Assessment of hedgerow species for seed size,stand establishment and seedling height

The relationships between seed size, emergence, stand establishment and seedling height were examined in a trial comparing tree and shrub species as hedgerows for alley cropping in four environments in Haiti. Logarithmic functions relating % emergence, % stand establishment and seedling height to seed weight were positive and significant. These relationships were stronger when species weighing > 10 g 100⁻¹ seed were excluded from the analysis. Higher R² values were obtained regressing % stand than regressing % emergence on seed weight. Although exceptions were noted, a majority of species having seed weights between 2.5 g and 10 g 100⁻¹ had good stands. Establishment was poor or inconsistent for species with seed < 2.5 g 100⁻¹. The effect of seed size on height was more important for seed weights < 5 or 8.8 g 100⁻¹, depending upon the site, than for larger seed. Species with < 2.5 g 100⁻¹ seed are unsuitable for direct seeding where the chance of drought is high.     

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.     

Effects of seed water content and storage temperature on the germination parameters of white spruce, black spruce and lodgepole pine seed

The effect of seed water content (WC) (2–3, 5–6 and 22–25%, on a fresh weight basis), storage temperature (+4, −20, −80 and −196°C) and storage duration (6, 12, 24, 48 and 60 months) on the germination of white spruce (Picea glauca (Moench) Voss), black spruce (Picea mariana (Mill.) B.S.P.) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) seed was investigated. Germination of white spruce control (untreated) seeds and seeds adjusted to 2–3% and 5–6% WC declined after 48 months of storage at −80 and −196°C, with a further decline at 60 months at −20, −80, −196°C. Germination remained high when control white spruce seeds and seeds with 2–3, 5–6% WC were stored at +4°C, over all storage durations. Generally, black spruce and lodgepole pine exhibited high germination at all storage temperatures at 2–3% and 5–6% WC as well as the control (untreated) seed, for up to 60 months in storage. Germination declined for all three species when seed was conditioned to 22–25% WC. This loss in germination was partially recovered in white spruce seed stored at +4, −20 and −80°C after storage durations of 24, 12 and 48 months, respectively, and in black spruce seeds stored at −20 and −196°C after storage durations of 24 months. Mean germination time (MGT) was relatively constant for all species, under all conditions, except for seed conditioned to 22–25% WC, where MGT increased for white spruce seed stored 48 months at −80 and −196°C, and for black spruce seed stored 24 months at +4 and −80°C and 60 months at −196°C. These results show that the optimal storage temperatures are 4°C for white spruce, and 4, −20, −80, and −196°C for black spruce and lodgepole pine, and 2–6% water content is optimal for all 3 species at these temperatures.     

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.     

Alley cropping in the moist savanna of West-Africa: II. Impact on soil productivity in a North-to-South transect in Togo

The moist savanna of West-Africa is characterized by a wide range of climates and soil types. The impact of the biophysical environment on hedgerow N uptake, wood production and maize grain yield was assessed for three years in three alley cropping trials with a selected number of hedgerow species in Glidji (Southern Togo), Amoutchou (Central Togo), and Sarakawa (Northern Togo). Senna siamea hedgerows accumulated significantly more N in the first pruning in Glidji (129−138 kg N ha−1) and Sarakawa (102−185 kg N ha−1) than in Amoutchou (17–26 kg N ha−1). This difference in N uptake was attributed to the infertile subsoil in Amoutchou, which was sandy up to 1 m and had a shallow groundwater-table. The amount of N accumulated in the Gliricidia sepium biomass varied between 38 kg N ha−1 in Glidji and 142 kg N ha−1 in Amoutchou. Averaged over all species and sites, 9 to 29% and 9 to 39% of the annual N accumulation in the hedgerow biomass is incorporated in the second, respectively third pruning. The Gliricidia trees produced between 12 and 26 ton fresh matter ha−1 of wood and the Senna trees between 4 and 38 ton fresh matter ha−1. Maize grain yield in Glidji was not affected by treatments (3196 kg ha−1, on average). In Amoutchou, the highest grain production was observed in the Gliricidia treatment (2774 kg ha−1 vs 1007 kg ha−1 in the control), while in Sarakawa, the Gliricidia (3786 kg ha−1) and Senna (3842 kg ha−1) plots produced a greater grain yield than the control plots (2123 kg ha−1). Maize yield increase in the alley cropping systems relative to the control plots was related to the soil total N content. Top and sub-soil characteristics were shown to be an important modifier of the functioning of alley cropping systems and should be taken into account when deciding on whether to use alley cropping and when selecting the hedgerow species. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date.     

Alley cropping in the moist savanna of West-Africa: I. Restoration and maintenance of soil fertility on ’terre de barre‘ soils in Bénin Republic

The potential of alley cropping systems supplied with a limited amount of fertilizer to restore crop productivity on a degraded site and to maintain crop productivity on a recently cleared, non-degraded site on ‘terre de barre‘ soils in Southern Bénin was investigated from 1994 to 1996. Leucaena leucocephala, Senna siamea and Gliricidia sepium were used as hedgerow species. Maize yields of the no-tree control plots dropped from the initial (1990) 401 kg ha−1 and 2181 kg ha−1 on the degraded and non-degraded sites, respectively, to 109 kg ha−1 and 1346 kg ha−1 in 1996, even with application of a minimal amount of mineral fertilizer. The alley cropping systems produced on average (mean of three treatments and three years) 107% more grain than the initial 1990 values on the degraded site and 11% less grain than the initial 1990 values on the non-degraded site. Especially the Senna and to a lesser degree the Leucaena treatment yielded consistently more grain than the control. The Senna trees contained a larger amount of N and produced more wood during the first pruning on the degraded site (155 kg N ha−1 and 14.0 ton fresh wood ha−1) than on the non-degraded site (49 kg N ha−1 and 6.6 ton fresh wood ha−1) most likely because of differences in subsoil fertility, as indicated by the higher clay, exchangeable bases, and N content between 60 and 125 cm cm. N accumulation and wood production by the Leucaena and Gliricidia trees was similar in both sites (82 and 36 kg N ha−1 and 4.6 and 9.3 ton fresh wood ha−1, respectively). When a limited amount of fertilizer is available, Senna appears to be the best choice as hedgerow species on sites with a relatively fertile subsoil. For other soils, a N2-fixing species may be a better choice. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date.     

Genetic analysis of crossing effects for growth traits of Pinus massoniana and selection of cross combinations

Two groups of filial generations derived from two different Pinus massoniana complete-diallel crosses were analyzed. Results show that the general combining ability (GCA), specific combining ability (SCA) and reciprocal effects were significant for some growth traits, including height, DBH and volume index. The heredity of these growth traits was controlled by additive and non-additive genes, of which the additive genes played a dominant role. The epistatic effect was greater for group I (cross in 1992) than group II (cross in 1993). The SCA of P. massoniana growth traits was significantly greater than GCA, which may be related to different geographical provenance for parents and the indirect selection by GCA. Inbreeding depression was commonly observed for P. massoniana growth traits. The extent of inbreeding depression was −17.8%–−18.4%, −23.3%–−27.7% and −44.3%–−50.6% for height, DBH and volume index, respectively. It was observed that parents with small GCA values exhibited a greater extent of inbreeding depression. Large differences in hybrid vigor of different crosses were observed and the difference between original cross and reciprocal cross was not significant. Based on the volume index, 10 fine crosses were selected for two groups respectively, and the average increment of volume index was 59.41% and 41.76%, respectively, in comparison with the average of the testing groups, and was 100.58% and 74.61% in comparison with the local commercial variety. __________ Translated from Scientia Silvae Sinicae, 2008, 44(6): 28–33 [译自: 林业科学]     

Relative effects of irrigation and intense shade on productivity of alley-cropped tall fescue herbage

The relative effects of irradiance and soil water on alley-cropped herbage are poorly understood. Our objective was to determine effects of irrigation on herbage productivity when tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] was grown in two sites, a meadow and a loblolly pine (Pinus taeda L.) alley (620 trees ha⁻¹), near Booneville, Arkansas. Three tall fescue entries were space planted in the meadow and pine alley with or without irrigation. Herbage mass and nutritive value were determined at 8-week intervals for 2 years. Mean daily PAR was 33.9 (2004) and 37.5 mol m⁻² d⁻¹ (2005) in the meadow, while the pine alley received 5.6 mol m⁻² d⁻¹ (17% of the meadow) in 2004 and 4.3 mol m⁻² d⁻¹ (11% of meadow) in 2005. Effect of tall fescue entry tended to be small relative to site and irrigation. Irrigation compensated for evapotranspiration in the meadow, but not in the pine alley when summer rainfall was about normal (2004) or low (2005). Nevertheless, site (PAR) had a greater effect on herbage specific leaf weight, leaf elongation rate, tillers plant⁻¹, mass tiller⁻¹, and total nonstructural carbohydrate concentration than soil water. Irrigation might have had greater impact on herbage productivity if more water had been applied or if canopy cover had been less extreme. Silvicultural practices should be imposed to improve penetration of solar irradiance to the alley crop.     

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.     

Responses of germination and radicle growth of two Populus species to water potential and salinity

The effects of water potential, NaCl and Na2SO4 on germination and radicle growth of two riparian tree species, Populus euphratica Oliv. and P. pruinosa Schrenk (Salicaceae), were tested. Growth chamber studies revealed an optimum temperature range for seed germination of both species between 15-35℃. The final germination percentage of both species decreases with decreasing water potential in all types of solution applied in the experiments. P. pruinosa was less tolerant to low ψw stress than P. euphratica, especially in salt solutions. Germination percentages fell below 20% for P. pruinosa at -0.6 MPa (NaCl) or -0.4 MPa (Na2SO4) and for P. euphratica at -1.2 MPa (NaCl) or-0.6 MPa (Na2SO4). Radicle growth of both species was inhibited by high concentrations of PEQ NaCl and Na2SO4. However, growth was enhanced at -0.13 and -0.29 MPa in PEG or at -0.13 MPa in NaCl solutions compared to distilled water. Radicle growth of P. euphratica was higher than that of P. pruinosa. Germination and radicle growth of both species exhibited ion toxicity. Na2SO4 was more toxic than iso-osmotic solutions of NaCl. Radicle growth proved to be more sensitive than seed germination. Thus, flooding does not only yield the necessary soil moisture for germination but also favors seedling establishment of both species through leaching of salts from the soil surface. The different sensitivity of the species during their early growth stages might, moreover, contribute to the observed differences in their distribution in the Talim Basin (northwest China).     

Eucalyptus plantations in Israel: an assessment of economic and environmental viability

This paper discusses a plantation management approach involving a combination of “short” and “long” rotations designed to allow farmers to receive income from trees as soon as possible after establishment. We present results from two plots that represent extreme conditions: (a) a seasonally waterlogged, non-saline site (Nahalal), and (b) a saline site (Ginnegar) located in the Yizre’el Valley, Israel. Six improved seed sources, four of Eucalyptus camaldulensis and two of E. occidentalis, were examined. The local Israeli seed source of E. camaldulensis (HA) performed best at both sites. In Nahalal, the short rotation thinning of the slower growing (50%) plantation trees could provide economic returns approximately five years after establishment. The calculated mean annual increment (MAI) of these trees reached 12.2 t ha⁻¹ year⁻¹. The long rotation, or better performing half of the plantation trees, could be used as a source of sawn timber, providing higher-value products. By nine years after establishment, the average DBH of the various seed sources reached 25.8 ± 1.9 cm. The calculated MAI of the combined cutting rotations reached 48.3 t ha⁻¹ year⁻¹. Eucalyptus grown under the combined (short- and long-term) management approach at Nahalal was more profitable than many other non-irrigated local crops. Eucalyptus production in Ginnegar would be less profitable than in Nahalal. However, an additional ecological benefit was provided by the crop’s ability to lower the water table. When this contribution to regional drainage is taken into account, trees become economically competitive with other non-irrigated field crops under saline conditions. Jim Morris–Deceased.     

Tree Performance and Root-Zone Salt Accumulation in Three Dryland Australian Plantations

Doubts exist about the effectiveness of establishing trees near saline discharge areas on farmland to manage dryland salinity. These centre on low rates of water uptake from saline water tables, salt accumulation in tree root zones and the consequent poor growth and survival of trees. Despite this, trees still survive in many plantations established adjacent to saline discharge areas and land-holders often favour such locations, as they do not compete for arable land such as that occurs with plantings in recharge areas. Tree performance and salt accumulation were assessed in three experimental plantations established adjacent to saline discharge areas 20–25 years ago. These were all in the 400–600 mm rainfall zone of south-western Australia. Mean soil salinity, within 1 m of the surface, ranged from 220 to 630 mS m⁻¹, while permanent ground-waters occurred within 2–5 m of the surface and had electrical conductivities ranging from 175 to 4150 mS m⁻¹. The study confirmed the low growth rates expected for trees established over shallow, saline water tables in a relatively low rainfall environment, with estimated wood volumes in Eucalyptus cladocalyx, E. spathulata, E. sargentii, E. occidentalis and E. wandoo of between 0.5 and 1.5 m³ ha⁻¹ yr⁻¹. Values of up to 3 m³ ha⁻¹ yr⁻¹ were obtained on soils with low salinity (<200 mS m⁻¹). The excellent survival (>70%) of several Eucalyptus species confirms that discharge plantations species can persist, despite increasing soil salinity. However, the long-term sustainability of such plantings (50–100 years) without broader landscape treatment of the present hydrological imbalance must be questioned.     

Scots pine (Pinus sylvestris L.) plantations contribute to the regeneration of holly (Ilex aquifolium L.) in mediterranean central Spain

The aim of this study is to evaluate the recruitment possibilities of holly (Ilex aquifolium L.) populations under Pinus sylvestris plantations in the mountains of Central Spain. Population recruitment of holly under P. sylvestris L. plantations was studied at two localities. We sampled holly seed rain, seed bank, and seedling emergence and survival (of both emerged and planted seedlings) in both localities. Seed germination was analysed by randomly sowing Ilex seeds and their subsequent recollection and analysis over the following 3 years (only in one locality). Seed rain, seed bank and emerged seedling densities did not differ between localities. Seed bank density was between 10 and 20 seeds m⁻², considerably higher than the observed seed rain (0.4–1.2 seeds m⁻²), and also higher than the emerged seedling density (0–4 seedlings m⁻²). But Ilex is not very efficient in germinating under pine forests (29.1% germination after 3 years). This may indicate a seed accumulation process of at least 5 years. Seedling survival for the first year differed among the studied sites (50–60 vs. 17%). Nevertheless these survival rates are higher than those found for the same seedling populations in different forest habitats (not Scots pine forests) from near locations. Differences in summer water stress between the study sites are proposed as the main cause of the observed differences in seedling survival. It is concluded that P. sylvestris forests may provide one of the best regeneration habitats for holly in the Mediterranean area, where this species is close to the Southern limit of its distribution.     

Time consumption, productivity, and cost analysis of the motor manual tree felling and processing in the Hyrcanian Forest in Iran

An empirical time study was conducted to evaluate the per- formance of the current felling and tree processing methods used in Northern Iran’s Hyrcanian forest. Motor-manual felling is done mostly in winter, while tree processing starts when the felling season ends. We identified the elements of felling and processing work phases, and 142 cycles and 110 cycles were respectively recorded for felling and proc- essing. On the basis of data analysis (time study), we developed statisti- cal models of effective time consumption in the respective work phase and for its total productivity. The production rate of felling with and without delay time was 9.7 and 11.65 trees per hour (0.17 USD·m -3 and 0.21 USD·m -3 ), and the average production cost with and without delay was 1.21 USD and 1.45 USD per tree, respectively. The average produc- tivity of processing was 35 m 3 per effective hour and the average unit cost of processing was 0.22 USD·m -3 .     

Evaluation of the inorganic compound leakage and carbohydrates as indicator of physiological potential of <Emphasis Type="Italic">Ulmus parvifolia</Emphasis> seeds

Inorganic compound leakage and change of carbohydrate were measured in Ulmus parvifolia seeds throughout accelerated aging under 35°C and 75% relative humidity (RH) to investigate whether these indicators can be used as a rapid vigor test for efficient seed bank management. Accelerated aging seeds treated for 0–14 days exhibited loss of germinability in the longest aging treated seeds (11%, 14 days) compared to a good performance of 52% for control (0 day) seeds. Leachate electrical conductivity (EC) increase had strong negative correlation with seed vigor (−0.9). Magnesium ion concentration in electrolyte leakage from artificial aged seeds showed positive correlation (r = 0.94, P < 0.01). The ratios of inorganic ions showed that K⁺/Mg²⁺, Ca²⁺/Mg²⁺, and Na⁺/Mg²⁺ were inversely correlated with germination (−0.93, −0.82, and −0.91, respectively). Increases in starch and total soluble sugar content in aged seeds were associated with a decrease in seed vigor. In conclusion, EC, magnesium ion concentration, K⁺/Mg²⁺, Ca²⁺/Mg²⁺, and Na⁺/Mg²⁺ ratios and starch and total soluble sugar content could provide a sensitive and accurate index for the assessment of U. parvifolia seed vigor.     

火炬松八年种源试验研究

本文总结了1981年在我国3个气候带7个试验点火炬松8a种源试验结果:①对不同种源火炬松的树高、胸径生长进行了显著性检验;②火炬松种源(树高、材积)×地点的互作显著;③火炬松种源2、4年生树高、胸径和至8年生高、径生长相关显著,为早期选择提供依据;④根据生长快、适应性强两项因子,综合评选出一批适合我国不同气候带及自然类型区的国外松树种及火炬松优良种源。     

Management of pigeon pea in short fallows for crop-livestock production systems in the Guinea savanna zone of northern Ghana

Crop and livestock production in the Guinea savanna zone of northern Ghana has been declining over the past years as a result of increasing pressure on land. To sustain soil productivity, pigeon pea(Cajanus cajan), a leguminous perennial crop was evaluated for its potential as a short duration fallow crop for fodder and grain, and maize (Zea mays)production. It involved comparing a natural fallow (i.e., control) and four improved fallows of pigeon pea pruned annually at 30 cm, 60 cm and 90 cm from the ground, and unpruned pigeon pea over a two-year period. After this time, the land was cleared manually and planted to maize. The highest mean annual biomass of pigeon pea over the two-year period of 6.1 t ha⁻¹ dry matter (DM) was obtained by pruning at 60 cm. The highest leaf litter production and pigeon pea seed yield was obtained from the no pruning treatment. The mean maize grain yield from the improved fallow (3.02 t ha⁻¹) in the first year after clearing was significantly (P < 0.05) greater than that of the natural fallow (1.54 t ha⁻¹). Considering the biomass of pigeon pea from pruning, pigeon pea seed yield and maize grain yield after the pigeon pea, pruning pigeon pea at 60 cm is the most promising regime for crop-livestock production systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Interactions between Widely Spaced Young Poplars (Populus spp.) and Introduced Pasture Mixtures

Silvopastoral systems involving poplars are widespread in rural landscapes in a number of regions of New Zealand. The effect of widely spaced trees of Populus nigra × P. maximowiczii, aged 8–11 years, on the growth and botanical composition of understorey pasture mixes was determined over 3 years at a southern North Island hill country site. Pasture mixes comprised existing pasture, and two introduced test swards comprising new grass (Agrostis capillaris, Dactylis glomerata, Lolium perenne) and legume (Lotus uliginosus, Trifolium repens) cultivars. Pasture accumulation beneath trees (6.6 t DM ha⁻¹ year⁻¹) was 23% less than open (unshaded, no trees) pasture (8.6 t DM ha⁻¹ year⁻¹) and differences in accumulation occurred between tree aspects (North and South sides of trees) when trees were foliated. In early spring, North plots produced 11–14% more herbage than South plots whereas in late summer, South plots produced up to 44% more herbage than North plots. Yield of both test swards (6.4 and 8.0 t DM ha⁻¹ year⁻¹) was not significantly different from that of the existing sward (7.4 t DM ha⁻¹ year⁻¹) but productivity varied between swards in spring and summer. One test sward included Lotus uliginosus cv. Grasslands Maku, and the sward produced 30% more DM than the other swards in mid-summer. Dactylis glomerata cv. Grasslands Wana comprised 37% of the DM of swards in which it was sown and was the most successful cultivar, followed by Grasslands Maku. Both cultivars are recommended for silvopastoral systems where pasture is lightly grazed.     

Variation in Seed and Seedling Traits of Celtis australis, a Multipurpose Tree, in Central Himalaya, India

Seeds of Celtis australis were collected from 13 different sources, ranging from 550 to 1980 masl, in Central Himalaya, India. Significant (p = 0.05) variations were observed for seed traits among provenances. However, among various characters, seed weight exhibited maximum variation between seed populations compared to other morphological characters. Between provenances, seed weight ranged from 47.8 to 83.1 g/1000 seed, with mean value of 66.9 ± 10.7 g/1000 seed. Significant (p = 0.01) positive correlation was found between morphological characters of seeds including seed weight and elevational range of seed source. For one year old seedlings, average shoot and root growth was 61.1 ± 13.3 and 30.5 ± 5.4 cm, respectively, irrespective of provenance variation. Inter-comparing biomass yield of the seedlings with altitude, average biomass production was 8.4 ± 2.5, 9.4 ± 3.3 and 12.7 ± 1.7 g/plant, respectively, for low (550–1000 masl), middle (1050–1250 masl) and high (1350–1980 masl) altitudinal populations. Significant (p = 0.01) positive correlation between growth performance of seedlings and altitude of the seed source was recorded. Across the provenances, shoots had the highest proportion of total biomass (42.3%), followed by leaves (32.6%) and roots (24.6%). Among various provenances, Badiyargaon, Agroda, Guptakashi, Jakholi, Gajeli, Srinagar and Palampur populations produced heavier seedlings and grew faster compared to seedlings of other sources.     

Culling phenotypically inferior trees in seed production area enhances seed and seedling quality of <Emphasis Type="Italic">Acacia auriculiformis</Emphasis>

Improvement in seed and seedling quality of Acacia auriculiformis after culling phenotypically inferior trees was studied in a 6-year old seed production area (SPA). A 5-ha plantation was identified, of which 2.3 ha was converted into SPA. The initial stocking, 1 612 trees·ha⁻¹, was thinned down to 982 trees·ha⁻¹ based on growth characteristics. The following fruiting season, seeds were collected from 10 randomly selected trees in culled and non-culled stands, and seed physical characters, germination and seedling traits were assessed. Seed weight, seed thickness and percentage germination increased by 32.1%, 4.43% and 22.37%, respectively in the culled stand compared to the non-culled stand. Culling also increased the speed of germination, seedling dry weight and seedling vigor index. Heritability values were high for seed weight (0.974) and seed thickness (0.948) while medium values were observed for percentage germination (0.577) and total dry weight (0.534). Predicted genetic gain was 11.13% and 11.22% for seed weight and percentage germination, respectively. The actual gain was 32.1, 51.9 and 22.9% for seed weight, percentage germination and total dry matter, respectively. In conclusion, SPAs established by culling inferior trees could serve as sources of good quality seeds for reforestation programs until genetically improved seeds are made available.