Provenance Differences Research Articles

Genetic variation in seed germination and seedling growth of 24 Gliricidia sepium provenances

Gliricidia sepium is gaining attention as a potential agroforestry tree species for fuelwood production in densely populated dry areas in Malawi. Accordingly, a provenance trial was undertaken to evaluate variation within the species. The nursery stage of this trial showed significant differences in seed germination and seedling survival between provenances. Although germination was good with most provenances, three provenances from Mexico (Barrosa, Francisco and San Jose) achieved less than 50% germination. However, once germinated, the ability of the seedlings to survive in the nursery was high (> 50% in all cases) although minor significant provenance differences in survival occurred. Seedling growth varied significantly between provenances, but none of the traits assessed (height, diameter and dry-weight) was related with any of the seed-origin site characteristics (latitude, longitude and altitude). The nursery results therefore have demonstrated considerable genetic variation in G. sepium, emphasizing the importance of a nursery-evaluation phase in provenance-elimination trials. The levels of genetic variation observed during this phase suggested that useful gains might be obtained in this species by breeding.

Provenance trials of Eucalyptus globulus and related species in Tasmania

Summary Two Tasmanian provenance trials of Eucalyptus globulus Labili, and related species of blue gum—E pseudoglobulus Naudin ex Maiden, E. bicostata Maid, et al., and E. maidenii F. Muell.—were analysed for growth, form and survival differences between species and between provenances within species. E globulus and E pseudoglobulus were not significantly different in growth but both were much faster growing than E bicostata and E maidenii which appeared to be poorly adapted to the cool temperate climate of Tasmania. Cross sites analysis did not identify significant consistent variation between provenances within species for height at age 4 years or diameter at age 7 years. Provenance differences were significant when sites were analysed separately although there was little differentiation within E globulus for growth characters. Significant differences were found in survival and form score between species and provenances within species. Implications for future work within this group of species are discussed.

Seasonal variation in root hardiness of container-grown Scots pine, Norway spruce, and lodgepole pine seedlings

Roots of containerized seedlings of Scots pine (PinussylvestrisL.), Norway spruce (Piceaabies (L.) Karst.), and lodgepole pine (Pinuscontorta Dougl.) grown for one season were experimentally frozen during autumn, winter, and spring. After freezing, root growth capacity and seedling survival were determined by growing the seedlings for 3 weeks in a growth chamber. Root vitality was also tested with the triphenyl tetrazolium chloride method. The seedlings showed a progressive increase in root hardiness towards midwinter and a dehardening as spring approached. Scots pine and lodgepole pine roots were more sensitive to low temperatures than Norway spruce roots. Northern provenances of Scots pine and Norway spruce had the hardiest roots during the autumn. During winter and spring, provenance differences became less clear. Northern Scots pine and lodgepole pine seedlings sown in July tended to be more sensitive to low root temperatures than older seedlings sown in May. No age effects were found in southern Scots pine and Norway spruce seedlings. Although the root systems survived temperatures as low as −15 °C to −25 °C during late fall and midwinter, the capacity to grow roots tended to be stunted at considerably higher temperatures. This indicates the sensitivity of roots and emphasizes the importance of protection against low root temperatures.

Seasonal patterns of net photosynthesis of loblolly pine from diverse origins

Growth and photosynthesis were examined in seedlings of Pinustaeda L. (loblolly pine) from six widely separated provenances. The seasonal patterns of net photosynthesis were similar for each. Seedling net photosynthesis peaked in late October and net photosynthesis per unit leaf area peaked before midsummer and again in late October. When averaged over the entire season, seedling photosynthesis was greatest for Florida seedlings and least for Arkansas–Oklahoma and Texas seedlings. Seedling photosynthesis was strongly correlated with final size on all sampling dates and when averaged over the entire season. Both leaf area and net photosynthesis per unit leaf area contributed to the differences among provenances. Late season growth and photosynthesis, observed in the Florida provenance, increased provenance differences established early in the growing season.

Relationships between shoot length and shoot length components in Douglas-fir and blue spruce

Number of stem units (NSU) and mean stem unit length (MSUL) were examined for their influence on first-order lateral shoot length in a 14-year-old, range-wide provenance test of interior Douglas-fir and an 8-year-old, range-wide provenance–progeny test of blue spruce. The degree to which each component influenced variation in shoot length depended on (i) the population, (ii) the level of population structure (between and within provenances), and (iii) whether phenotypic, genotypic, or environmental data were considered. In Douglas-fir, northern and southern trees were consistently different in MSUL. However, in northern and southern Douglas-fir considered separately and in blue spruce, provenance differences in shoot length were primarily due to variation in NSU. Within provenances, phenotypic variation in shoot length was caused equally by MSUL and NSU in both Douglas-fir and blue spruce. However, in blue spruce, genetic variation was mostly due to the MSUL component, while environmental variation was caused primarily by the NSU component. As a result, MSUL had a higher heritability than NSU. MSUL was also well correlated with tree height (within provenances) while NSU was not. MSUL and NSU were negatively correlated among provenance means, within provenances, on a phenotypic, genetic, or environmental basis. This limits the usefulness of these components as selection criteria and emphasizes the need for better understanding of shoot growth physiology to identify independent sources of variation in growth rate.

Provenance Trials ofEucalyptus maculataIn South Africa: Tenth Year Results

SYNOPSIS A series of provenance trials of Eucalyptus maculata, using seedlots imported from Australia, was planted at seven locations in the Transvaal and Zululand between 1971 and 1974. Several trials were written off at an early stage because of frost damage or poor design. The remaining trials revealed that E. maculata can withstand moderate drought and frost, with the more northerly provenances having the best growth under both conditions. In the more humid areas there were very few significant differences between provenances in growth vigour, although this lack of significance was due, in large measure, to large between plot variation. Based on absolute differences, several provenances showed superior growth vigour and volume production in all areas and also displayed above average stem form. The presence of kino rings was influenced more by the environment and individual tree sensitivity than provenance differences. It might therefore be possible to select for trees resistant to kino damage among th...

Early genetic differentiation of sugar maple by accelerating seedling growth

A method is described for accelerating growth of sugar maple (Acersaccharum Marsh.) seedlings for early progeny and provenance evaluation and plantation establishment. Outdoor nursery production methods produced relatively small seedlings, few seed-lot differences, and no provenance differences in seedlings 4 and 16 months of age. In contrast, accelerated seedlings exhibited pronounced seed-lot and provenance differences at both ages and had a 29 and 80% height superiority at 4 and 16 months, respectively. Provenance differences in height, budbreak, nodes, and growth flushes revealed by the accelerated treatment and supplemented by seed characteristics indicate existence of Upper and Lower Peninsula races in Michigan. Accelerated growth techniques may have considerable potential for reducing the time required for genotypic evaluation of sugar maple and possibly other tree species, but results must be substantiated by subsequent field observations.

A provenance test of red spruce in nine environments in eastern Canada

Survival and total height of red spruce (Picearubens Sarg.) at ages 15 and 22 years from seed are reported. Twelve provenances distributed from North Carolina to Quebec were grown in three experiments each in Ontario, Quebec, and New Brunswick; seven additional provenances were only partially represented. Variance, correlation, and regression analyses were made. Results at both ages were very similar. Provenance differences in survival were small at individual sites and significant only when the results from all nine sites were combined. Provenance differences in height were well expressed and significant in each of the three groups of tests, with northern provenances growing best. Several provenances were also relatively stable and performed well from site to site. Correlation and regression analyses showed that variation in height was more closely related to the degree of introgressive hybridization with black spruce (Piceamariana (Mill.) B.S.P.) than to latitude, elevation, or precipitation at the place of seed origin. These results were conditioned by development on open sites which are not typical red spruce sites.In contrast with expectations when the study was initiated, it is now apparent that provenances from the southern Appalachian Mountains in West Virginia and North Carolina are less variable than expected and not suitable for reforestation in Canada.

Neutron activation analysis for provenance studies of archaeological artifacts

Differences in composition of archaeological artifacts may only in distinct cases be interpreted in terms of provenance differences. This point is discussed with examples: the large number of elements analyzed with precision and the relative lack of sensitivity of many of them to the presence of crystalline inclusions, made of NAA the method most commonly used for provenance studies of ceramics.

Shoot apical growth and cataphyll initiation rates in provenances of Pinusconforta in Scotland

The dynamics of terminal bud development on seven 3-year-old nursery-grown provenances of Pinuscontorta Dougl. were monitored by sampling buds at 1- to 3-weekly intervals during one growing season. Differences in rates of cataphyll initiation occurred which were analysed in terms of (a) the projected areas of the apical domes, which changed over the season, (b) the relative rates at which the apical domes expanded radially during a plastochrone (square millimetres per square millimetre), as shown by the extent to which the new cataphyll primordia receded away from the domes, and (c) the projected areas of the tissues used to form new cataphyll primordia. Component a was a measure of the size of the apical dome meristems and b was a measure of their rates of 'activity.' A model-matching method is described to measure b.Those provenances which produced most cataphylls during the growing season developed and maintained large apical domes (component a above). There were unexpectedly small provenance differences in the apical dome 'activity' in midsummer (component b defined above), although differences occurred in spring and autumn. Differences in the projected areas of the new cataphyll primordia (component c) were inversely related to cataphyll initiation rates. Apical dome tissue doubling times in midsummer were estimated to be less than 120 h, irrespective of provenance.Inland provenances had small but relatively 'active' apical domes in spring, but they produced cataphyll primordia as products of this growth rather than reinvesting in apical dome 'capital.' Consequently, their apical domes remained small. Coastal Alaskan provenances, on the other hand, developed large apical domes, but these domes ceased to be very 'active' after the end of August. The apical domes on south coastal provenances did not become 'active' until early summer, but their domes were relatively large even in spring, became much larger by late summer, and they remained 'active' until mid-September.Implications are noted regarding cross-breeding of complementary genotypes to increase needle production and height growth.

Production of Branches and Foliage by Young trees of Pinus contorta and Picea sitchensis: Provenance Differences and Their Simulation

Pinus contorta Dougl. (Lodgepole pine) and Picea sitchensis (Bong.) Carr. (Sitka spruce) account for c. 50 and 20%, respectively, of the forest trees currently being planted by the Forestry Commission in Britain. Both have extensive natural ranges in western North America, and provenances (seed populations) collected in different geographic zones differ in morphology and phenologyPinus contorta (Critchfield 1957; Jeffers & Black 1963; Roche 1966; Hagner 1970); Picea sitchensis (Burley 1965; Daubenmire 1968; Roche 1969). The variation in yield and quality on sites in Britain is currently being assessed and exploited by Forestry Commission staff (Lines 1965, 1966, 1968; Faulkner, Herbert & Fletcher 1969) who made provenance trials available for this study. Rapid leader growth and stem volume increase is required, but with few short branches in a narrow crown to minimize the number of wood knots and risk of wind damage (e.g. causing 'basal bowing' or 'butt sweep' in Pinus contorta, Edwards, Atterson & Howell 1963; Lines & Booth 1972). However, stem volume is proportional to crown volume in young trees (Assman 1970), and therefore a compromise in branch development may be sought to ensure a rapid early build-up in photosynthetic tissue, light interception and suppression of ground vegetation, which seem to confer lasting yield advantages (Lines 1971; Lines & Booth 1972). The size and form of the individual tree crowns depend on (a) the amount of leader extension growth, and (b) the numbers, sizes and disposition of the branches. Seedling studies have usually shown that leader growth of Picea sitchensis, and in part, of Pinus contorta, tends to increase with decrease in latitude or elevation of seed origin, reflecting ecotypic or clinal differences in photoperiodic and temperature response-P. contorta (Critchfield 1957; Sweet & Wareing 1968; Hagner 1970); Picea sitchensis (Aldhous 1962; Burley 1966a, b; Lines & Mitchell 1966). Provenance differences in branch development, however, have not been described in sufficient detail to identify the morphological characters responsible for well-known differences in crown form. This study first tested the assumption that the length of needle-bearing shoot determined the amount of needle tissue produced, and that this was correlated with stem volume production. This was necessary because, in both Pinus contorta and Picea sitchensis, provenance differences are known in needle size, closeness, display (Critchfield 1957; Jeffers & Black 1963; Lamb 1970; Burley 1965) and photosynthetic rate (Sweet & Wareing 1968; Ludlow & Jarvis 1971). Following this, the lengths of all the shoots on young trees were measured to trace how some provenances had built-up much more shoot than others. A simple model was used to establish how much these differences stemmed from differences in (a) leader growth, (b) the length of each branch relative to its neighbours and the leader, and (c) lateral bud production.

Geochemistry of continental margin sediments from northwest Africa

The geochemistry of the non-carbonate fraction of sediments from the continental shelf and slope off northwest Africa has been investigated using R-mode factor analysis. The geochemistry is governed by a small number of factors controlled quantiatively by glauconite, phosphorite, quartz, clay minerals and secondary iron oxides. The distributions of the factors and of their controls are governed by mineral provenance and by depositional processes. Clay mineral factors predominate in fine grained sediments. Phosphorite, glauconite and oxide factors and quartz predominate in sands. Provenance controls the relative abundances of the minerals of the sand fraction all of which, except a proportion of the glauconite which is clearly recent, are relict and detrital. The recent glauconite is concentrated in poorly oxidised sediments off the southern Sahara. Provenance differences are detected between Saharan and Moroccan clays, and also exist between the clays of north and south Morocco.