Combining Ability and Genetic Effects of Germination Traits of Brassica napus L.Under Waterlogging Stress Condition

Cross combinations from six rapeseed cultivars and lines were evaluated under waterlogging stress condition in order to understand the genetic mechanism of waterlogging tolerance of Brassica napus L.and provide reasonable improvement programs.There were six germination traits investigated on combining ability and heritability using complete diallel crossing method designed for 30 combinations from those six cultivars and lines.The traits included relative root length,stem length,fresh weight per plant,survival rate,electrical conductivity,and vigor index.After flooding treatment,the six traits of parents and F1 were analyzed.The general combining ability（GCA） and special combining ability（SCA） of germination traits were analyzed using Griffing I method.Among 30 cross combinations,the GCA was significantly different among six waterlogging resistance traits.The SCA of these traits was significantly different except the SCA of electrical conductivity.As a representative trait of waterlogging tolerance in rapeseed,relative vigor index had the highest narrow heritability and relatively low broad heritability.The cultivars Zhongshuang 9 and P79 had higher tolerance potential to waterlogging stress.It can be concluded that combining ability and genetic effects of relative vigor index during germination stage could be used to identify the waterlogging tolerance of rapeseed in breeding program.     

Analysis on Breeding Potential of 17 Maize Inbred Lines from Land Races

[Objective] The primary objective of this study was to estimate combining ability and genetic parameters of 17 new inbred lines.[Method] By using 11 commonly used maize inbred lines from Southwest China as testers and incomplete diallel cross design,combining ability and heterosis of 17 new inbred lines bred from the land races in Sichuan Basin and its surrounding areas were analyzed.In addition,the genetic parameters and heterotic groups were also investigated based on combining ability.[Result] P1-1,P1-16 and P1-14 with the better comprehensive characters can be directly used in maize breeding program.The SCA of P1-10×P2-4 was high in most traits.It is more possible to obtain high-yield hybrid combinations by the pattern Sipingtou × Lancaster.GCA variance was bigger than SCA variance in four traits such as rows per ear,grains per row,which were affected by the environments slightly and should be selected at early generations;while SCA variance was bigger than GCA variance in five traits such as 100-grain weight and plant weight,which were significantly influenced by environment and thus should be selected in later generations.[Conclusion] The paper will provide theoretical basis for further improvement of local maize varieties.     

Some Eco-Physiological Characteristics at R4-R5 Stage in Relation to Soybean Yield Differing in Maturities

Digital plant canopy imager and photosynthesis analyzer system were used to analyze the characteristics of canopy structure, photosynthetic physiology and micro-environmental factors at R4-R5 stage in different yielding soybean cultivars or lines with different maturities. The results showed that the common characteristics of high yielding soybean cultivars were high LAI, uniform foliage distribution in all horizontal directions, less variance of photosynthetic rate between top and bottom leaves in canopy and relatively higher photosynthetic rate of the whole canopy. All these characters combined in all resulted in higher canopy photosynthetic productivity, and pod number, seed number and seed weight per plant, especially pod and seed number in top and middle canopy were increased. The characters of high yielding canopy varied among maturities. Light interception was more important to early cultivars. Less foliage inclination angle was benefit to intercept more solar energy during yield formation. As late soybean cultivars had a more closure canopy and higher LAI, greater foliage inclination angle in all layers of high yielding canopy made more solar radiation penetrate into canopy, which was beneficial to yield formation.     

Combining Ability and Breeding Potential of Rapeseed Elite Lines for Pod Shatter Resistance

Pod shatter resistance of rapeseed is of great importance for modern farming practice. In order to determine the combining ability of elite inbred lines and the breeding potential of rapeseed hybrids in terms of pod shatter resistance, analysis of a 6×6 incomplete diallel cross was conducted at two locations. Results showed that a significant variation existed among breeding lines and their F1 hybrids for pod shatter resistant index (SRI), pod length and width. Pod shatter resistance was significantly positively correlated with pod length. The general combining ability (GCA) effects (GCA=1.58) played a more important role than specific combining ability (SCA) effects (SCA=0.20) for pod shatter trait. The elite lines R1, 1019B and 1055B displayed significant positive GCA effects for pod shatter resistance. Four crosses (1019B×R1, 1015B×R1, 6098B×R1, and 8908B×R1) with high mean performance and positive SCA effects were recommended for developing new hybrids for mechanical harvest in the middle reaches of the Yangtze River.     

Genetic and Genotype x Environment Interaction Effects for Appearance Quality of Rice

This study was conducted to generate genetic information in rice varieties based on a complete diallel crosses over two years. The results indicated that genotype effect was significant for all traits. Genotype × environment interaction effects were significant only for cooked grain length （CGL） and cooked grain shape （CGSH）. General combining ability （GCA） and specific combining ability （SCA） effects were significant for entire traits, which indicated the important roles of both additive and non-additive gene actions. GCA x environment interaction effects were significant for CGL, CGSH and grain elongation index （GEI）. In the controlling of the inheritance of milled grain shape （GSH）, milled grain width （MGW）, GEI, milled grain length （MGL）, CGSH and cooked grain width （CGW）, the additive gene effects were more important than non-additive one. The average degree of dominance was within the range of partial dominance for all of the traits. The narrow-sense heritability was ranged from 0.65 （GSH） to 0.36 （CGL）. GCA effects were significant for all of the parents in milled grain length and it was significant for some of the parents in other traits. The crosses of Deilmani × IRFAON-215 exhibited significant SCA for GEI. The positive mean of heterosis was observed for CGW. The highest maximum values of heterosis were revealed in GEI, flowed by GSH, MGW and CGW. GCA and MPV were significantly and positively correlated together for all traits.     

基于AMMI模型的杂交高粱籽粒淀粉含量的配合力分析(英文)

[Objective] Analysis of combining ability of starch content variation in hybrid sorghum with the assistant of AMMI model. [Method] Based on the analyses of GCA using incomplete diallel cross(NCII), the SCA of hybrid sorghum was analyzed by AMMI model. [Result] For the starch content change of F1 hybrid sorghum, the effects of GCA and SCA accounted for 81.06% and 17.97%, respectively. In the present study, CMS lines 45A, 29A and restorer lines Hui 1, 44R were proved to be the excellent parent materials for preparing high starch hybrid sorghum cultivars. [Conclusion] The improvement of starch content in parents should be mainly concerned in breeding high starch content hybrid sorghum.     

Estimation of Genetic Effect for 2N Pollen Producing Diploid Hybrids

Three 2x clones with 2n pollen production,BPH32-2,BPH32-5 and W5295,7,were each mated with three 4x cultivars,Raritan,Superior and Trent,in an incomplete diallel cross design.Estimates of various heritability for tuber yield per plant are that hm^2 is 37.20%,hf^2 16.30%,hB^2 76.70% and hN^2 53.40%.Estimates of general combining ability (GCA) and specific combining ability (SCA) are 69.60% and 30.30%,respectively.The results suggest that additive effect of genes for tuber yield is obvious.The 2n pollen producing diploid hybrids have good breeding values for yield,earliness and starch content.     

Chromosomal Location of the Genes Associated with Photosynthesis of Lophopyrum elongatum （Host） A.Loeve in Chinese Spring Background

Researches on the relationship between photosynthesis and wheat yield have equally attracted the attention of both domestic and overseas scholars. No report has existed so far on the study of the effects of exogenous chromosomes on photosynthesis using the substitution series as materials. In this research, Triticum aestivum cv. Chinese Spring-Lophopyrum elongatum （Host） A.Loeve disomic substitution series were used as materials and flag leaves as the measuring position. And the CI-310 Portable Photosynthesis System made by CID Co. in USA was used to measure the net rate of photosynthesis of flag leaves in different developing stages and also to correlate photosynthesis with yield. Results showed that, out of the whole developing stages, at the anthesis stage the line of DS2Ee （2A） had the highest photosynthetic rate, therefore it could be used in improving process of the character of kernel number. The flag leaves of DS4Ee （4A, 4B, 4D） lines demonstrated certain high net photosynthetic rate from heading to grain filling stage, so it is valuable in the researh of promoting the yield index like 1 000-grain weight through improvement of the photosynthetic rate at grain filling stage.     

In situ measurements of winter wheat diurnal changes in photosynthesis and environmental factors reveal new insight into photosynthesis improvement by super-high-yield cultivation

In past 30 years, the wheat yield per unit area of China has increased by 79%. The super-high-yield(SH) cultivation played an important role in improving the wheat photosynthesis and yield. In order to find the ecophysiological mechanism underneath the high photosynthesis of SH cultivation, in situ diurnal changes in the photosynthetic gas exchange and chlorophyll(Chl) a fluorescence of field-grown wheat plants during the grain-filling stage and environmental factors were investigated. During the late grain-filling stage at 24 days after anthesis(DAA), the diurnal changes in net CO_2 assimilation rate were higher under SH treatment than under high-yield(H) treatment. From 8 to 24 DAA, the actual quantum yield of photosystem II(PSII) electron transport in the light-adapted state(ΦPSII) in the flag leaves at noon under SH treatment were significantly higher than those under H treatment. The leaf temperature, soil temperature and soil moisture were better suited for higher rates of leaf photosynthesis under SH treatment than those under H treatment at noon. Such diurnal changes in environmental factors in wheat fields could be one of the mechanisms for the higher biomass and yield under SH cultivation than those under H cultivation. ΦPSII and CO_2 exchange rate in wheat flag leaves under SH and H treatments had a linear correlation which could provide new insight to evaluate the wheat photosynthesis performance under different conditions.     

Leaf Photosynthesis in Response to Removing Fruit During Different Phenological Stages of Fruit Development in Peach Trees

Removing fruit (RF) and retaining fruit (CK) were carried out during different phenological stages of fruit development on one-year-old shoot of Okubo peach trees [Prunus persica (L.) Batsch.] under preventing exportation of the assimilates to the non experimental parts of the tree by girdling one-year-old shoot and keeping the same leaves between RF and CK. The results showed that fruit removal significantly decreased net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (E), but significantly increased leaf surface temperature (TLeaf) at about midday as compared with CK. Internal CO2 concentration, soluble sugar content, reductive sugar content, starch content except that during the final rapid fruit growth stage, ADP-glucose pyrophosphorylase and amylase activities in source leaves were not significantly affected by fruit removal. There was a significantly positive parabolic correlation between Pn and Gs, and a strong positive linear correlation between Pn and E. Moreover, Pn increased with increased TLeaf if TLeaf was below 38℃, thendecreased sharply when TLeaf exceeded the above critical temperature for both RF and CK. Pn of RF was lower, however, than that of CK in the same TLeaf, especially if TLeaf exceeded 38℃. It is suggested that the decreased stomatal aperture and increased TLeaf may be the important mechanism in regulating photosynthesis under a decreased strength of sink demand by RF in fruit trees.     

辣椒净光合速率配合力分析

 【目的】选育高产杂交辣椒品种。【方法】选用6个亲本，按（1/2）n（n-1）双列杂交法配制15个杂交组合，对辣椒不同开花结果时期净光合速率进行配合力分析。【结果】不同开花结果时期不同杂交亲本净光合速率的一般配合力效应和不同杂种一代的特殊配合力效应差异较大，晚熟亲本的一般配合力大，早熟亲本的一般配合力小，杂种一代熟性与特殊配合力关系不明显。特殊配合力方差明显大于一般配合力方差，遗传力小，环境影响大。净光合速率与农艺性状、抗病性间的配合力相关分析表明，一般配合力是中、后期的相关性较强，与叶片性状、果实性状相关密切；特殊配合力是前期、后期的相关性较强，前期与叶片性状、株型性状相关密切，后期与株型性状和果实性状相关密切；与抗病性的相关性是特殊配合力大于一般配合力；开花结果不同时期净光合速率配合力都与单株产量配合力呈正相关。【结论】配合力是选育强光合杂交辣椒品种的重要参数。     

辣椒净光速率与农艺性状间的关联性研究

辣椒净光合速率与农艺性状间的灰色关联分析结果表明,平均净光合速率与农艺性状间灰色关联度的大小顺序为叶长>叶柄长>叶宽>第一花节位>果肉厚>株幅>株高>疫病抗性>果宽>TMV抗性>主茎高>果长>CMV抗性>疮痂病抗性>侧枝数。相关分析结果表明,净光合速率与叶片性状的相关性最强,但与侧枝数、株高、主茎高、果肉厚、CMV和疮痂病抗性的偏相关系数也达到了显著或极显著水平。通径分析结果表明,叶长和侧枝数对净光合速率的直接作用较大,叶柄长、叶宽和第一花节位次之,其它植株性状的直接作用相对较弱。净光合速率在开花结果前期受叶片性状影响大,后期受抗病性的影响大。     

辣椒净光合速率杂种优势与农艺性状间相关性研究

为了选育高产辣椒品种,用6个亲本,按(1/2)n(n-1)双列杂交法配制15个杂交组合,研究了辣椒净光合速率杂种优势与农艺性状的相关性.结果表明,辣椒净光合速率离中优势在开花结果前期受叶片、疫病抗性的影响较大;中期主要受叶片、植株生长势和分枝力的影响,对果实发育、产量形成、营养含量产生较大的影响;后期主要受植株生长势和分枝力的影响,对产量形成、抗病性产生较大的影响.超亲优势在开花结果前、中、后期受叶片、CMV、疫病抗性的影响较大,受植株生长势和分枝力的影响较小,3个时期都对果实发育、产量形成、干物质、纤维素含量产生较大的影响.     

高粱净光合速率的遗传分析

为筛选净光合速率配合力较高的亲本,选育高光效的高粱杂交品种,选用3 个高粱不育系和6 个恢复系,采用不完全双列杂交法,组配18 个杂交组合,在高粱抽穗期、开花期和灌浆期对亲本和杂交组合的净光合速率进行一般配合力(GCA)效应、特殊配合力(SCA)效应分析,并对高粱净光合速率与主要农艺性状和产量性状进行相关性遗传研究。结果表明,在高粱抽穗期、开花期和灌浆期不育系162273A净光合速率一般配合力均最高,其效应值分别为16.2706、9.7331 和11.9907,3 个不同时期净光合速率一般配合力最高的恢复系分别为16727、161011 和161026,其效应值分别为10.6624、23.7309、18.0146。3个不同时期高粱净光合速率特殊配合力最高的组合分别为162273A×16878、162279A×161026 和162279A×161026,其效应值分别为35.0123、19.9455 和33.0046。3 个不同时期高粱净光合速率加性方差与基因型方差比值较低,狭义遗传力也较低。相关性分析研究表明,灌浆期净光合速率与穗粒重、千粒重、籽粒产量、生物产量和收获指数均呈极显著正相关。     

花生品种间净光合速率的遗传分析

选用8个品种作为亲本,其中包括2个龙生型品种A596和荔浦大花生,4个中间型大花生品种丰花1号、丰花3号、丰花5号及鲁花11,2个珍珠豆型小花生品种白沙1016和丰花2号.采用GriffingⅡ杂交设计配制28个杂交组合,F_1进行田间试验,3次重复,结荚后期测定植株单叶光合速率.结果表明:龙生型品种的净光合速率最高,如A596达到22.45 μmol·m~(-2)·s~(-1),中间型大花生其次,小花生最低,白沙1016的净光合速率仅为16.0 μmol·m~(-2)·s~(-1);亲本净光合速率的一般配合力效应和不同杂交组合的特殊配合力效应差异均较大;龙生型亲本的一般配合力大,小花生品种亲本的一般配合力小;丰花5号与荔浦大花生杂交组合的特殊配合力最大,达到2.8933,而丰花1号与荔浦大花生杂交组合的特殊配合力最小,仅为-3.2767.     

西瓜杂优利用中的配合力分析

对7份西瓜亲本材料及其12个杂交组合的单瓜重和中心糖含量进行了亲本一般配合力(GCA)和杂交组合特殊配合力(SCA)的分析.结果表明,平均单瓜重亲本GCA方差占总遗传方差的25.62%,杂支组合SCA方差占总遗传方差的74.36%;中心糖含量的亲本GCA方差占总遗传方差的87.42%,组合SCA方差占总遣传方差的12.58%.选出了平均单瓜重和中心糖含量GCA相对效应值较高的亲本4份,SCA相对效应值较高的杂交组合1份.     

水稻越冬品系的杂种优势及配合力分析

对3个越冬品系与4个籼稻品种配制的16个正反交F1代主要农艺性状的杂种优势、母体效应值和按不完全双列杂交配制的12个正交组合及亲本主要农艺性状的配合力、遗传力进行了分析,结果表明:(1)所有组合的播始历期、株高和结实率具有超亲优势,千粒重接近中亲值.(2)所有组合的播始历期、每穗总粒数和结实率的母体效应值较高.(3)亲本SW-1 和R195的一般配合力(GCA)较好,其所配制组合的特殊配合力(SCA)效应值也较高;而SW-3和R128的GCA也较好,其所配制组合的SCA效应值却偏低;表明亲本的GCA效应与组合的SCA效应关联不大.(4)亲本的播始历期、株高、结实率、谷粒长、谷粒长宽比、千粒重6个性状的GCA基因型方差在基因型总方差中比重大于60%,且它们的H2N也均大于60%,说明这些性状遗传主要受基因加性效应的影响;而单株产量的SCA方差对总方差的贡献率大于60%,且它的H2N仅为18.83%,说明其遗传主要受基因非加性效应的影响.父本和母本对GCA方差的贡献率在所有性状表现上相差较大,母本GCA方差的贡献率远大于父本,且双亲的互作效应不明显.(5)利用越冬品系进行品种选育应注重对杂交后代株高、结实率和千粒重等性状的选择.     

两系杂交粳稻主要性状的配合力分析

以4个粳型光敏核不育系和8个恢复系为亲本,采用p×q不完全双列杂交(NCⅡ)设计对8个主要性状的配合力进行了分析。结果表明:所有测定性状的一般配合力和特殊配合力均达到了显著或极显著水平,所测性状主要受亲本一般配合力的制约,每穗实粒数和单株粒重受组合特殊配合力的影响相对较大;父本一般配合力的作用明显大于母本一般配合力的作用,不育系“S23”和恢复系“选二”、“C418”等亲本多数性状的一般配合力效应和特殊配合力方差较高。     

陆地棉产量性状的配合力及其与亲子的关系

采用6×6双列杂交(不包括反交),研究了陆地棉(Gossypium hirsutum L.)有关产量性状的配合力及其与亲子的关系。结果如下: (1)所有产量性状的一般配合力方差均极显著,除单株籽棉产量外,其他9个性状的特殊配合力方差均显著或极显著。所有性状的一般配合力方差与特殊配合力方差之比值均大于2(3.139～30.520)。 (2)相同性状不同亲本之间、相同亲本不同性状之间的一般配合力不同。同一性状不同组合之间、同一组合不同性状之间的特殊配合力各异。 (3)亲本的一般配合力与其组合的特殊配合力相对独立。 (4)产量性状的亲本表现与其一般配合力呈明显正相关,而与特殊配合力无必然联系。F_1表现与其特殊配合力呈不明显的正相关,而与双亲一般配合力及总配合力呈极显著的正相关。     

8个玉米自交系穗部性状配合力分析

采用NC11完全双列杂交设计,对8个玉米自交系的穗长、穗重、秃尖长、穗行数、穗粒数、穗粒重6个性状的一般配合力和特殊配合力进行了分析。结果表明：所有性状的一般配合力（GCA）和特殊配合力（SCA）差异均达显著水平,其中2711、2713、2716的主要性状一般配合力表现较高,2709×2715、2709×2716、2710×2712、2713×2714、2713×2715有较高的特殊配合力;在性状选择时,穗长、穗行数宜早代选择,穗重、穗粒数、穗粒重宜晚代选择。