大豆突变体与亲本过氧化物同工酶酶谱的比较研究

通过对氮离子注入大豆产生的两个突变体及亲本过氧化物同工酶酶谱的比较研究，旨在明确其谱型特征及其分布，并通过酶谱差异探讨其变异程度和主要变异部位。电泳结果表明，两个突变体与其亲本的叶、茎、根过氧化物同工酶电泳图谱在谱带数量、位置、宽度和颜色深浅方面都具有明显差别。每一个样本都有各自特征的图谱类型，其中尤以根的谱带变化最大。因此用过氧化物同工酶作为变异依据之一是有一定价值的。     

Field evaluation of resistance to aflatoxin accumulation in maize inbred lines in Kenya and South Africa

Aflatoxin, a carcinogenic toxin, is produced mainly by Aspergillus flavus and Aspergillus parasiticus. Contamination of maize (Zea mays L.) grain by these fungi occurs before harvest, and the easiest strategy to prevent this is to develop/use maize varieties resistant to Aspergillus spp. and aflatoxin accumulation. The objective of this investigation was to identify potential sources of resistance among 23 maize inbred lines (13 obtained from the MAIZE Competitive Grants Initiative, International Maize and Wheat Improvement Centre and 10 from Agricultural Research Council, South Africa). The inbred lines were planted in a randomized complete-block design at two locations each in Kenya and South Africa. Maize ears were inoculated at silking with three toxigenic strains of A. flavus. The inoculated ears in each plot were harvested at 12–18% moisture, dried, and visually assessed for Aspergillus ear rot (AER). Aflatoxin concentration in the kernels was determined using liquid chromatography–tandem mass spectrometry. Significant variation for both AER and aflatoxin concentration existed among the inbred lines at both locations in Kenya and one location in South Africa. Combined analysis revealed a significant (p < 0.001) lines × locations interaction for both AER and aflatoxin concentration. Higher incidences of AER (0–86.0%) and aflatoxin concentration (0.21–6.51 µg/kg) were recorded at Kiboko in Kenya than at the other three locations. A stronger genetic correlation (r_G = 0.936, p < 0.0001) between the AER and aflatoxin concentration was recorded in Potchefstroom than at the other three locations. Repeatability of aflatoxin concentration was high at Kiboko (0.87) and Potchefstroom in South Africa (0.74). Three inbred lines, CML247, CML444, and CML495, emerged as potentially useful sources of resistance to AER and aflatoxin accumulation as they showed low levels of aflatoxin contamination in both localities in Kenya and in South Africa.     

高产杂交种组配中马齿型亲本的选择与利用

近十年来,我国玉米育种有两个重要的变化,一是含有热带、亚热带种质的国外杂交种引入,二是群体改良工作取得进展。各地育种家从这两类材料中选获了不同类型的自交系,为组配高产强优势组合创造了条件。本文就是以具有国外血缘的硬粒型自交系与改良群体中选出的马齿型自交系为材料,进行双列杂交试验的结果,评价了马齿系在组配高产杂交种中的作用。试验结果表明,马齿系金黄96B是一个配合力较高、综合性状较好的亲本,可在今后育种中进一步加以选择利用。     

Allele and isozyme patterns of UDP-glucose pyrophosphorylase as a marker for cold-sweetening resistance in potatoes

Uridine-5-’diphosphoglucose pyrophosphorylase (UTP α-D-glucose-l-phosphate uridylyltransferase, E.C. 2.7.7.9) (UGPase) was cloned from 16 potato cultivars(Solanum tuberosum L.) that differed in their ability to accumulate reducing sugars in cold storage (3 C) using RT-PCR. Two UGPase-alleles designatedas UgpA (minus a BamHl site) and UgpB (containing oneBamHl site), were present in most cultivars. Cultivars that were cold-resistant (CR) to sweetening demonstrated an UgpA:UgpB ratio favoring the UgpA allele (4:0 or 3:1), while cultivars that were cold-sensitive (CS) exhibited a predominance for the UgpB allele (1:3 or 0:4). Following cold-storage at 3 C for two months, the CR and CS clones accumulated 10.3 ± 2.1 and 31.2 ± 2.2 umol glucose/g FW, respectively. The glucose content and chip color between the CR and CS clones were significantly different at the 99% level of confidence. Staining for UGPase activity in nondenaturing polyacrylamide gels of proteins extracted from CS potatoes revealed up to three acidic isozymes of UGPase (i.e., UGP1, UGP2, UGP3) with UGP3 being the most abundant. Activity staining using CR cultivars demonstrated two additional isozymes of UGPase with greater electrophoretic mobility (more basic in charge) which were designated UGP4 and UGP5. The potential for using UGPase allelic ratios and/or UGPase isozymic patterns as a selective tool to screen segregating progeny in a potato breeding program for cold-sweetening-resistant germplasm is discussed.     

Evidence from the use of isozyme markers of competition in swards between short-leaved and long-leaved perennial ryegrass

Intraspecific competition in Lolium perenne was studied using a replacement series of a short-leaved and a long-leaved genotype that was managed under different cutting frequencies and nitrogen supplies. Leaf length, tiller density and yield were recorded 6 months after sowing. Since the two competitors were labelled at the PG1/2 locus, it was possible to identify unambiguously the origin of tillers in the mixtures and to estimate the average length of lamina of each genotype. The difference in leaf length between the two competitors was maintained under particular types of management and generated contrasting competitive abilities leading to evolution of the genotypic composition of the mixtures. Thus, under infrequent cutting, competition for light resulted in the domination of the long-leaved genotype and in a concomitant intragenotypic selection for leaf length. Supplying nitrogen fertilizer emphasized the phenotypic plasticity of the genotypes, particularly of the dominated one. Frequent cutting reduced competition for light and the change towards the short-leaved genotype was far less rapid. The yielding and competitive abilities of ryegrass genotypes and the implications for breeding are briefly discussed.     

Cultivar evaluation and trait analysis of tropical early maturing maize under Striga-infested and Striga-free environments

Striga hermonthica is a major constraint to maize (Zea mays L.) production in sub-Saharan Africa. The use of secondary traits that have high heritability and genetic correlation with grain yield can improve the precision with which Striga resistant genotypes are identified. Fifteen early cultivars were evaluated under Striga-infested and Striga-free conditions for 2 years at Mokwa and Abuja, Nigeria. The objective was to examine their performance based on multiple traits under stress and non-stress conditions and analyze the interrelationship among traits using genotype-by-trait (GT) biplot so as to assess the value of traits used in the base index for selection for Striga resistance and improved grain yield (YLD). TZE-W DT STR C₄ had the best performance based on multiple traits while TZE-W DT STR C₄, TZE-Y DT STR C₄, Multicob Early DT, and TZE-W DT STR QPM C₀ were the closest to the ideal cultivar when Striga infested. Ears per plant, Striga damage at 8 and 10 weeks after planting, and ear aspect (EASP) were the most reliable traits for selecting for resistant genotypes. Striga emergence count at 8 and 10 weeks after planting were not among the reliable traits identified for selection for improved grain yield and their inclusion in the base index needs to be further verified. EASP had high correlation with grain yield and was one of the most reliable traits for selection for increased grain yield under Striga infestation and should be included in the index.     

Field evaluation of a modified augmented design for early stage selection involving a large number of test lines without replication

Summary The modified augmented design, recently proposed as a method of adjusting for environmental heterogeneity where large numbers of cultivars are being tested in non-replicated plots, was used in a potato breeding programme at four locations in 1982. Of three methods of adjusting for soil variation, only the row-column and covariance adjustments worked efficiently. Decisions about which adjustment method to use could be based on easily computed mean squares. Changes in ranking due to adjustment of test cultivars were large in three of the seven trials, but application of inappropriate adjustment methods produced large and misleading ranking changes in some trials. Because of ease of use and ability to investigate environmental variation, the design can be recommended for use in early stages of potato breeding programmes.

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Zusammenfassung Selektion bei frühen Generationen in Kartoffelzüchtungsprogrammen beruht auf hochvererbbaren Merkmalen, wie Augentiefe, Knollengestalt, Chipsfarbe, spezifischem Gewicht etc. Weitere Selektion betont Adaption an Umgebungen innerhalb des Schwerpunktes des Zuchtprogrammes und in diesem Selektionsstadium wird gr?sser Aufmerksamkeit auf den Knollenertrag gerichtet. Allerdings verbietet die grosse Zahl oft einbezogener Linien, zusammen mit der begrenzten Verfügbarkeit an Material von jeder Linie, die Anwendung von Standardmodellen mit Wiederholungen. Das modifizierte erweiterte Modell (MAD), kürzlich von Lin u. Poushinsky (1983) als Methode zur Anpassung von umweltbedingter Heterogenit?t vorgeschlagen, wurde in Adaptionsversuchen des ‘Prairie Cooperative Kartoffelzuchtprogramms’ (Kanada, 1982) an vier Stellen erprobt. In dem MAD werden Kontrollsorten, die in Mengen erh?ltlich sind, welche Wiederholungen erlauben, zufallsgem?ss auf eine Gruppe ganzer Parzellen verteilt, die in einem Standardmuster ausgelegt sind, hier als Lateinisches Quadrat (Abb. 1). Anpassungen für die Testlinien erfolgen auf der Basis von Trends, die sich in den Kontrollparzellen ergeben. Die Daten der Kontrollparzellen werden entsprechend der Varianzanalyse (ANOVA) für das Lateinische Quadrat geprüft. Wenn S?ulen- und Reiheneffekte zum gesamten Parzellenfehler relativ gross sind, werden die nicht wiederholten Testlinien anhand der Reihen-und/oder S?ulenkorrekturen nach Sch?tzung der Kontrollparzellen berichtigt (Methode 1). Wenn Bodenunterschiede dadurch nicht eliminiert werden k?nnen, dient ein Index für N?hrstoffgehalt für jede Parzelle, als Differenz zwischen dem Wert der Kontrollparzelle für diese gesamte Parzelle und dem Mittel aller Kontrollparzellen mit der entsprechenden Sorte entweder als Anpassungsfaktor (Methode 2), oder wird als begleitende Variable behandelt und die Testlinien werden durch Kovarianzanalyse berichtigt (Methode 3). Der durchschnittliche Gesamtertrag und die mittleren Quadrate, in der ANOVA als Gesamtertrag der Kontrollparzellen an den vier Versuchsorten, ergibt sich aus Tabellen 1 bzw. 2. Die Reihen- und S?ulenvarianzen waren gross (im Verh?ltnis zum Gesamt-Parzellenfehler) für Edmonton I und II und für Brooks II, sie deuten auf die Notwendigkeit für Reihen- und S?ulenanpassungen hin. Eine Prüfung der Irrtumsvarianzen für Carman I und II, m?glicherweise auch Brooks I zeigen starke Heterogenit?t in mehrere Richtungen zwischen den Parzellen, zumal die ganzen Varianzen der Parzellen gr?sser als die doppelte H?he der Unterparzellen-Varianzen waren. Bei Outlook war keine der Varianzen relativ gross gegenüber den anderen. Diese Trends erkl?ren die Anpassungsmethode 1 für Edmonton I und II, die Anpassungsmethode 3 für Carman I und II und Brooks I und II, und keine Anpassung bei Outlook I. Detaillierte Kriterien zur Entscheidung für die angemessene Anpassungsmethode wurden im Computer verrechnet. Die durchschnittlich gesch?tzte Varianz einer Differenz zwischen beliebigen zwei Testlinien wurden für jede Methode berechnet, dann wurden die Methoden durch Berechnung der Verh?ltnisse dieser Varianzen ermittelt (Tabelle 3). Ebenso wurden die Methoden durch Anwendung der Anpassungen an die Kontroll-Unterparzelle und druch Berechnung der gepoolten Varianzen innerhalb der Linien von angepassten Daten (Tabelle 4) verglichen. Die relativen Effizienzen der Anpassungsmethoden wurden als Verh?ltnisse der Varianz der nichtangepassten Daten zu den angepassten Daten berechnet. Die Varianzdaten in Tabelle 4 zeigen, dass im allgemeinen die Anpassung durch Regressionsanalyse (Methode 3) sich entweder durch geringfügige ?nderungen oder durch betr?chtlichen Gewinn an Effizienz auswirkten. Ausser bei Edmonton I verursachten die Methoden I und II einen deutlichen Anstieg in der gepoolten Varianz innerhalb der Linien und folglich einen Verlust an Effizienz. Das wichtige Ergebnis der Anpassung bei der Selektion von Zuchtmaterial sind die ?nderungen bei den relativen Schwankungen in der Rangfolge der Testlinie. Diese ?nderungen, nach Verwendung der drei Anpassungsmethoden verrechnet, zeigt Tabelle 5. Verwendung ungeeigneter Testmethoden ergibt oft sehr grosse, wahrscheinlich auch unechte Rangfolge-?nderungen. Die Leichtigkeit der Anwendung und die M?glichkeit nachzuforschen sowie der groberen Anpassungen wegen umweltbedingter Heterogenit?t machen das Modell sehr geeignet für den Gebrauch in frühen Stadien von Kartoffel-Züchtungsprogrammen.

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Résumé La sélection des premières générations dans les programmes d'hybridation de la pomme de terre est basée sur la haute héritabilité des caractères tels que la profondeur des yeux, la forme des tubercules, la couleur après friture, le poids spécifique, etc. Plus tard, la sélection met l'accent sur l'adaptation aux conditions d'environnement et, à ce stade, la plus grande attention est apportée au rendement. Cependant, un grand nombre de lignées est souvent impliqué et le matériel disponible pour chaque lignée est limité, empêchant des répétitions conformément au modèle standard d'expérimentation. Le modèle modifié (MAD) récemment proposé par Lin et Poushinsky (1983) comme méthode d'ajustement de l'hétérogénéité a été adapté dans des essais réalisés par le Prairie Cooperative Potato Breeding Program (Canada) en 1982 sur quatre localités. Dans le MAD, le contr?le des variétés disponibles en quantité permettant les répétitions est randomisé en une série de parcelles établies selon un modèle standard, ici un Carré Latin (figure 1). Pour les lignées-tests, les ajustements sont faits sur la base des valeurs fournies par les parcellestémoins, après une analyse de variance (ANOVA) adaptée au Carré Latin. Si les effets du rang et de la colonne sont grands par rapport à l'erreur de la parcelle entière, les valeurs des lignées-tests sans répétition sont ajustées en utilisant les corrections rang et/ou colonne estimées à partir des parcelles-témoins (méthode 1). Si l'effet de l'hétérogénéité du sol ne peut être éliminé par ce procédé, un index de fertilité pour chaque parcelle entière, évalué comme la différence entre la valeur de cette parcelle et la valeur moyenne de toutes les parcelles-témoins des autres variétés, est utilisé comme facteur d'ajustement (méthode 2) ou est traité comme une variable concomitante et les valeurs des lignées-tests sont alors ajustées par l'analyse de covariance (méthode 3). La moyenne du rendement total en tubercules et les carrés moyens du rendement total des parcelles-témoins des quatres localités d'essais, calcultés par l'ANOVA, sont présentés respectivement dans les tableaux 1 et 2. Les variances du rang et de la colonne sont grands (relativement à la parcelle entière) pour Edmonton I et II et pour Brooks II, suggérant la nécessité d'ajustements. L'observation des variances de l'erreur de Carman I et II et probablement de Brooks I montre une forte hétérogénéité multidirectionnelle entre parcelles puisque les variances des parcelles entières sont deux fois plus grandes que celles des sous-parcelles. Pour Outlook, aucune des variances n'est élevée par rapport à chacune des autres. Ces résultats suggèrent l'emploi d'un ajustement de type méthode 1 pour Edmonton I et II, de type méthode 3 pour Carman I et II, Brooks I et II et pas d'ajustement pour Outlook I. Des critères détaillés pour décider de la méthode d'ajustement à utiliser ont été étudiés. La variance moyenne estimée entre deux lignées-tests a été calculée pour chaque méthode et les méthodes ont été comparées en calculant les rapports de ces variances (tableau 3). Elles ont été aussi comparées par application des ajustements aux sousparcelles-témoins et pour l'ensemble des données ajustées au sein de chaque lignée (tableau 4). L'efficacité relative des méthodes d'ajustement a été calculée comme un rapport entre la variance de la donnée non ajustée et celle de la donnée ajustée. La variance de la donnée présentée dans le tableau 4 indique qu'en général l'ajustement par l'analyse de régression (méthode 3) provoque un petit changement ou cause un gain substanciel d'efficacité. Excepté pour Edmonton I, l'ajustement par les méthodes I et 2 apporte une augmentation marquée de la variance de l'ensemble interlignées, donc une perte d'efficacité. Les résultats importants de l'ajustement dans la sélection du matériel d'hybridation modifient le classement relatif des lignées-tests. La modification de ce classement, apportée par les trois méthodes d'ajustement est présentée dans le tableau 5. L'emploi des méthodes d'adjustement inappropriées conduit vraisemblablement souvent à des modifications de classement erronées. La facilité d'utilisation et la capacité d'investigation pour déceler l'hétérogénéité due aux conditions d'environnement fait de ce modèle un outil bien souhaitable durant les premiers stades du programme d'hybridation de la pomme de terre.

     

Cultural control of leafhopper-induced maize wallaby ear symptom in forage maize via early planting dates

Maize wallaby ear symptom (MWES) is induced by maize orange leafhopper (Cicadulina bipunctata) feeding and stunts the growth of maize. We examined the relationship between maize developmental stage and MWES occurrence and the effect of planting date on injury from MWES in western Japan. MWES was more pronounced on young maize, and rarely observed on maize older than the 5th or 6th leaf stage, indicating that younger maize is more susceptible to MWES. In a field experiment, early planting (before late July) avoided MWES and resulted in higher yields of forage maize, whereas MWES occurrence and yield loss gradually increased with late planting (from early to middle August) because of a rapid increase in C. bipunctata density during this period. Leaf and stem dry matter of the MWES-susceptible maize variety “3470” decreased together with increase in density of C. bipunctata, whereas leaf and stem dry matter of the MWES-tolerant maize variety “30D44” decreased little. These results indicate that earlier planting together with the use of MWES-tolerant varieties can significantly improve MWES control on forage maize.     

Combining ability analysis for Phaeosphaeria leaf spot resistance and grain yield in tropical advanced maize inbred lines

Phaeosphaeria leaf spot (PLS) disease (causal agent Phaeosphaeria maydis (Henn.) Rane, Payak & Renfro) of maize is increasing in importance in sub-Saharan Africa (SSA). However, there is still limited information on the combining ability for disease resistance of the germplasm that are adapted to African environments. Evaluating combining ability effects and their interactions with the environment would provide valuable information that can be used in the development of cultivars that are resistant to PLS. This study was therefore conducted to determine the combining ability, gene action and the relationship between grain yield and PLS disease severity among selected tropical advanced maize inbred lines. Forty five F₁ hybrids were generated by crossing 10 inbred lines in a half diallel mating scheme. The 45 hybrids along with the ten inbred parents were evaluated in four environments, with two replications each between 2007 and 2009. General and specific combining ability (GCA and SCA) effects were highly significant (P ≤ 0.001) for PLS, grain yield and days to anthesis. GCA effects accounted for 66–90% and SCA effects for 10–34% of the variation in the hybrids for PLS resistance, grain yield and days to anthesis. This indicated predominance of additive over non-additive gene action for the three traits in these inbred lines. The resistant inbred lines to PLS were A1220-4, N3-2-3-3, CML312, MP18 and CML488. These lines had good combining ability for PLS resistance and contributed towards resistance in their crosses. In general, resistant hybrids involved a susceptible and a resistant parent, where at least one of the parents had a negative GCA effect. In addition, lines A1220-4 and CML312 contributed towards high yield and were late maturing. Inbred line CZL00009 conferred genes for early maturity. Linear regression analysis indicated that grain yield of maize was suppressed by about 250 kg ha⁻¹ per each increase in PLS disease severity score, underscoring the need to control the disease. Significant (P < 0.01), negative correlations (r = −0.29 to −0.43) between grain yield and PLS severity were also detected. This showed the potential of PLS to reduce yield when favourable conditions for disease development are present. By and large, highly significant additive gene action implied that progress would be made through selection. Although non-additive effects were small (±10%), observation of dominance effects which were associated with reduced disease levels in some hybrids may be exploited in developing single cross maize hybrids among these inbreds when one parent is resistant.     

筛选早代大豆品系提高豆腐产量及豆酱微观结构

在大豆育种工作中，应施行强制性选育，尽快尽早地保证原种品系的研究和开发。如果培育做豆腐的大豆品系，那么这种品系一定具有提高豆腐产量的优势。然而在大豆育种中，能够送去进行早代分析研究的大豆种子一般是很少的，但筛选品系的数量却很大。加拿大制定了豆腐产量和结构评估标准，以帮助检测非常优良的品系或商业样品应用价值。这种方法需要大量的种子和时间，不适合于筛选大量的试验品系。为了避免这些，正在采用试管法，其原则同大豆豆腐规程一致。     

Simulation of soil drying induced phosphorus deficiency and phosphorus mobilization as determinants of maize growth near tree lines on a Ferralsol

Understanding the effect trees have on the growth of crops requires an understanding of the multiple interacting processes that determine resource uptake by the crops. On a Ferralsol in sub-humid western Kenya maize (Zea mays L.) growth was primarily limited by phosphorus availability. We observed that maize growth near grevillea (Grevillea robusta A. Cunn.) tree lines was strongly reduced, while maize growth was slightly increased near cassia (Cassia spectabilis DC (syn. Senna spectabilis, DC, H.S. Irwin and R.C. Barneby). This was contrary to expectations because grevillea has a relatively low nutrient demand while Cassia has a relatively high nutrient demand.We compared maize growth in an experiment with simulations using the mechanistic tree–crop interaction model WaNuLCAS. The model simulations showed that the measured 30–40% decrease in maize growth near the Grevillea tree line was due to 0.025 m³ m⁻³ lower soil water contents (at mean levels of 0.35 m³ m⁻³ and high pF). This was not due to direct water limitation. The lower soil water content caused decreased P diffusion to roots and a cumulative decrease in crop root-growth and a concomitant decrease in crop growth over time.Measured maize yield near Cassia was 115%, unaffected by trees. Model simulations predicted it should be reduced to 80% due to direct competition for P between tree and crop. This suggests that rhizosphere modifications measured near Cassia roots probably supplied P to the tree itself and also to the maize crop.On P-limiting tropical soils, it is important to prevent soil drying to avoid soil drying induced P deficiency. In these conditions tree species that are able to mobilize P can prevent competition with the crop and may even increase crop performance.     

Growing maize in clumps as a strategy for marginal climatic conditions

Under dryland conditions of the Texas High Plains, maize (Zea mays) production is limited by sparse and erratic precipitation that results in severe water stress particularly during grain formation. When plant populations are reduced to 2.0–3.0 plants m⁻² to conserve soil water for use during grain filling, tillers often form during the vegetative growth and negate the expected economic benefit. We hypothesized that growing maize in clumps spaced 1.0 m apart would reduce tiller formation, increase mutual shading among the plants, and conserve soil water for grain filling that would result in higher grain yield. Studies were conducted during 2006 and 2007 at Bushland, TX. with two planting geometries (clump vs. equidistant), two irrigation methods (low-energy precision applicator, LEPA, and low-elevation spray applicator, LESA) at three irrigation levels (dryland, 75 mm and 125 mm in 2006; and dryland, 50 mm and 100 mm in 2007). For dryland plots in 2007, clump plants had only 0.17 tillers (0.66 tillers m⁻²) compared with 1.56 tillers per plant (6.08 tillers m⁻²) for equidistant spacing. Tillers accounted for 10% of the stover for the equidistant plants, but less than 3% of the grain. Clump planting produced significantly greater grain yields (321 g m⁻² vs. 225 g m⁻² and 454 g m⁻² vs. 292 g m⁻² during 2006 and 2007, respectively) and Harvest Indexes (0.54 vs. 0.49 and 0.52 vs. 0.39 during 2006 and 2007, respectively) compared with equidistant plants in dryland conditions. Water use efficiency (WUE) measurements in 2007 indicated that clumps had a lower evapotranspiration (ET) threshold for initiating grain production, but the production function slopes were 2.5 kg m⁻³ for equidistant treatments compared to 2.0 kg m⁻³ for clump treatments. There was no yield difference for method of irrigation on water use efficiency. Our results suggest that growing maize in clumps compared with equidistant spacing reduced the number of tillers, early vegetative growth, and Leaf Area Index (LAI) so that more soil water was available during the grain filling stage. This may be a useful strategy for growing maize with low plant populations in dryland areas where severe water stress is common.     

甘蓝型油菜pol CMS育性恢复基因的分子标记

以甘蓝型油菜pol CMS不育系1141A及其恢复系花叶恢为亲本构建F2分离群体，并进一步构建可育和不育分离群体集团。利用RAPD、SSR、AFLP等技术进行标记筛选，获得与Rfp基因连锁的2个分子标记，这2个标记分布于Rfp的两侧，其中，AFLP标记E7P16230与Rfp遗传图距最近，为4.3cM；另一侧的RAPD标记S1-500与Rfp遗传图距为10.8cM。     

国内胡麻育成品种的遗传多样性分析

胡麻是我国主要的油料作物,在区域经济发展中起着重要作用。胡麻的遗传多样性分析工作对胡麻种质资源的收集、保存、分类、鉴定以及育种都是非常必要的。本试验对目前国内不同时期选育的96份胡麻品种进行形态学标记和SRAP分子标记分析以评价其种质间的遗传多样性。通过比较形态学标记和SRAP分子标记的聚类图,都得到了预期的试验结果,两者都可以用于胡麻遗传多样性和亲缘关系的分析。对于国内胡麻育成品种之间的划分总体一致,但在具体类别中却存在着一定程度上的偏差,可能是因为SRAP标记在DNA水平上反映了更多的的差异,而形态标记的基因型与SRAP标记检测出的位点相关性很小。     

用灰色局势决策法多因素综合评估甘蓝型油菜早代自交系的一般配合力

运用灰色局势决策法多因素综合评估对信阳市农科所选育的10个早代（S2代）自交系一般配合力测定试验结果进行分析。结果表明：测交种12个性状（单株产量、株高、分枝部位、一次有效分枝数、主花序长度、主花序角数、主花序角长、主花序结角密度、全株总角数、角粒数、千粒重、生育期）的权系数分别为：0.11、0.09、0.08、0.07、0.09、0.08、0.08、0.08、0.08、0.09、0.08、0.07；测交种的综合效果测度值大小顺序为：K1> K2> K9> K5> K10> K3> K7> K4> K8> K6；其中K1的综合效果测度值是0.9376，综合表现最大，其次是K2，它的综合效果测度值为0.8933，K6综合效果测度值是0.8226，综合表现最差。此排序值与以产量性状进行方差分析的位次排序值高度相关，以此来对评估早代自交系的一般配合力是一种较为简便的、有效的测定方法。     

Kernel metabolites depict the diversity of relationship between maize hybrids and their parental lines

As the end products of cellular regulatory processes,metabolites provide the link between genotypes and phenotypes.Althoughmetabolites have been widely applied for functional gene detection and phenotype prediction in maize,there is little research focusing on the genetic information of metabolites per se.Here,we performed genetic analyses for the kernel metabolites of 11 parental inbred lines of six representative maize varieties,including Zhongdan 2,Danyu 13,Yedan 13,Zhengdan 958,Xianyu 355,and Suyu 16,as well as their 26 reciprocal hybrids.We identified a total of 208 metabolites in maize kernels using untargeted metabolite profiling technology.Both cluster analysis and principal component analysis indicated that kernel metabolites could distinguish hybrids from their parents.Analysis of variance further revealed that 163 metabolites exhibited significant differences between parents and hybrids,and 40 metabolites showed significant differences between reciprocal crosses.We also investigated the genetic effects and heterosis for each metabolite.By taking all hybrids into consideration,about two-thirds of all metabolites displayed overdominant with 36.8%and 31%of them displaying positive overdominant and negative overdominant,respectively.Besides,27.5%and 20.4%of all hybrid combinations showed significant mid-parent heterosis and over-parent heterosis,respectively.Our findings revealed that kernel metabolites exhibited the diversity of relationship between maize hybrids and their parental lines.Additionally,we identified 25 significant metabolicmarkers related to 11 agronomic traits using the LASSO method.Seven metabolic markers were associated with more than one trait simultaneously.These results provide a genetic basis for further utilization of metabolites in the genetic improvement of maize.     

青海省几个主要春性甘蓝型油菜杂交种的SSR分析

为了探明青海省主要甘蓝型油菜品种的遗传变异,建立准确高效的种子纯度鉴定方法,本研究选取5个青海省甘蓝型油菜主栽品种,利用140对简单重复序列(Simple sequence repeat,简称SSR)引物对其进行分子标记分析,从中筛选出26对能清晰扩增出多态性主带的引物,进一步对包括这5个品种及其中4个杂交品种的7个亲本系进行扩增后,经6%聚丙烯酰胺凝胶电泳分离和带型分析,成功构建出5个青海省甘蓝型油菜主栽品种及其中4个杂交种亲本系的指纹图谱,并鉴定出了这4个杂交种的共显性标记。这些标记不仅可用于亲本材料和杂交品种真伪的鉴别,还可为杂交种纯度的鉴定提供可靠方法,对亲本知识产权的保护及杂交种推广具有重要的意义。     

Swiss Flint maize landraces—A rich pool of variability for early vigour in cool environments

Today's modern Dent × Flint maize (Zea mays L. ssp. mays) hybrids have a high yield potential but often lack satisfying early vigour under typical low spring temperatures of temperate latitudes. Maize was introduced into Europe already in the 16th century and until the 1950s, landraces evolved and adapted well to various geographically restricted and climatically marginal regions in Europe. Therefore, the objective of this study was to assess representatives of the large pool of Swiss Flint maize landraces for their early vigour under cool conditions in the field. A set of 17 landrace accessions were tested for 2 years at sites on the Swiss plateau (450 and 550 m a.s.l.) and in the foothills of the Swiss Alps (830 and 870 m a.s.l.). Plant emergence (PE), emergence index (EI), the efficiency of the photosystem II (F_v/F_m), leaf greenness (SPAD) and plant dry weight at the three- and six-leaf stages (DW3_P, DW6_P) were measured.     

Nutritional evaluation of spent grains from sorghum malts and maize grit

Potential use of the high protein by-product of beer production from 77% sorghum malt and 23% maize grit was investigated. Red sorghum spent grains (RSSG) and white sorghum spent grains (WSSG) contained 23.4 and 19.3% crude protein (CP), 54 and 43% dietary fiber (NDF), 1.44 and 0.78% ash, 4.5 and 3.2% hexane extract and tannin content of 7.5 and 1.0 mg/g catechin equivalent respectively. Magnesium was the most abundant mineral in both RSSG and WSSG — 185 and 140 mg/kg, respectively. Calcium, zinc, iron and copper were generally low. Both samples contained cadmium 1.12 (WSSG), 1.19 (RSSG) and lead at 1.38 mg/kg. Lysine was the limiting amino acid (chemical score 0.55) in both samples. Other essential amino acids were adequate or surplus. Stearic acid was the predominant fatty acid with varying levels of lauric, myristic, palmitic, and oleic acids in both samples. Feed intake and weight gain were highest in rats fed 26.3% WSSG (contributing 50% of the diet protein) but protein efficiency ratio (PER) and net protein retention (NPR) were highest in diets where spent grains contributed just 25% of the diet protein. True digestibility of diets decreased as dietary fiber content increased such that animals on diets containing 100% spent grain protein (above 20% NDF) lost weight.     

Field evaluation of upland rice lines selected for QTLs controlling root traits

A marker-assisted back-cross (MABC) programme was used to introgress four root quantitative trait loci (QTLs) from the tropical japonica rice variety Azucena into the Indian upland rice variety, Kalinga III. Previously we tested the products for root traits and reported that the introgressed QTL9 (on chromosome 9) significantly increased root length in the new genetic background. Here we describe field testing for agronomic traits in near-isogenic lines (NILs) that differ for introgressed QTLs. Four NILs were selected and characterised in replicated field experiments in eastern and western India over 3 years. They were tested by upland farmers in a target population of environments (TPE) in three states of eastern India, over 2 years. NILs out-performed Kalinga III for grain and straw yield and there was interaction between the genotypes and the environment (G × E). No effect was found for the root QTL9 on grain or straw yield, however, the presence of several introgressions significantly improved both traits. Some of this effect was due to introgression of Azucena alleles at non-target regions. Overall, the Azucena introgressions increased straw yield more than grain yield. While it has yet to be demonstrated whether this effect is due to improved root systems, this finding fits with the assumption that introgressed genes are involved in partitioning of biomass to the roots and stems, rather than to the grain. The NILs could replace Kalinga III for cultivation in medium upland environments in eastern India.