Generation mean analysis of pearl millet [Pennisetum glaucum (L.) R. Br.] grain iron and zinc contents and agronomic traits in West Africa

Pearl millet is the most important staple food crop for millions of people across the world. Micronutrient malnutrition is the major problem for people living in the semi-arid regions of Africa. Identification of gene effects controlling the inheritance of grain Fe and Zn will be helpful in formulating suitable breeding strategies for biofortified pearl millet development. Hence, generation mean analysis was used to study epistasis and estimate gene effects for grain iron and zinc contents along with the agronomic and morphological traits. Six generations P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂ were generated and were evaluated during the 2018–19 off season. Analysis of variance showed significant variability for all the traits in both generations. Six parameter model revealed predominance of additive gene effects for inheritance of grain iron concentration, and additive × additive type of non-allelic interactions. For grain zinc concentration additive gene effects were preponderant compared to non-additive gene effects, and only additive × dominance gene effects were significant among the three types of epistasis. Grain weight per plant was predominantly under non-additive gene effects and additive × additive and additive × dominance gene effects type of epistasis was detected in each cross. Likewise, for flowering non-additive gene effects were most important with the presence of dominance × dominance type of epistasis. For plant height, panicle circumference and length, additive × additive genes effects were the most important among the three type of non-allelic gene action.These findings can be helpful in enehancing the pearl millet breeding programs in Africa.     

玉米纹枯病抗性的主基因+多基因混合遗传分析

利用自交系CML429(高抗)、CI23(中抗)、DM9(高感)和478(高感)组配得到6对正反交组合以及抗感组合CML429×DM9的P₁(CML429)、P₂(DM9)、B₁、B₂、F₁和 F₂ 6个世代材料进行玉米纹枯病抗性鉴定,研究分析这些抗感组合的抗性遗传特性。结果表明：玉米纹枯病抗性基本不存在胞质效应,抗性遗传符合两对加性-显性-上位性主基因+加性-显性-上位性多基因遗传模型;主基因间表现为加性-显性-上位性作用,两对主基因的加性效应分别为-1.228 4和-1.228 4,显性效应分别为-0.206 5和-0.206 3,其遗传效应值大小基本相同,且两对主基因间的加性效应与显性效应互作的上位性效应也相差不多,分别为0.293 1和0.293 5,两对主基因的遗传效应基本相同。抗感组合不同世代中F₂的主基因遗传率最高(70.22%);多基因遗传率在B₂最高(10.17%)。因此,在F₂的选择效率最高。     

Inheritance of glandular trichomes in crosses withSolanum berthaultii

The inheritance of trichome density and droplet size was investigated in diploid and tetraploid crosses. In haploidTuberosum ×Solanum berthaultii and (S.phureja ×haploid Tuberosum) × S.berthaultii crosses, droplet size on type B trichomes was small or droplets were lacking on F₁ hybrids. Parental phenotypes were recovered in the F₂ and backcross generations. Trichome density was more variable within a clone that was droplet size. Density of both type A and type B trichomes appears to be under the control of small numbers of genes, as parental phenotypes were recovered in the F₂ and backcross generations. The variation observed for each of the three traits studied could not be explained by hypotheses based on the segregation of one or two loci. The insect resistance ofSolanum berthaultii appears to be due to the interaction of several chemical and physical factors, thus potato breeders should handle it as a quantitatively inherited trait.     

玉米雌穗一节多穗性状的遗传研究

以玉米自交系XL21和PH6WC组成的6世代群体为材料,调查各群体同一穗位处果穗数量。利用P₁、P₂、F₁、F₂、BC₁和BC₂多世代联合分析法,研究控制玉米一节多穗性状的基因分离规律。结果表明,该性状在F₂分离世代表现为斜率负值的直线分布,BC₁群体主要呈类似于偏正态分布,BC₂群体呈类似于反比例函数分布。通过群体AIC值进行适合性检验,该性状符合一对加-显主基因+加-显-上位性多基因遗传D模型,主基因效应大于多基因效应,且加性效应大于显性效应,主基因遗传率为49.5%～60.2%,多基因遗传力为27.4%～41.1%,两者累加贡献率达到87.6%～90.6%。控制玉米一节多穗性状以加性效应为主,在遗传育种中针对该性状对早代试材进行重点选择和淘汰。     

玉米回交后代群体中供体基因组成分分析

以郑58为受体亲本,昌7-2为供体亲本,通过杂交、回交和79对亲本间有多态的SSR标记,分析BC₂F₁和BC₃F₁世代供体的基因组成分。结果表明：BC₂F₁世代单株内的供体染色体片段数平均为11.4个,BC₃F₁世代为4.8个,从BC₂F₁到BC₃F₁单株内的供体染色体片段数减少了57.6%;BC₂F₁世代单株内的供体染色体片段长度平均为99.3 cM,BC₃F₁世代为87.1 cM,BC₃F₁较BC₂F₁减少了12.3%;BC₂F₁世代单株内的供体基因组大小平均为1 132.8 cM,BC3F1世代为421.4 cM,BC₃F₁较BC₂F₁减少了62.8%。     

小麦农艺性状的主基因+多基因遗传分析

为明确小麦重要农艺性状的遗传组成,并筛选适于QTL的性状,以西农817和中国春为亲本,构建F2、F3群体,采用P1、P2、F1、F2、F3五世代联合分析方法,研究了株高、有效分蘖、小穗数、穗粒数、穗长、穗下节间距、小穗着生密度等产量相关性状的遗传模型.结果表明,7个性状不仅受基因的控制,同时也受到不同程度的环境影响.其中,穗长、穗粒数符合多基因遗传模型,无主基因存在;株高、小穗数、小穗着生密度符合一对加显性主基因+加性-显性多基因混合遗传模型;穗下节间距符合一对完全显性主基因+加性-显性多基因模型;有效分蘖符合一对负向完全显性主基因+加性-显性多基因模型.     

玉米品种通育189的雄穗分枝数F1平均优势及遗传分析

针对PH6WC、PH4CV、B20、D1279及PH6WC×PH4CV、PH6WC×B20、PH6WC×D1279、D1279×PH6WC鉴定试验进行雄穗分枝数差异分析,PH6WC×D1279(通育189)组建6世代群体(P₁、P₂、F₁、B₁、B₂、F₂),运用主-多基因混合模型遗传分析方法对雄穗分枝数遗传进行分析。结果表明,通育189雄穗分枝数存在细胞质遗传效应,F₁雄穗分枝数平均优势为28.57%～132.41%;雄穗分枝数遗传模型为2对主基因加、显、上+多基因加、显混合模型,2对主基因为正向完全显性,主基因上位性效应>显性效应>加性效应;主基因效应是多基因效应的41.25倍,主基因遗传率为27.58%～88.87%,多基因遗传率为0～41.78%。     

玉米低钾耐性性状的主基因+多基因遗传分析

应用植物数量性状主基因+多基因混合遗传模型多世代联合分析方法,以玉米缺钾症状叶片数为指标,对1个耐低钾玉米自交系T和2个低钾敏感玉米自交系S1和S2配制成的2个组合的P1、P2、F1、B1、B2和F2世代进行遗传分析,研究明确玉米耐低钾性状的遗传机制。结果表明,玉米低钾耐性遗传在2个组合中都由1对加性+加性-显性多基因控制;主基因遗传率(F2)平均为60.43%,多基因遗传率(F2)平均为15.35%;T×S1组合的遗传变异占表型变异值为80.20%,T×S2组合的遗传变异占表型变异值为71.35%,表明耐低钾性状以主基因遗传为主。育种应用上可以在低世代进行这一目标性状的选择。     

Genetic adaptability of the inheritance of the resistance to different levels of aggressiveness of Septoria tritici isolates in durum wheat

The aim of this study was to evaluate the variation in the mode of inheritance for resistance in durum wheat to Septoria tritici with the aggressiveness level of the pathogen. Material for the study involved two wheat cross-combinations and offspring populations. In each cross, the parental genotypes, F₁, F₂, BC₁P_r and BC₁P_s were inoculated with 15 isolates of S. tritici with different levels of aggressiveness. Generation mean analysis revealed that the mode of inheritance varied with the aggressiveness level of isolates. For less aggressive isolates, in both crosses, only additive and dominance effects were determined. When tested with isolates with moderate levels of aggressiveness, the additive-dominance model was not sufficient to explain the variation in generation means; and a di-genic epistasis model was found appropriate. For a high level of aggressiveness, both additive-dominance and di-genic epistatic models failed to explain the phenotypic variation in generation means, and probably higher order interaction or genes linkage were present. The quantification of gene effects revealed that the absolute total of epistatic effects increased with aggressiveness level of the isolate. Selection based on less aggressive isolates would be simpler, because only additive and dominance effects are implicated, but the genetic mechanism will not be stable with isolates of high aggressiveness level. Thus, selection with highly aggressive isolats is suggested for the stability of resistance to S. tritici in durum wheat.     

微胚乳超高油玉米子粒含油率的遗传效应分析

以3个微胚乳超高油玉米组合的各6个世代(P₁、P₂、F₁、B₁、B₂、F₂)为材料,利用Mather世代平均数分析法估计了子粒含油率的遗传效应。结果表明,子粒含油率的遗传在3个组合中几乎完全一样。显性效应、加性效应和两种上位性效应都达到显著或极显著水平,其中显性效应最大。以显性效应作用为主,但是加性效应和上位性效应的作用也比较重要,表明微胚乳超高油玉米的含油率性状符合显性-加性-上位性遗传模型。     

Introgression and stabilization oferwinia tuber soft rot resistance into potato after somatic hybridization ofsolanum tuberosum ands. brevidens

Resistance to potato tuber soft rot caused byErwinia carotovora was transferred fromSolanum brevidens to the cultivated potato over the course of four backcross generations originating from a somatic hybrid. Soft rot reactions were determined via a tuber plug inoculation method developed during the course of these experiments. Soft rot resistance was highest in the somatic hybrid (only ca. 20% of tubers and plugs showed evidence of severe rotting) and lowest among progeny of control potato x potato crosses (ca. 80% of tuber plugs showed severe rot). Backcross generations involving somatic hybrids were intermediate in their reaction, and resistance stabilized to about 60% of tuber plugs showing severe rot in the BC₂ through the BC₄. Reciprocal crosses showed no difference in the inheritance of soft rot resistance, indicating that neitherS. brevidens norS. tuberosum donor cytoplasm had a significant effect on the expression of resistance. Crosses between BC₃ siblings where noS. brevidens genetic markers were detected but resistance was segregating demonstrated a dosage effect for soft rot resistance. We conclude that introgression of soft rot resistance has occurred and that at least one locus responsible for resistance inS. brevidens now resides in theS. tuberosum genome.     

转Cry1A.401基因抗虫玉米CM8302和CM8303对亚洲玉米螟的抗性研究

采用农杆菌介导法获得转Cry1A.401基因抗虫玉米CM8302和CM8303,通过多代回交与自交获得BC₄F₁、BC₄F₂和BC₄F₃世代的转基因玉米材料。利用qRT-PCR和ELISA方法明确转基因抗虫玉米叶片、花丝和子粒均有Cry1A.401基因表达,不同世代间目的基因表达量无显著差异。田间接虫鉴定结果表明,CM8302和CM8303三个世代心叶期和吐丝期的抗性等级均为1级,抗性水平为高抗。室内生测结果表明,亚洲玉米螟幼虫取食CM8302心叶、花丝和子粒第6天存活率分别为0、4.0%和4.0%;取食CM8303心叶、花丝和子粒第6天存活率分别为0、4.0%和2.0%。分析显示转基因抗虫玉米CM8302和CM8303的心叶、花丝和子粒均具有显著杀虫效果且遗传稳定。     

Characterization of a new gibberellin related dwarfing locus in potato (Solanum tuberosum L.)

Gibberellins have been shown to be involved in such important processes as seed germination, flowering, maturation and tuberization in potato. Parents fromSolanum tuberosum Groups Andigena and Tuberosum were found to produce progeny containing dark green, rosette dwarf individuals which could be completely restored to normal appearance by exogenous GA₃. Test crosses indicated that this phenomenon can be explained by the action of a single locus, the dwarfing characteristic being conferred by the nulliplex condition. The gene symbol “ga₁” is proposed. Group Andigena dwarfs demonstrated much greater tuberization compared to their normal full sibs or dwarfs restored to normal phenotype by exogenous GA₃. The possibility that such gibberellin mutants may be involved in the long day adaptation of Gp. Tuberosum is discussed. This character may also be a useful tool for investigating various aspects of the gibberellin status of the potato.     

Utilizing the frost resistance of diploid solanum species

Introductions of 13 frost-resistant diploid (2n=2x=24)Solanum species (2 non-tuberous) were inter-crossed to produce F₁ hybrids involving two frost resistance sources. Successful F₁ combinations were: (i) inter-crossed to produce hybrids involving 3 to 4 frost resistance sources, (F₁×F₁); and (ii) crossed with haploids (2n=24) of frost-susceptible tetraploid (2n=4x=48)S. tuberosum subsp.tuberosum, (F₁×tbr). Thirty-five of the 75 crosses between the 13 species produced viable seed. The F₁ and F₁×F₁ progenies segregated to yield plants more resistant to freezing temperatures than the parental species. All attempts to cross these hybrids with 24-chromosometbr were successful. Although tuber production improved following the first cross totbr, the frequency of resistant plants decreased approximately 50%. Thus far, all first back-cross attempts, (F₁×tbr)×tbr, have succeeded. Utilizing hybrids synthesized from several sources of frost resistance as the donor parents, and clonal selections of 24-chromosometbr as the recurring parents, may provide a high order of resistance throughout the backcrossing program and implement selection of frost-resistant, long-day tuberizing parental stocks acceptable to the potato breeder.     

Insect-mediated cross-pollination in soybean [Glycine max (L.) Merrill] : I. Agronomic performance

In soybean, manual cross-pollination to produce large quantities of F₁ hybrid seed for yield trials is difficult and time-consuming. Conversely, insect-mediated cross-pollination has been shown to produce large quantities of hybrid seed in soybean and could facilitate the identification of heterotic patterns. The objective of our study was: (1) evaluate F₁ hybrid soybean plants from single crosses for yield and agronomic traits over several environments and (2) compare hybrid performance of the single crosses to lines developed from three-way crosses and backcrosses. In 2003, F₁ seed of single-crosses and their parent lines were evaluated in replicated experiments at three locations. Also in 2003, three-way crosses, and BC₁F₁ seed were produced. In 2004, three-way crosses, BC₁F₁ crosses, and their parent lines were evaluated at one location. High-parent heterosis (HPH) in single-crosses for grain yield ranged from −41.11% to +11.19%; for protein content from −4.34% to +3.53%, and for oil content from −13.22% to −0.84%. In three-way crosses, HPH for yield ranged from −25.21% to −4.50%, for protein from −2.72% to +1.92%, and for oil from −5.87% to −1.20%. For BC₁F₁ crosses, HPH for yield ranged from −15.65% to +41.97%, for protein from −2.57% to +1.69%, and for oil from −2.47% to +2.22%. Although positive heterosis levels were observed across all populations tested to determine the economic feasibility it is imperative that more tests of more cross-combinations be evaluated in replicated environments. Extensive research in different environments must be conducted to determine what parental combinations will produce the highest heterosis levels, and to develop criteria for selecting the parents with the best combining ability. This will be important to maximize agronomic performance that can economically justify the use of hybrids in soybean production.     

栽培稻与药用野生稻杂种后代的形态学和细胞遗传学研究

 选用两个抗褐飞虱的药用野生稻编号材料与两个感虫栽培品种杂交，通过胚培养获得了F₁、BC₁F₁和F₂植株。F₁杂种表现出野生亲本紫色柱头、长芒及抗褐飞虱等特性，其花粉母细胞中期I染色体多为单价体(仅0.77个二价体)，甚至不能形成花药，因而表现雄性不育，仅获得一株F₂，染色体数目为2n=46。用栽培稻回交获得BC₁F₁植株为异源三倍体，中期I染色体构型为12.25Ⅰ+11.85Ⅱ+0.01Ⅲ。     

在构建QPM近等基因系过程中对回交群体的SSR标记选择

优质蛋白玉米(QPM)遗传基础狭窄,以普通玉米自交系为遗传背景培育opaque-2近等基因系是QPM种质改良的重要途径。本文利用SSR标记技术,以opaque-2基因序列为背景开发的特异SSR引物phi057和umc1066作为标记,对构建中的95个QPM近等基因系回交群体BC1F1和BC2F1进行目标基因选择。结果表明,SSR标记phi057对大多数回交群体中的opaque-2基因的选择是有效的;在少数回交群体,如(多黄29×CA335)×多黄29,SSR标记phi057和umc1066不能区分单株间的基因型变异,针对这些材料,需要进行更深入的研究或开发新的SSR。     

一个玉米无叶舌突变体Y43的遗传分析

在EMS法构建的玉米骨干自交系昌7-2突变体文库中,发现了一个玉米无叶舌突变体,随后通过连续自交,获得了纯合一致、稳定遗传的无叶舌自交系,命名为Y43。该突变体穗上部叶片直冲,表现为无叶舌,其他农艺性状与受体一致。通过对Y43与昌7-2及海9-21的F1、F2、BC1分析,初步确定该突变体无叶舌性状受一对隐性单基因控制。     

Inheritance of resistance to sclerotinia stem rot (Sclerotinia trifoliorum) in faba beans (Vicia faba L.)

Stem rot, a fungal disease caused by Sclerotinia trifoliorum Eriks., is often a serious problem in many important forage legumes including faba beans (Vicia faba L.). Understanding the inheritance of resistance to the disease is essential for effective breeding of resistant cultivars. Experiments were conducted to study the inheritance of resistance to stem rot of faba beans. The F₁, F₂, and the backcross generations of five crosses between four resistant and four susceptible populations (Alto × Polycarpe, A-90 × Polycarpe, ILB-1814 × A-247, A-90 × A-244, VT × Tanagra) were used. The eight populations were crossed properly in the field, and progenies of F₁ and F₂, as well as backcross progenies of F₁ with each of their parents, were evaluated for resistance to stem rot disease under controlled conditions after artificial inoculation of the plants with carrot root pieces colonized by the fungus. On the assumption that inheritance of stem rot resistance is governed by a single dominant gene, no significant differences were found between the observed and the expected frequencies of resistance for progenies, except for one cross. As the expression of resistance to the disease fits the expected ratios for a single dominant gene model, it is concluded that the inheritance of resistance to sclerotinia stem rot in the evaluated faba bean populations is controlled by a single dominant gene.     

水稻亚种间杂种配子育性的研究

水稻亚种间杂种配子育性的研究何光华，郑家奎，阴国大，杨正林（四川省农业科学院水稻高粱研究所泸州６４６１００）关键词亚种间杂种，雄性不育，雌性不育ＧａｍｅＦｅｒｔｉｌｉｔｙｏｆＦ＿１ｂｅｔｗｅｅｎＩｎｄｉｃａａｎｄＪａｐｏｎｉｃａ￥ＨＥＧｕａｎｇｈｕａ...