不同熟期和结荚习性大豆品种的固氮活性差异及其遗传变异

不同熟期大豆品种固氮活性为中热组>中早熟组>早熟组。不同结荚习性大豆品种的固氮活性为无限结荚习性>亚有限性结荚习性。以方差分析估算的大豆固氮活性的广义遗传力平均为42.21％,其中中熟组大豆品种为52.01％,无限结荚习性大豆品种为51.10％。     

微胚乳超高油玉米子粒含油率的配合力研究

按Griffing方法4,用6个微胚乳超高油玉米自交系配制15个组合,研究微胚乳超高油玉米子粒含油率的配合力。结果表明:子粒含油率高的双亲在组配时有可能表现出超亲优势;子粒含油率的一般配合力(GCA)在各亲本间及特殊配合力(SCA)在各组合间均存在显著差异;子粒含油率的GCA效应与SCA效应之间无明显关系;以提高子粒含油率为育种目标,应选择具有较高子粒含油率和GCA效应值的自交系作亲本;子粒含油率有较高的遗传力,加性方差在遗传变异中起主要作用,子粒含油率宜在早代选择。     

不同种植方式下小麦主要性状与产量的关系

本文以近年黄淮麦区大面积推广应用和正在参加区试的 30个品种 (系 )为材料 ,在两种种植方式下 ,对 9个主要性状进行了方差分析、遗传力分析、相关分析和通径分析。结果表明 ,在方差分析中 ,除行区法中的总穗数外 ,其它性状均达极显著水平。在相关分析中 ,穗粒重与产量的相关在两种种植方式下表现一致 ,达显著水平 ;行区法中还有株高、小穗数和穗粒数与产量的相关达显著水平 ,穴区法中还有总穗数与产量的相关达极显著水平。在通径分析中 ,直接遗传通径系数 ,行区法为 :穗粒数 >穗下节间 >总穗数 >穗长 >株高 >穗粒重>千粒重 >小穗数 ;穴区法为 :穗粒数 >千粒重 >株高 >小穗数 >总穗数 >穗长 >穗下节间 >穗粒重。在遗传力分析中 ,千粒重、穗粒重、穗长、穗下节间长度、株高的遗传力较高 ,说明在早代选择有效。     

Genetic variability and interrelationship among various morphological and quality traits in quinoa (Chenopodium quinoa Willd.)

Evaluation of seed yield, morphological variability and nutritional quality of 27 germplasm lines of Chenopodium quinoa and 2 lines of C. berlandieri subsp. nuttalliae was carried out in subtropical North Indian conditions over a 2-year period. Seed yield ranged from 0.32 to 9.83 t/ha, higher yields being shown by four Chilean, two US, one Argentinian and one Bolivian line. Two lines of C. berlandieri subsp. nuttalliae exhibited high values for most of the morphological traits but were low yielding. Seed protein among various lines ranged from 12.55 to 21.02% with an average of 16.22 ± 0.47%. Seed carotenoid was in the range of 1.69–5.52 mg/kg, while leaf carotenoid was much higher and ranged from 230.23 to 669.57 mg/kg. Genetic gain as percent of mean was highest for dry weight/plant, followed by seed yield and inflorescence length. All morphological traits except days to flowering, days to maturity and inflorescence length exhibited significant positive association with seed yield. The association of leaf carotenoid with total chlorophyll and seed carotenoid was positive and highly significant. The path analysis revealed that 1000 seed weight had highest positive direct relationship with seed yield (1.057), followed by total chlorophyll (0.559) and branches/plant (0.520). Traits showing high negative direct effect on seed yield were leaf carotenoid (−0.749), seed size (−0.678) and days to flowering (−0.377). Total chlorophyll exerted strongest direct positive effect (0.722) on harvest index, followed by seed yield (0.505) and seed protein (0.245).     

小麦碱水保持力的遗传分析小麦碱水保持力的遗传分析

为给优质小麦选育提供参考依据,以籽粒硬度、蛋白质含量、面筋强度和碱水保持力不同的6个常用优质小麦品种为亲本,按Griffing双列杂交法Ⅱ配制15个杂交组合,研究了小麦碱水保持力的遗传规律.结果表明,碱水保持力在杂交组合间存在显著差异,且受环境条件的影响较大.6个亲本中,宁麦9号和皖麦48的一般配合力较好,均表现为较大的负向效应,能极显著地降低杂种后代的碱水保持力,在优质软麦育种中利用价值较高.碱水保持力的遗传符合加性-显性模型,同时受加性和显性效应的作用,且加性效应更重要.控制碱水保持力的减效基因为显性,亲本中增效和减效基因分布不对称.宁麦9号和皖麦48控制碱水保持力的显性基因最多.碱水保持力可能受1～2对主效基因的控制,狭义遗传力较低,早代选择不宜太严.     

鲁麦21慢白粉病抗性基因数目和遗传力分析

以多年鉴定具有慢白粉抗性的小麦品种鲁麦21和感白粉病品种京双16及其杂交组合F_2:3和F_2:4代株系200个为材料, 于2005—2007年连续2个生长季, 在北京和安阳两地分别进行田间病害鉴定, 并采用质量性状和数量性状2种分析方法估算鲁麦21的慢病基因数目和遗传力。结果表明, 在这2个群体中至少存在4对抗性基因, 其广义遗传力为0.53~0.78。由于出现超亲分离, 因此推测京双16可能贡献1对微效抗病基因, 而鲁麦21至少含有3对慢白粉病抗性基因。     

Variance component analysis of plant architectural traits and fruit yield in melon

Summary  A cross was made between a unique highly branched, early flowering line, U. S. Department of Agriculture (USDA) 846-1 (P_1; 7 to 11 lateral branches), and ‘Topmark’ (P₂; 2 to 4 lateral branches), a U.S. Western Shipping melon, to produce an array of 119 F₃ families. Subsequently, a genetic analysis was conducted at Arlington and Hancock, Wisconsin in 2001 to evaluate the segregating progeny for factors likely involved in yield-formation, including days to anthesis, percentage of plants with early pistillate flowering, primary branch number, fruit number and weight per plant, average weight per fruit, percentage of plants with predominantly crown fruit set, and percentage of plants with early maturing fruit. Although, genotype × environment (G × E) interactions were important for some traits (e.g., fruit number and fruit weight), considerable additive and/or dominance variance was detected for all traits. This research provides critical data associated with highly branched melon germplasm including trait correlations and heritabilies (broad- and narrow-sense ranged between 0.28 and 0.91) that used judiciously will allow the development high yielding melon cultivars with early, basally concentrated fruit suitable for once-over or machine harvesting operations.     

Genetic variation in F<Subscript>2</Subscript> populations and their potential in the improvement of grain yield in tef (<Emphasis Type="Italic">Eragrostis tef</Emphasis>)

Tef is a staple cereal of Ethiopia in high demand by consumers. In order to cope up with this high consumer demand, productivity per unit of land must increase through the development and use of high-yielding varieties. To this effect, the National Tef Research Project has long been striving towards the development of high yielding varieties through direct selection from germplasm and concentrating favourable alleles through hybridization and selection, despite the tedious crossing technique. The objective of this study was to assess the degree of genetic variation in F₂ populations of tef as a basis for improving grain yield. F₂ populations from 12 crosses and their parents were grown at the Debre Zeit Agricultural Research Center, Ethiopia, and assessment was made on eight traits on individual plant basis. Eleven of the 12 crosses showed substantial genetic variation for grain yield and its components, indicating the potential for improvement through selection. Moreover, grain yield, plant weight and yield related traits showed moderate to high heritability values (17–80%). In all the crosses, tiller number, panicle weight, yield per panicle and panicle length showed significant (P ≤ 0.05) and positive association with grain yield. Considering the degree of genetic variation and heritability values, emphasis should be given to selected crosses in an effort to developing high-yielding tef varieties.     

6个玉米自交系配合力分析及应用评价

The 6 maize inbred lines have been tested on the paper with the design of p1×p2 uncomplete diallel crossing of NCⅡ method to study on combining ability and its genetic parameters of 9 characters.The result indieated that the lines of Zheng311,Zheng314 and Ye478 with the higher common combining ability can be directly used,the lines of Zheng312 and Zheng315 with less comprehensive character must be modified before used.The 6 combinations with higher heterosis have potentiality of increasing yield production.In maize breeding program.The 8 characters such as kernel high per plant should be selected earlier and the 1 characters such as kernel weight per plant should be selected later.     

Genetic parameter estimates for growth and form traits in common ash (Fraxinus excelsior, L.) in a breeding seedling orchard at Little Wittenham in England

Data from a trial of 36 families at Little Wittenham, North Oxford was used to assess growth traits and stem form in common ash (Fraxinus excelsior, L.). The trial followed a design described by Barnes (Silv Genet 44(2–3):81–88, 1995) as the Breeding Seedling Orchard (BSO). The objectives of the study were to determine variation in growth and form traits and estimate genetic parameters of families. Assessments conducted at 3–8 years for height, diameter at breast height (dbh), straightness and forking showed significant differences (P < 0.05) among families with Guys (19), Settrington (34), Overbury (23) and Grimthorpe (36) being the best performers while Coleford (3 and 5) Gwynedd (27) and Bacheiddon (32) were the least performers. At the overall level, the additive genetic coefficient of variation (CV_A) ranged between 10.2 and 12.7% for height and 1.5 and 2.1% for dbh. Height had a high genetic correlation (r_g = 0.85) with dbh whilst forking had low correlation (r_g = 0.25) with height. Estimates of heritability decreased with age from  = 0.62 at 3 years to  = 0.30 at 8 years for height while values for dbh decreased from  = 0.48 at 4 years to  = 0.27 at 8 years. Some genetic gains are possible despite the low genetic variation among families; height had the greatest potential of genetic gain (12.5% at 8 years). Results suggest that early selection of superior families of Fraxinus excelsior appears to be feasible and it could be possible to achieve simultaneous improvement in both growth and form.