DNA fingerprinting of Indian cashew (Anacardium occidentale L.) varieties using RAPD and ISSR techniques

Indian cashew breeding programme has produced 24 selections and 11 hybrids with increased yield and excellent nut characters. Molecular profiles of these varieties were developed using a combination of five RAPD and four ISSR primers pre-selected for maximum discrimination and repeatability. A total of 94 markers were generated which discriminated all the varieties with a probability of identical match by chance of2.8 × 10^-11. There was no correlation between the relationships based on molecular data and the pedigree of the varieties. Narrow range of average similarity values among major cashew breeding centres with only 3.6% of molecular variance partitioned between them was attributed to the exchange of genetic material in developing varieties. Difference in the average similarity coefficients between selections and hybrids was low indicating the need and scope for identification of more parental lines in enhancing the effectiveness of hybridisation programme. This revised version was published online in August 2006 with corrections to the Cover Date.     

Leaf and stem rust resistance of hexaploid wheat cultivars salzmünder bartweizen and weique

Summary Wheat cultivars Salzmünder Bartweizen and Weique gave a similar pattern of reaction type when tested with 27 different races of stem rust and 17 races of leaf rust from Canada and Czechoslovakia. Both cultivars were resistant to all races of stem rust and most of the races of leaf rust. Genetic studies indicated that the two varieties have the same genes for rust resistance, with the genes for leaf and stem rust being closely linked.Transmission of the genes for rust resistance was irregular and appeared to be associated with meiotic irregularities in chromosome pairing. In all F₂ populations which deviated significantly from a 3:1 ratio, a deficiency of resistant plants was noted. The greatest deficiency was in the F₂ of crosses involving Salzmünder Bartweizen, of which the F₁ hybrid also had the greatest meiotic irregularities.Chimeral plants, of which the longitudinal half of the leaf showed a resistant reaction and the other half a susceptible reaction, were observed in crosses with Salzmünder Bartweizen.     

Breeding for tolerance to beet-cyst eelworm Heterodera schachtii Schm. in sugarbeet

Summary Successive mass selections were made in sugarbeet varieties (Beta vulgaris L.) and in B. vulgaris × B. maritima L. hybrids for tolerance to wilting caused by beet-cyst eelworm attack. The selected lines showed improved tolerance to wilting, but no evidence of resistance to eelworm infection was demonstrated. By repeated back-crossing of the selected lines with the commercial varieties and concurrent selection root yield could be improved without substantially decreasing the tolerance to eelworm attack. These results indicate that tolerance is partly conditioned by complete and incomplete dominant genes.     

矮抗58及其衍生小麦品种在南阳麦区条锈抗性、农艺性状、品质及利用分析

为给矮抗58及其衍生品种在南阳麦区育种上的利用提供参考,对矮抗58及其49个衍生品种的系谱、条锈抗性、农艺性状及品质进行分析.结果表明,48个品种都属于矮抗58衍生的子一代,强筋(中强筋)品种7个,中抗及以上有16个(含矮抗58).16个中抗及以上品种农艺性状在平方欧式距离10时聚为3个群体,第Ⅰ群包括洛麦34、新麦3...     

Diallel study of open-pollinated maize varieties in Trinidad

Summary In Trinidad, maize (Zea mays L.) is primarily harvested in the immature stage as green ears for human consumption. The purchase of popular imported hybrid seed has become a substantial component of the economic inputs of maize production. The objectives of this study were to investigate combining abilities and heterotic patterns among available open-pollinated varieties and to assess correlations among five important traits: time to silking, plant height, grain yield, ear size, and marketable ears per hectare. General combining ability was significant for all traits. Specific combining ability was significant for all traits except ear size. Three intervarietal crosses showed moderate levels of heterosis (10–27%), and several yielded similarly to the control hybrids, Pioneer X304 and Pioneer 3078. The cross Acid Soil Tolerant 1991 SA-3 X ICTA Farm Corn was selected as the most suitable base population for mass selection. Phenotypic and genotypic correlations among the five traits studied were all positive and significant. Populations which flowered early were shorter and yielded less than the late flowering and taller populations and population crosses included in this study.     

Cytogenetic analysis of a spontaneous 5B/6B translocation in tetraploid wheat landraces from Ethiopia, and implications for breeding

Three tetraploid (2n= 4x= 28) wheat Triticum turgidum L. landrace morphotypes (= genotypes) from Ethiopia were found to carry a variant karyotype directly discernible under the microscope. This was possible because the rearrangement involved one of the satellited chromosomes. Giemsa C-banding revealed that the rearrangement resulted from a 5BS.6BS(5BL.6BL) centric reciprocal translation. The banding pattern on 5BL was polymorphic, suggesting that this translocation might have occurred more than once. There was little C-band polymorphism for the remaining chromosomes, except for 2A. As pure lines, all three morphotypes showed normal chromosome pairing at metaphase I (MI) in pollen mother cells (PMCs). indicating that they are genomically stable. Meiotic analyses of F₁ hybrids and F₂ segregates derived from crosses with tester varieties clearly indicated that one of them (B-l–9) carried another translocation. However, we were not successful in delecting the chromosomes involved, presumably the interchanged segments did nol include C-banding regions. By using T5BS.6BS, direct evidence for segregation distortion against translocation homozygotes in intervarietal hybrids was obtained. The distorted segregation was attributed lo zygotic selection. No aneuploid plants were obtained from the F₂ segregates. However, translocation heterozygotes resulting in unstable meiosis were abundant in the F₂ generation. The implications of the results in using the indigenous landraces in hybridization breeding are discussed.     

Genetic variability and heterotic groups of Brazilian popcorn populations

The development of successful advanced lines and cultivars in maize is dependent on parental selection and assignment to defined heterotic groups. So, the objectives of this study were to evaluate genetic variability and identify heterotic groups among Brazilian popcorn varieties. Thus, diallel crosses of advanced generations of the popcorn hybrids, IAC 112 and Zélia, and of three open-pollinated popcorn varieties, RS 20, Branco, and SAM were performed. Ten hybrid combinations, the five parents, and five check treatments were arranged in a block design with four replicates in two tropical-zone locations (CWb climate). Both additive and non-additive effects were important for grain yield, plant height, ear height, and husk cover. For popping expansion, only the additive effects were important. Hybrid combinations between the local variety (Branco) and F₂ populations (IAC 112 and Zelia) resulted in the third and fourth highest values for popping expansion. The best grain yields were obtained with hybrid combinations involving SAM. Cultivars Zélia, IAC 112, and RS 20 increased popping expansion, whereas cultivar Branco increased grain yield of hybrid combinations. The following conclusions may be drawn: Brazilian popcorn populations have reduced heterosis and genetic variability to popping expansion in relation commercial cultivars; there is genetic variability among Brazilian popcorn populations that allows the exploitation of additive and non-additive effects for grain yield; it is possible to increase grain yield by using local varieties; but it would be difficult to obtain commercial hybrids from local varieties because they have poor performance for popping expansion.     

运旱号强筋抗旱丰产系列小麦品种选育研究

为育成适宜中国黄淮麦区旱地种植的优质强筋抗旱丰产小麦新品种,选育研究突出了强筋力品质改良的的高产优质育种目标和重视利用具有国外优质种质背景的品种资源。通过生态适应合理组配亲本,调节花期活性杂交,高分子量麦谷蛋白亚基分子标记检测和面筋数量及质量的品质测定辅助选择,生态适应协调特征特性选育和生态适应异地多年多点及水旱地鉴定鉴选,重视系统观察考种和综合评价优选及优系优中选优等育种策略和方法技术的应用,克服了利用国外种质杂交和冬春杂交的抗旱、耐热、抗冻及适宜熟性等特性适应性差的技术问题,育成了以‘运旱20410’、‘运旱618’为代表的运旱号系列强筋小麦品种,品质特性实现了由中强筋到稳定性强筋的创新改良,具有比‘晋麦47’增产2%~10%的高产潜力和较强的抗旱抗干热风能力。实现了抗旱丰产与强筋品质性状的有机结合。     

Epicuticular waxes and regulation of ear wetting and pre-harvest sprouting in barley and wheat

Morphological features of the cereal ear, including awns, alter pre-harvest sprouting damage by changing the rate of water absorption during rainfall. In this paper, the potential for wheat (Triticum sp.) arid barley (Hordeum vulgare L.) waxes to reduce sprouting by increasing water repellency of the mature ear has been examined. Six barley F₂ populations segregating for different non-glaucous single-gene mutants controlling waxes on ears were examined. Water repellency was assessed by measuring both the contact angle of a water drop placed on the lemma surface (internal angle) and by repetitive weighings of whole ears during their exposure to simulated rainfall. The lemma of glaucous (wild type) lines had larger water drop contact angles, an indication of poorer spread of water over the surface. In simulated rainfall, ears of the glaucous lines showed a clear reduction of wetting (20–30% less) and, after 72 h of wetting, their in-ear sprouting was reduced by 50 to 65%. When pre-wet, the glaucous ears also shed water more readily when shaken to simulate the combined effect of wind and rainfall. To reduce pre-harvest sprouting of barley it may be possible to screen visually for ears that are more glaucous but a more specific screen would be to select for lemma water drop contact angle since it is a good indicator of ear wettability and so allows differences in surface properties to be assessed. For bread wheat (T. aestivumL.), as for barley, the more glaucous the ear, the greater the water drop contact angle and the more tubular surface wax coverage seen in scanning electron microscope images. In addition, surface wax amount apparently affected in-ear wettingin lines of durum wheat, (T. turgidum L.). Possible genetic relationships between waxy/waxless genes in wheat and barley are suggested with the aim, ultimately, of altering ear glaucousness to give increased water repellency and a reduction of in-ear sprouting of wheat. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetics of Cyst Nematode Resistance in Soybean PIs 467312 and 507354

Soybean Cyst nematode (SCN) Heterodera glycines Ichinohe is the most serious pest of soybean [Glycine max (L.) Merr.] in the world and genetic resistance in soybean cultivars have been the most effective means of control. Nematode populations, however, are variable and have adapted to reproduce on resistant cultivars over time due mainly to the narrow genetic base of SCN resistance in G. max. The majority of the resistant cultivars trace to two soybean accessions. It is hoped that new sources of resistance might provide durable resistance. Soybean plant introductions PI 467312 and PI 507354, are unique because they provide resistance to several nematode populations, i.e. SCN HG types 0, 2.7, and 1.3.6.7 (corresponding to races 3, 5, and 14) and HG types 2.5.7, 0, and 2.7 (corresponding to races 1, 3, and 5), respectively. The genetic basis of SCN resistance in these PIs is not yet known. We have investigated the inheritance of resistance to SCN HG types 0, 2.7, and 1.3.6.7 (races 3, 5, and14) in PI467312 and the SCN resistance to SCN HG types 2.5.7 and 2.7 (races 1 and 5) in PI 507354. PI 467312 was crossed to ‘Marcus’, a susceptible cultivar to generate F₁ hybrids, 196 random F₂ individuals, and 196 F_2:3 families (designated as Pop 467). PI 507354 and the cultivar Hutcheson, susceptible to all known SCN races, were crossed to generate F₁ hybrids, 225 random F₂ individuals and 225 F_2:3 families (designated as Pop 507). The F_2:3 families from each cross were evaluated for responses to the specific SCN HG types in the greenhouse. Chi-square (χ²) analyses showed resistance from PI 467312 to HG types 2.7, and 1.3.6.7 (races 5 and 14) in Pop 467 were conditioned by one dominant and two recessive genes (Rhg rhg rhg) and resistance to HG type 0 (race 3) was controlled by three recessive genes (rhg rhg rhg). The 225 F_2:3 progenies in Pop 507 showed a segregation of 2:223 (R:S) for response to both HG types 2.5.7 and 2.7 (corresponding to races 1 and 5). The Chi-square analysis showed SCN resistance from PI 507354 fit a one dominant and 3 recessive gene model (Rhg rhg rhg rhg). This information will be useful to soybean breeders who use these sources to develop SCN resistant cultivars. The complex inheritance patterns determined for the two PIs are similar to the three and four gene models for other SCN resistance sources known to date.     

转Bar基因小麦及其杂交后代旗叶光合特性的研究

Nong4是Bar基因插入在受体小麦D染色体组上的转Bar基因小麦,由于其具有抗除草剂功能,转Bar基因小麦将成为选育高产优质抗除草剂小麦品种的重要材料。笔者以转Bar基因小麦及其与当地常规品种皖麦48的杂交F1代为材料,结合光合和叶绿素荧光参数等指标,系统地研究了转Bar基因小麦及其F1代的产量性状、旗叶的光合特性,探讨了转Bar基因小麦及其F1代产量性状产生的影响,并从光合特性的角度揭示其原因所在,为转Bar基因小麦的高光效杂交后代的选育提供了科学依据。研究结果表明在农艺性状、光合特性的表现上,以Nong4为亲本的正交F1Nong4×Wanmai48比反交F1Wanmai48×Nong4有更好的优势表现,呈较强的中亲优势或一定的超亲优势,如其穗长、千粒重超亲优势率分别达到5.17%和4.41%。笔者研究分析Nong4及其正交F1Nong4×Wanmai48产量优势产生的原因可能是其光能转化效率高、电子传递能力强、光合产物积累多等的综合表现。所以,在选育抗除草剂小麦杂交后代时,可以以Bar基因插入在D染色体组上的Nong4为父本,以当地优质高产品种为母本,从而获得高光效的杂交后代。     

2个小麦品种抗条锈基因遗传分析

采用常规杂交方法,以重要小麦条锈菌鉴别寄主Heines kolben和Struba Dickkopf与冬性小麦感病品种铭贤169杂交、自交和回交,获F1、F2和BC1代种子,根据条锈菌系的毒性谱,选用2E16单孢菌系,在铭贤169上繁殖。苗期抗性鉴定在人工控制的环境中进行。当麦苗第一片叶全展大约7cm时,用扫抹法接种,置于（9±2）℃接种间内黑暗保湿24h后转入低温温室内（温度为昼15~19℃,夜10~14℃）潜育发病,待感病品种铭贤169充分发病时调查侵染型,苗期抗性鉴定,并进行卡方检验,结果表明：供试品种 Heines kolben对条锈菌生理小种2E16的抗性由两对隐性互补基因控制;Struba Dickkopf对小种2E16的抗性由一对显性基因控制。     

A valuable source of yellow rust resistance in Israeli populations of wild emmer,Triticum dicoccoides Koern.

Summary An extensive collection of wild emmer was screened for yellow rust resistance in a joint project by research institutes in Israel and The Netherlands. In inoculation experiments performed both in seedling stage and at maturity, the wild emmer accessions displayed a diversity of responses to yellow rust infection, ranging from immunity to complete susceptibility.SelectionTriticum dicoccoides var.aaronsohni G-25 was most promising proving highly resistant to all 21 races and field races used. Selection G-7, which was also very resistant in the trials, differed slightly from G-25 in infection types produced on inoculation with one of the isolates; this may be an indication that the genetic factors controlling resistance in these two selections are not identical.It is concluded that the diversified populations of wild emmer indigenous to Israel possess genes which confer high resistance to a very wide spectrum of yellow rust races, including all common races in Western Europe and the Middle East. As resistance factors can be transferred easily fromT. dicoccoides to durum and common wheat, this source may be utilized in producing varieties of cultivated wheat with improved yellow rust resistance.Joint contribution from the Volcani Institute of Agricultural Research, Bet Dagan, Israel, 1969 Series, No. 1594-E, and the Institute of Phytopathological Research, Wageningen, The Netherlands.     

Control and inheritance of resistance to yellow rust in Triticum aestivum-Lophopyrum elongatum chromosome substitution lines

A set of T. aestivum-L. elongatum chromosome substitution lines was tested for yellow rust resistance at the seedling stage. Inheritance of the resistance and esterase-5 (Est-5) variation were studied. The results demonstrated that L.elongatum carried a new gene(s) conferring yellow rust resistance. This gene was dominant and located on chromosome 3E of L. elongatum. The biochemical locus encoding Est-5was also located on chromosome 3E, and co-segregated with theYr gene(s) in the wheat background. The transmission frequencies of chromosome 3E in 3E(3A) × CS, 3E(3B) × CS and 3E(3D) × CS hybrids were scored.None of the hybrids transmitted the alien chromosome at thetheoretical maximum rate, but the transmission frequencies ofchromosome 3E in F₂ populations of 3E(3A) × CS and 3E(3D) × CS were significantly higher than in thatof 3E(3B) × CS.     

我国不同麦区小麦品种的面粉溶剂保持力

溶剂保持力(SRC)是评价软麦品质的一项重要指标。为了解我国不同麦区小麦品种溶剂保持力的差异, 2008—2009和2009—2010生长季测定了181个小麦品种的4种溶剂保持力, 并分析其遗传变异及不同麦区品种SRC特点。结果表明, 4种SRC值在品种、年度和麦区间均差异显著 (P<0.01或P<0.05), 此外, 年份´品种和年份´麦区的互作效应也达显著水平(P<0.01)。主成分分析表明, 仅主成分1的特征值大于1.0, 其对方差的解释率为72.3%;根据主成分综合得分对供试品种聚类, 结果显示各麦区品种SRC值变异明显, 存在不同SRC类型的品种资源, 低SRC品种在长江中下游麦区相对较多, 而中、高SRC品种多分布于黄淮麦区。筛选出阿勃、法展5号、淮麦17、宁麦3号、宁麦6号、皖麦48、选7、扬麦13、扬麦17、郑麦004等低SRC品种, 可用于弱筋小麦品种选育和品质改良。     

Analysis of the yield potential and yield components of F1 and F2 hybrids of crosses between wheat (Triticum aestivum L.) and spelt (Triticum spelta L.)

Summary Crosses of wild barley (Hordeum vulgare ssp. spontaneum and Hordeum vulgare ssp. agriocrithon) with Hordeum vulgare ssp. vulgare were used to select high yielding grain types under dryland Mediterranean conditions. No special difficulties were faced in making the crosses, in eliminating the brittle rachis genes from the grain types or in selecting 6-rowed types in crosses between 2-rowed wild barley and 6-rowed ssp. vulgare varieties. Brittle rachis genotypes, present in the segregating populations were used in developing self-reseeding permanent pastures for dry areas. The best selections were tested in seven trials during 1989–92 and some of them outyielded their parents and also the best improved check variety by 13–22%. Indications for transgressive segregation were obtained for grain yield, straw yield, total biological yield, harvest index and volume weight. The crude protein content of some of the selections was significantly higher than that of the checks. For breeding programs aiming at large seeds, special ssp. spontaneum lines should be used as parents. High grain yield was positively correlated with high straw yield, total biological yield, earliness in heading date, high harvest index and negatively with volume weight. It was concluded that unexploited useful genes, even when not directly observed in wild barley, could be transfered easily into high yielding genotypes by breeding.     

新疆冬小麦品种农艺及产量性状遗传多样性分析

Grain yield is one of the most important goals in wheat breeding, and agronomic or yield-related traits can directly reflect the characteristics of varieties. In order to determine the evolution of genetic diversity in agronomic traits of Xinjiang winter wheat varieties and their adaptabilities to different ecological environments, 134 winter wheat landraces and 54 moderns bred varieties from Xinjiang were selected for agronomic trait investigation. They were planted in three different ecological environments (Urumqi and Yining in Xinjiang province, and Tai’an in Shandong province) for two consecutive growth seasons, and nine agronomic and yield-related traits were surveyed and analyzed. The estimated broad sense heritability of nine agronomic and yield traits was in descending order: plant height > grain width > grain length/width ratio > spike length > spikelet number > thousand- kernel weight > grain number per spike > grain length > fertile spikelet number. Correlation analyses of nine agronomic and yield traits showed that these traits were correlated with each other. It was found that the plant height, spike length and grain length/width ratio of landraces were higher than that in modern bred varieties, but the grain number per spike, thousand kernel weight, grain length and grain width in landraces were less than that in modern bred varieties. However, the correlation coefficient of these nine traits was higher in modern bred varieties than that in landraces. These variations reflected the evolution of Xinjiang winter wheat varieties in agronomic traits in recent years. This study may provide important information for breeders to select the breeding parents in different winter wheat regions.     

Heterosis in landrace-based topcross hybrids of pearl millet across arid environments

This study quantified the magnitude of heterosis in pearl millet (Pennisetum glaucum) topcross hybrids produced by crossing 16 diverse landraces and three high yielding open-pollinating varieties on two homozygous male-sterile lines. Hybrids and pollinators were grown in 12 year ×;location combinations in India that were grouped into three zones. Genetic components of variance quantifying the differences among these hybrids were estimated. The hybrids showed a conspicuous heterosis for grain yield, earliness and biomass yield but not for straw yield. The level and direction of heterosis for time to flowering depended strongly on the earliness of the male-sterile line. In the terminal drought stress zone hybrids made on the early maturing male-sterile line 843A had the highest level of heterosis for grain yield (88%). This was partly due to escape from terminal stress. In the other two zones the heterosis for grain yield was on average 30%. Heterosis for biomass yield and biomass yield per day was on average also positive in all three zones. For all traits, except time to flowering and biomass yield per day, pollinator effects were the only significant source of variation. Differences between hybrids were mostly caused by additive genetic effects. Significant amount of heterosis observed in landrace-based topcross hybrids for grain yield and other productivity-related traits suggested that substantial improvement in pearl millet productivity in and environments can be obtained by topcrossing locally adapted landraces on suitable male-sterile lines. This revised version was published online in July 2006 with corrections to the Cover Date.     

The inheritance of stem rust and leaf rust resistance in some Ethiopian wheat collections

Summary Common and durum wheat populations obtained from Sweden and originally collected in Ethiopia were screened for resistance to steum rust and leaf rust. Resistant selections of common wheat were crossed and backcrossed with either stem rust susceptible RL6071, or leaf rust susceptible Thatcher. Genetic studies, based largely on tests of backcross F₂ families, showed that four of the selections had in common a recessive gene SrA. Plants with this gene were resistant (1⁺ infection type) to all stem rust races tested. This gene was neither Sr26 nor Sr29. The resistance of other selections, based on tests with an array of rust isolates, was due to various combinations of Sr6, 8a, 9a, 9d, 9c, 11, 13, 30, and 36. One of the selections had linked genes, Lr19/Sr25. Another selection had a dominant gene for resistance (;1 infection type) to all the races of leaf rust. With the possible exception of this gene for leaf rust resistance and SrA, no obviously new resistance was found.     

东北春小麦及部分外引小麦高分子量谷蛋白亚基组成分析

利用SDS-PAGE法分析了72份东北春小麦品种(系)和外引小麦品种HMW-GS组成及分布,结果表明:在Glu-A1位点上的3种变异类型null,1和2*亚基中,东北春小麦1和2*亚基出现的频率最高,均为36.1%,外引品种中null出现的频率最高,为41.7%;在Glu-B1位点上,检测到的6种变异类型(7,6 8,7 8,7 9,14 15,17 18)中7 8亚基类型的出现频率最高,东北春小麦为66.7%,外引品种为44.4%;在Glu-D1位点上的3种变异类型(2 12,2 10,5 10)中5 10出现频率最高,东北春小麦为55.6%,而外引品种高达72.2%。所有参试材料中共出现19种组合类型,其中出现频率最高的是1,7 9,5 10和null,7 8,2 12,均为19.4%。根据Payne的品质评分标准对部分材料进行评定,发现达到10分的材料出现了23份。这些材料可能成为东北春麦区小麦品质改良的宝贵资源。