Relative natural resistance of Populus deltoides clones against defoliator Clostera cupreata (Lepidoptera: Notodontidae) in northern India

Populus deltoides (poplar) that is extensively being planted commercially in agroforestry combinations in northern India is prone to attack by a defoliating insect, Clostera cupreata. In order to evaluate the relative susceptibility/resistance of different clones and to identify the resistant ones, 80 clones of American origin were evaluated in Dehra Dun, India. The feeding potential of the pest on different clones varied significantly. The clones were grouped into six categories depending on their susceptibility as most resistant or R1 (12 clones), moderately resistant or R2 (14 clones), marginally resistant or R3 (10 clones), marginally susceptible or S1 (17 clones), moderately susceptible or S2 (18 clones) and most susceptible or S3 (nine clones). Clone 110120 of Tennessee was most resistant where as Oklahoma clone 104 was most susceptible to this pest. Amongst the most resistant clones (R1), only three clones, WSL-4, WSL-12 and WSL-18 (source: WIMCO Seedlings Ltd, India) were found to be superior, in terms of growth increment, as compared to the standard and most widely planted clones in northern India i.e. G-3 and G-48, and are promising clones for plantation in defoliator prone areas.This revised version was published online in November 2005 with corrections to the Cover Date.     

Evaluation of management tools for the control of poplar leaf defoliators (Lepidoptera: notodontidae) in northwestern India

Populus suffers from multiple insect damage throughout its distributional range in northwestern India. The evaluation of various management tools was done based on the hypothesis that manipulation of insect habitat can provide tangible results. Manipulation of cultural practices, ploughing of field during December, and growing of crops (wheat, Trifolium alexandrinum and others) results in lower adult emergence, reduced leaf infestation, number of larvae and pupae per meter branch length of poplar leaf defoliators (PLD). Fallow plantations were more prone to attack of PLD than intercropped plantations. Higher incidence of Clostera restitura was recorded in southwestern dry zones due to unsuitability of the site, poor quality of irrigation water and dry weather conditions. Complete stripping of Populus trees does not occur in low temperature & high humidity, submountaneous zones of Punjab. Chemical control studies were conducted in laboratory & field conditions, and among the five insecticides tested, Profenophos 50 EC, Quinalphos 25 EC and Carbaryl 50 WP @ 0.05 and 0.1 percent concentration gave consistently high mortality of PLD larvae up to 21 days after spraying. Use of insecticides prior to peak activity periods & during evening hours enhances the efficiency of management options.     

Comparing growth and fine root distribution in monocultures and mixed plantations of hybrid poplar and spruce

Disease prevention, biodiversity, productivity improvement and ecological considerations are all factors that contribute to increasing interest in mixed plantations. The objective of this study was to evaluate early growth and productivity of two hybrid poplar clones, P. balsamifera x trichocarpa (PBT) and P. maximowiczii x balsamifera (PMB), one improved family of Norway spruce (Picea glauca (PA)) and one improved family of white spruce (Picea abies (PG)) growing under different spacings in monocultures and mixed plots. The plantations were established in 2003 in Abitibi-Témiscamingue, Quebec, Canada, in a split plot design with spacing as the whole plot factor (1 × 1 m, 3 × 3 m and 5 × 5 m) and mixture treatments as subplot factor (pure: PBT, PMB, PA and PG, and 1:1 mixture PBT:PA, PBT:PG, PMB:PA and PMB:PG). Results showed a beneficial effect of the hybrid poplar-spruce mixture on diameter growth for hybrid poplar clones, but not for the 5 × 5 m spacing because of the relatively young age of the plantations. Diameter growth of the spruces decreased in mixed plantings in the 1 × 1 m, while their height growth increased, resulting in similar aboveground biomass per tree across treatments. Because of the large size differences between spruces and poplars, aboveground biomass in the mixed plantings was generally less than that in pure poplar plots. Leaf nitrogen concentration for the two spruce families and hybrid poplar clone PMB was greater in mixed plots than in monocultures, while leaf nitrogen concentration of clone PBT was similar among mixture treatments. Because of its faster growth rate and greater soil resources demands, clone PMB was the only one showing an increase in leaf N with increased spacing between trees. Fine roots density was greater for both hybrid poplars than spruces. The vertical distribution of fine roots was insensitive to mixture treatment.     

Insect-resistant mechanism of transgenic triploid of Chinese white poplar

The activities of antidotal enzymes and digestive enzymes of Clostera anachoreta (Fabricius) instar larvae, feeding on leaves of three kinds of insect-resistant clones of transgenic triploid of Chinese white poplar, after 4, 12, 24, 48, 72 and 96 h, were investigated. The results showed that, feeding on clone 7, the activity of esterase, carboxylesterase, and mixed-function oxidases in the midgut of the larvae was very much decreased. Feeding on clone 10, those results were less than those of clone 7 and there were few changes on the larvae, which fed on clone 26. The changes of the amylase in the midgut of larvae were the same as those described above. However, the activities of glutathione S-transferase and proteinase were complex, increased markedly after 24 h feeding on clone 7, and then declined rapidly. The same changes were taking place on the larvae feeding on clone 10. There were many slight changes in glutathione S-transferase of the larvae, feeding on clone 26; no changes occurred in the proteinases of the midgut. Thus, the antidotal enzymes and digestive enzymes in the midgut of the larvae were inhibited. This may be the main mechanism of the transgenic triploid of Chinese white poplar. __________ Translated from Journal of Agricultural University of Hebei, 2005, 28(5) [译自: 河北农业大学学报, 2005, 28(5)]     

Field performance of ten clones and two sizes of planting stock of <Emphasis Type="Italic">Populus deltoides</Emphasis> on the Indo-gangetic plains of India

A study was conducted from 1996 to 2001 on well drained sandy loam soils in the central plain region of Punjab to determine the effect of initial size of planting stock and clones of poplar (Populus deltoides) on their height, diameter and volume growth. Two categories of planting stock viz. large size (height >4.7 m and collar diameter >4.2 cm) and small size (height 2.5–4.3 m and collar diameter 2.5–4.0 cm) of ten poplar clones were used for the experiment using a completely randomized design with single tree plots and ten replications. The large sized stock attained significantly greater diameter and volume growth at all ages than those of small size, whereas, the superiority of the former in plant height was only up to 3 years of age. The respective differences for diameter and volume between the stock sizes decreased from 11.7 and 27.96% at 3 years to 4.9 and 11.42% at 5 years of age. Significant differences were observed among clones for all the growth parameters. Clones G-48, 3167, WSL-31 and WSL-38 exhibited the highest growth.     

Variation among poplar clones for growth and crown traits under field conditions at two sites of North-western India

We evaluated the growth and crown traits of 36 poplar clones at two distinct agro-climatic regions of Punjab (Ludhiana and Bathinda) in northwestern India, following randomized block design with three replications and plot size of four trees. Significant differences among clones (p<0.001) were observed for diameter at breast height (DBH), tree height, volume, crown width and number of branches under both the site conditions. Clones ’G-3’, ’25-N’ and ’41-N’ at Ludhiana and ’G-3’, ’RD-01’ and ’S 7 C 8 ’ at Bathinda were found to be superior for volume production. All growth and crown traits registered significantly higher values at Ludhiana in comparison to those at Bathinda. Clone × site interaction was also significant (p<0.001). For volume, clones ’L-62/84’, ’113520’, ’25-N’ and ’S 4 C 2 ’ witnessed huge fluctuations in ranking between sites. The correlations between growth traits were positive and highly significant (p<0.001) at both sites. The clonal mean heritability was moderate for DBH and volume both at Ludhiana (0.61 0.66) and Bathinda (0.61 0.62). Across sites, the genetic advance was the highest for volume (49.76%) and the lowest (6.50%) in case of height.     

Germination of Melampsora larici-populina uredospores on poplar leaves1

Using an electron scanning microscope the germination of Melampsora larici-populina ure dospores was observed on the lower leaf surfaces of a susceptible poplar clone Populus trichocarpa and a resistant one P. בSerotina de Poitou’. The observations were made from a few hours to more then a day after placing the uredospores on the leaf surfaces.     

Impact of poplar water status on leaf-beetle (Chrysomela populi) survival and feeding

? The aim of this study is to assess the impact of drought on insect-tree relationships. Survival and feeding performances of leaf-beetles, Chrysomela populi put in cages with leaves of host-plants submitted to different levels of water stress were compared.

? Ninety 1-year-old poplar (Populus × euramericana) cuttings were grown in a greenhouse, and distributed into 3 groups submitted to different water treatments during six weeks. Adult C. populi were then encaged for four days with these cuttings, together with the five terminal leaves of a twig. Beetle survival and consumed leaf areas were then determined.

? Predawn leaf water potential values indicated that the drought treatments induced different levels of plant water stress. Plant height growth and total leaf numbers were reduced by plant stress. Beetle survival and leaf areas eaten were also reduced proportionally to plant water deficit.

? In conclusion, this experiment suggests that drought has a negative impact on C. populi survival and feeding.

     

Biomass production by two-year-old poplar clones on floodplain sites in the Lower Midwest, USA

Four Populus clones were grown for two years at 1×1 m spacing for study of total biomass production and carbon sequestration capacity on floodplain sites previously in forage grasses under climatic conditions of the lower Midwest, U.S.A. Total biomass (above-and below-ground) in the first year ranged from 3.9 Mg ha^–1 in a Populus deltoides x P. nigra clone (I45/51) to 1.9 Mg ha^–1 for a local-source Populus deltoides clone (2059). Second year total biomass production was substantially higher, ranging from 13.9 Mg ha^–1 in I45/51 to 7.4 Mg ha^–1 in P. deltoides clone 26C6R51. Second-year leaf area index (LAI) values for I45/51 plants reached 4 during mid-season, indicating essentially complete canopy closure in this clone by the second year after planting. In contrast, maximum mid-season, second-year LAI was significantly lower in P. deltoides clones ( 2.4). There was some evidence for differential allocation to roots and shoots among Populus clones, with 26C6R51 showing relatively more allocation to root biomass than other clones. Second-year growth in Populus deltoides clone 2059 accelerated substantially, and this genotype exhibited two-year biomass accumulation nearly equal to that of I45/51 despite having less leaf area. This result suggested a higher photosynthetic capacity or assimilation efficiency in the former. This revised version was published online in August 2006 with corrections to the Cover Date.     

Field test of new poplar clone in Shangdong Province

Poplar is one of the dominant tree species for the establishment of fast growing plantations in Shandong Province.Eighteen poplar clones belonging to Populus aigeiros section were introduced from Italy, Turkey and domestic regions. Populus deltoides cv. ‘Lux‘ 1-69/55 (1-69), which was widely used in Shandong Province, China, was taken as control clone (1-69).Following a randomized complete block design, seedling test and controlled afforestation trials were carried out at Juxian County,Caoxian County and Laiyang City. The results showed that the poplar clone (Populus x euramericana cv. ‘102/74‘), namely 102/74, performed well both in terms of adaptability and growth rate. The mean height of 13.9 m (H), diameter at breast height of 18.0 cm (DBH) and volume growth of 0.1445 m3 (V) were 2.2 %, 21.6% and 52.9% higher than those of 1-69 (CK), respectively,at the age of 5 years at three experimental sites. Moreover, the clone can be propagated easily and showed high resistance to poplar disease, pest as well as salinity and had longer growing period. Furthermore, wood basic density and fiber length of new poplar clone (102/74) were as same as 1-69 (CK). It was concluded that the selected clone (102/74) was ideal for the estab-lishment of fast-growing poplar plantations, especially for the pulpwood plantations in Shandong Province.     

Early stand production of hybrid poplar and white spruce in mixed and monospecific plantations in eastern Maine

Forest plantations in the northeastern United States comprise a small proportion of the total forest area. Most plantations are typically softwood dominated and managed for sawlog and pulpwood production, while high-yield hardwood plantations for bioenergy feedstocks have not been as widely investigated. The objective of this study was to compare the biomass production of planted white spruce (Picea glauca (Moench) Voss) and hybrid poplar (Populus spp.) plantations (four clones) in monoculture, and in mixture of the two on a typical reforestation site in Maine. Three years following planting, hybrid poplar height and ground line diameter growth rates began to diverge among clones, and by 6?years, the Populus nigra?×?Populus maximowiczii (NM6) clone clearly outperformed three Populus deltoides?×?Populus nigra clones (D51, DN10 and DN70) both in pure stands and in mixtures with white spruce. In mixture, we found the yield of white spruce to decline as the yield of hybrid poplar increased. Overall, yields of white spruce monocultures were comparable to those reported in eastern Canada, while the hybrid poplar biomass yields were substantially lower than those reported from studies on abandoned agricultural lands, likely due to the harsher soil conditions at our site. The dominance of rocky and poorly drained sites (like the one tested in this study) across Maine will likely limit the feasibility of widespread hybrid poplar plantations, and thus constrains their potential use as a bioenergy feedstock.     

福州地区半常绿及落叶杨树无性系引种试验

杨树（Ｐｏｐｕｌｕｓｓｐｐ．）是重要的速生用材树种,在国内一般认为杨树是北方树种,不注意在南方发展杨树。实际上不少亚热带和热带国家（印度、南非、澳大利亚、巴基斯坦、伊朗、阿根廷和巴西等）都广泛栽培杨树［１,２］。为探讨南方营造杨树工业用材林的可能性,...     

Oviposition preference and larval performance of Aeolesthes sarta (Coleoptera: Cerambycidae) in six hardwood tree species

Sarta longhorned beetle (SLB), Aeolesthes sarta Solsky, is an economically important pest of fruit and shade trees in central and east Asia. Choice, no-choice, and larval insertion experiments were conducted to determine SLB oviposition preference and larval host suitability on six hardwood tree species including Ulmus carpinifolia Borkh., Ulmus carpinifolia var. umbraculifera Rehd., Platanus orientalis L., Populus alba L., Salix alba L., and Fraxinus rotundifolia Miller subsp. persica (Boiss.), under laboratory conditions. In the choice and no-choice experiments, significantly greater numbers of eggs and living larvae, and greater mass of living larvae were found on U. carpinifolia and U. carpinifolia var. umbraculifera compared to those on the other tree species. In the choice experiment, oviposition did not occur on F. rotundifolia subsp. persica. There were a few eggs on P. alba but no living larvae. The mean mass of living larvae was lowest on P. orientalis. In addition, in the no-choice experiment significantly fewer numbers and mass of living larvae were found in P. alba and F. rotundifolia subsp. persica. In the larval insertion experiment, more larvae survived on U. carpinifolia and U. carpinifolia var. umbraculifera compared to the other trees. Larvae recovered from U. carpinifolia and U. carpinifolia var. umbraculifera weighed significantly more than larvae from the other trees. These results suggest that U. carpinifolia and U. carpinifolia var. umbraculifera are the most preferred and suitable hosts for SLB adults and larvae. Salix alba is an acceptable host for adult oviposition and a potentially suitable host for larval development. Platanus orientalis and P. alba are less suitable, and F. rotundifolia subsp. persica appeared to be unsuitable as a host for SLB.     

Potential of different poplar clones for sugar production

In a poplar clonal plantation with different species and hybrids, established at 13,333 cuttings ha^?1, biomass production was assessed at the end of the first rotation (3 years) and the potential of the different clones for sugar production was evaluated. The highest biomass production was observed for clones ‘AF2’ and ‘Viriato’ (46.5 and 42 t dm ha^?1, respectively). After a mild acid pretreatment and an enzymatic saccharification, the highest sugar digestibility was found for ‘Viriato’ and ‘Unal’. A clear relation between sugar digestibility and xylan removal during pretreatment was observed, while no relation with lignin content was found. Taking into account the results, the highest production of sugars per hectare was estimated for the poplar clone ‘Viriato’, being 18–48% higher than that achieved with the other clones. Therefore, this clone is a promising candidate to be used as feedstock for sugar production in a forest biorefinery.     

Zur Wirkung der Nahrungspflanze auf die Entwicklung und Vermeharung der Baumwolleule,Spodoptera littoralis (Boisd.) (Lep.,Noctuidae)

Effect of some host plants on development and reproduction of Spodoptera littoralis (Boisd.) (Lep., Noctuidae) Investigations were performed to study the effect of some hostplants on development and reproduction capacity of the Egyptian cotton leaf-worm,Spodoptera littoralis (Boisd,), Larval and pupal weights, life span, average number of eggs laid per female and percent digestability for fifth instar larvae were measured. Cotton leafworm was able to complete its life cycle only when reared on eigher castor bean leaves, clover, sweet potato leaves, or the outer green cabbage leaves. Chlorophyl-free inner white cabbage leaves, maize, and grape vine are nutritionally insufficient to support growth and development of larvae and, in turn, cause increase in span of survived larvae and none of these larvae metamorph to pupae. It seems that there is a positive correlation between larval and pupal weights and average number of eggs laid per female; the greater the weight of larvae and pupae the higher the number of eggs laid. Castor bean leaves seem to be the most favorable host plant for rearing cotton leafworm in the laboratory. The differences and variations in the growth and development of cotton leafworm due to feeding on different host plants are discussed.     

Performance of wheat as intercrop under poplar (Populus deltoides Bartr.) plantations in Punjab (India)

In an agrisilvicultural system having poplar (Populus deltoides, clone G-3) as a tree component and wheat crop as an intercrop, wheat yield was studied under five age classes of poplar and compared to wheat yield under pure cropping. A substantial reduction in wheat yield (23.3%) under three-year-old poplar plantation was observed. Maximum MAI (GBH, 20 cm) was recorded in a three-year-old poplar planting. Pruning after the third year permitted some recovery in yield. The reduction in wheat yield was significantly correlated with MAI (GBH) of poplar and occurred even under one-and-two-year-old poplar plantings.     

转抗虫基因三倍体毛白杨成年树木节肢动物及抗虫稳定性调查

对田间生长的8 a生转抗虫基因（Bt cry1A和API）三倍体毛白杨进行分子生物学检测,证明外源基因在杨树基因组中稳定存在。对试验林进行节肢动物调查表明,林内节肢动物共有11个目、26个科,已明确为害虫的有11种,占整个群落的42%;天敌（包括捕食性与寄生性）8种,占群落的31%;中性昆虫7种,占群落的27%,其中主要害虫为美国白蛾。秋季对试验林叶面积损失调查表明,不同转基因系号的抗虫性有明显差异,有4个株系没有被美国白蛾啃食,10个株系的食叶面积小于10%,6个株系的食叶面积在10%~15%之间。     

桑天牛对白杨派树种的选择及其防治措施的研究

为选育抗桑天牛的杨树树种，对桑天牛危害白杨派杨树的产卵选择性进行了研究。通过事内饲养及野外接种桑天牛，并对试验数据进行方差分析，表明，桑天牛在白和其他白杨派树种之间，桑天杨派杨树的不同树种或无性系卜的产卵和孵化选择性无显著差异，在林间三倍体毛白杨牛产卵选择也无显著差异；根据桑天牛的发生特点，确定了简便易行的综合治理方案。     

Resistance of new Belgian poplar clones to British isolates of the bacterial canker pathogen,Xanthomonas populi

Forty-nine new poplar clones, bred in Belgium and screened there for resistance to bacterial canker caused by Xanthomonas populi, were additionally screened in southern England, using British isolates of the bacterium. Thirty-five of the test clones ranked better than the clone ‘Boelare’, which is already registered in the UK as an approved clone, and is regarded as having acceptable resistance. The registered clone ‘Ghoy’ was more susceptible, and outranked only four test clones. Preliminary measurements of canker length and stem girdling index showed differences between five bacterial isolates.     

Leaf eating insect damage on different poplar clones and sites

As much for the geneticist as for the planter, information on sites, clones, and other factors would be decisive to reduce insect damage on poplars. In this perspective, a study was done in eight field trials in Belgium and in Luxembourg, considering two types of leaf damage on 24 clones from Italy, Belgium and the Netherlands. Damage varied considerably, depending on the clones, sites, species and parental individuals. Clone’s ranks concord on the different sites; site’s ranks are similar for the various clones. Clones with same parents have similar levels of resistance. The two types of damage are not correlated. Hybrids of P. deltoides × nigra show widespread variability; those with genetic material of P. trichocarpa are generally more resistant to caterpillar-like damage. The maximal differences are about 1 to 5 for the clones, and 1 to 10 for the sites. But the most vulnerable clone on the most favourable site was damaged almost 70 times more often than the opposite combination.