Genetic diversity analysis in a seed orchard of <Emphasis Type="Italic">Eucalyptus tereticornis</Emphasis>

India is the largest grower of Eucalyptus with an area of 3.943 million hectares under plantations and E. tereticornis is the predominant species in the plains of southern India with an average productivity of 12–25 m³ ha⁻¹ year⁻¹. With the aim to establish seedling seed orchards of the species, seed lots of fifteen provenances were imported from Australia and a trial was laid. In the present study the genetic diversity existing in the seed orchard was estimated using ISSR–PCR. Seven ISSR primers amplified 663 amplicons in the size ranging from 255 to 2,711 bp. The total number of polymorphic bands varied from 59 to 123 with 100% polymorphic banding profiles. The average gene diversity (Hj) of all the provenances ranged from 0.0589 to 0.1109 and the total gene diversity estimated was low (H _T = 0.130) when compared to the earlier reports from other eucalypts species. Analysis of Molecular Variance partitioned the ISSR variation into inter and intra population components. The inter population component accounted for 55.2% of the variation and the intra population component accounted for 46.3% (P < 0.001). A neighbour-joining analysis was done using the dissimilarity matrix to determine the aggregation of the individuals into clusters. Existence of population structure among the populations was revealed in STRUCTURE analysis but geographical region based clustering was not observed. The assessment of intra and inter genetic variation documented in the present study suggests that, along with the phenotypic traits, knowledge about genetic diversity measured at the DNA level in individuals of seed orchards provide an objective guide for selective culling of trees for maintaining optimal diversity for enhanced genetic gains.     

Genetic diversity and mating system of <Emphasis Type="Italic">bracatinga</Emphasis> (<Emphasis Type="Italic">Mimosa scabrella</Emphasis>) in a re-emergent agroforestry system in southern Brazil

Bracatinga (Mimosa scabrella) is a legume tree species common in the early stages of succession in Araucaria angustifolia forests in southern Brazil. Bracatinga can form high-density monospecific stands called bracatingais. Its traditional management for charcoal production involves maintenance of the seed bank. Our objective was to analyze the genetic diversity and structure of bracatingais to understand the mechanisms by which intraspecific diversity of M. scabrella is created and maintained in landscapes managed by family farmers in their agroforestry mosaics. We analyzed 14 bracatingais using 8 allozyme loci. We compared parental and progeny generation indices (7 loci) and described the mating system (9 loci) of two progenies. Overall diversity was high: A = 2.69, H _o = 0.257, H _e = 0.382 and similar between populations. Overall fixation (F = 0.364) was similar to the fixation index (f = 0.329). The genetic divergence among populations was low (Θ_p = 0.052) but significant. The progenies’ genetic diversity values were similar to those of the previous generation (H _{e pop11} = 0.342 vs. 0.420/H _{e pop10} = 0.432 vs. 0.400). Progenies were compatible with half-sib and full-sib crossing expectations (θ _xy  = 0.204 and 0.194). Our data showed that there is a tendency for genetic structuring caused not only by the reproductive system but also by genetic drift. It is very likely that the high genetic diversity is amplified by internal migration within each bracatingal. This study showed that current landscape management can contribute to maintaining high levels of bracatinga genetic diversity, which contributes to its regional conservation.     

Variation in cone and seed characters in clonal seed orchards of <Emphasis Type="Italic">Pinus sylvestris</Emphasis>

Cone and seed characters were observed on top, middle and bottom portions of tree crown in 3 ramets/clone in three Turkish Pinus sylvestris seed orchards. Broad sense heritability (clonal repeatability), and correlations among characters were estimated. Around one quarter of the seed production occurred in the top portion, half in the middle and one quarter in the bottom portion of the crown for all orchards. The percentage of filled seeds varied little with the crown position, indicating more or less similar levels of selfing in the bottom of the crown as in the top. The seed weight was typically 11 mg. Differences were found for studied cone and seed characters among orchards and crown positions. Variation among grafts within clone was higher than among clones for most characters. The heritability was on average below 0.5 (e.g., cone diameter, number of filled seed per cone) and rarely rose above that (e.g., cone form, length/diameter; percentage of filled seed) for any individual characters. The coefficient of variation within clones was often higher than among clones. Thus, non-genetic factors seem often more important for the variation in performance of grafts than their genetic constitution. Cone form (length/diameter) was the character where the clone influence was the strongest. Cone number and cone dry weight showed significant correlations with seed characters (numbers of total and filled seed, percentage and weight of filled seeds). Significant correlation was found between seed characters.     

Comparative efficacy of NeemAzal and local botanicals derived from <Emphasis Type="Italic">Azadirachta indica</Emphasis> and <Emphasis Type="Italic">Plectranthus glandulosus</Emphasis> against <Emphasis Type="Italic">Sitophilus zeamais</Emphasis> on maize

The efficacy of NeemAzal powder, two local neem (Azadirachta indica ) products [neem seed powder (NSP) and neem seed oil (NSO)], as well as a local Lamiaceae, Plectranthus glandulosus leaf powder, applied at four different rates for the control of Sitophilus zeamais was determined. Mortality was recorded 1, 3, 7 and 14 days after S. zeamais infestation, followed by the determination of F₁ progeny production. Grain damage, population increase and grain germination were assessed for treated grains that were stored for 4 months. Grains treated with P. glandulosus powder and NSP had relatively low mortality (5.0–22.5%) after 3 days whereas NeemAzal and NSO had higher mortality (55.0–98.8%). Maximum mortality of 99, 100, 96 and 74% were achieved for NeemAzal (12 g/kg after 14 days), NSO (4 ml/kg after 7 days), NSP (40 g/kg after 14 days) and P. glandulosus powder (40 g/kg, after 14 days), respectively. In the same order, 7-day LC₅₀ values were 0.02 g/kg, 1.46 ml/kg, 12.44 g/kg and 28.9 g/kg. The three neem products greatly reduced progeny emergence, while P. glandulosus powder was less effective. NeemAzal protected the grains against S. zeamais damage better than the local neem products, which in turn provided far better grain protection against the weevil damage than P. glandulosus powder. NeemAzal was superior to the local neem products in grain protection against germination loss, with P. glandulosus being the least effective. NeemAzal and NSO had sufficient efficacy to be a component of an integrated management package for S. zeamais.     

Seed rain and natural regeneration in <Emphasis Type="Italic">Lophostemon confertus</Emphasis> plantations in Hong Kong,China

Natural forests have been increasingly replaced by artificial plantations around the world. Some research results suggest that artificial plantations can promote natural regeneration. The efforts in establishing protective forests in Hong Kong over the last 50 years after the Second World War have resulted in many exotic tree plantations which are ideal sites for the study of natural regeneration. This study looked at the seed rain and understorey woody plant diversity in three Lophostemon confertus plantations (25–40 years old) in Hong Kong. All the plantations were > 1 km from the nearest seed sources. Two of the plantations had a seed rain comparable in density and diversity to unplanted grasslands, and the understorey plant diversity was also low and dominated by shrubs. The other site had a higher and more diverse seed rain, as well as higher understorey stem density, but both the seed rain and the understorey were dominated by the shrub Psychotria asiatica. The poor seed rain at two sites and the rarity of potential canopy tree species in both the seed rain and understory regeneration at all sites suggest that planting exotic monocultures does not promote succession. Enrichment planting will be needed to restore forest diversity.     

Mating patterns in an indoor miniature <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> seed orchard as revealed by microsatellite markers

To evaluate the practical application of an indoor seed orchard, we compared the seed production, final germination rates and mating patterns of potted Cryptomeria japonica D. Don clones in two miniature seed orchards: one in a glasshouse and the other outdoors. There was no statistically significant difference in total seed production between the orchards (P = 0.275, ANOVA). However, the final germination rate of seeds produced in the indoor orchard was significantly lower than that of seeds produced in the outdoor orchard (P < 0.01, Wilcoxon test). The average self-fertilization rate was higher in the indoor orchard (27.2%) than in the outdoor orchard (5.6%), and this parameter was strongly associated with the reduced final germination rates of the seeds harvested in the glasshouse. Pollen contamination was considerably lower in the indoor seed orchard (48.9% in the outdoor seed orchard and 4.4% in the indoor seed orchard). χ² tests indicated that the paternal contributions of each constituent clone differed significantly in both orchards (P < 0.001 in both cases). The strong variations in paternal contributions among indoor orchard clones was significantly correlated with their respective pollen production capacities (Spearman ρ = 0.693, P < 0.001). To reduce the high self-fertilization rates, we recommend the use of orchard clones with similar pollen production capacity in indoor seed orchards.     

Variability in seed- and seedling-related traits of <Emphasis Type="Italic">Millettia ferruginea</Emphasis>, a potential agroforestry species

Millettia ferruginea (Hochst.) Baker is a potential agroforestry species endemic to Ethiopia. No documented information exists about genetic variation in this species, thus baseline information is needed to initiate improvement program. Here, we quantified variations in seed size, germination and seedling growth at nursery stage based on seeds collected from six sites across the natural range of distribution of the species in Ethiopia. All seed- and seedling-related traits exhibited highly significant differences among seed sources (P < 0.01), and the magnitude of genetic variation was substantially higher (77–99%) than the environmental variation. The genetic advance as percent of the mean was higher for germination capacity (69.4%) and seed weight (31.7%) than for other traits, suggesting that the population means for these traits may be changed considerably by selecting the superior 5% of the genotypes. There were strong phenotypic (r_p = 0.81) and genotypic (r_g = 0.89) correlations between seed width and seed weight, so also between seedling height and root collar diameter (r_p = 0.95 and r_g = 1.00). In conclusion, the results reveal the existence of substantial genetic variation, which can be utilized to initiate tree improvement program of the species and for gene conservation in seed banks. In memory of the late Abraham Loha, who passed away during the writing process.     

Optimum lifetime for Swedish <Emphasis Type="Italic">Picea abies</Emphasis> seed orchards

The optimum lifetime of Picea abies seed orchards in Sweden was calculated using a model which considers changes in seed yield over time, annual progress of genetic gain, establishment, management and seed costs, and both the monetary and genetic value of the seeds produced. The longer the seed orchard is active, the more genetically outdated the produced seeds will become, and thus their value will decline with time. A main scenario was constructed using the best available estimates for Swedish Norway spruce and was compared to various alternatives reflecting likely variations. The optimal lifetimes in all of these scenarios was in the order of 40 years. Sensitivity analyses showed that use of orchards for slightly more or less than their optimal lifetimes does not lead to large losses. A more effective tree breeding program could slightly reduce the optimal lifetimes. The optimal lifetime depends strongly on the relationship between monetary value and genetic gain. Thus, in cases where genetic progress is sufficiently rapid, the optimal lifetime may be less than 30 years.     

Insecticidal efficacy of <Emphasis Type="Italic">Isaria farinosa</Emphasis> in different life stages of <Emphasis Type="Italic">Pissodes punctatus</Emphasis> (Coleoptera: Curculionidae)

The insecticidal activity of an entomopathogenic fungus, Isaria farinosa on pine bark-weevil (Pissodes punctatus) at different life stages underwent laboratory testing. Larvae, pupae and adults of Pissodes punctatus were exposed to a range of concentrations of fungal conidia in suspension for 5 s; mean mortality and LC₅₀ values were calculated. The results showed I. farinosa can effectively infect larvae, pupae and adult pine bark-weevils, and the highest mean mortalities at each life stage can exceed 88%. The mean mortalities increased with higher concentrations of I. farinosa. Larvae were most susceptible with LC₅₀ 1.2 × 10⁶ conidia ml⁻¹ (15 days), pupae (30 days) exhibited the second largest effects, and adults (15 days) with LC₅₀ 1.72 × 10⁶ and 1.99 × 10⁶ conidia ml⁻¹, respectively, at end of the experiments. This suggests that I. farinosa could be a potential bio-control agent against the pine bark-weevil.     

Assessment of morphological and genetic diversity in <Emphasis Type="Italic">Gmelina arborea</Emphasis> Roxb.

Gmelina arborea is an important timber-yielding tree that grows naturally in the tropical and subtropical regions of Southeast Asia and has also been introduced as a plantation species outside these regions. Genetic diversity in this tree species was observed in stone/seed-related traits and in vitro responses of cultured nodal segments from plants of eight different populations representing natural forests, fragmented forests and plantations. Variance analysis showed significant differences between populations for these traits. However, it was not possible to separate the different populations using these traits by multivariate analysis, even after environmental variation was reduced over six subcultures. Genetic diversity was therefore analysed using molecular markers. Inter-simple sequence repeat (ISSR) primers yielded 95% polymorphic loci among the eight populations and UPGMA analysis enabled separation of these populations on the basis of their genetic distances. Diversity was also analyzed using population genetics parameters like Nei’s genetic diversity and gene differentiation. Nei’s genetic diversity was 0.29 between populations and 0.11 within populations. AMOVA analysis indicated 41 and 59% within- and between-population genetic diversity, respectively. Mantel test suggested that genetic differentiation between six Indian populations was positively correlated to geographic distance (r = 0.626, P = 0.029). Assessment of the genetic variation in G. arborea populations is an important step in selection of conservation strategies for this species since diversity forms the basis for species adaptation.     

Comparison of postfire mortality in endemic Corsican black pine (<Emphasis Type="Italic">Pinus nigra</Emphasis> ssp. <Emphasis Type="Italic">laricio</Emphasis>) and its direct competitor (<Emphasis Type="Italic">Pinus pinaster</Emphasis>)

• Introduction   

Laricio pine (Pinus nigra J.F. Arn. ssp. laricio (Poiret) Maire var Corsicana Hyl.) is a form of black pine endemic to Corsica, that may now be under threat due to current fire regimes and competition with maritime pine (Pinus pinaster Aiton).     

Clonal variations in nutritional components of <Emphasis Type="Italic">Pinus koreansis</Emphasis> seeds collected from seed orchards in Northeastern China

From four Korean pine (Pinus koraiensis) orchards, 60 clones were selected and analyzed for the fatty acid and amino acid components of the seeds to reveal the variations and correlations of the seed characteristics among the clonal source orchards and clones. The nutritional components of the seeds of the P. koraiensis trees exhibited rich genetic variation; the variation coefficient of the fatty acids was 2.24–66.83 %, while the variation coefficient of the amino acids was 14.70–38.88 %. Relatively high genetic-improvement potential exists for the nutritional components of the seeds. The phenotypic differentiation of the fatty acid and amino acid components reveals that variation within the population (85.18 %) was the primary source for the variation of the fatty acid components; variation among the orchards (63.08 %) was the primary source of the variation of the amino acid components. Data drawn from various clonal source orchards all showed that the seed characteristics were highly controlled by heritability (h² > 80 %), and the seed characteristics of the P. koraiensis trees exhibited a similar genetic gain trend. The principal components were analyzed to obtain the comprehensive principal component value for each clonal seed orchard. Twelve clones were selected based on a clonal selection rate of 20 %. Correlation and multiple stepwise-regression analyses were conducted, considering different location conditions, to reveal the stable correlations between the seed characteristics to facilitate improvements of the seed yield of P. koraiensis trees and the clonal selection. Species of real characteristics in P. koraiensis were controlled by higher heritability. Genetic gain was obtained by selecting of superior clones.     

Factors affecting radial growth of the invasive <Emphasis Type="Italic">Prunus serotina</Emphasis> in pine plantations in Flanders

Prunus serotina is an invasive species that causes problems mainly in pine forests on sandy soils in Western Europe. Thus far, there have been almost no studies considering the diameter growth of P. serotina in its introduced range. We analysed the radial growth of P. serotina in seven Scots pine (Pinus sylvestris) plantations in Flanders (Belgium) using multiple linear regression and a potential × modifier approach. The radial growth of P. serotina in the understory of the studied pine plantations was reduced by up to 50% when compared to potential P. serotina growth in full light conditions. Size and site effects were strongly growth-reducing; crowding effects were important only for small individuals. The actual radial growth of P. serotina below pines was determined primarily by the diameter and age of the P. serotina tree and by competition with neighbouring trees.     

Genetic evaluation of twenty seed sources of <Emphasis Type="Italic">Asparagus racemosus</Emphasis>

A field trial of 20 seed sources of Asparagus racemosus was conducted at the Forest Research Institute, Dehradun, Uttarakhand, India to evaluate their performance of different economic traits. Genotypic variance, phenotypic variance, genotypic coefficient of variance (GCV) and phenotypic coefficient of variance (PCV) for number of shoots, shoot height, shoot weight, number of roots, root length, root diameter and root weight were calculated. Maximum genotypic and phenotypic variance was observed in shoot height among the shoot — related traits and root length among the root — related traits. For the shoot height, genotypic variance, phenotypic variance, genotypic coefficient of variance, phenotypic coefficient of variance were 231.80, 3924.80, 61.26 and 1037.32, respectively, where those of the root length were 9.55, 16.80, 23.46 and 41.27, respectively. The maximum genetic advance and genetic gain were obtained for shoot height among the shoot-related traits and root length among the root-related traits. Index values were developed for all the seed sources based on the four most important traits, and Panthnagar (Uttrakhand), Jodhpur (Rajasthan), Dehradun (Uttarakhand), Chandigarh (Punjab), Jammu (Jammu and Kashmir) and Solan (Himachal Pradesh), were promising seed sources for root production.     

Insecticidal properties of <Emphasis Type="Italic">Thymus persicus</Emphasis> essential oil against <Emphasis Type="Italic">Tribolium castaneum</Emphasis> and <Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Red flour beetle Tribolium castaneum (Herbst) and rice weevil Sitophilus oryzae (L.) are considered to be the major insect pests in storage. Essential oils from aromatic plants are recognized as proper alternatives to fumigants. Thymus persicus (Ronniger ex Rech. f.) is one of these plants that have medicinal properties and is indigenous to Iran. The essential oil was obtained from aerial parts of the plant and analyzed by GC and GC–MS. Carvacrol (44.69%) and thymol (11.05%) were the major constituents of the oil extracted. In this experiment, fumigant toxicity of the essential oil was studied against T. castaneum, S. oryzae at 27 ± 1°C and 60 ± 5% RH in dark condition. The adult insects were exposed to the concentrations of 51.9, 111.1, 207.4 and 370.4 μl/l air to estimate median lethal time (LT₅₀) values. The fumigant toxicity was increased in response to increased essential oil concentrations. The LT₅₀ values at the lowest and the highest concentrations tested were ranged from 28.09 to 13.47 h for T. castaneum, and 3.86 to 2.30 h for S. oryzae. It was found that S. oryzae adults were much more susceptible to the oil than T. castaneum. After 24 h of exposure, the LC₅₀ values (95% fiducial limit) for T. castaneum and S. oryzae were estimated to be 236.9 (186.27–292.81) and 3.34 (2.62–4.28) μl/l air, respectively. These results suggest that T. persicus essential oil merits further study as potential fumigant for the management of these stored-product insects.     

Variability in cone and seed characteristics and seed testing in various provenances of Himalayan spruce (<Emphasis Type="Italic">Picea smithiana</Emphasis>)

We investigated the effect of provenance variation on cone and seed morphology and germination behaviour under different pre- treatments in Picea smithiana. Three categories of cones were recognized: large (13.18 cm × 3.30 cm 15.42 cm × 4.35 cm), medium (10.85 cm × 3.93 cm 12.18 cm × 3.98 cm) and small (7.69 cm × 3.06 10.98 cm× 3.39 cm). Significant variation was observed for various cone and seed characteristics. Seeds moisture content varied from 44.48% to 56.91%, seed size from 0.64 cm × 0.31 cm (largest seed) to 0.49 cm × 0.10 cm (smallest seed), and the seed weight from 2.45 g per 100 seeds to 1.36 g per 100 seeds on fresh weight basis of P. smithiana. The highest seed germination (72.0±7.53%) at 10°C was observed under chilling treatment in Tapovan provenance, while the minimum (15.0±5.71%) seed germina- tion was recorded at 25°C under control set in Tapovan provenance. Further among all the sources Pandukeshwar consistently had the highest average (38%) percent germination across all treatments. Compared to other temperature regimes and pretreatments, seeds subjected to 10°C and chilling treatment had the highest germination and took the least time for germination irrespective of provenance effects. Altitude (provenance) had little or no relationship with germination following laboratory treat- ments. Seeds from Tapovan provenance subjected at 10°C following chilling treatment may be suggested for further multiplication of this species.     

Molecular cytogenetics and flow cytometry reveal conserved genome organization in <Emphasis Type="Italic">Pinus mugo</Emphasis> and <Emphasis Type="Italic">P. uncinata</Emphasis>

• Introduction   

The most common representatives of the European mountain pine complex (Pinus mugo s.l.) are P. mugo s.s. and Pinus uncinata.     

Recessive inheritance of morphological characteristics of utsukushimatsu,<Emphasis Type="Italic">Pinus densiflora</Emphasis> f.<Emphasis Type="Italic">umbraculifera</Emphasis>

Pinus densiflora f.umbraculifera, commonly known as utsukushimatsu, is a distinctively shaped form of Japanese red pine whose growth is restricted to a forest stand in Shiga Prefecture, Japan. The inheritance mode of morphological characteristics of utsukushimatsu was studied to preserve the genetic resource of this pine. As previously reported, F₁ trees grown from open-pollinated seeds harvested from trees inhabiting the native stand showed two phenotypes: one resembling utsukushimatsu, which produces multiple trunks, and the other resembling normalP. densiflora, which produces one or a few trunks. In the present study, controlled pollination was carried out using F₁ and normalP. densiflora trees. Segregation ratios of the two phenotypes observed in the F₂ population showed that the morphological characteristics of utsukushimatsu are inherited recessively. This suggests that the mutation of one gene or a few closely linked genes controls the morphological characteristics of utsukushimatsu. Since multiple trunk formation of utsukushimatsu might be related to a loss of lateral bud inhibition, it follows that a simple gene mutation breaks apical dominance inP. densiflora.     

Effects of different treatments on seed germination and breaking seed dormancy of <Emphasis Type="Italic">Prosopis koelziana</Emphasis> and <Emphasis Type="Italic">Prosopis Juliflora</Emphasis>

For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for 10 and 15 min, sandy paper, hot water for 5 and 10 min, potasium nitrate 0.1%, gibberellic acid at 250 mg·L⁻¹ and 500 mg·L⁻¹ and combinational treatment of scarification with gibberellic acid of 250 mg·L⁻¹ and 500 mg·L⁻¹. The results show that scarifications with sandy paper and sulfuric acids 98% were the most effective treatments on breaking seed dormancy and seed germination induction. Scarification with sulfuric acid 98% for 15 min was the best treatment. According to the positive effect of scarification and lack of reaction of seeds against KNO₃ and gibberellic acid, the kind of seed dormancy was determined as exogenous.     

Using agroforestry to improve soil fertility: effects of intercropping on <Emphasis Type="Italic">Ilex paraguariensis</Emphasis> (yerba mate) plantations with <Emphasis Type="Italic">Araucaria angustifolia</Emphasis>

This study assessed the use of agroforestry to improve soil nutrient properties in plantations containing Ilex paraguariensis St. Hilaire (yerba mate). Intercropping within tree plantation systems is widely practiced by farmers around the World, but the influence of different species combinations on system performance still requires further investigation. I. paraguariensis is a major South American crop commonly cultivated in intensive monocultures on low activity clay soils, which are highly prone to nutrient deficiencies. Study plots were established in 20 plantations in Misiones, Argentina. These involved two species combinations (I. paraguariensis monoculture and I. paraguariensis intercropped with the native tree species Araucaria angustifolia) and two age classes (30 and 50 years old). Chemical soil samples were analysed to determine Ca, Mg, K, P, N, C and Al concentrations, effective CEC (eCEC) and pH at two soil depths (0–5 cm and 5–10 cm). In the younger plantations, the agroforestry sites had lower nutrient levels than I. paraguariensis monoculture sites. However, the monoculture plantations were more susceptible than agroforestry sites to a decline in soil nutrient status over time, particularly with respect to Ca, eCEC, N and C for both soil depths. P concentrations were below detection limits for all sites, potentially reflecting the high P-fixing capacity of the kaolinic soils of this region. While agroforestry systems may be better at maintaining soil quality over time, significant growth increase of I. paraguariensis was apparent only for the monoculture sites.