Wild Stands Research Articles

The historical perspective of dryland agriculture: lessons learned from 10 000 years of wheat cultivation

Wheat is one of the founder crops of Western agriculture. This study reconstructs agronomic conditions, potential yields, and kernel weight in the beginnings of cultivation of domesticated free-threshing wheat, c. 8000 BC. The carbon and nitrogen stable isotope compositions and the dimensions of fossil grains of naked wheat (Triticum aestivum/durum) were analysed. Samples were collected in Tell Halula and Akarçay Tepe, two Neolithic archaeological sites from the Middle Euphrates (the claimed core area for wheat domestication). The samples analysed include the oldest reported remains of naked wheat. Consistently wetter conditions but lower kernel weights were found in the Neolithic compared with the present day. Besides, the estimated yields were clearly beyond what is expected from the gathering of wild stands of cereals. Patterns of phenotypic adaptation achieved by wheat after its diffusion through the Mediterranean were also assessed. On the one hand, the study looked at variation in morphophysiological traits as related to local climate in a set of 68 durum wheat landraces from the Middle Euphrates. On the other hand, an assessment was made of regional adaptation around the Mediterranean Basin in a set of 90 landraces, traditional varieties, and modern cultivars from different origins by characterizing agronomic and morphophysiological variability. Significant relationships were observed between phenotypic variation among landraces from the Middle Euphrates and both minimum temperatures and the ratio of precipitation to potential evapotranspiration of the sites of origin. In addition, consistent differences in grain yield, plant structure, and water status were found among genotypes following both north-south and east-west gradients across the Mediterranean. These differences are associated with contrasting environmental and selection pressures.

Wild bamboo stands fail to compensate for a heavy 1-year harvest of culm shoots

Bamboo is an important resource for humans, particularly in Asia, providing shoots for food and culms for construction. It is also an ideal subject for intensive management. However, most of the resource is obtained from wild stands for which the sustainability of harvests is poorly documented and intensive management is often impractical or inappropriate. I conducted two shoot harvest trials in riparian stands of the north Australian bamboo Bambusa arnhemica F. Muell. (Poaceae), testing a harvest protocol in which stands are rotated among years. In both trials, harvest had no effect on recruit numbers, but recruits were markedly smaller than in control clumps. There was no residual effect of the harvest on recruit size or number in subsequent years. However, both trials demonstrated that the harvest clumps failed to increase recruitment in subsequent years to compensate for the loss of biomass in the harvest year. This rotational harvest system cannot be recommended because a cumulative loss of biomass is predicted with multiple harvest cycles. Alternative management protocols involving within-season harvest limits may prove practical for wild bamboos, but achieving sustainability in the absence of intensive management may not be easy.

Comparison of Genetic and Virulence Diversity ofMelampsora larici-populinaPopulations on Wild and Cultivated Poplar and Influence of the Alternate Host

ABSTRACT The aims of this study were, first, to compare the genetic and virulence diversity between populations of the rust fungus Melampsora larici-populina on wild and cultivated poplar stands and, second, to investigate the influence of the presence of the alternate host of the pathogen, larch, on which its sexual reproduction occurs, on these diversities. Nine French M. larici-populina populations collected from poplar trees in autumn and four populations collected from larch trees during the following spring were analyzed using both virulence factors and neutral markers. In all, 30 pathotypes were identified within the 13 populations studied. The pathotypic structure clearly distinguished the cultivated stands with high richness and complexity from the wild stands with low richness and complexity. High linkage disequilibria between virulences indicated preferential virulence associations, probably due to selection by the host. In all, 19 random amplified polymorphic DNA (RAPD) markers were used, which revealed a very high genetic diversity in the 743 isolates analyzed. The nine populations from poplar appeared moderately differentiated, indicating long-distance gene flow, and no isolation by distance was found. Linkage disequilibria between RAPD markers generally were low, indicating frequent recombination, but they were not lower in populations located near larch, probably due to long-distance dispersal.

BLUEBERRY PRODUCTION AND RESEARCH TRENDS IN NORTH AMERICA

BLUEBERRY PRODUCTION AND RESEARCH TRENDS IN NORTH AMERICA

Palms in Indigenous and Settler Communities in Southeastern Ecuador: Farmers’ Perceptions and Cultivation Practices

Most palms used in agroforestry systems are exploited from wild stands or are only occasionally cultivated, while only a few palms have been domesticated. In this study we investigated how socio-economic factors and people's perceptions of changes in palm use and availability, influenced palm cultivation among indigenous Shuar and mestizo settlers in south-eastern Ecuador. We also looked at how different uses of palms influenced which species they cultivated. Our results showed that perceptions of declining palm availability in combination with heavy reliance on palm products was positively related to palm cultivation. Hence, cultivation was more common in more remote villages where alternative products were hard to get. In addition, palm cultivation was more common among wealthier people and among indigenous people than among recent settlers. This points to a limiting role of assets such as land and to the importance of history and culture with regard to cultivation. It was not possible to identify any single palm use as the primary reason for cultivating a species, but the more uses a species had, the more likely it was to be cultivated. These findings have important implications for development projects that promote cultivation of palms and other long-lived tree crops. They illustrate how market access and lack of necessary assets may undermine cultivation of native species even though these are regarded as important resources.

Evaluation of Selfing Effects on Western Redcedar Growth and Yield in Operational Plantations Using the Tree and Stand Simulator (TASS)

Abstract Seed lots of western redcedar (Thuja plicata) from both wild stands and seed orchards contain a relatively large proportion of self-pollinated seeds compared to other tree species. Selfed seeds do not exhibit early inbreeding depression, and thus have the same probability of producing acceptable seedlings for field planting as outcrossed ones. However, selfed trees show, on average, about 10% reduction in 9-year height after outplanting. To evaluate the potential negative effects of selfing on productivity at harvest, growth and yield of stands comprising selfs were simulated using TASS (tree and stand simulator) with various planting sites and initial planting densities in this study. Height distributions of selfed and outcrossed individuals were also compared and modeled, which provided a solid basis for accurate TASS simulations and some inside view of selfing in this species. Our results indicate that effects of selfing are smaller on stand final productivity (8% on average) than on 9-year-young trees due to natural selection (competition) against slower-growing trees after crown closure, resulting in more selfs being purged than outcrossed trees. Using better planting sites with higher initial planting densities can substantially intensify the selection and reduce the negative effects of selfing on final productivity.

Insect pests of wild cranberry, Vaccinium macrocarpon, in Newfoundland and Labrador

Cranberry (Vaccinium macrocarpon) has been commercially developed since the late 1990's in Newfoundland and Labrador. At that time, the insect fauna of the extensive stands of native, wild cranberry was not known, although these might provide a reservoir for pests to move to commercial sites. The occurrence and distribution of cranberry-feeding insects were assessed in wild stands to help cranberry growers prepare for the insect pests they might have to manage. Adults of the cranberry fruitworm, Acrobasis vaccinii were recovered in pheromone traps and larvae found in berries. The fruitworm was common and widespread. Moths of the cranberry girdler, Chrysoteuchia topiaria were caught in pheromone traps, but larvae were not recovered from plant or soil samples. There was no evidence of the black-headed fireworm, Rhopobota naevana, the cranberry weevil, Anthonomus musculus, the red-headed flea beetle, Systena frontalis, or the cranberry tipworm, Dasineura oxycoccana, serious cranberry pests in other areas. However, larvae of the lingonberry fruitworm, Grapholita libertina, were found infesting cranberry at one site in 1998. Of the species found in this study, A. vaccinii probably represents the most serious threat to the industry.

Effect of Pruning and Urea Fertilization on Rejuvenation of Cultivated Lingonberry (Vaccinium vitis-idaeaL.) with Special Reference to Mycorrhizal Infection

Abstract Lingonberry (Vaccinium vitis-idaea L.) growth and development was studied in field experiments in Viikki, Finland (60°10′N, 25°00′E). The effects of pruning height (1 and 5 cm above ground) and urea fertilization (0-10 g m−2) were examined for their capacity to rejuvenate 10 year old lingonberry vegetation. Lingonberry roots collected from an experimental field were compared with those from wild stands for the presence of mycorrhizas. Lingonberry vegetation recovered exceptionally well from pruning after one growing season. High pruning (5 cm) resulted in higher number of new shoots than low pruning (1 cm), but low pruning and 5 g urea produced the most generative shoots and the greatest number of flower buds. Fertilizer application, in general, had very little effect. Fungal hyphae were detected in the root epidermis. Advantages of low pruning in lingonberry management and the effect of ammonium and nitrate nitrogen and role of mycorrhizal infection in nutrient uptake of lingonberry are discussed.

HORTICULTURAL POTENTIAL OF ANDEAN FRUIT CROPS EXPLORING THEIR CENTRE OF ORIGIN

HORTICULTURAL POTENTIAL OF ANDEAN FRUIT CROPS EXPLORING THEIR CENTRE OF ORIGIN

Fatty acid and triacylglycerol composition and thermal behaviour of fats from seeds of Brazilian Amazonian Theobroma species

AbstractRaw materials for cocoa butter substitutes, replacements or equivalents depend mostly on the unsteady supply from wild stands of plants, while there is no current supply of Neotropical origin. Seed fats from Theobroma species (T cacao, T bicolor, T grandiflorum, T obovatum, T subincanum, T speciosum, T sylvestre and T microcarpum, plus the closely related species Herrania mariae) were analysed for fatty acid and triacylglycerol composition by gas and liquid chromatography respectively, for iodine value, for melting point by open capillary tube and for solid fat content (SFC) by nuclear magnetic resonance. All Theobroma species had significantly lower palmitate levels than T cacao, except for T sylvestre and T speciosum, T microcarpum presented highly unsaturated fat (C18:2), while H mariae had high levels of arachidate. Fats from T sylvestre and T speciosum had a similar iodine value to T cacao and a higher melting point. No fat from the other species presented a similar melting profile to cocoa butter. T sylvestre and T bicolor were the most similar to T cacao but had a higher SFC at human body temperature. T sylvestre and T speciosum seed fats had more POP than cocoa butter. Fats from seeds of T speciosum, T sylvestre and T bicolor could be recommended as cocoa butter substitutes, while fats from species of the section Glossopetalum could be employed in products requiring fats with a lower melting point.© 2002 Society of Chemical Industry

Phytochemical variation in echinacea from roots and flowerheads of wild and cultivated populations.

Quantitative phytochemical variation was determined from roots and inflorescences of native plant populations in the genus Echinacea. Specimens were collected in situ throughout the natural range of each putative taxon and transplanted to greenhouse cultivation. Ethanolic extracts from individual plants were separated by reversed-phase HPLC to quantify the alkamides, polyenes/ynes, and phenolics, and then grouped by age and taxonomically, according to a recent morphometric taxonomic revision of the genus. Canonical discriminant analysis revealed that cichoric acid, the diene alkamides 1-3 and 7, and ketoalkene 24 were the best taxonomic markers. Mean content for each of 26 phytochemicals revealed useful agronomic information, such as those varieties and organs with the highest accumulations, as well as the optimal age and growth conditions for each variety. The highest amounts of cichoric acid were measured from the older, wild inflorescences of E. pallida var.sanguinea, whereas the highest quantities of the alkamides 1-3 and 7 were present in roots of wild and transplanted E. purpurea. Baseline phytochemical data and chromatographic profiles for all types of wild Echinacea may be used for protection of wild stands, germplasm identification, and crop improvement.

Plant cell factories as a source for anti-cancer lignans

The review places podophyllotoxin, a powerful anti-cancer material used in clinical treatment of small cell cancers, in focus. The economical synthesis of podophyllotoxin is not feasible and demand for this material outstrips supply. At present, Podophyllum hexandrum (Indian May apple) is the commercial source but it grows in an inhospitable region (the Himalayas) where it is collected from wild stands. Furthermore, the plant is now an endangered species. Alternative sources of podophyllotoxin are considered, e.g., the supply of podophyllotoxin and related lignans by establishing plant cell cultures that can be grown in fermentation vessels. Increase of product yields, by variation of medium and culture conditions or by varying the channelling of precursors into side-branches of the biosynthetic pathway by molecular approaches, are discussed.

Rubber yield and guayule populations' attributes in naturally reestablished wild stands in México

Medical latex goods provide opportunity for the commercial exploitation of hypoallergenic guayule ( Parthenium argentatum, Gray). This, however, requires an adequate latex supply. Wild stands of guayule exist in México. These have naturally reestablished over the last 15 years from previous harvesting of the whole plant. These stands constitute an excellent source of genetic material for selection, cropping and industrialization of guayule. The objectives of this study were: (a) to evaluate plant density and the spatial distribution pattern of the naturally occurring guayule shrubs in two types of topography within a wild stand at the Gómez Farı́as locality, at Coahuila, México; (b) to determine the effect of main stem diameter on biomass, rubber and resin content, rubber and resin yield, and height for plants naturally occurring in slopes of less than 8% (Site A) and between 8 and 20% slope (Site B); and (c) to correlate total rubber yield with the other variables. Plant density was evaluated using the point centered quarter (PCQ) method based on a sample size of 40 random points per site. The spatial distribution pattern was estimated by the block quadrant variance method with two 64×3 m belts at each site. Production variables in the Site A were evaluated from 45 shrubs classified into three diameter classes according to the shrub's dominant sizes. The Site A had a total shrub density of 7890 plants/ha, whereas the Site B had 31 900 plants/ha. The distribution of guayule plants was uniform for the Site A and clumped for the Site B. The plant branches showed high biomass production and the greatest rubber content was found in the main stem. Resin content was higher than rubber content in all the three diameter classes with a high positive correlation between these two parameters.

Correlation and path coefficient analyses of the agronomic trait of a native population of guayule plants

Correlation and path coefficient analyses have been successfully used for plant selection for increasing yields of different crops. This approach could be applied to increase guayule latex production. Natural stands of guayule ( Parthenium argentatum) in México may constitute a source for plant selection. This paper reports on the correlation coefficients for phenotypic characteristics and path coefficient analysis of guayule to evaluate the direct and indirect effects of the rubber production components. The variables evaluated were plant height, main stem diameter, dry weight, rubber and resin content, and yields. These were measured from different part plants of shrubs a wild stands of Gómez Farı́as, México. Rubber yields of the first-year stem and the diameter of the main stem are the variables that relate to rubber yield per plant. Based on the correlations and path coefficient analysis results, we found that the dry weight of the first-year stems is a good indicator for selecting high rubber yielding plants in wild stands.

ORNAMENTAL ATTRIBUTES OF THE NATURAL VARIANTS OF CORDYLINE AUSTRALIS

Cordyline australis (New Zealand cabbage tree) is widely grown in temperate climates as a garden and landscape subject and as a tub plant. Diversification of its use as an ornamental has been based on discoveries of plants with unusual leaf colours and growth forms, and hybridization with the other New Zealand Cordyline species. A systematic assessment of the genetic variation of wild populations of C. australis began in 1994 with measurements of the phenotypes and collection of seed of trees in 29 natural stands located over 12o of latitude. Progeny of these stands have been cultivated under uniform garden conditions at Auckland (36o 53 S), Christchurch (43o 38 S), and Dunedin (45o 51 S) and their growth and phenology recorded. This has shown variation of leaf characteristics, tree habit, growth rate, susceptibility to low temperature damage, and onset of flowering, much of which is related to the latitude of origin of the populations. As well unusual plants within populations provide material of ornamental interest. The study relates to the use of C. australis in ecological restoration plantings and threats to conservation of the genetic integrity of wild stands.

Phenology of strawberry guava (Psidium cattleianum) in ReÂunion Island

SummaryThe phenology of wild stands of strawberry guava (Psidium cattleianum Sabine) was studied at 100, 480 and 720.m over 2 years in ReÂunion Island. The shoots bore flower buds at the basal nodes, and vegetative buds at the apical nodes. Trees produced vegetative growth from September to December, flowers from November to January and fruit from February to June. Shoot growth was earlier at 100 and 720.m the first year, but were synchronized in the second year. Flowering and fruiting were also earlier at 100.m. The intervals between shoot emergence and flowering, and flowering and fruit maturity were strongly related to temperature, with base temperatures of 5.58C and 2.68C, and heat units requirements of 675 and 2,5528C.d, respectively. The number of shoots, flowers and fruit per branch varied across sites and years, unrelated to temperature. However, production was significantly higher at 720.m. Production was much lower after a hurricane. Flowering (y) was related to shoot production per branch (x) (log(y)=111.33.log(x); r2.=.0.78), whereas the fruit set rate was highly variable between trees (26±100%). The number of fruits per branch (1±6) was possibly related to poor shoot growth or fruit set, but unrelated to the timing of the phenological events. It is expected that commercial orchards would be more productive than feral stands.

INFECTIOUS DISEASES IN MACRO‐ALGAE: THE EFFECT ON HOST FITNESS

The understanding of infectious diseases of algae has improved significantly in recent years, particularly in the area of recognition and signaling, key processes that determine the success or failure of host invasion by the pathogen. Ecological studies have also contributed to better understanding the role of diseases in wild stands of the affected hosts. An aspect that has received only limited attention is the effect of the infections on host fitness, and in this context, we report a first attempt to quantifying the effects of Pleurocapsa sp. (Cyanophyta) on the reproductive potential of its host Mazzaella laminarioides (Rhodophyta). Infections by Pleurocapsa trigger the development of tumors that can result in major changes in frond morphology and texture. Two populations of the host were considered in the study. Our results indicate that infections do not cause a significant effect on the density or quality of the reproductive structures (i.e. cystocarps and tetrasporangia). However, the number of spores, settlement rates, germination success and offspring survival, were all affected negatively by the endophytic infections. The reported information and field‐collected data, strengthen the notion that pathogens of algae may exert strong effects on their hosts at several levels, including reproduction. These effects can vary from host death during infections by highly pathogenic organisms to more subtle effects like those observed in the studied pathosystem. Infections by less aggressive pathogens, however, still may determine important effects at the population level by inducing differential mortality and reproductive success in infected individuals.

601 Development of Cultural Methods for Beach Plum (Prunus maritima Marsh.) Fruit Production

Beach plum is a shrub native to Atlantic coastal sand dunes from Maine to Maryland, where it is subject to drought and low nutrient and water holding soil. Since colonial times beach plum fruit has been collected from the wild for the production of preserves, an activity that endures today as a cultural tradition and cottage industry. Currently, the supply of fruit from wild stands does not meet the market's demand; hence, beach plum could be a new crop for many growers in the Northeastern U.S. For the past 4 years, a partnership of growers, Univ. of Massachusetts Extension, and Cornell Univ. has experimented with standard orchard cultural methods for beach plum production in coastal Massachusetts. During Aug. 1999, we harvested the first crop from our experimental orchard. The factorial experiment evaluates the effects of irrigation, mulch, and fertilizer on growth and yield of beach plum. Basal and axial growth were strongly correlated and were greater in fertilized than unfertilized treatments. Within fertilizer regime irrigation and mulch had less effect on growth than fertilizer. Fruit yield (dry weight and fresh weight) was greater in fertilized plots. Irrigation had no positive influence on yield. Average fruit diameter and °Brix were greater in the fertilized and unirrigated treatments.

Exploratory Survey in Venezuela for Biological Control Agents of Passiflora mollissima in Hawaii

Passiflora mollissima (H.B.K.) Bailey, a South American vine that grows at high altitudes, is the most important weed pest of the upper-elevation rainforests of Hawaii. Mechanical and chemical methods of controlling this weed are impractical and expensive. Natural enemies appear to restrain this member of the Passifloraceae in its native Andean countries, and the introduction of biological control agents to Hawaii is the only viable control method available. Previous surveys of natural enemies of P. mollissima in its native range resulted in the introduction but unsuccessful establishment of two agents, calling for a renewed search for candidate insects. Detailed studies were conducted for 4 years in Venezuela to survey and evaluate insects attacking P. mollissima. Twelve insect species may have an important effect on the growth and reproduction of this target plant. Three bud-feeding species, Zapriothrica salebrosa Wheeler (Diptera: Drosophilidae), a Mycetophila sp. (Diptera: Mycetophilidae), and Pyrausta perelegans Hampson (Lepidoptera: Pyralidae), as well as a fruit feeder, Dasiops caustonae Norrbom and McAlpine (Diptera: Lonchaeidae), limited flower and fruit production and were believed to play the most important role in regulating wild stands of P. mollissima in Venezuela. The mycetophilid and D. caustonae were not collected from previous surveys and are recommended as potential biological control agents.

SEX PHEROMONE OF CONOPHTHORUS PONDEROSAE (COLEOPTERA: SCOLYTIDAE) IN A COASTAL STAND OF WESTERN WHITE PINE (PINACEAE)

An isolated stand of western white pine, Pinus monticola Dougl. ex D. Don, on Texada Island (49°40′N, 124°10′W), British Columbia, is extremely valuable as a seed-production area for progeny resistant to white pine blister rust, Cronartium ribicola J.C. Fisch. (Cronartiaceae). During the past 5 years, cone beetles, Conophthorus ponderosae Hopkins (= C. monticolae), have severely limited crops of western white pine seed from the stand. Standard management options for cone beetles in seed orchards are not possible on Texada Island. A control program in wild stands such as the one on Texada Island requires alternate tactics such as a semiochemical-based trapping program. Females of the related species, Conophthorus coniperda (Schwarz) and Conophthorus resinosae Hopkins, produce (+)-pityol, (2R,5S)-2-(1-hydroxyl-l-methylethyl)-5-methyl-tetrahydrofurana, sex pheromone that attracts males of both species (Birgersson et al. 1995; Pierce et al. 1995). The host compound a-pinene significantly increases attraction of male C. coniperda to pityol-baited traps in stands of eastern white pine, Pinus strobus L. (de Groot et al. 1998).