Stage-specific population dynamics of cottony cushion scale,Icerya purchasi (Hemiptera: Monophlebidae), in citrus orchards in Jeju,Korea

The cottony cushion scale, Icerya purchasi Maskell (Hemiptera: Monophlebidae), is a polyphagous, cosmopolitan and destructive pest of citrus. This study was conducted to obtain the stage-specific phenology of I. purchasi for seasonal management strategies in the field. Movement of crawlers (hatched nymphs) in egg sacs of overwintered females started in late May, peaked in early to mid-June, and was completed by late June. Generally, the 1st generation occurred from late May until late September and the overlapping second generation occurred from early September. The 1st nymphs in the 1st generation peaked in mid June. The 2nd nymphs showed peak activity in late July. The 3rd nymphs showed peak population in early September. The 1st generation adults peaked in mid September. In the 2nd generation, the 1st nymphs peaked in early October, the 2nd nymphs showed peak activity in late October, and the 3rd nymphs reached a plateau after mid October. The 2nd generation adults occurred from late October. Consequently, two life cycles were competed in the Jeju area. The average fertilities of I. purchasi were 623 and 247 crawlers per female in overwintered and summer generations, respectively. An average of 20.7% of all citrus orchards was infested with I. purchasi, with a mean of 3.9% infested trees in Jeju. These results should be useful in establishing management strategies for I. purchasi in citrus orchards.     

Seasonal variation in honeyeater foraging behaviour,infloresence abundance and fruit set in Banksia spinulosa (Proteaceae)

Seasonal variation in the foraging behaviour of honeyeaters and the production of fruit were examined in relation to the flowering intensity of Banksia spinulosa over two flowering seasons. The abundance of inflorescences was greater in the mid than in the early and late periods of the flowering season. In the mid period, many plants were blooming and each plant had many flowering inflorescences. Inflorescences received most visits by honeyeaters in the early flowering period; the visitation rate declining as flowering progressed. Eastern spinebills were the most common floral visitors at all times during the season. The number of foraging probes made at inflorescences by eastern spinebills did not differ throughout the season. Foraging movements between inflorescences on the same plant were more frequent in the mid period than in the early and late periods. Long distance movements between plants (more than 10 m apart) were promoted by aggressive interactions between honeyeaters. Inflorescences flowering in the late period were less likely to develop follicles because there were fewer visits by birds and/or because resources had been allocated to inflorescences pollinated earlier in the season. The number of follicles produced per infructescence did not differ between flowering periods. Overall, the number of inflorescences produced per plant, the number of visits received per inflorescence and the proportion of inflorescences that developed follicles were greater in 1987 than in 1988.     

A fully in vitro protocol towards large scale production of recombinant inbred lines in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

A bottleneck for genetic research and breeding of crop plants is the time taken to producing large pure line segregating populations so called recombinant inbred lines (RILs). One way to overcome this problem is through use of the single-seed-decent (SSD) process under in vitro conditions. A number of factors that may affect in vitro SSD approach of wheat including temperature, light duration and intensity, salt strength and carbohydrate concentration were investigated in this study. Under the in vitro conditions, 45 days per generation was achieved for an early flowering wheat genotype Emu Rock, allowing eight generations per annum; 58 days per generation was achieved for mid flowering genotypes, allowing six generations per annum. The results showed that a variation of growth environment before and after three-leaf stage allowed in vitro seed-set with a relatively short generation time. Specifically, the plantlets were first grown under 22?°C with a light intensity of 145 μmol m^?2 s ^?1 (16 h d^?1) for 20 days (around three-leaf stage), and then moved to an environment of 28?°C and 500 μmol m^?2 s^?1 (20 h d^?1) light. The culture medium was 1/2 strength Murashige and Skoog (MS) with modification of adding ten times of extra KH₂PO₄ and 4% sucrose. The fully in vitro protocol resulted in 100% flowering rate and average seed set rate of 91.5% in Emu Rock and Zippy. It can be further fine-tuned to suit different genotypes and it has a potential for factory scale mass-production of RILs for genetic studies and practical breeding programs.     

Phenology and life cycle of the annual, <Emphasis Type="Italic">Chamaesyce maculata</Emphasis> (L.) Small (Euphorbiaceae), with multiple overlapping generations in Japan

The phenology of germination, vegetative growth and sexual reproduction in the annual Chamaesyce maculata (L.) Small (Euphorbiaceae) were investigated in a natural population in western Japan. Seedlings emerged from mid-June to early October, with three peaks: mid-June, late July and late August. Plants that emerged in June commenced sexual reproduction from late July, and thereafter both vegetative growth and sexual reproduction occurred together until early November, the plants showing no switching from vegetative growth to sexual reproduction. Seedlings that emerged in June and July suffered high mortality, but most seedlings that emerged from August onward survived until the reproductive stage. The minimum size for reproduction was largest for plants that emerged early in the season, and it decreased with a delay in seedling emergence. The late emergence of seedlings that resulted in low reproductive output may be to some extent compensated for by the increased probability of survival in the seedling stage. A transplant experiment clarified that C. maculata can repeat a maximum of three overlapping generations within a year. Multiple generations per year were attained by non-dormant seeds produced in the first and second generations and clearly resulted in an increased reproductive output per year. The life cycle with multiple overlapping generations may have been acquired in habitats where unpredictable disturbance results in temporally unsuitable conditions for germination, vegetative growth and sexual reproduction of annual plants, but where suitable conditions frequently continue over a period longer than the single generation time of annual plants.     

Life cycle of the lilac pyralid Palpita nigropunctalis (Bremer) (Lepidoptera: Crambidae) on five oleaceous tree species

The seasonal abundance of Palpita nigropunctalis larvae was studied on five oleaceous tree species in Ibaraki, central Japan, for two years. The larval population peaked on some tree species in both spring and autumn while it peaked on other tree species only in autumn. In bimodal populations, the spring peaks consisted of larvae infesting leaves, while the autumn peaks consisted of larvae infesting various tree parts (flowers, fruits and leaves). Larval development was longer and pupal weights were lower on Ligustrum lucidum fruits than on Ligustrum japonicum fruits. Thus, L. japonicum fruits were suitable for larval development in autumn. First-instar larvae appeared to occur three times per year (in late April to early May, mid to late September and early to mid October). Adults were observed from late March to early April, mid May to early June, and early September to mid November at the census sites, showing that P. nigropunctalis had three generations a year. The percentage of females having premature ovaries were 64.3 and 12.5% at 15 °C under 14-h and 15-h photophases, respectively, and 28.6 and 25% at 20 °C under the respective photophases. These temperatures and photoperiods are typical of those in May and June in the census sites. The ovaries of females collected in the field between late May and mid July were premature, in agreement with the laboratory experiments. The pupal duration was prolonged under the short photoperiod, especially at reduced temperatures. We discuss a possible life cycle of P. nigropunctalis in Ibaraki.     

Life cycle of <Emphasis Type="Italic">Harmonia axyridis</Emphasis> in central Europe

The development and reproduction, and maximum number of generations across seasons were ascertained for populations of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) in Central Europe. Number of generations was calculated using the thermal characteristics of development and summation of daily average air temperatures, in 2007–2016. This species can produce 2–3 generations per year. However, there is insufficient time for it to achieve its full reproductive potential. Delayed emigration from hibernacula (late April) shortened the period of seasonal activity by 1–6%. Breeding occurred from May to mid September. Oviposition continued into late summer, which left insufficient time for the late-hatching immatures to complete their development before the onset of winter. A high mobility, opportunistic use of prey patches and weak tendency to enter dormancy provide the potential for population increase by extending the period of development of immatures at the risk of failure if the cold period comes early.     

The rates of shoot and root growth in intact plants of pea mutants in leaf morphology

Isogenic lines of pea (Pisum sativum L.) with the genetically determined changes in leaf morphology, afila (af) and tendril-less (tl), were used to study the relationship between shoot and root growth rates. The time-course of shoot and root growth was followed during the pre-floral period in the intact plants grown under similar conditions. The af mutation produced afila leaves without leaflets, whereas in the case of the tl mutations, tendrils were substituted with leaflets, and acacia-like leaves were developed. Due to the changes in leaf morphology caused by these mutations, pea genotypes differed in leaf area: starting from day 7, the leaf area was lower in the af plants and larger in the tl plants as compared to the wild-type plants. Such divergence was amplified in the course of plant development and reached its maximum immediately before the transition to flowering. Plants of isogenic lines did not notably differ in stem surface areas. In spite of significant difference in total leaf area, the wild type and tl plants did not differ in leaf dry weight. Starting from leaf 9, the af plants lagged behind two leaflet-bearing genotypes (wild type and tl) in leaf dry weight, whereas stem dry weight was similar in the wild type and tl forms and slightly lower in the af plants. Root dry weights were practically similar in the wild type and tl plants until flowering. The reduction of leaf area in the af plants drastically reduced root dry weight. In other words, the latter index was related to the total weight and total area of leaves and stems. The correlation analysis demonstrated an extremely low relationship between leaf and stem area and dry weight and those of roots early in plant development (when plants develop five to seven leaves). Later, immediately before flowering (nine to eleven leaves), root weight was positively related to leaf weight and area; however, stem area and root weight did not correlate. Thus, in three genotypes (wild type, af, and tl), at the end of their vegetative growth phase, leaf and root biomass accumulated in proportion, independently of leaf area expansion.     

Phenology ofHippodamia undecimnotata (Col.: Coccinellidae) in Greece

Hippodamia (Semiadalia) undecimnotata (Coleoptera: Coccinellidae), collected from central Greece and reared in cages during 1993–1994 and in vials during 1994–1995 outdoors at Kifissia, Athens, completed 5 generations per year. In both cases, adults of the 1^st, 2^nd and 3^rd generations reproduced, completing their egg laying in the same year; 4^th and 5^th generation adults reproduced both in the year they emerged and the following year. In both cases, adults of the 1^st and 2^nd generations died before winter; in 1993, adults of the 3^rd generation died before winter, in 1994, they survived until April 1995. Adults of the 4^th and 5^th generations overwintered successfully. The greatest numbers of eggs were laid by females of the 1^st and 2^nd generations. Field observations and timed counts of specimens (30 minutes per location) made on the tops of Mounts Chlomo and Kitheron and on the neighboring plain of Kopais between 1991 and 1994 revealed that most adults arrived on the mountains between late June and early September and left between the end of March and beginning of May.H. undecimnotata were not found on the plain of Kopais during the winter. Overwintered adults arrived between the end of March and beginning of May; 1^st generation adults emerged in June. The presence of a few eggs, larvae, pupae and newly-emerged adults observed on the plain during August-September 1993 suggests that at least a portion of theH. undecimnotata population in central Greece completes 2 or more overlapping generations per year.     

Precocious floral initiation and identification of exact timing of embryo physiological maturity facilitate germination of immature seeds to truncate the lifecycle of pea

We propose herein a novel single seed descent protocol that has application across a broad phenotypic range of pea genotypes. Manipulation of key in vivo growing conditions, including light, photoperiod and temperature, combined with precocious in vitro germination of the embryo at full physiological maturity substantially shortened the pea lifecycle. We define full embryo physiological maturity as the earliest point in seed development when precocious in vitro germination and robust seedling growth can be reliably achieved without supply of exogenous hormones. Under our optimised conditions for accelerated plant growth, embryo physiological maturity was attained at c. 18 days after pollination, when seed moisture content was below 60?% and sucrose level under 100 mg g^?1 DW. No delay penalty in terms of time to flowering and plant development was caused by the culture of immature seeds 18 days after pollination compared to the used of mature ones. Determining the role embryo maturity plays in the fitness of the germinated plant has facilitated the truncation of the lifecycle across pea genotypes. The accelerated single seed descent system proposed within this research will benefit complex genetic studies via the rapid development of recombinant inbred lines (RIL) and multi-parental advanced generation intercrosses (MAGIC) populations.     

中华稻蝗长沙种群的生活史及其卵滞育的进化意义

中华稻蝗Oxya chinensis为重要的水稻害虫,在我国除青海、西藏、新疆、内蒙古等未见报道外,南起海南北至东北均有分布,在许多的分布区域1年发生1代。为探索中华稻蝗长沙种群的生活史及其季节适应特征,通过野外和实验室的研究,调查了其发生代数、孵化率和卵滞育率的季节变化及越冬卵的存活率。结果显示,中华稻蝗长沙种群为1年2代和1年1代混合发生:第1代卵产卵后大部分孵化为若虫而1年完成2代,但亦有19.4% -4.1%的卵不孵化而1年只能完成1世代。第1代成虫于6月上旬至8月上旬羽化,6月下旬至8月中旬产卵;第2代若虫于7月初开始孵化,9-10月羽化为成虫,10月上旬至11月下旬产卵。在室外自然条件下,中华稻蝗长沙种群6-8月(第1代)和10-11月(第2代)所产卵块均为部分滞育,滞育率为30%左右,皆无显著差异。然而,其卵滞育率在12月以后显著降低,仅为6.6%或以下,卵滞育快速地得以解除。因此,包括非滞育卵和滞育解除卵,中华稻蝗长沙种群的越冬卵皆以非滞育状态度过其后的寒冷季节。即使是遭遇长江流域2007年末至 2008年初异常寒冷的冬季,在长沙地区越冬后其卵的存活率亦在98%以上。非滞育状态的中华稻蝗长沙种群越冬卵完全能安全地越冬,其滞育的发生并非是为了提高其耐寒性而安全度过不适环境。并探讨了中华稻蝗长沙种群卵滞育的进化意义。     

Photosynthetic Studies on a Pea-mutant Deficient in Chlorophyll

A chlorophyll-deficient mutant of pea (Pisum sativum) was found as a spontaneous mutation of the variety Greenfeast. Total chlorophyll of the mutant leaves was about one-half that of normal pea leaves per mg dry weight, and the ratio of chl a:chl b ranged from 10 to 18, compared with 3 for normal pea. In each generation the mutant plants gave rise to normal and mutant plants and lethal plants with yellow leaves.     

The influence of planting date,transgenic Bt maize and hybrid relative maturity on European corn borer Ostrinia nubilalis (Lepidoptera: Crambidae) ovipositional patterns

A three year study was carried out at Hoytville and at Wooster, Ohio, USA from 2006 to 2008 to investigate the influence of planting date, transgenic maize and hybrid maturity on Ostrinia nubilalis (Hubner) population dynamics and oviposition patterns. Maize plants were planted in late April or early May, mid‐May and early June during each year. The moth flight pattern showed bivoltine generations during the three years. The first moth flight peaked in June, with the populations declining during July. The second moth flight peaked in August and declined towards the end of September or early October. Egg mass density did not differ significantly between transgenic and non‐transgenic maize of different maturities. Significant differences were observed, however, among planting dates, sampling dates, and sampling date × planting date interactions. Generally higher numbers of egg masses from second generation moths were deposited on late planted maize than middle and early plantings.     

黑刺粉虱及其天敌的研究

黑刺粉虱Aleurucamhus spiniferus Quaint．是柑桔、茶树等经济作物的重要害虫。福建一年发生4-5代,闽北、闽中发生4代,世代重叠。主要以若虫在柑桔等叶背越冬,越冬若虫于翌年2月间开始化蛹(伪蛹),4月间成虫羽化并产卵。各世代若虫发生期为第一代4月上旬至6月上旬;第二代6月中旬至7月下旬;第三代7月中旬至9月上旬;第四代9月中旬至翌年3月,11月进入越冬期。一年中以6-9月为发生为害高峰期。黑刺粉虱的寄生性天敌和捕食性天敌资源丰富,蛹期被寄生率甚高,对该虫的综合治理可以生物防治为主要措施。     

Seasonal Populations of Pratylenchus penetrans and Meloidogyne hapla in Strawberry Roots

Strawberry roots were sampled through the year to determine the populations and distribution of Pratylenchus penetrans and Meloidogyne hapla. Three strawberry root types were sampled—structural roots; feeder roots without secondary tissues; and suberized, black perennial roots. Both lesion and root-knot nematodes primarily infected feeder roots from structural roots or healthy perennial roots. Few nematodes were recovered from soil, diseased roots, or suberized roots. Lesion nematode recovery was correlated with healthy roots. In both 1997 and 1998, P. penetrans populations peaked about day 150 (end of May) and then declined. The decline in numbers corresponded to changes in total strawberry root weight and root type distribution. The loss of nematode habitat resulted from loss of roots due to disease and the transition from structural to suberized perennial roots. Meloidogyne hapla juvenile recovery peaked around 170 days (mid June) in 1997 and at 85, 147, 229, and 308 days (late March, late May, mid August, and early November, respectively) in 1998. There appear to be at least four generations per year of M. hapla in Connecticut. Diagnostic samples from an established strawberry bed may be most reliable and useful when they include feeder roots taken in late May.     

Pre-dispersal seed predation in gynodioecious Geranium sylvaticum is not affected by plant gender or flowering phenology

Sex-specific interactions with antagonists may explain female maintenance in gynodioecious populations if seeds produced by hermaphroditic plants are preferred over seeds produced by female plants. Among antagonistic interactions, pre-dispersal seed predators have received relatively little attention even though they may exert sex-specific selective pressures on the evolution of floral and flowering traits. In this work, I investigate temporal variation in seed predation in gynodioecious Geranium sylvaticum, where in addition to female and hermaphrodite individuals, plants with an intermediate sexual expression are also present in most populations. Specifically, I examined whether seed predation is linked to flowering phenology, plant gender, and sexual dimorphism in floral and seed traits over the flowering season using an experimental field population. Within the population, I selected female, intermediate, and hermaphrodite plants with different timing of flowering onset (early, mid, or late), and collected seeds across the fruiting period. Seeds were weighed and examined for seed predator damage. The results show that the three genders experienced similar levels of seed predation attack regardless of their flowering phenology, and that overall seed predation was not related to changes in seed production or seed mass. These results suggest that sexual dimorphism in seed predation cannot be responsible for female maintenance in this species.     

Acclimatization of In Vitro-Raised Asiatic Hybrid Lily Plants in Subtropical Climate and Associated Changes in Stress Proteins and Antioxidant Enzymes

A protocol for direct differentiation of shoots from leaf segments of Litium cv ‘Orange Pixie’ was developed through in vitro methods. After hardening, tissue-raised plants were transferred in the open field conditions from the very beginning. The acclimatized plants not only grew well but flowered also at 43°C under subtropical climatic conditions and regenerated a new bulb at their base after flowering. The activity of different antioxidant enzymes like superoxide dismutase, peroxidase, catalase and ascorbate peroxidase and their isoenzymes patterns showed differential up and down regulation in control and in different parts of in vitro-raised plants. Characterization of both high and low molecular mass heat-shock proteins (HSPs) was done using HSP70 and HSP 18.1 antibodies against pea (Pisum sativum L), respectively. The level of high molecular mass proteins did not change much and was found to be of constitutive nature, whereas a new small protein of 21 kD was induced only in tissue culture-raised flowering (TF) plants indicating the possible role of this stress protein in acclimatization and flowering of Asiatic hybrid lily plants at 43°C under tropical conditions. The amount of this protein was much higher in petals as compared to stem and leaf.     

Integration and inheritance of transgenes in crop plants and trees

Transgene integration and inheritance have been investigated in a number of crop plants and few tree species. Transgene integration is predominantly a random process, whether mediated by Agrobacterium or particle bombardment. Depending on the genomic position of the integrated transgene and structure of the integration site as well as copy number of the transgene in the genome, its expression may be stable or variable. Therefore, integration patterns would affect the mode of transgene inheritance in plants, regardless of the method of gene transfer. So far, both Mendelian and non-Mendelian inheritance of transgenes has been reported across several generations (T1–T3) of crop plants. In few tree species (apple, poplar, plum, and American chestnut), mostly Mendelian inheritance of the transgenes has been observed in the T1 or BC1 generations. However, detailed studies in the transgenic papaya trees showed Mendelian segregation of the transgene in the T1 generation but non-Mendelian inheritance in the T2 generation. Variation in transgene inheritance was also detected in transgenic apple and plum trees. Long generation cycles in many economically important tree species preclude investigation of inheritance of transgenes in the tree progeny. Production of early flowering trees, either by genetic modification or by environmental modulation, would facilitate the study of transgene inheritance across generations of transgenic trees. In order to overcome problems of randomness of transgene integration, targeted transgene insertions by homologous or site-specific recombination or by designer recombinases or nucleases offer prospects for stable integration of transgenes in predetermined locations in the plant genome. And perhaps, that might provide a platform for stable expression and Mendelian inheritance of transgenes in plants.     

In planta transformation of pigeon pea: a method to overcome recalcitrancy of the crop to regeneration in vitro

Development of transgenics in pigeon pea remains dogged by poor plant regeneration in vitro from transformed tissues and low frequency transformation protocols. This article presents a non-tissue culture-based method of generating transgenic pigeon pea (Cajanus cajan (L.) Millisp.) plants using Agrobacterium-Ti plasmid-mediated transformation system. The protocol involves raising of whole plant transformants (T₀ plants) directly from Agrobacterium-infected young seedlings. The plumular and intercotyledonary meristems of the seedling axes are targeted for transformation. The transformation conditions optimized were, pricking of the apical and intercotyledonary region of the seedling axes of two-day old germinating seedlings with a sewing needle, infection with Agrobacterium (LBA4404/pKIWI105 carrying uid A and npt II genes) in Winans’ AB medium that was added with wounded tobacco leaf extract, co-cultivation in the same medium for 1h and transfer of seedlings to soilrite for further growth and hardening and subsequent transfer of seedlings to soil in pots in the greenhouse. Out of the 22–25 primary transformants that survived infection-hardening treatments from each of the three experiments, 15 plants on the average established on the soil under greenhouse conditions, showed slow growth initially, nevertheless grew as normal plants, and flowered and set seed eventually. Of the several seeds harvested from all the T₀ plants, six hundred were sown to obtain progeny (T₁) plants and 350 of these were randomly analysed to determine their transgenic nature. PCR was performed for both gus (uid A) and npt II genes. Forty eight of the 350 T₁ plants amplified both transgenes. Southern blot analysis substantiated the integration and transmission of these genes. The protocol ensured generation of pigeon pea transgenic plants with considerable ease in a short time and is applicable across different genotypes/cultivars of the crop and offers immense potential as a supplemental or an alternative protocol for generating transgenic plants of difficult-to-regenerate pigeon pea. Further, the protocol offers the option of doing away with a selection step in the procedure and so facilitates transformation, which is free of marker genes.Key words: Cajanus cajan, Transformation, Tissue culture-independent plant regeneration     

Effectiveness of nectarivorous birds and honeybees as pollinators of Banksia spinulosa (Proteaceae)

Abstract The effectiveness of nectarivorous birds and honeybees (Apis mellifera) as pollinators of Banksia spinulosa (Proteaceae) was investigated. Birds visited inflorescences in the early, mid and late flowering seasons. In contrast, honeybees visited only on days in the late flowering period when maximum temperatures exceeded 15°C. Self pollen remained on pollen presenters of flowers for up to 5 days in the early and mid periods. In the late period, when honeybees visited inflorescences, self pollen was removed within 2 days. Pollen removal was similar for caged (birds excluded) and open inflorescences in the late period, indicating that most pollen was removed by honeybees. In the early and mid periods, honeyeaters pollinated 22% and 27% of flowers on open inflorescences, respectively. In the late period, when both birds and bees visited inflorescences, 64–73% of flowers on open inflorescences were pollinated. Foraging by honeybees resulted in pollen deposition as 38% of flowers on caged inflorescences were pollinated. Throughout the flowering season a similar number of pollen grains was deposited per stigma. There were 3.0–3.7 pollen grains per stigma on open inflorescences in the late period, although only 2.0 grains per stigma on caged inflorescences. In the early and mid periods, fewer caged than open inflorescences produced fruits, indicating the importance of honeyeaters to reproductive success at these times. In contrast, in the late period when honeybees visited inflorescences, fruit-set was similar on caged and open inflorescences. Overall, these results indicate that honeybees were effective pollinators of B. spinulosa.