低温胁迫对油棕幼苗光合作用及叶绿素荧光特性的影响

在30 μmol/(m2.s)的弱光条件下,以25℃、10℃、7℃、4℃、1℃各处理油棕幼苗3天,测定了油棕幼苗叶片光合参数及叶绿素荧光参数的变化。结果表明：温度由 25℃降至4℃,净光合速率（Pn）显著下降的同时,气孔导度(Gs)、蒸腾速率(Tr)、胞间CO2浓度（Ci）也显著下降,但气孔限制值(Ls)和水分利用效率(WUE)却显著增加,说明光合作用的下降主要由气孔因素引起;之后随温度下降至1 ℃,净光合速率、气孔导度、蒸腾速率、水分利用效率、气孔限制值均出现显著下降,但胞间CO2浓度却显著上升,说明光合作用的下降主要由非气孔因素引起。叶绿素荧光参数显示,随温度下降,初始荧光(Fo)不断上升,PSⅡ最大光化学效率（Fv/Fm）、光化学猝灭系数(qP)、非光化学猝灭系数（qN）不断下降,其中以4 ℃以下的低温胁迫,这些参数的变化最为显著。表明严重低温对油棕幼苗产生了显著的光抑制,过剩的激发能不能通过热耗散途径散失,大量积累于PSⅡ反应中心,使光合机构遭受了较大程度的破坏,最终导致油棕幼苗光合能力的急剧降低。     

The physiological basis for genetic improvement of oil palm in Malaysia

Summary Yield of Deli dura oil palms after four generations of selection was 60% greater than that of the unselected base population. Total above-ground dry matter production was increased by selection, apparently through better utilisation of solar radiation. The dry matter requirement for vegetative growth was unchanged, so a greater surplus remained for fruit production in the selected palms. Crossing the dura and pisifera to give the thin-shelled tenera fruit type improved partitioning of dry matter within the fruit, giving a 30% increase in oil yield at the expense of shell, without changing total dry matter production.     

Estimates of within family genetic variability for clonal selection in oil palm

Within family genetic and environmental variabilities in oil palm dura (D) ×pisifera (P) hybrid progenies were estimated from a D × P progeny test trial, a clonal trial and a clonal cum D × P progeny test trial and with the objective of examining the efficiency of selecting source palms (ortets) within family for clonal propagation. The clones were derived from seedling embryos or seedlings that were progeny reproductions of families proven in the first trial. The progenies in the second trial represented the source families of two sets of clones planted in the same trial. Estimates were obtained from: between and within family variance components; between and within clone variance components; and difference between pooled within family variance and pooled within clone variance. Estimates were generally similar with the different methods used. Within family genetic variabilities were generally low in progenies derived from more inbred parents especially in bunch and oil yields. In progenies from more outbred or variable parents, within family genetic variabilities were relatively higher particularly for oil to bunch and palm height; nevertheless environmental variabilities predominated. The low efficiency of within family palm or ortet selection for clone production and the need for repeated clonal tests over time and space to identify outstanding clones are stressed and the implications to commercial clonal propagation of oil palm discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Candidate traits for index selection in choice of oil palm ortets for clonal propagation

Summary The objective of the study was to examine the usefulness of: principal component scores (PC), factor analysis cum stepwise regression identified traits (FASR) and selected traits based on their higher heritabilities and genetic correlations to the objective traits (HGC); as selection traits in a desired gains selection index (Yamada et al., 1975) to improve objective traits (oil yield, kernel oil yield, height increment, bunch index and leaf area ratio) as compared to those based on all the observed traits (AO); in selecting oil palm ortets for cloning.Based on the required selection intensities (i^*) to achieve the desired gains AO indices having smaller i^*'s were most efficient followed by PC, HGC and FASR indices. Expected selection response (1/i^*), however, is expected to increase with additional selection traits. As such HGC (bunch number, kernel to fruit and mesocarp to fruit) and FASR (mesocarp to fruit, fresh fruit bunch yield, fruit to bunch and average bunch weight) indices would be useful as they achieved expected selection responses close to AO indices with a small number of traits and would also minimise the contribution of highly correlated traits to sampling errors. The results also suggested considering selection indices for only two objective traits-oid yield and kernel oil yield-instead of all five objective traits in which case screening of impracticably large populations is needed to obtain desired genetic gains.     

荫蔽锻炼对大豆苗期光合特性的影响

荫蔽是影响间套作大豆产量进一步提高的限制因素。为探究荫蔽锻炼对大豆叶片光合、荧光特性的影响,本研究采用盆栽试验,分别用远红光LED灯(λ=730nm)、30%透光率遮阳网模拟荫蔽信号和荫蔽胁迫,分锻炼(S1)–恢复(S2)–胁迫(S3)3个阶段,以全过程自然光照为对照(LLLL),设荫蔽信号锻炼(LFLS)、荫蔽胁迫锻炼(LSLS)、不锻炼(LLLS) 3个处理,分析其S3阶段遭受荫蔽胁迫时叶片光合色素含量、光合参数以及叶绿素荧光参数的响应特征。结果表明, LFLS和LSLS较LLLS老叶和成熟叶叶绿素a、叶绿素b、类胡萝卜素含量以及叶绿素总含量显著增加,老叶和新叶叶绿素a/b显著下降。除LSLS成熟叶外,各叶位净光合速率、气孔导度均较未锻炼处理显著增加,老叶和成熟叶锻炼与未锻炼处理胞间二氧化碳浓度差异不显著。与对照相比,无论锻炼与否,后期荫蔽使Fo、qp、NPQ、ΦPSII、ETR降低,而F_v/F_m和F_v'/F_m'则升高,其中,S1阶段的锻炼处理较未锻炼处理Fo下降的幅度更小;老叶qp较对照降低幅度依次为LFLSLLLSLSLS,成熟叶为LSLSLFLSLLLS,新叶为LSLSLFLSLLLS;ΦPSII、ETR均较对照降低但处理间差异不显著; LLLS、LFLS、LSLS新叶中F_v'/F_m'则分别比对照增加6.51%、8.79%和12.05%(P0.05),锻炼后增加幅度更大。由此可见,通过荫蔽锻炼,大豆能通过光合特征的可塑性来适应光环境并表现出更强的荫蔽耐受能力。     

Outlines of the oil palm breeding programme in Portuguese Guinea

The methods and techniques of oil palm selection and breeding are discussed in relation to the problems of the oil palm industry in Portuguese Guinea.A general survey of the oil palm populations, both cultivated and natural palm groves, was carried out in order to determine existing varieties, their distribution, range of variability, disease incidence and palm oil quality.Yield was established as the major aim in the breeding programme. Short-stem habit and adaptability to different sets of conditions are also considered.Both a long-term and a short-term project are undertaken simultaneously.The long-term programme includes selection of Deli female parents, pollen and seed introductions from pisifera and tenera palms selected in San Thome and single crosses among selected parents. Emphasis is laid on the Deli × pisifera cross to increase oil content, though Deli × tenera and Deli × Deli seed are also produced.The short-term programme involves multiple crosses. A number of mass-selected Deli palms is pollinated using pollen from pisifere or tenera palms selected in San Thome. As a result of the short-term programme over 450,000 hybrid seeds were produced up to the end of 1964.Abbreviations INEAC Institut National pour l'Étude Agronomique du Congo Belge - IRHO Institut de Recherches pour les Huiles et Oléagineux - MEAU Missão de Estudos Agronómicos do Ultramar - WAIFOR West African Institute for Oil Palm Research     

Epistasis for crown disease in the oil palm (Elaeis guineensis Jacq.)

Summary The presence of crown disease (cc) in the oil palm can be masked by an intermediate gene (I _c). Presence of the gene inI _c i _c-condition results in incomplete genetic penetrance in thecc-genotypes. No penetrance is observed in theccI _c I _c-palms. The existance of theI _c-gene complicates selection work as a testcross with acci _c i _c-genotype is required to identify the genotype of the selections. This procedure requires 3 years.     

Experimental modification of reciprocal recurrent selection in oil palm breeding in Cameroon

Reciprocal recurrent selection (RRS) exploits the genetic complementarity of dura populations of palms with a small number of large bunches and tenera/pisifera group of palms with large number of small bunches. An extra phase was introduced to RRS just after the second cycle of selection where outstanding dura derived from (DA3D × DA5D) combinations of the second cycle were self-pollinated for seed production. Best palms based on the phenotype were selected and crossed with pisifera of second cycle offspring of LM2T. [(DA3D × DA5D) self-pollinated × LM2T self-pollinated] progenies were field tested at La Dibamba (Cameroun) from 1987 to 1997. They were precocious with regard to the three-first years’ bunch yields (13.16–15.77 t/ha). Homogeneity for all bunch yield components and homogeneity for vertical growth were illustrated by low values of the variation coefficient (5.75–7.75%). The oil yield was 107% of the control against 115% from [(DA3D × DA5D) × LM2T self-pollinated] progenies of the second cycle of RRS, mostly due to poor mesocarp to fruit and poor oil to mesocarp ratios which led to a low oil extraction rate. The extra selection phase led mainly to homogenisation of progenies but also reduced the fruit quality. However, three progenies whose average oil yield represented 115% of the control (4.87 t/ha) in addition to their precocity can be released to oil palm growers. The extension of RRS did not fully meet expectations and poses the problem of its reliability.     

Parent selection for yield and bunch index in the oil palm in West New Britain

Summary Selection criteria of dura female parents and pisifera male parents were investigated by employing a step-wise multiple regression procedure. Independent parental variables entered in the regression equation were (1) yield (Y) and (2) bunch index (BI), i.e. the proportion of total dry matter used for fruit bunches, of the female parents. As secondary characters of both parents were included: (3) leaf-Mg level (LMG), (4) leaf area ratio (LAR), i.e. the ratio of new leaf area produced to new dry matter used for vegetative growth, and (5) sex ratio (SR), i.e. the ratio of female to total inflorescences. The joint contribution of LMG in both parents accounted for 80% of the variance in Y of the offspring. The amount of the total variance in BI of the offspring was substantially explained, in decreasing order, by LMG of the pisifera parents, and Y and LAR of the dura parents. The first two variables explained 70% of the variation in offspring BI. SR and BI appeared to be not significant for explaining Y as well as BI of the offspring. A practical implication is that for pisifera testing programs, pisifera can be efficiently screened on the exclusive basis of LMG. Dura tester parents should be selected for high, and little variable, values of LMG, Y and LAR.     

Effects of inbreeding on growth and yield of oil palm

The effects of inbreeding were studied in three oil palm (Elaeis guineensis Jacq.) trials in the Democratic Republic of Congo (Congo). In selfings, marked inbreeding depression was observed for yield of fruit bunches, mean bunch weight and bunch number, but there was little effect on bunch composition. Most vegetative measurements were significantly affected by selfing, but leaf production rate and leaf area ratio were unaffected. Sib-crossing had less depressive effect than selfing, and in some families sib-crosses were superior to outcrosses. Where selection needs to be done within inbred families, our study suggests that leaf area ratio and bunch composition would be useful criteria.     

Heterosis in growth and photosynthetic rate in hybrids of cotton

Summary The intraspecific (Gossipium hirsutum) and interspecific (G. hirsutum x G. barbadense) F₁ hybrids of cotton were found to exhibit a high degree of heterosis in the production of fruiting branches, number of bolls (fruits), yield of seed cotton and photosynthetic rates over the parent plants. The developing bolls of the hybrids had significantly higher weights than their parents until the 20th day after anthesis. The patterns of leaf area development among interspecific hybrids differed when compared with the parent plants. The photosynthetic rates of the hybrids were comparable with those of maize and sorghum and much higher than the average rate reported so far for the cotton plant.     

Climate impacts on palm oil yields in the Nigerian Niger Delta

Palm oil production has increased in recent decades and is estimated to increase further globally. The optimal role of palm oil production, however, is controversial because of conflicts with other important land uses and ecosystem services. Local conditions and climate change affect resource competition and the desirability of palm oil production in the Niger Delta, Nigeria.The objectives of this study are to (1) establish a better understanding of the existing yield potentials of oil palm areas that could be used for integrated assessment models, (2) quantify for the first time uncertainties in yield potentials arising from the use of climate output data from different Global Circulation Models (GCM’s) with varied West African Monsoon (WAM) system representations forced to the same Regional Climate Models (RCM’s). We use the biophysical simulation model APSIM (Agricultural Production Systems Simulator) to simulate spatially variable impacts of climate change on oil palm yield over the Nigerian Niger Delta. Our results show that the impact of climate change on oil palm yield is considerable across our study region. The yield differences between the IPCC RCPs were small. The net impact of climate change on oil palm is positive and is dynamically inconsistent. There is no significant change in the simulated yield arising from the differences in the forcing’s data. We found the most effective strategy for oil palm yield optimization under climate change to be shifting of sowing dates and introduction of irrigation.     

Yield gaps in oil palm: A quantitative review of contributing factors

Oil palm, currently the world’s main vegetable oil crop, is characterised by a large productivity and a long life span (≥25 years). Peak oil yields of 12 t ha⁻¹ yr⁻¹ have been achieved in small plantations, and maximum theoretical yields as calculated with simulation models are 18.5 t oil ha⁻¹ yr⁻¹, yet average productivity worldwide has stagnated around 3 t oil ha⁻¹ yr⁻¹. Considering the threat of expansion into valuable rainforests, it is important that the factors underlying these existing yield gaps are understood and, where feasible, addressed. In this review, we present an overview of the available data on yield-determining, yield-limiting, and yield-reducing factors in oil palm; the effects of these factors on yield, as measured in case studies or calculated using computer models; and the underlying plant-physiological mechanisms. We distinguish four production levels: the potential, water-limited, nutrient-limited, and the actual yield. The potential yield over a plantation lifetime is determined by incoming photosynthetically active radiation (PAR), temperature, atmospheric CO₂ concentration and planting material, assuming optimum plantation establishment, planting density (120–150 palms per hectares), canopy management (30–60 leaves depending on palm age), pollination, and harvesting. Water-limited yields in environments with water deficits >400 mm year⁻¹ can be less than one-third of the potential yield, depending on additional factors such as temperature, wind speed, soil texture, and soil depth. Nutrient-limited yields of less than 50% of the potential yield have been recorded when nitrogen or potassium were not applied. Actual yields are influenced by yield-reducing factors such as unsuitable ground vegetation, pests, and diseases, and may be close to zero in case of severe infestations. Smallholders face particular constraints such as the use of counterfeit seed and insufficient fertiliser application. Closing yield gaps in existing plantations could increase global production by 15–20 Mt oil yr⁻¹, which would limit the drive for further area expansion at a global scale. To increase yields in existing and future plantations in a sustainable way, all production factors mentioned need to be understood and addressed.     

Development of elite families in oil palm (Elaeis guineensis Jacq.)

Summary Data from 29 dura female parents, 14 pisifera male parents and their offspring were assembled to obtain quantitative genetic information on optimizing selection of elite families. Phenotypic values of the offspring were partitioned into general combining ability (GCA) of the parents and their specific combining ability (SCA). Parental GCA-values for leaf-Mg content (LMG), height increment (HT), leaf area ratio (LAR), leaf area (LA), frond production (FPR), vegetative dry matter production (VDM), the rate of increase in leaf area against age (k) and maximum leaf area (L_m) were entered in a multiple regression analysis as predictors of oil-and-kernel yield and Harvest Index (HI), i.e. the proportion of dry matter used for oil and kernel production, of the offspring. The analysis revealed that both selection objectives are positively influenced by indirect selection for high LAR and LMG, and for reduced VDM with FPR as main component. But palms with high values for LA, L_m and HT should not be considered to avoid selecting palms partly for their ability to compete with neighbouring palms for light. The contribution of SCA was relatively small for most of the characters studied, except HT, FPR and HI. From the standard deviations for GCA and SCA of the dura and pisifera parents, i.e. _GCA and _SCA, it was extrapolated that selection can potentially enhance bunch yield (by 24%), oil-to-bunch ratio (19%), kernel-to-bunch ratio (29%), oil-and-kernel yield (31%) and HI (56%) above the mean phenotypic value obtained for the offspring of the present investigation. Heritabilities, calculated as the square of the correlation of the GCA-and phenotypic values of the female parents, were low for bunch yield, oil-and-kernel yield and HI, but moderate for LAR, LMG and VDM; levels were high for oil and kernel extraction rate. These outcomes were confirmed by the correlations between values of the female parent and their offspring. Among the unbalanced incomplete mating designs studied, the rectangular lattice and the alpha design are most suitable to compare GCA-values of pairs of parents. A breeding strategy adapting the recently introduced practical possibility of clonal reproduction is discussed.     

Prediction of precocity in the oil palm (Elaeis guineensis Jacq.)

Summary Precocity in the oil palm (Elaeis guineensis Jacq.) is defined, for the purpose of this study, as the percentage of palms bearing female or hermaphrodite inflorescences 36 months after germination. A method of calculating breeding values for precocity is described and it is shown that the character is predictable. An upper limit for heritability (h²) of 0.68 and a correlation between observed and predicted values of r=+0.77 (significant at P=0.01) have been calculated from the available data. The available information suggests that precocity could easily be adjusted to the desired level by breeding and selection.     

Climate,soil and land-use based land suitability evaluation for oil palm production in Ghana

In the past decade, oil palm (Elaeis guineensis Jacq.) has become the world’s most important oil crop. The large demand for palm oil has resulted in a rapid expansion of oil palm cultivation across the globe. Because of the dwindling availability of land in Southeast Asia, most expansion of the industry is expected in Central and South America and sub-Saharan Africa, where land with suitable agro-ecological conditions is available. Using Ghana as a case study, a method for evaluating areas that are both suitable and available for oil palm production is presented. Our assessment used spatial data and GIS techniques, and showed that areas with suitable climatic conditions (annual average water deficit <400 mm) is about 20% greater than was previously identified. The observed differences are the result of using different methods to determine suitability, and climate change. A major climatic factor limiting suitability for oil palm production in Ghana is the annual water deficit, with the most suitable areas located in the rainforest and semi-deciduous forest zones with higher rainfall in southern Ghana. Opportunities for large-scale oil palm plantation development is limited, however, because of the lack of availability of large and contiguous tracts of land that are required for commercial plantation oil palm development. A feasible strategy for oil palm expansion is therefore smallholder production, which can make use of smaller parcels of land. Alternatively, oil palm production in Ghana can be increased by yield intensification on land already planted to oil palm. This can also reduce the requirement for further land clearance for new plantations to meet the growing demand for palm oil. Such assessments will be essential for guiding government policy makers and investors considering investments in oil palm development.     

Prospects of breeding for blast disease resistance in the oil palm (Elaeis guineensis Jacq.)

Summary Breeding for nursery blast resistance in the oil palm can reduce blast from around 50% to 1–6% loss, when a parent is carrier of dominant resistant gene(s). At such low blast levels, most of the costly agronomic methods to reduce blast incidence, need not be used.Plant material originating from the arid regions in Nigeria is more blast susceptible than that from the rain forest areas.     

油棕叶片4种微量元素含量季节性变化影响研究

选取丹那拉变种(E.guineensis.var.tenera)的成龄树作为研究对象,在2007-2011年间,研究了油棕叶片铁、锰、铜、锌4种微量元素含量在不同季节的变化情况。发现油棕叶片铁含量明显受到季节性影响,冬、春季节含量明显高于夏、秋季节,周年的平均含量为129.05mg/kg,平均变化幅度为55.0mg/kg。油棕叶片锰含量明显受到季节性的影响,冬、春季节含量明显低于夏、秋季节,周年的平均含量为142.8mg/kg,平均变化幅度为25.7mg/kg。研究发现铁锰之间表现出相反的季性变化规律,两者之间存在明显的拮抗关系。油棕叶片的铜、锌含量,虽然也受到一定的季节性影响,但没有表现出明显的规律性,铜的周年平均含量为5.62mg/kg,变化幅度为1.23mg/kg,锌的周年平均含量为19.7mg/kg,变化幅度为2.1mg/kg。     

Heritability estimates of variation for NaCl tolerance in Sorghum bicolor (L.) Moench seedlings

Summary Data on root lengths of two-week-old seedlings of 51 Sorghum bicolor (L.) Moench accessions germinated in 50, 100, 150, 175, and 200 mM NaCl solutions were used to estimate broad sense heritabilities of variation for salinity tolerance.Estimates of broad sense heritabilities ranged from 0.38 to 0.73, the highest being in 50 mM NaCl, suggesting that there is potential for improving salinity tolerance in the species through selection and breeding.