Screening for resistance against Rhopalosiphum padi (L.). 2. Hordeum species and interspecific hybrids

Summary Twenty-seven accessions of Hordeum species and interspecific hybrids were screened in a growth chamber for resistance against the aphid Rhopalosiphum padi. Resistance measurement was based on the aphids' population growth during a 16-day period. The mean number of nymphs produced per female was only about 14% of that on the control cv. Tellus. H. bogdani was the most resistant accession. As a group, interspecific F₁-hybrids with common barley (H. vulgare × H. sp.) held an intermediate position. Differences in resistance between hybrids as well as between species (H. jubatum and H. lechleri) were observed. The most resistant species were all diploids. No effects of the host plant on formation of alatae or on the within-plant distribution of aphids were found.     

Inheritance and allelic relationships of resistances to the Russian wheat aphid in two Iranian wheat lines

Russian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is a serious pest of small grains in many countries. A previous study screened 70 genotypes, collected from different parts of Iran, for RWA resistance. Four crosses were made between two resistant lines (Shz.W-102 and Shz.W-104) and two susceptible lines (Shz.W-101 and Shz.W-103). Parents, F₁, F₂, and BCF₁ seedlings were screened for RWA resistance in the greenhouse by artificial infection. To determine allelism, the two resistant lines were intercrossed and F₁, and F₂ seedlings were evaluated. Resistance in Shz.W-102 and Shz.W-104, when crossed with Shz.W-101, was controlled by one dominant gene. However, resistance in Shz.W-102 and Shz.W-104, when crossed with Shz.W-103, was controlled by two dominant genes. Genes in two resistant lines segregated independently of each other. A three-gene system was proposed to govern resistance in the lines under study . This revised version was published online in July 2006 with corrections to the Cover Date.     

油菜蚜虫田间防治药剂筛选

为了有效地控制油菜蚜虫的危害,筛选出可作为油菜蚜虫大田防治的经济、有效、环保的药剂,通过对药剂的安全性测定、田间药效试验以及各种药剂的经济效益分析来验证所选取的药剂对油菜蚜虫的防治效果和应用技术。试验表明:70%吡虫啉WP、5%地蚜灵DP、50%烯啶虫胺SWG、10%氟氯氰菊酯EC、1.8%阿维菌素EC、2.5%高效氯氰菊酯EC等6种药剂对油菜具有较好的安全性。田间药效试验结果表明:6种药剂对油菜蚜虫均有一定的防效,其中70%吡虫啉WP、5%地蚜灵DP、50%烯啶虫胺SWG第一次施药后10天防效为89.31%、93.99%和79.18%,而第二次施药后10天防效为89.80%、80.40%和86.35%。各药剂有利于油菜的生长发育,且油菜的经济性状较对照好,通过药剂防治油菜蚜虫,对其经济效益分析可知,6种药剂的投入产出比为1:6.53,其中地蚜灵DP投入产出比达到了1:11.88。5%地蚜灵DP、70%吡虫啉WP、50%烯啶虫胺SWG对油菜蚜虫有较好的防效,且对油菜安全,成本低,可作为油菜蚜虫大田的防治药剂。     

Resistance to bird cherry-oat aphid (Rhopalosiphum padi L.) in winter wheat varieties

Summary In Hungary the bird cherry-oat aphid (Rhopalosiphum padi L.) is the most frequent aphid species in winter wheat (Triticum aestivum L.). Estimations of infestation by R. padi as well as measurements of grain yield and thousand-kernel mass were carried out in 26 winter wheat genotypes in conditions of naturally infested and not infested (protected) control plots. The experiment was performed in isolated conditions in two field cages covered by nets. The aphids overwintered on wheat and got into cage, extremely quickly multiplied, therefore there was no need to apply any artificial aphid infestation. Highly significant differences were demonstrated among genotypes in infestation severity of R. padi as well as in losses of grain yield and thousand-kernel mass. The most resistant variety GK Zombor had 25% infestation, and the most susceptible one GK Lili had 79.2%. The reduction of grain yield of the most tolerant genotypes (GK Korány, Downy, Mv 4, Jubilejnaja 50, Mv 8, GK Kincsö and GK Zombor) was 26–33%, and that of thousand-kernel mass was 23–30%. The most sensitive genotypes (GK Lili, GK Örzse, GK Koppány and Mv 13) suffered 58–63% losses in yield, and 40–50% in thousand-kernel mass. A close correlation was found between infestation of R. padi in different wheat genotypes and losses of grain yield (r=0.7572, P<0.001). Also there were tolerance differences among genotypes even within the same level of infestation. The reductions of thousand-kernel mass correlated very closely with the reductions of grain yield (r=0.9212, P<0.001), that makes screening possible by reductions of thousand-kernel mass. These results have found application in breeding. The leaf pubescence of the varieties studied did not generally influence the infestation by R. padi.     

Genetics of resistance to Aphis craccivora in cowpea

Summary Inheritance of aphid resistance and allelic relationships among sources of resistance was studied in the parents, F₁, F₂, F₃, and backcross populations of cowpea crosses. Each 4-day old seedling was infested with five fourthinstar aphids. Seedling reaction was recorded 14–16 days after infestation when the susceptible check was killed. The segregation data from eight crosses between resistant and susceptible cowpea cultivars indicated that aphid resistance was inherited as a monogenic dominant trait. Segregation data from crosses among eight resistant cultivars indicated that one or two loci and modifier(s) were involved in the expression of resistance to aphids. It was suggested that further studies on allelism among sources of resistance needed to be conducted in order to resolve this.     

Chloroplast DNA diversity in eggplant (Solanum melongena) and its related species S. incanum and S. marginatum

Summary The potential of isozymes for distinguishing asparagus varieties was carried out by a survey on 21 varieties using 10 enzyme systems: GOT, SkDH, DIA, PGM, MDH, IDH, PGD, ACP, PGI, MR and ADH. Only 3 enzymes, SkDH, GOT and PGM, showed useful polymorphisms. The varieties were found heterogeneous according to their genetic structure: open pollinated varieties were more heterogeneous than clonal hybrids; the F1 hybrid and the vitroclones were homogeneous. As expected from the narrow genetic basis of the varieties, only a few alleles per isozyme locus were present. Moreover, for each enzyme, one allele or type was predominant so that the discriminating power of the method was low. However some of the varieties could be identified and different applications of the results are presented.Abbreviations D.U.S.- Distinction-Uniformity-Stability - ACO- aconitase - ACP- acid phosphatase - ADH- alcohol dehydrogenase - CAT- catalase - DIA- diaphorase - END- endopeptidase - GOT- glutamate oxaloacetate transaminase - IDH- isocitrate dehydrogenase - MDH- malate dehydrogenase - MR- menadione reductase - PGI- phosphoglucoisomerase - PGM- phosphoglucomutase - PGD- phosphoglucose dehydrogenase - POX- peroxidase - SkDH- shikimate dehydrogenase     

滨旋花和兴安天门冬种子萌发特性的研究

从温度、pH值、盐分及混播方面对滨旋花和兴安天门冬种子萌发特性进行了研究。结果表明，滨旋花种子萌发的适宜温度为15～2．3℃，最适温度为20℃；而兴安天门冬种子萌发的适宜温度为23-28℃，其中25℃时发芽率最高；二者的种子适合在稍偏碱性环境下萌发；盐分对种子的萌发有抑制作用。滨旋花种子硬实率高，属于环境强迫休眠，人工处理种皮，可以解除休眠。     

从天冬-玉米的示范种植探讨"粮-药间套"增益模式

采用天冬单作、玉米单作和天冬-玉米套作3种种植模式,考查了整个生产过程中其主要生产资料和劳动力的投入以及产值等关键指标.对不同种植模式的经济效益对比分析结果表明,天冬-玉米套作比天冬单作增收21.8%,比玉米单作增收564.9%.天冬单作虽比玉米单作增收446.0%,但天冬种植三年后才能收获药材,没有短期收益.因此,3种模式中天冬-玉米套作的效果最佳.这一研究结果为种植业提供了一条"粮-药间套"的有效增益模式.     

中国北方棉区转基因抗虫棉对棉苗蚜及其两种天敌的影响（英）

2001年田间小区试验研究了转Bt基因棉和转双价基因(Bt+CpTI)棉对棉苗蚜及其天敌种群动态的影响;室内研究了转基因抗虫棉对两种棉蚜天敌的生物学影响.结果表明,转基因抗虫棉对棉蚜种群数量的影响不明显,未达显著水平.单作转基因棉田棉蚜发生期比麦套棉田提前5天左右,发生数量是麦套棉田的1.6倍,表明麦棉套作可有效的控制苗蚜的为害.室内研究表明,异色瓢虫对用Bt棉处理的的棉蚜的捕食量比对照增加22.0%,棉蚜茧蜂对用Bt棉处理的棉蚜的寄主率降低23.5%.     

Breeding of Polyploid Asparagus (Asparagus officinalis L.)

Asparagus is especially suitable for polyploidy breeding. The aim is to develop clone-based hybrid varieties, in particular male 4 × varieties. For this purpose, genetically divergent diploid idiotypes * * Idiotye (according to Reiger et al. 1976) is the sum of total hereditary determinants of an organism, consisting of its genotype (all determinants localized in the chromosomes) and its plasmotype (all determinants localized extra-chromosomally).
) are subjected to mitotic or meiotic polyploidization. In developing hybrid partners, special attention is paid to resistance in addition to yield and quality characters. Early diagnoses are applied in selection so as to shorten breeding times. Somaclonal variations may occur relatively often on in vitro propagation; these need to be eliminated. Triplex and quadruplex type males are suitable for paternal hybrid partners. Strong inbreeding depressions need to be avoided in their production.