不同花生品种对花生褐斑病和网斑病抗病性鉴定

本研究旨在明确不同花生品种对花生褐斑病和网斑病的抗性,为品种选育及田间病害防治提供依据。采用田间病圃鉴定法鉴定了花生不同品种对褐斑病和网斑病的抗性,结果表明,参试的9个花生品种中有6个品种对花生褐斑病的相对抗病指数在0．6以上,花育23、日花1号和四粒红属于高抗病类型,其中花育23相对抗病指数最高为0．87;鲁花8号、青花7号和冀花4号属于抗病类型。13个花生品种中只有2个花生品种对花生网斑病的相对抗病指数在0．6以上,其中花育36属于高抗类型,相对抗病指数为0．81;农大056属于抗病类型,其余花生为敏感性,但是每个花生品种对花生叶斑病的综合抗性较差。     

Progress and challenge towards reducing wheat spot blotch threat in the Eastern Gangetic Plains of South Asia: Is climate change already taking its toll?

Spot blotch, caused by Cochliobolus sativus, is a serious constraint to wheat production (Triticum aestivum L.) in the warmer plains of South Asia. Fourteen genotypes were tested in Bangladesh, India and Nepal during 6 years (2000–2005) to determine disease severity and resistance stability over these years. We analyzed the area under the disease progress curve per day (AUDPC/day) to assess spot blotch severity, and examined grain yield, 1000-kernel weight (TKW), days to heading, and plant height. Disease severity differed in the 6 years and several genotypes showed low disease severity in all years. A few genotypes had high grain yield and low disease severity in all years. Genotype Altar-84/Ae. Sq. (224)//Yaco, with the lowest disease severity and highest 1000-kernel weight (TKW) and grain yield was also the most stable for spot blotch resistance, TKW and grain yield. Results demonstrated that wheat genotypes with improved spot blotch resistance, high grain yield, acceptable TKW, and plant height are available as a result of the regional and international collaboration in South Asia. Despite this progress, the challenge lies ahead because of an apparent tendency of increasing spot blotch overall severity in the region and decreasing TKW over 6 years (2000–2005). Higher, average night time temperature during the month of March is an indicator showing that wheat crop performance is challenged in two ways—increasing spot blotch severity and decreasing TKW causing lower yield. The results underline the possible effect of changing climatic factors on disease pressure and the continuous need to identify new resistance sources to develop more spot blotch resistant wheat for the warmer Eastern Gangetic Plains of South Asia.     

大麦白粉病抗性的遗传分析

为给大麦抗白粉病育种提供参考依据,以1个感白粉病、4个抗白粉病大麦品种为亲本,按Griffing的双列杂交法Ⅰ配制20个杂交组合,在田间自然条件下研究了大麦白粉病抗性的遗传特性。结果表明,大麦白粉病抗性在杂交组合间存在显著差异。5个亲本中,木石港3号和CM72的一般配合力较好,均表现为较大的负向效应,能极显著提高杂种后代抗白粉病能力;S096的一般配合力中等,也表现为负向效应,能显著地提高杂种后代抗白粉病能力,因而这三个品种在大麦抗白粉病育种中利用价值较高。大麦白粉病抗性遗传符合加性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。大麦白粉病抗性的狭义遗传力较低,早代选择不宜太严。     

几个常用玉米自交系主要数量性状的配合力分析

采用P（P－1）／2完全双列杂交设计4，对8个常用玉米自交系主要数量性状进行一般配合力和特殊配合力分析。结果表明8个性状同时受加性和非加性效应控制，以加性效应为主，在选育亲本或者组配时，不能只考虑一般配合力或者特殊配合力，要综合考察配合力总效应。研究还发现穗粗、株高、穗位高的遗传力较高，在早代进行选择便可收到显著成效；而茎粗、穗行数受环境影响较大，在后期选择方可取得良好效果。     

Genetic analysis for resistance to bean fly (Ophiomyia phaseoli) and seed yield among common bean genotypes in a semi-arid environment

Bean fly (Ophiomyia spp.) is a major field pest limiting common bean production in eastern Africa. The genetic enhancement of beans for resistance to insect pests is essential for minimizing yield losses arising from crop damage. The objectives of this study were to (1) assess combining ability for bean fly resistance and seed yield accumulation in common bean and (2) estimate genetic parameters associated with resistance for formulating further breeding strategy. Four parents with known reaction to bean fly were crossed with four locally adapted genotypes in an 8 × 8 half diallel mating design. Parents and F₂ progenies were grown in an alpha-lattice design replicated twice in an open-field and subjected to natural populations of bean fly for two cropping seasons under semi-arid conditions. Similarly, two resistant and two susceptible parents were selected and crossed to produce populations for generation means and variances components analysis. Results revealed that both general combining ability (GCA) and specific combining ability (SCA) mean squares were significant (p ≤ 0.05) for all four traits studied except SCA for stem damage during one cropping season. Among the parents, GBK 047858 was the best general combiner for all the traits studied across seasons except for stem damage during long rains (LR) 2009. Besides, genotypes GBK 047821 and Kat × 69 (a locally adapted variety) were generally good general combiners for resistance traits as well as seed yield. General predictability ratio (GPR) values ranging from 0.63 to 0.90 were obtained for plant mortality, stem damage, pupae in stem and seed yield across cropping seasons. These results established the predominance of additive gene effects (fixable variation) over the non-additive effects in controlling the traits. Low to moderate narrow sense heritability values ranging from 0.22 to 0.45 were obtained for pupae in stem. Such heritability estimates indicate that although additive gene components were critical in the inheritance of resistance for the trait, non-additive gene action were also important in addition to the environmental effects.     

Effect of mineral nutrients on spot blotch severity in wheat,and associated increases in grain yield

Spot blotch, caused by Cochliobolus sativus, is a serious disease of wheat (Triticum aestivum L.) in the warm lowlands of South Asia. A field study was conducted using two wheat varieties (Bhrikuti and Sonalika) during the 2001 and 2002 wheat seasons in Rampur, Nepal, to determine the effect of nitrogen, phosphorus, potassium, and chlorine fertilization on reducing spot blotch severity in wheat, and its associated increase in grain yield. Application of N alone reduced spot blotch severity by 8% in 2002. Phosphorus fertilization had no effect on spot blotch development. The balanced application of N, P, and K reduced disease severity by 15 and 22% in 2001 and 2002, respectively. Application of KCl as well as CaCl₂ reduced spot blotch severity, but the former caused 11% greater reduction than the latter. The two varieties responded differently to the mineral nutrients’ effect on spot blotch severity, suggesting the nutrients’ importance in cultivar selection when considering the effect of soil fertility on susceptibility to foliar diseases. The lower disease severity and higher grain yield observed after the application of KCl compared to CaCl₂ showed that KCl should be used on K-deficient soils in the warmer wheat growing regions of South Asia where spot blotch is a serious perennial wheat disease in intensive rice–wheat cropping systems.     

Genetics and mapping of resistance to spore inoculum and culture filtrate of Phaeosphaeria nodorum in spring wheat line ND 735

Stagonospora nodorum blotch (SNB), caused by Phaeosphaeria nodorum, is one of the most devastating foliar diseases on wheat (Triticum aestivum L.) in the northern Great Plains of North America. This study was conducted, under controlled environmental conditions, to elucidate the genetics and map the resistance to SNB caused by spore inoculum and culture filtrate of P. nodorum isolate Sn2000. A hard red spring wheat population was developed from a cross between the susceptible cultivar Steele-ND and the resistant line ND 735 for this study. Two-leaf seedlings of the parents, F₁ and F₂ generations, and F_2:6 recombinant-inbred lines (RILs) were inoculated with spore suspensions while independent two week old seedlings of segregating generations were infiltrated with culture filtrate. Disease reaction was assessed 8 days after inoculation based on a lesion-type scale while plants were evaluated for culture filtrate response four days after infiltration for the presence or absence of necrosis. Genetic analysis revealed that a single recessive gene, Tsn1, in ND 735 confers resistance to both spore suspension and culture filtrate of P. nodorum isolate Sn2000. Mapping analysis using Diversity Arrays Technology (DArT) and simple sequence repeat (SSR) markers indicates the gene, Tsn1, is located on the long arm of chromosome 5B and is flanked by the DArt markers wPt-8285 and wPt-3049 at a distance of 7.0 cM and 2.9 cM, respectively. This gene also controls resistance to tan spot caused by Pyrenophora tritici-repentis race 2. Results of this study reveal that wheat-P. nodorum interaction follows the toxin model of gene-for-gene hypothesis. Additionally, the finding of single gene control in the line ND 735 for both tan spot and SNB enhances the utility of the line ND 735 in wheat breeding program as a source of multiple disease resistance.     

Combining ability among apomictic and sexual parents of Urochloa humidicola

The diallel cross constitutes an informative genetic design for choosing genitors and crosses in breeding programmes since it provides estimates of general (GCA) and specific (SCA) combining abilities. Because the breeding programme for Urochloa humidicola ([Rendle] Morrone & Zuloaga; syn. Brachiaria humidicola [Rendle] Schweick) at Embrapa Beef Cattle is recent, these estimates are still unknown. Thus, the aim of this study was to obtain the estimates of GCA and SCA from the partial diallel cross design between sexual and apomictic parents. The crosses involved nine sexual and ten apomictic parents. Seventy‐one full‐sib progenies were obtained and evaluated in an incomplete block design, using all parents and the cv. BRS Tupi as a check. The agronomic and forage quality traits were evaluated using seven harvests. Statistical analysis was performed using the mixed model approach. Significant variations were associated with GCA among sexual parents for biomass yield and forage quality traits. However, this cannot be observed for apomictic parents for GCA. The SCA effect was not significant for the assessed traits. These results showed the predominance of additive effects. Sexual parents SEX3 and SEX4 presented the highest potential for contributing favourable alleles in hybrid combinations. The absence of GCA among apomictic parents and SCA suggests the need to increase genetic variability for the generation of breeding populations of U. humidicola.     

水稻白叶枯病的抗性遗传研究

 以4个晚粳品种为材料，采用双亲本回交设计对白叶枯病抗性的遗传特性及基因效应作了分析。参试的晚粳品种对两个菌系KS-6-6和浙173的抗性是不完全隐性遗传，符合加性－显性模型；基因的加性效应为极显著，显性效应和上位性效应则皆不显著。加性变异和显性变异并存，但以加性遗传变异为主，表现具有较高的广义、狭义遗传率。菌系Ⅱ与Ⅳ的病级间的关联性表明，晚粳品种嘉23对白叶枯病两菌系的抗性属同一多基因系控制的不完全隐性的数量性状遗传；从有效因子数目估值来看，本研究参试材料至少有一对隐性抗病基因在起作用。     

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.     

玉米抗青枯病遗传规律研究

本试验通过对青枯病抗性不同的几个材料进行接种．用不完全双列杂交方法对玉米青枯病遗传规律进行了研究。试验结果表明，玉米对青枯病遗传为微效多基因控制的数量性状遗传，并且基因效应是以加性基因效应为主，非加性基因效应所起作用不大．同时又得到所研究的六个亲本中Mo17、E28是选育高抗青枯病杂交组合的优良亲本．     

花生抗网斑病品种筛选及抗病性与产量损失的关系

花生茎点霉（Phoma arachidicola Marasas Pauer & Boerema）引起的花生网斑病在生产上普遍流行、危害严重,2018-2019年通过2年的田间接种试验对国内65份花生种质资源网斑病抗性进行测评。以采自山东莱西的病原菌菌株Wb2制备105/mL的孢子悬浮液喷洒于花生叶片表面进行接种,对照区喷施50%咯菌腈WP防治花生网斑病菌。结果表明,65份种质中,抗病（resistant,R）资源8份,占鉴定资源总数的12.3%;中度抗病（moderately resistant,MR）资源9份,占比13.8%;感病（susceptible,S）资源37份,占比56.9%;高度感病（high susceptible,HS）资源11份,占比16.9%。测定抗病性不同资源产量损失差异,结果表明,花生网斑病菌对花生产量影响显著,产量损失率随抗病性的降低而升高。本研究为花生抗网斑病育种提供抗源材料,并为病害产量损失评估提供理论依据。     

水稻抗病优质品种主要性状的配合力分析

 选用10个优质的或抗稻瘟病的品种,通过双列分析研究了稻瘟病抗性、有效穗、直链淀粉含量和胶稠度的遗传和配合力进行了分析。结果表明,稻瘟病抗性、直链淀粉含量和胶稠度主要受加性基因效应控制。每株分蘖数、穗数、穗长和株高既受加性效应也受非加性效应控制。外选35是具有抗稻瘟病、粒形美观和高配合力和抗性遗传力强的品种,但在胶稠度和直链淀粉上不佳。试验还发现,二八占抗性和米质性状结合较好,其抗性和米质的一般配合力效应均较显著,可以作为新的抗性材料。     

5个草莓品种抗病虫性试验初报

对福安草莓主栽区5个草莓品种抗病虫性观察表明,公四莓品种抗枯萎病、褐斑病、灰霉病,中感叶枯病;且较抗红蜘蛛、蚜虫,中感斜纹夜蛾。法兰地品种抗灰霉病,中抗枯萎病,中感褐斑病、叶枯病;较抗斜纹夜蛾、蚜虫,中抗红蜘蛛。鬼怒甘品种抗褐斑病、叶枯病,中感枯萎病、灰霉病,且抗斜纹夜蛾,中感红蜘蛛、蚜虫。麦特来品种较抗叶枯病,中抗褐斑病,中感灰霉病;且抗蚜虫,感斜纹夜蛾、红蜘蛛。瑞菲品种较抗枯萎病,感褐斑病、叶枯病,中感灰霉病、斜纹夜蛾,感红蜘蛛、蚜虫。综合来看,公四莓表现综合抗病虫性强、品质较好、产量较高;法兰地、鬼怒甘抗病虫性较强;麦特来、瑞菲抗病虫性较差。     

小麦赤霉病的抗性遗传分析

为给小麦抗赤霉病遗传改良提供参考,利用苏麦3号及5个当地推广小麦品种为亲本,按Griffing双列杂交法Ⅱ配制15个杂交组合,以赤霉病病小穗率为抗性指标,研究了小麦赤霉病抗性的遗传。结果表明,在6个小麦品种中,苏麦3号和扬麦9号赤霉病抗性的一般配合力最好,能极显著地提高杂种后代的赤霉病抗性。小麦赤霉病抗性的遗传符合加性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,显性程度为部分显性。控制赤霉病遗传的增效等位基因为显性,增减效等位基因频率在亲本中的分配存在显著差异。苏麦3号具有最多的控制赤霉病抗性遗传的显性基因,而宁麦8号则具有控制赤霉病抗性遗传最多的隐性基因。小麦赤霉病抗性可能受2~3对主效基因的控制,狭义遗传力较高,早代选择有效。论文最后还就小麦抗赤霉病育种进行了探讨。     

Combining superior agronomic performance and terminal heat tolerance with resistance to spot blotch (Bipolaris sorokiniana) of wheat in the warm humid Gangetic Plains of South Asia

Seven hundred twenty-nine lines of diverse wheat germplasm lines were evaluated in eight locations of three countries (India, Nepal and Bangladesh) of South Asia for 5 years (1999–2000 to 2003–2004) through Eastern Gangetic Plains Screening Nursery (EGPSN) organized by CIMMYT South Asia, Nepal, for agronomic performance and tolerance to spot blotch of wheat. Each year, the number of lines represented a new set of 150 lines that included six common checks and a different local check at each of the eight locations. One hundred and five lines, 21 in each year, advanced from EGPSN were also tested for 5 years (2000–2001 to 2004–2005) in five locations of South Asia through Eastern Gangetic Plains Yield Trials (EGPYT) to verify spot blotch tolerance and superior yield performance of the selected germplasm. Many lines yielded significantly more than the best check and possessed high levels of spot blotch resistance under warm humid environments of South Asia. The most promising 25 lines have been listed as sources of strong resistance, with 9 lines better yielding than the best resistant check PBW 343 in fewer days to maturity. Most of these superior lines represented elite CIMMYT germplasm and around half were derived from Kauz and Veery. The line EGPYT 67, Kauz//Kauz/Star/3/Prinia/4/Milan/Kauz, was the best for spot blotch resistance, yield, days to maturity, and 1000 grain weight (TKW). The next two lines in the order of merit were EGPYT 84 (Mrng/Buc//Blo/Pvn/3/Pjb 81) and EGPYT 69 (Chirya3/Pastor). The results demonstrate that additional spot blotch resistant wheat genotypes with high grain yield and TKW, and early maturity, have become available as a result of the regional and international collaboration in South Asia.     

杂交水稻种子穗萌遗传效应的研究

 以穗萌抗性水平不一的6个不育系和7个恢复系为亲本材料，采用不完全双列杂交的试验设计，并运用包括胚乳、细胞质和母体植株三套遗传体系的种子遗传模型及估算遗传方差分量和预测遗传效应值的统计分析方法，对杂交水稻种子穗萌特性的遗传效应进行了研究。结果表明，杂交水稻种子的穗发芽率同时受种子直接加性、种子直接显性和母体加性效应的影响，且以种子直接效应为主，不受细胞质和母体显性效应的影响。在选择育种中，田间穗上发芽率以单粒选为好。而穗萌指数同时受制于种子直接遗传效应、母体效应和细胞质效应，但母体植株中只测到显著的母体加性效应。     

Integrated management of major wheat diseases in Brazil: an example for the Southern Cone region of Latin America

Wheat is an important crop in the Southern Cone region of Latin America. Some of the common wheat diseases in this region are Xanthomonas streak, spot blotch, tan spot, and leaf blotch and the rusts. Rice blast on wheat could also be a problem in certain years. Disease management through varietal resistance, cultural practices including appropriate fungicidal spraying schedule, levels of tolerance for field and seed infections and seed treatment criteria, have been integrated and used for several years in Brazil. Emphasis in integrated disease management (IDM) is on reduction in use of fungicides and consequently in the cost of production. Wheat productivity in Brazil has almost doubled during the past 10 years, owing mainly to the IDM approach. The IDM practices used in Brazil for each of the major diseases can also be adopted in other Latin-American countries with similar agroecosystems.     

粳型杂交稻稻米外观品质性状的遗传效应研究

 以宁67A等4个粳型不育系与K1722等9个粳型恢复系进行不完全双列杂交，采用禾谷类作物胚乳品质性状的遗传模型及其分析方法，对粳型杂交稻稻米外观品质性状进行了遗传研究。结果表明，稻米的糙米长、糙米长宽比、糙米长厚比主要受母体加性效应控制，而透明度以母体加性效应和种子直接加性效应为主；垩白率、垩白度主要受种子直接加性和母体加性效应所控制，以种子直接加性效应为主。多数性状的种子直接遗传率、细胞质遗传率和母体遗传率均达显著或极显著水平，其中糙米长、糙米长宽比、糙米长厚比、透明度以母体遗传率为主，垩白率、垩白度以种子直接遗传率为主。另外，根据性状的遗传效应预测值对各亲本的育种利用价值作了评价     

Heritability of resistance in maize to sorghum downy mildew (Peronosclerospora sorghi (Weston and Uppal) C.G. Shaw)

Host-plant resistance is an effective and economical means of controlling downy mildew (DM) diseases in maize (Zea mays L.). Crosses involving 10 inbred maize lines in all possible combinations (diallel cross) showed that susceptibility to sorghum DM (Peronosclerospora sorghi (Weston and Uppal) C. G. Shaw) is generally inherited as a dominant characteristic. However, progenies of crosses between one of the lines (CM105) resistant to DM, and susceptible lines, showed intermediate levels of resistance, indicating that several genes are involved and that their effects are additive. Progenies of crosses between resistant lines were more resistant than their parents, probably because of interactions between different resistance genes (epistasis). Both additive and non-additive gene action was detected by partitioning gene effects by generation mean in each 16 DM-resistant × DM-susceptible combinations, which indicates that the reactions of maize to DM are governed by several genes (i.e. polygenically) and that the inheritance of resistance is complex. An inbred line from Mexico, Tuxpeno Gpo. 48-Var. 168-1, is a particularly promising general source of resistance to DM.