Dynamics of fallow successions and introduction of robusta coffee in shifting cultivation areas in the lowlands of Papua New Guinea

The traditional shifting cultivation system in the lowlands of Papua New Guinea consists of mixed food crop gardens in which yams (Dioscorea spp.), bananas, taro (Colocasia esculenta) and sugarcane predominate. The cropping cycle is usually for 18 months, followed by a fallow cycle of up to 30 years. During the cropping cycle, two species of fruit trees, Pometia pinnata and Artocarpus altilis are also planted, the leaves of the former also being used as a mulch and green manure in yam cultivation. Fallow succession follows rather systematic patterns about which farmers have a thorough understanding. Robusta coffee, a cash-crop component, has been added to the system in some areas since the late 1950s. It is usually grown in permanent blocks, but is interplanted with Leucaena as shade. Food crops are planted in the establishment stage, bananas and Xantohosoma being retained even in mature coffee gardens. The system seems to be a potentially promising one. But very little quantitative information is available on the production and performance of the system and practically no systematic research has been undertaken. Since the Papua New Guinea fallow gardeners are willing to accept innovations, it will be appropriate and timely to undertake serious studies so that the system can be improved. A few items that merit immediate research attention are indicated.     

海南省典型咖啡园植株矿质养分状况评价

对海南省典型咖啡种植园植株样品(叶片)进行了测试分析。结果表明:调查区域植株叶片P、S、Fe含量均处于适宜范围,Mn、Zn含量均高于适宜范围,N、B含量在适宜或高量范围,K含量大部分也在适宜或高量范围,Ca、Mg含量较缺乏,Cu含量严重缺乏。     

咖啡品种的特性及历史迁移

中国的咖啡规模化种植历史不足百年,从国外引进品种的渠道窄,品种少,规模化种植的品种不足20个,种植区对各品种的根源及特性了解也不多。阐述各品种的特性,为今后咖啡引种提供理论依据。     

The effect of leaf age on incomplete resistance of coffee to Hemileia vastatrix

The influence of leaf age on incomplete resistance to race II of coffee leaf rust (Hemileia vastatrix), which is the most common race in Brazil, was tested in the greenhouse and in the field. Three stages of leaf age were distinguished: young leaves which had just fully expanded and still had a shiny appearance on the day of inoculation, adult leaves of 1 to 4 months old, and old leaves of 6 to 12 months old which were formed in the foregoing growing season.The effect of leaf age varied with the coffee genotype. With the susceptibleCoffea arabica cvs Mundo Novo and Catuai no important effect of leaf age on latency period and reaction type was observed. Lesion density, depending on inoculation method, was affected to some extent, older leaves showing lower values. With genotypes of theC. canephora cv. Kouillou, which varied in level of incomplete resistance, adult leaves appeared to be more resistant than young and old leaves. This adult leaf resistance was expressed mainly by a lower lesion density, but also by a longer latency period and a lower reaction type.Within the hybrid populations Icatu and Catimor, genotypes with race-specific incomplete resistance were tested and others of unknown specificity. Resistance was expressed mainly by a low reaction type. Generally, resistance decreased with increasing leaf age, which was occasionally associated with a complete change in reaction type. Contrary to cv. Kouillou, in Icatu and Catimor no higher susceptibility of young leaves than of adult leaves was observed.The incomplete resistance to race I of the differential CIFC H152/3, heterozygous for S_H4, was also better expressed in young leaves, older ones becoming gradually more susceptible.It is concluded that for screening incomplete resistance to coffee leaf rust leaves of different ages should be tested.Samenvatting Het effect van bladleeftijd op incomplete resistentie van koffie tegen fysio II van koffieroest (Hemileia vastatrix), het algemeen voorkomende fysio in Brazilië, werd getoetst in de kas en in het veld. Drie stadia in de bladleeftijd werden onderscheiden: jong blad dat net volgroeid was en nog glansde op de dag van inoculatie, volwassen blad van 1 tot 4 maanden oud en oud blad van 6 tot 12 maanden oud dat gevormd was in het voorafgaande groeiseizoen.Het effect van bladleeftijd varieërde met het koffiegenotype. Bij de vatbareCoffea arabica rassen Mundo Novo en Catuai werd geen belangrijke invloed waargenomen van bladleeftijd op latentieperiode en reactietype. Lesiedichtheid werd, afhankelijk van de inoculatiemethode, wel enigszins beïnvloed. Bij vijf genotypen van hetC. canephora ras Kouillou, die varieerden in niveau van incomplete resistentie, bleek volwassen blad veelal resistenter dan jong en oud blad. Deze resistentie uitte zich voornamelijk door een lagere lesiedichtheid maar ook door een langere latente periode en een lager reactietype.Van de hybride populaties Icatu en Catimor werden enkele genotypen met fysiospecifieke incomplete resistentie getoets alsmede genotypen waarvan de specificiteit van de resistentie onbekend was. Verschillen in resistentie uitten zich voornamelijk door verschillen in reactietype. Over het algemeen nam de resistentie af bij toenemende bladouderdom. Anders dan bij de cv. Kouillou werd bij Icatu en Catimor geen grotere vatbaarheid van jong ten opzichte van volwassen blad waargenomen. Bij sommige genotypen kwam resistantie zelfs alleen maar tot uiting in het jonge blad, terwijl het volwassen blad normaal vatbaar was. Een soortgelijk effect van bladleeftijd werd waargenomen bij inoculatie van de koffiedifferentieel CIFC H153/3, die heterozygoot is voor het resistentiegen S_H4, met het incompatibele fysio I.Er wordt geconcludeerd dat voor het bepalen van incomplete resistentie tegen koffieroest bladeren van verschillende ouderdom getoetst dienen te worden.     

Distinguishing characteristics and vegetative compatibility of Colletotrichum kahawe in comparison with other related species from coffee

On the basis of pathogenicity tests on green berries or hypocotyls of coffee and by morphological and biochemical characteristics in culture, 31 isolates of Colletotrichum were classified into C. kahawe (24 isolates), C. gloeosporioides (six isolates) or C. acutatum (one isolate). Within these groups of isolates, vegetative compatibility groups (VCGs) were determined by complementation tests with mutants in the nitrate assimilation pathway. There were distinct incompatibility barriers between the three species. Among the C. gloeosporioides group, the three isolates tested were self-compatible but incompatible with each other. Within C. kahawe , 18 isolates were self-compatible and only one main VCG was detected. However, partial compatibility in C. kahawe was also indicated by variation in the intensity of heterokaryon formation between different pairs of isolates and between different types of mutant. The existence of only one VCG in C. kahawe is consistent with the low level of variation found in previous work on DNA polymorphism.     

超微粉碎对咖啡果皮理化性质、结构及吸附能力的影响

本研究以咖啡果皮为原料,对其进行传统粉碎和超微粉碎,分别得到不同粒度的咖啡果皮粉。通过测定不同粒度粉体的持水性、膨胀性、持油性、溶解性和阳离子交换能力表明,随着粒度的减小,粉体的物理性状都有不同程度的改善,其中膨胀性和溶解性显著增加,分别从3.86 mL/g增加到6.14 mL/g、13.23%增加到44.50%;通过测定不同粒度粉体的吸附性能表明,随着粒度的减小,粉体对葡萄糖、胆固醇和亚硝酸盐的吸附能力增强,且超微粉与传统粉间差异显著,超微粉对三者的吸附能力分别为42.42 mg/g、29.34 mg/g、224.56 μg/g,吸附率分别为63.04%、67.38%、75.91%;扫描电镜和傅里叶变换红外光谱结果表明,超微粉碎能显著降低粉体粒度,但对粉体结构组成无显著改变。本研究结果表明超微粉碎能赋予咖啡果皮更好的加工和功能特性,下一步可考虑作为新的食品加工配料资源,提高咖啡副产物的利用价值。     

咖啡双根嫁接苗生长及光合特性比较研究

以大粒种咖啡‘1号’（Caffea liberica No. 1）和中粒种咖啡‘热研1号’（Caffea canephora Reyan No. 1）的种子苗形成不同双根靠接苗组合,以‘热研1号’高产无性系为接穗,包括中粒种双根嫁接苗（T1）,大粒种中粒种双根嫁接苗（T2）,大粒种双根嫁接苗（T3）,以常规种间嫁接苗（CK,植株地下部为一条大粒种1号根系,地上部与双根苗一致）为对照,比较不同嫁接处理植株生物量、根系形态及光合特性,并分析高径比及苗木质量指数。结果表明：T1和T2处理较CK植株根尖数分别提高407.14%和780.28%、净光合速率分别提高25.11%和57.49%、总生物量分别提高168.26%和209.35%。同时,苗木质量指数分别提高195.79%和244.17%,苗木长势较粗壮,T1和T2处理通过提高植株根系吸收及光合能力提升苗木质量。而T3较CK植株高径比提高25.28%,较CK增加一条大粒种根系,并未显著提高T3处理植株生物量,且苗木长势较细高,后期易形成“高脚苗”,大田定植效果差。因此,中粒种双根苗和大粒种中粒种双根苗生长优势明显,以大粒种中粒种双根苗长势最佳。     

Deforestation and degradation of natural resources in Ethiopia: Forest management implications from a case study in the Belete-Gera Forest

The major causes of deforestation and degradation of natural resources in the Belete-Gera Forest of Ethiopia are coffee production activities and encroachment into forestland to expand farmland and pasture. Population growth, and the government’s land-reform and re-settlement programs have caused local residents to lose harmony with the land. Forest management in this area hasn’t yet been fully developed. The objectives of this study are to identify the extent of deforestation and natural resource degradation, in preparation for a sound management plan. Encroachment of farmland and pasture into natural forest during the past four years has been identified through interviews and aerial photo interpretation. The encroachment rate is 1.45% per year. Encroachment occurred mostly on areas with gentle slopes adjacent to populated villages and along roads and footpaths. The extent and impact of coffee production activities were examined through agency documents, forest survey data and vegetation survey. It is estimated that up to 49% of the accessible natural forest is under the influence of coffee production activities, among which collecting of naturally grown coffee beans has the least and the coffee plantations has the most impact on the natural forest. Coffee plantations in natural forest have reduced the forest density and species diversity. Age structure of the trees is limited to mature and old classes only, which eventually endangers their function as shade for coffee plantations. This project was funded by the Japan International Cooperation Agency.     

The potential protective value of ants in Northern Australian coffee plantations

Abstract

Native ants are the oldest example of biological control agents used in tropical tree crops. Unfortunately, intensification of agricultural practices has led to a simplification of habitat and subsequent loss of native ant biodiversity. This article describes research that evaluated the native and introduced ants present in the canopies of two Australian sun coffee plantations, their distribution pattern and their potential to limit pests. The presence in coffee plantations of a range of beneficial insects and parasites, plus the effect of ants, most notably Iridomyrmex suchieri Forel, may maintain potential pests at low levels in coffee plantations. These effects may be important for future biological control programs of coffee pests in Australia, although the sun coffee grown here does not harbor a large variety of canopy ant species.     

海南省典型咖啡园土壤养分状况评价

对海南省典型咖啡种植园土壤样品进行测试分析。结果表明:咖啡种植园土壤大量元素仅全氮含量高于临界值,全磷、全钾含量均低于临界值,而速效养分高于临界值。Ca、Mg、B元素含量缺乏,S、Fe、Mn、Cu、Zn元素含量丰富。