 / 383×桂 73/ 16 7、CP85 /14 32×科 5各性状sca和tca较大 ,为较好的高生物量高光效组合 ;(3)茎径、锤度和丛重母本gca方差大于父本 gca方差 ,丛有效茎数、锤度和地上部鲜重的广义遗传力在 5 0 %以上 .表 7参

马尾松生长性状交配效应的遗传分析及杂交组合选择

利用2份6×6全双列交配设计子代测定林材料,对马尾松生长性状的配合力、杂种优势和自交效应等进行分析。结果表明:2份测定材料的树高、胸径和材积等生长性状的一般配合力、特殊配合力和正反交效应都极为显著,这些性状的遗传是由加性和非加性基因共同控制,其中非加性效应起主导作用,加性基因效应相对较小,而基因上位效应材料Ⅰ(1992年制种)明显大于材料Ⅱ(1993年制种)。马尾松生长性状的特殊配合力效应明显大于一般配合力效应,这可能与亲本来源于不同地理种源和经过一般配合力间接选择有关。马尾松生长性状普遍存在自交衰退现象,2份材料中各亲本树高、胸径和材积的平均自交衰退程度分别为-17.8%^-18.4%、-23.3%^-27.7%和-44.3%^-50.6%,一般配合力小的亲本自交衰退程度呈明显增加趋势。马尾松不同交配组合间的杂种优势差异巨大,正反交杂种优势在总体上大致相似。以材积为评选指标,2份材料各选出10个优良杂交组合,其平均材积增益分别为测验群体的59.41%和41.76%,是对照的100.58%和74.61%。