塔斯曼海南部更新世放射虫的生物地层学

本研究利用保存丰富、完好的放射虫对塔斯曼海更新世层序进行地层学分析。对塔斯曼海南部更新世的KH94-4TSP-4PC岩芯的放射虫组合进行了详细的生物地层学分析,并从8 .6 m长的岩芯中识别出83种放射虫。依据放射虫属种的出现和消失,可得到两个放射虫带,即Chi带(老)和Psi带(新)。Chi带的顶部以Saturnalis cir-culariHaeckel ,Cycladophora pliocenicaHays的最后出现和Triceraspyris antarcticaHaecker的首次出现为标志。Psi带的顶部以Stylatractus universusHay和Antarctissa cylindricaPetrushevskaya的最后出现为标志。这些放射虫带可与浮游生物的有孔虫Globorotalia ( G.) truncatulinoides带进行对比。     

Changes in Kit Fox Defecation Patterns During the Reproductive Season: Implications for Noninvasive Surveys

Abstract: Noninvasive survey methods based on analyzing DNA extracted from feces can be useful for carnivores that are difficult to study by other methods. Changes in fecal deposition patterns associated with reproduction in kit foxes (Vulpes macrotis) might affect results of such surveys. We used a trained dog to collect fresh scats on 2-km transects in the home ranges of 11 radiocollared female kit foxes in January, February, and March 2008 and determined sex of the individual that deposited the scats by amplifying the zinc finger protein gene. Female foxes give birth in mid-February to mid-March. We found a similar number of scats each month. In January, the sex ratio of the scats was not different from the expected 1:1. However, in February there were almost 2 male scats for every female scat and in March there were >8 male scats for every female scat. Comparing March to January, there were more male scats on all 11 transects and fewer female scats on 10 of 11 transects. Around the time pups are born, both sexes appear to show changes in fecal deposition patterns that make it easier to find male scats and harder to find female scats. Effects of these changes on survey results will vary depending on the purpose and design of the survey. Surveys to determine distribution and relative abundance would probably not be negatively affected by these changes. However, if surveys to estimate abundance are conducted during the reproductive season, they could result in an underestimate of population size unless the increased heterogeneity in scat detectability is taken into account.     

Development and use of anchored‐SSRs to study DNA polymorphism in bread wheat (Triticum aestivum L.)

In bread wheat, 21 anchored simple sequence repeat (SSR) primer pairs detecting SSR length polymorphism and 42 anchored SSR primers detecting microsatellite‐anchored fragment length polymorphisms (MFLPs) are reported. Eight bread wheat genotypes were used for detecting polymorphism. The number of alleles in SSR analysis ranged from two to six, with a mean of 2.9 alleles per SSR. The number of polymorphic bands in MFLP ranged from two to 40, with a mean of 12.74 polymorphic bands/primer combination, the SSRs with CT/GA motifs giving the highest level of polymorphism (a mean of 18.37 bands). The average value of polymorphic information content (PIC) was 0.473 for SSRs and 0.061 for MFLP.     

Effect of inter-cropping bell-pepper with ginger on plant parasitic nematode populations and crop yields

During 1994 studies were undertaken to improve ginger (Zingiber officinale Roscoe) yield against the nematodes Pratylenchus penetrans, Meloidogyne incognita, Helicotylenchus dihystera and Tylenchorhynchus mashhoodi in Himachal Pradesh (HP) (India) by inter-cropping bell-pepper (Capsicum annum L) in eight different sequences (treatments). Inter-cropping of “one rhizome of ginger x one plant of bell-pepper” gave the highest ginger yield (600 g per rhizome). This treatment was completely free from P. penetrans and M. incognita. All treatments with bell-pepper plants equal to or higher in number to that of ginger rhizomes had higher ginger yields than treatments with ginger alone or with fewer bell-pepper plants. In the former, populations of P. penetrans and M. incognita were lower than in the latter treatments. The yield of ginger varied irrespective of population densities of H. dihystera and T. mashhoodi, indicating that P. penetrans and M. incognita are the major nematode problems of ginger in HP. Bell-pepper was a non-host to P. penetrans and non-preferred host to M. incognita. This helped to improve ginger yields by making the rhizosphere unfavourable for the development and multiplication of the major ginger nematode pests.     

A screening technique to evaluate pigeonpea for resistance to Rotylenchulus reniformis*

Rotylenchulus reniformis is one of the most important nematode pests of pigeonpea. A simple greenhouse technique has been developed to aid evaluation of pigeonpea genotypes for resistance to R. reniformis. In greenhouse pot experiments, eggsacs of R. reniformis in pigeonpea (cv. ICPL 87) roots were counted by eye and with the aid of a stereoscopic microscope at 15, 30 and 45 days after seedling emergence in soils infested with various numbers of vermiform R. reniformis. Seedlings were rated for the number of eggsacs per root system on a one (no eggsacs) to nine (more than 50 eggsacs) scale. Eggsac ratings were more uniform when roots were evaluated at 30 – 45 days than at 15 days and an inoculum of 15 to 30 individuals/cm³ soil also helped reduce variability. Eggsacs were not easily visible without the aid of a stereoscopic microscope. Of the 14 stains tested, exposure of nematode-infected roots to 0.25% trypan blue for three min was effective in staining the eggsacs blue without staining the roots. Using the stain, the assessment of infestation by R. reniformis was equally accurate with or without the aid of a stereoscopic microscope. Exposure of eggsacs to trypan blue enhanced the emergence of juveniles from the eggsacs.     

Components of resistance to the sorghum midge, Contarinia sorghicola

Studies were conducted on components of resistance to sorghum midge on four resistant (DJ 6514, AF 28, TAM 2566 and IS 15107) and two susceptible cultivars (CSH 1 and Swarna). Data were recorded on the numbers of eggs, larvae, emerged adults and grain damage in panicles of different genotypes infested with 60 midge females/panicle under no-choice conditions. The size of floral parts (glume, lemma, palea, lodicule, stigma, style, ovary and anther), rate of grain development and tannin content of grain were measured. The lengths of glume gl and 82, lemma L1 and L2, palea, lodicule, anther, style and stigma were positively associated with susceptibility to sorghum midge. Rate of grain development (between 3rd and 7th day after anthesis) was negatively associated with susceptibility to sorghum. Tannin content of grain was also negatively correlated with midge susceptibility, although there were distinct exceptions (e.g. DJ 6514 is highly resistant bur has a low tannin content).     

Antibiosis component of resistance in sorghum to sorghum midge, Contarinia sorghicola

Sorghum midge, Contarinia sorghicola Coq. (Diptera: Cecidomyiidae) is an important pest of grain sorghum, and host-plant resistance is one of the most effective means of controlling this pest. We studied the antibiosis mechanism of resistance in sorghum to C. sorghicola in a diverse array of midge-resistant and midge-susceptible genotypes. Data were recorded on adult emergence, postembryonic developmental period, number of mature eggs in the ovary, fecundity, larval survival from artificially implanted eggs; and the tannins, soluble sugars, and protein content of 10-day old and mature grains during the 1982-91 rainy and post-rainy seasons. Adult emergence was significantly lower in the midge-resistant genotypes compared with the susceptible controls. Initiation of adult emergence was delayed by 4–8 days on DJ 6514, IS 8571, IS 9807, IS 10712, IS 19474, IS 19512, ICSV 830 and ICSV 197. Postembryonic developmental period was prolonged on DJ 6514, IS 15107, IS 3461, IS 7005, IS 19474, ICSV 831 and ICSV 197. However, the delay in adult emergence or the extended developmental period was not observed during the post-rainy season in some genotypes. These differences in the expression of antibiosis to midge in resistant genotypes over seasons may be attributed to the effect of environmental conditions on the insect development and chemical composition of sorghum grain. Amounts of tannins and proteins were generally greater in the midge-resistant lines compared with the susceptible ones (except tannins in DJ 6514) while the soluble sugars were low in the midge-resistant lines (except TAM 2566). These differences in chemical composition of the grain between genotypes and variations over seasons have been discussed in relation to the expression of antibiosis mechanism of resistance to the sorghum midge. Antibiosis to sorghum midge was also evident in terms of smaller size of larvae, lower number of eggs in the ovary, reduced fecundity, and larval survival. Midge-resistant lines have diverse effects on the biology of this insect. Antibiosis along with other components of resistance can be used to develop cultivars with stable resistance to C. sorghicola.     

感染家蚕浓核病毒BmDNV1对家蚕抗性和敏感品种生化参数的影响

在家蚕疾病中,病毒性疾病是危害茧产品的主要且最普遍的疾病。病毒性蚕软腐病是由BmIFV, BmDNV1 和 BmDNV2引起的。对印度种质库（Indian Germ plasm stock）中的BmDN V1有抗性和敏感的家蚕品种进行了鉴定。利用标准方法对在BmDNV1感染过程中抗性和敏感品系的主要有机成分的变化（包括总蛋白、碳水化合物和脂类）进行了检测。结果表明： 随着幼虫年龄的增长,对照组和处理组中有机成分（即蛋白质和碳水化合物）的含量也随之增长,但是处理组的增长水平明显地低于各自对照组的增长水平。接种BmDNV1后,与对照组比较,敏感品种体内的血淋巴和中肠组织的总蛋白的量显著地下降。在抗性品种,接种4天后的总蛋白的量有了显著地下降,之后,下降水平小于各自的对照组。在抗性和敏感品种中,血淋巴和中肠组织中的总碳水化合物的量略有下降。在变化不显著的抗性和敏感品种中,血淋巴和中肠组织中的脂质的量有显著地提高。在敏感家蚕品种,生化变化清晰地显示： BmDNV1感染消耗作为主要能量来源的总蛋白和碳水化合物。这些成分的损耗导致了被感染家蚕的生长受阻。