杂交粳稻同核异质不育系细胞质效应的研究

 以具有ChinsurahBoroⅡ（BT）、滇型（D）、野败型（WA）和野栽型（WC）4种不育细胞质的不育系南粳11A和南粳34A及其相应保持系与77302－1、宁恢3－2、C57和C堡4个恢复系配制的杂种F₁为材料,探讨了不育系细胞质对F₁代12个性状的遗传效应。不育系细胞质对F₁代的株高、穗颈长、每稳实粒数、结实率、收获指数和单株产量等性状有明显的负效应,而对稳数、每穗总粒数、千粒重和生物产量则有明显的正效应。不育系细胞质的这种遗传效应随细胞质来源的不同表现明显的差异,D型和BT型细胞质在多数性状上的表现优于WA型和WC型细胞质。此外,不育系细胞质与保持系细胞核和恢复系细胞核及三者之间的互作在多数性状上也有明显差异。     

Effects of cytoplasm,male and female parents on biomass productivity in sorghum (Sorghum bicolor L. Moench)

Production of renewable fuel requires biomass sources. To meet this need, energy sorghum was identified as a potential biomass source. Hybrid sorghum development involves the use of cytoplasmic male sterility (CMS) and since there are multiple CMS systems, it is important to determine if any of the CMS systems has an effect on agronomic performance and biomass composition. Energy sorghum hybrids were produced using four seed and four pollinator lines, resulting in 16 hybrid genotypes in three different cytoplasms (A1, A2, and A3). These hybrids were evaluated in three environments across 2 years for agronomic and biomass composition traits. For most traits, differences among hybrids and environments accounted for most of the variation, cytoplasm did not in any trait. These results indicated that different CMS systems can be used for energy sorghum hybrids without affecting yield or composition.     

Genetic enhancement of Sorghum (Sorghum bicolor (L) Moench) for grain mould resistance: II. Breeding for grain mould resistance

Grain mould causes qualitative and quantitative loss to grain in sorghum. Grain mould resistance is a complex problem as grain mould is caused by complex of fungi and the resistance is governed by many traits. Breeding efforts during the last 3 decades to develop grain mould resistance in high yielding genotypes have not paid many dividends. We developed a strategy to breed for grain mould resistance in high yielding back ground. Twenty five crosses between elite lines and grain mould resistant genetic stocks (susceptible × resistant/moderately resistant and moderately resistant × resistant crosses) were evaluated in F₁, and derivatives performing superiorly for grain mould resistance in F₂-F₄ at physiological maturity were advanced. The early generation material F₂s (10) and F₃s (125) in 6 locations (representing rainy-season-sorghum growing 6 states of India where grain mould is one of the major biotic stresses), and later generations F₄s and F₅s in 3 locations (one location, Parbhani is a hot spot for grain moulds and 2 locations, Hyderabad and Coimbatore in epiphytotic conditions) were evaluated. Only 25 selections out of 384 derivatives in F₄ were superior over locations for grain mould resistance at physiological maturity and harvest maturity (Our simultaneous studies in RILs for grain mould resistance across years and locations have shown that the variation obtained for grain mould resistance at physiological maturity is genetically governed and the grain mould score further gets compounded at harvest maturity depending on rainfall received after physiological maturity). These superior lines were advanced and further evaluated in F₅ and F₆ for grain mould resistance and grain yield. During 2007, out of 25 F₅ derivatives, 12 were on par (scored 3.1-4.4) with resistant check, B 58586 (3.2 score) where as susceptible check, 296 B registered a score of 7.5. GMN nos. 41, 52, 59, and 63 performed on par with resistant check, B 58586 for grain mould resistance over 9 environments. Since we selected for grain mould resistance in early generations at physiological maturity in multi-locations, we could identify superior lines for grain mould resistance. Most of these lines are high yielding and on par with elite check, C43 for grain yield. These lines are distinct for DUS testing traits from grain mould resistant check, B 58586.     

A comparison of inbred line and F1 testers for evaluating sorghum experimental lines in testcrosses

Selecting an effective tester for evaluating the hybrid performance and heterosis of new inbred lines is crucial to ensure their accurate evaluation. Most sorghum breeding programs use at least two elite inbred line testers when evaluating new inbred lines. These testcrosses provide valuable information, but the specificity of inbred line testers may incorrectly characterize experimental lines that would combine well with other genetic backgrounds. Reducing this risk by increasing the number of preliminary testcrosses is limited in breeding programs by resource availability. Efficiently diversifying testcrosses may be accomplished through the use of F₁ testers. Testcrosses made with F₁ testers simultaneously evaluate inbred lines against two genetic backgrounds. In preliminary testcrosses, this may reduce the probability of incorrectly discarding new lines or improve the efficiency of preliminary testcrossing. The objective of this research was to compare two sorghum inbred line testers to their respective F₁ as a tester for evaluating sorghum inbred lines (R-lines) in testcrosses for grain yield. The testers used were A.Tx623, A.Tx2752 and their F₁ hybrid, A.Tx623/B.Tx2752. Data from testcross hybrids from 33 different inbred lines grown in three environments indicated that the F₁ tester was comparable in accuracy and discriminatory efficiency to the inbred line testers. The results indicated that a single cross tester in sorghum can serve to effectively evaluate new germplasm.     

Yield and agronomic performance of maize hybrids resistant to the maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

This study evaluated improved maize hybrids (Zea mays L.) with varying level of resistance to the maize weevil, Sitophilus zeamais Motschulsky, for yield and agronomic traits for two seasons. A total of 22 improved maize hybrids and three commercial standards were tested. Out of the 22 tested, two hybrids CKPH08035 (7.4–9.9 t ha⁻¹) and CKPH08039 (7.3–9.8 t ha⁻¹) significantly out yielded the commercial standards WH505 (8.8 t ha⁻¹) and BH140 (5.5 t ha⁻¹). In addition to yield, the improved hybrids also possess desirable traits including good plant height, good plant and ear aspects and good husk cover. The hybrid CKPH08004 had the lowest Dobie index of susceptibility and was regarded as resistant to S. zeamais. Weevils fed with the resistant hybrids produced low numbers of F₁ generation weevils, had a high median developmental time and a low percentage of grain damage and grain weight loss. An increasing number of F₁ generation resulted in an increasing grain damage and grain weight loss. We found an inverse relationship between the susceptibility index and percent mortality. However, the numbers of F₁ generation, percent grain damage and grain weight loss were positively correlated with the susceptibility index. The use of resistant maize hybrids should be promoted in managing S. zeamais in stored maize under subsistence farming conditions in Africa.     

Assessment of sorghum germplasm from Burkina Faso and South Africa to identify new sources of resistance to grain mold and anthracnose

Sorghum is an important worldwide crop whose yield can be significantly reduced by anthracnose (Colletotrichum sublineola) and grain mold diseases (multiple fungi). The identification of new genetic sources of resistance to both diseases is imperative for the development of new sorghum varieties. To this end, a total of 80 exotic germplasm accessions from Burkina Faso (BFA) and South Africa (ZAF) were evaluated for anthracnose and grain mold resistance during two planting periods in 2012 at the USDA-ARS experimental farms in Isabela, Puerto Rico. Twelve accessions were resistant to anthracnose during both evaluations of which 10 are originally from BFA. The anthracnose resistant accessions identified herein had a hypersensitive reaction characterized by lesions having red and purple color. Likewise, 9 accessions exhibited grain mold resistance after being inoculated with a mixture of a conidial suspension of Fusarium thapsinum, Fusarium semitectum, and Curvularia lunata during both periods. Eight of these accessions (PI 586182, PI 586186, PI 647705, PI 647706, PI 647707, PI 647708, PI 647710, and PI 647712) originated from BFA, while one (PI 61666) is from ZAF. The PI 586186 was the only accession that exhibited resistance to both anthracnose and grain mold. The grain mold resistant accession PI 61666 has a panicle shape that resembles a standard United States commercial type sorghum and is also photoperiod insensitive. The results presented herein indicate that the BFA germplasm could be an important source for anthracnose and grain mold resistance genes. The integration of these anthracnose and grain mold resistant germplasm into sorghum breeding programs should aid in expanding the genetic diversity and in the development of new resistant varieties.     

干旱胁迫下披碱草属种间杂种F1的DNA甲基化MSAP分析

为了研究披碱草属种间杂种抗旱性优势的遗传机理，以加拿大披碱草（J1）、老芒麦(L1)及其种间杂种F₁为试验材料，经干旱胁迫处理，采用甲基化敏感扩增多态性（MSAP）方法，探究干旱胁迫后亲本及种间杂种F₁的DNA甲基化变化规律。结果表明，亲本材料L1和J1的DNA平均甲基化水平分别为45.41%和59.53%，杂种F₁的DNA甲基化水平为44.24%，说明杂种在形成过程中发生了DNA去甲基化作用。全甲基化在杂交种的DNA甲基化模式中占主导地位。干旱胁迫前亲本L1、J1和杂种F₁的DNA甲基化程度分别为32.73%、41.54%和28.00%，杂种F₁甲基化水平为亲本材料的75.40%；干旱胁迫后各材料的DNA甲基化程度均增加，平均增幅分别为14.99、20.44和19.78个百分点，说明干旱胁迫对不同材料DNA甲基化水平均有明显影响，且具有特异性。杂种F₁的抗旱性最强，其DNA甲基化水平低于亲本，说明杂交种的抗旱性与DNA甲基化水平存在一定的负相关。     

甘蓝型油菜雄性不育细胞质遗传效应的研究

本文从两个方面,即不育胞质与可育胞质之间的差异和几种不同不育肥质之间的差异,研究了渭A、波里马A和75—3A等三种雄性不育系不育胞质在13个农艺性状和对菌核病抗性的遗传效应。试验结果初步表明:三种不育胞质对杂种F_1的农艺性状和抗病性无不良影响;三种不同质源的不育胞质间在杂种F_1主要农艺性状和抗病性上无显著的差异。但作者认为,开展新的不育胞质的研究,防止细胞质单一化也是必要的。     

Hydraulic Resistance of Sorghum (C4) and Sunflower (C3)

Summary

It is well known that C4 crops have a lower water requirement than C3 crops. Reasons for the difference are not well understood. Therefore, hydraulic resistance of sorghum [Sorghum bicolor (L.) Moench] (C4) and sunflower (Helianthus annuus L.) (C3) was determined to see if it might be one explanation for the lower water use of crops with the C4 photosynthetic pathway. Plants were grown under greenhouse conditions in pots with soil, which was well watered (soil matric potential of ～0 MPa) or allowed to dry (soil matric potential of ?0.038 MPa and ?0.065 MPa for sorghum and sunflower, respectively). Hydraulic resistance was calculated in two ways: (1) using the classic Ohm's law analogue, which assumes that the relation between flux (transpiration) and difference in water potentials of the soil and plant is linear and (2) using an equation that considers diurnal changes in leaf water content along with transpiration and difference in water potentials. Because change in leaf-water content during a day was small, hydraulic resistances calculated by the two methods resulted in similar values. Sorghum had a linear relationship between flux and difference in potentials (constant hydraulic resistance), but sunflower had a nonlinear one (variable hydraulic resistance). The hydraulic resistance of watered sunflower increased only slightly during a day and averaged about 40 MPa m² s mol^?1, which was 3.5 times less than that of watered or water-stressed sorghum (-140 MPa m² s mol^?1). The hydraulic resistance of water-stressed sunflower increased steeply during a day and by the end of the day it had a hydraulic resistance that approached that of sorghum.     

新质源优质不育系岳4A的选育与应用

岳４Ａ是一个新胞质籼型优质三系不育系,花粉不育度和不育株率均为１００％,米质优,株叶型好,异交习性优良,配合力强,杂种一代米质优、丰产性好,利用前景广阔     

Male sterility and 2n pollen in 4x progenies derived from 4x×2x and 4x×4x crosses in potatoes

Summary The objectives of these experiments were to evaluate male sterility (MS) and 2n pollen frequency in 77 4x×2x families and 26 4x×4x families. The 2x parents were haploid-species hybrids and the 4x parents mainly clones withS. tuberosum ssp.tuberosum (tbr) andS. tuberosum ssp.andigena (adg) in their genetic background. The female parents had different cytoplasms: adg, tbr,S. demissum (dms), andS. stoloniferum (sto). Families from female parents with adg or dms cytoplasm did not have MS plants. However, families derived from crosses of many tbr females with 2x hybrids and a 4x adg clone had a high percentage of MS plants; all the progenies from cv. Serrana (sto cytoplasm) possessed tetrad sterility. These results can be explained as due to an interaction between a dominant male sterility (Ms) gene with tbr and sto cytoplasms. Some MS 4x hybrids (tbr×adg) used as females had the Ms gene, but male fertility was restored in some plants of their progenies when they were crossed with 4x tbr clones. This indicates that some tbr clones have a fertility restorer gene (Rt). The results from both 4x×2x and 4x×4x families fit the expected ratios assuming chromatid segregation for both the Ms and Rt loci. The gene frequency of parallel spindles was estimated in the 4x population as 0.74.     

粳型陆稻恢复系资源的筛选及其利用研究

对不同粳稻不育系与146个粳型陆稻品种测交所得21 7个组合的结实率观测结果表明,测交组合的平均结实率为36.3%,其中24个组合(占11.1%) 的结实率＞70%,说明与普通粳稻不同,粳型陆稻品种中存在丰富的恢复系资源.与不同地区的陆稻品种测交,不同质源的不育系的可恢性有一定差别.对7个组合的产量、8个组合的米质(糙米率和垩白粒率)与其相应的父本进行比较的结果表明,测交组合产量优势明显,且米质也得到显著改善.另对2个测交组合进行旱作种植,不仅比大面积应用的杂交粳稻黎优5 7大幅增产(增幅达93.2%),而且比陆稻父本也增产;在旱种和水田条件下产量接近黎优 57的水平.如对亲本进一步筛选和改良,有望育成水旱兼用、在不同栽培条件下均能显著增产的水陆稻杂交种,在旱涝并存地区具有广阔的应用前景.     

Improvement of bacterial blight resistance of hybrid rice in China using the Xa23 gene derived from wild rice (Oryza rufipogon)

A novel bacterial blight (BB) resistance gene, Xa23, identified from Oryza rufipogon was introgressed into three popular restorer lines (Minghui63, YR293 and Y1671) for wild abortive cytoplasmic male sterility by marker-assisted backcross breeding approach in combination with artificial inoculation and stringent phenotypic selections. The three derived BB resistant restorer lines (Minghui63-Xa23, YR293-Xa23 and Y1671-Xa23) and their hybrid combinations with Zhenshan97A (Shanyou63-Xa23), NongfengA (Fengyou293-Xa23) and Zhong9A (Zhongyou1671-Xa23) demonstrated similar BB resistance spectrum as the donor parent, CBB23 (B). The newly developed BB resistant restorers and their derived hybrids were identical to their respective original versions for agronomic traits especially under disease free condition. However, under severe disease condition, the three BB resistant restorer lines exhibited significantly higher grain weight and spikelet fertility as compared to the respective original restorer lines thus further resulting in BB resistant hybrids with significantly higher grain yields than their respective popular original hybrids. The results indicated that the Xa23 gene could completely express its dominant broad spectrum resistance in different backgrounds of both restorer and male sterile lines across different growth stages, suggesting its immense breeding value in BB resistance improvement for hybrid rice. Moreover, a reasonable utilization and deployment of Xa23 gene for efficient control of BB disease in hybrid rice production was recommended.     

Conversion into bioethanol of insect (Sitophilus zeamais Motschulsky), mold (Aspergillus flavus Link) and sprout-damaged maize (Zea mays L.) and sorghum (Sorghum bicolor L. Moench)

The bioconversion into ethanol of insect (Sitophilus zeamais), mold (Aspergillus flavus) and sprout-damaged maize and sorghum was investigated. Kernel test weight losses due to insect damage in maize were almost twice compared to sorghum (18.6 vs. 10.7%). All damaged kernels lost some of the starch and increased soluble sugars, ash and crude fiber. The mold-damaged sorghum contained approximately five times more FAN compared to the control. The sprout-damaged kernels contained the highest amounts of reducing sugars prior (11 g/L) to and at the end (146.5 g/L) of liquefaction with α-amylase. Ethanol yields based on the already damaged grain indicated that sprout-damaged kernels yielded similar amounts compared to sound kernels (381.1 vs. 382.6 L/ton and 376.6 vs. 374.8 L/ton of sorghum or maize respectively). The insect-damaged maize and sorghum have reduced ethanol yields compared with the controls (29 and 23% respectively), and this negative result was mainly due to dry matter losses during the inadequate storage. Despite differences in ethanol yield, all treatments have similar conversion efficiencies (76.1–89.9%) indicating the robustness of yeast facing biotic-damaged feedstocks. This research demonstrates that the use of already damaged insect, mold or sprouted kernels is feasible and a good alternative for biorefineries.     

Introgression of resistance to reniform nematode (Rotylenchulus reniformis) into upland cotton (Gossypium hirsutum) from Gossypium arboreum and a G. hirsutum/Gossypium aridum bridging line

Gossypium hirsutum L. is the predominant cotton of commerce and all cultivars of this species are susceptible to the reniform nematode, Rotylenchulus reniformis. To introgress resistance to R. reniformis into the tetraploid 2(AD₁) G. hirsutum, a resistant diploid A₂-genome Gossypium arboreum accession (A₂-190) was crossed with a hexaploid 2((AD₁)D₄) bridging line (G 371) to obtain a tetraploid triple-species hybrid. The triple-species hybrid was back-crossed to G. hirsutum and a population of 277 BC₁ individuals was produced. The BC₁s and controls were assayed in growth chambers for resistance to R. reniformis. Fortuitously, the hexaploid bridging line G 371 was also found to be resistant to R. reniformis. The BC₁ segregated 3:1, resistant:susceptible, indicating that resistance was conferred by dominant genes at two different loci, with each originating from a distinct germplasm source. This study demonstrated that it is possible to introgress and pyramid genes for resistance to R. reniformis in G. hirsutum.     

A3、A4细胞质对甜高粱产量及其重要性状的影响

高粱杂种优势利用是以细胞质雄性不育为前提,通过利用细胞质雄性不育的“三系”配套而实现的,也是不育化育种以及杂种优势利用的主要途径。试验对可诱导高粱雄性不育的细胞质A1、A2、A3、A4开展甜高粱细胞质雄性不育研究,对于提高杂交高粱产量、品质、种子纯度,拓宽种质资源利用范围,实现异质高粱杂交种在生产中的应用提供一定的依据。     

斯卑尔脱细胞质对小麦种子长度、重量及杂种优势的遗传效应

为了筛选优良的新型小麦雄性不育系，对斯卑尔脱、云南铁壳麦、提莫非维小麦、拟斯卑尔脱山羊草等四种异源细胞质在同核异质条件下对不育系及其杂种一代的种子长度、重量及杂种优势的遗传效应作了比较研究。结果表明，斯卑尔脱细胞质对小麦种子大小、重量具有明显正效应，且筛选出了两个由其所配制的具明显杂种优势的杂交组合。这说明，斯卑尔脱细胞质不育系在栽培小麦中易于找到恢复源且恢复度高，其对种子大小和重量的稳定的正效应可能是产生较强杂种优势组合的重要原因之一。     

Yield dilution of grain Zn in wheat grown in open-top chamber experiments with elevated CO2 and O3 exposure

Wheat (Triticum aestivum L.) grain Zn data from six open-top chamber experiments performed in south-west Sweden were combined to study the relationship between Zn accumulation and grain yield, grain protein, and yield components. Treatments included, in addition to open-top chamber controls, elevated CO₂, elevated O₃, combined CO₂ and O₃ exposure, combined elevated CO₂ and supplemental irrigation, supplemental irrigation, and ambient air comparison plots. The grain Zn concentration was strongly correlated with grain protein (R² = 0.90) over the range of the experimental treatments, representing non-soil factors. A significant yield dilution effect was found for Zn. For a 10% increase in grain yield, Zn yield was increased by 6.8% on average. Effects on Zn yield correlated strongly with effects on grain protein yield, with a slope close to unity, showing that yield dilution effects for grain Zn and grain protein were similar. Treatment effects on grain Zn concentration were related to effects on grain weight (P < 0.01) and grain number (P < 0.05), but not to harvest index. It was concluded that yield stimulation caused by rising CO₂ concentrations is likely to lead to reduced Zn concentrations of wheat grain, thus reducing the nutritional quality.     

玉米抗粗缩病主效QTL (qMrdd1)的基因多效性分析

前期研究中将主效抗病QTL(qMrdd1)定位在第8染色体分子标记M103.4-M105.3之间,该抗病QTL表现为隐性基因遗传,可降低24.2%~39.3%的发病率。通过分子标记检测,在抗病系NT411(供体亲本)和感病系NT409(轮回亲本)回交多代的群体中,选择7个含有抗性QTL(qMrdd1)的杂合单株自交得到分离群体B1、B2、B3、B4、B5、B6、B7和来源于同一回交后代的两对抗感病近等基因系(B8-R、B8-S和B9-R、B9-S),利用这两对近等基因系与自交系A7110、Q319、CT03、昌7-2、43684、43683、43946组配13对杂交种,在植株整个生育期内无粗缩病病毒接种的条件下,在北京、海南和山东种植不同的材料并对7个分离群体和13对杂交种进行农艺性状调查,结果表明,7个分离群体中各基因型植株以及13对杂交种在株高、穗长、穗行数等农艺性状上差异不显著,qMrdd1基因对玉米产量性状不存在多效性现象,可以应用于抗粗缩病育种。     

BT型粳稻不育系8006A的选育与应用

8006A是用BT型不育系863A与优质早熟晚粳稻品种8006杂交并回交转育而成的早熟晚粳稻不育系,具有米质较优、不育性稳定、较易制繁种等特点,所配组合结实率和千粒重高、丰产性好、米质较优,具有较好的应用前景。8006A及其与恢复系湘晴配组育成的新组合苏粳优2号(原名T优011)均于2006年1月通过江苏省品种审定。