Postharvest dropping of macadamia nut-in-shell causes damage to kernel

Macadamia nuts (‘nuts-in-shell’) are subjected to many impacts from dropping during postharvest handling. Kernels are enclosed in hard shells and quality may be lost from damage incurred during postharvest dropping. Kernel quality loss from dropping macadamias was investigated in three experiments in which nuts of several cultivars at different moisture contents were dropped onto a bed of nuts-in-shell or a metal plate. For each dropped treatment there was an undropped control at the same moisture content. Dropped and control kernels were assessed for quality parameters: whole kernel; shoulder damage; weight of pieces; oily kernels; and dusty kernels. Dropped and control kernels were also examined by scanning electron microscopy (SEM). Dropping macadamia nuts-in-shell at 3% moisture content onto nuts-in-shell significantly increased shoulder damage, oily kernels and dusty kernels. Shoulder damage doubled compared with the control (30% cf. 15%). Oily kernels more than doubled (38% cf. 18%). There were very few dusty kernels in controls at 3% moisture content, but 15–30% of kernels were dusty when dropped. Kernel quality was also reduced at higher moisture content when nuts were dropped onto nuts-in-shell twice, once at 10% and once at 20% moisture content. Shoulder damage was almost three times the control (46% cf. 16%), and 10% of kernels were dusty while controls had no dusty kernels. SEM showed that dropping caused an abraded abaxial cuticle with visible dust particles. Oily appearance following dropping was an indicator of cell membrane damage and potential for further deterioration in quality. Typical macadamia postharvest practices such as frequent dropping cause significant commercial losses due to quality reduction, visible as shoulder damage, oiliness and dustiness.     

基于颜色和纹理特征的花生仁外观品质检测研究

为了提高对花生仁外观缺陷的在线分类准确率及效率。通过对采集完好、破损、霉变的花生仁RGB图像进行均值位移法、灰度处理以及阈值分割等预处理,研究提取了花生仁HSV颜色空间下的H、S、V各分量的一阶矩和二阶矩共6个颜色特征值,再基于灰度共生矩阵法提取能量、熵、对比度、逆差分矩共4个纹理特征值,构建颜色和纹理结合的特征向量,最后分别采用BP神经网络和SVM分类器对花生仁进行分类识别。结果表明：在花生仁的整体识别准确率上,BP神经网络为96.67%,SVM分类器为97.22%,后者优于前者,在识别时间上BP和SVM分别为2.5 s和1.1 s,识别效率上也是SVM更好,综合识别准确率和效率两方面考虑,优先选择SVM分类器模型来对花生仁进行分类识别。     

Heritability, variance components and correlation of morphological and phenological traits in hazelnut

Most traits of interest in hazelnut are quantitative, yet there is little information available on heritability, variance components, or correlations. In this study, 13 morphological and four phenological traits were observed for 3 years on 41 parental genotypes, and for 2 years on seed‐lings representing 35 progenies. Narrow‐sense heritability estimates obtained by regression of offspring means on midparent values were all high, ranging from 0.56 for amount of kernel fibre to 0.89 for nut depth. Data on the parent genotypes was used to analyse variance components and showed that genotypic variance accounted for most of the phenotypic variance for all traits, and there was very little variation among trees within genotypes. Genotype‐year interaction accounted for only a very small part of the phenotypic variance for most traits, and changes in genotype rank were few and minor. Thus, selection based on genotype means is appropriate. The largest genotype‐year interaction components were observed for time of nut maturity, time of stigma exsertion, time of catkin elongation, number of nuts per cluster and amount of kernel fibre. For these five traits, evaluation over a period of years is advised. Correlation coefficients were large and positive for four nut size traits, indicating some redundancy in these measurements. Three of the phenological traits (time of stigma exsertion, time of catkin elongation, and time of leaf budbreak) were also highly and positively correlated. A large genetic correlation (0.44 < r < 0.73) was noted between good blanching and early phenology (catkin elongation, stigma exsertion and leaf budbreak), although plots of individual seedling values showed a large degree of scattering. Genetic correlations also indicated that seedlings with small nuts also tend to have compressed nuts, short husks and catkins that elongate later, but plots of individual seedling values showed large scattering. Correlations among the six traits directly related to the objectives of the Oregon State University hazelnut breeding programme (kernel weight, per cent kernel, nut shape index, blanching ability, relative husk length and nut maturity) were very low, indicating that they can be handled as independent traits.     

Selection for Yield and its Components in a Winter Wheat Population under Different Environmental Conditions in Albania

Wheat breeding programmes in Albania depend upon the use of diverse genetic material of local origin and on special environmental conditions; the present study being conducted under drought stress conditions. Grain yield, yield components, plant height and test weight were estimated in an F₅ generation of a winter wheat population at Kamez in 1989—90 and 1990—91 and at Lushnje in 1989—90. The highest values of heritability were observed for plant height, kernel weight and spike length. Due to drought stress the heritability of kernels per spike was low. None of the correlated responses was higher than the direct response for yield. Maximum genetic gain was expected when yield, plant height, spike length, kernels/spike and kernel weight were included in the index.     

玉米籽粒蛋白质含量的遗传效应及其与产量的关系

用来自5个不同基础群体的14个自选系作母本,不同优势群的5个测验系作父本,采用NC II交配设计配成70个杂交组合,进行了2年3点的田间试验。利用近红外光谱,对亲本及其杂交种的籽粒蛋白质含量进行了分析,同时分析了籽粒产量与蛋白质含量的相关性。结果表明,父、母本及其70个杂交组合间的基因型方差均达到极显著水平;8822和M是蛋白质含量较高的两个基础群体,以之作母本对提高杂交种籽粒的蛋白质含量起主导作用。控制籽粒蛋白质含量的基因以加性效应为主,加性方差占基因型方差的94.29%,但广义遗传力和狭义遗传力相对较低,分别为35.83%和33.94%,说明环境因素对籽粒蛋白含量影响明显。籽粒产量与蛋白质含量相关不显著(r = 0.053),因此,扩大变异选择范围,实现优良基因聚合,产量和蛋白质含量性状可以同步得到改良。     

Genotypic and environmental variation of resistance to head blight in triticale inoculated with Fusarium culmorum

Fusarium head blight (FHB) is a widespread disease of small‐grain cereals and can cause substantial losses in grain yield. To assess quantitative genetic parameters as a basis for an efficient breeding programme for resistance, 100 triticale (×Triticosecale Wittm.) genotypes were tested in various environments and artificially inoculated at anthesis with an aggressive isolate of Fusarium culmorum. A visual rating (1–9 scale) was used to assess head blight infection. Five grain yield traits relative to an uninoculated control were also measured. The mean value of the average rating, calculated from four or five readings, was 4.4. It ranged from 3.0 to 5.9 and showed continuous variation. Infection caused a 48% reduction of mean kernel weight per spike, which was the result of 26% fewer kernels per spike and a 32% lower 1000‐kernel weight. The 50‐ml kernel weight was affected by only 20%. The range and genotypic variation was highest for relative kernel weight per spike. For all relative grain yield traits, the most important source of variation was the environment, followed by genotype‐environment interaction, with genotype generally coming last. In contrast, genotypic variation was the most important factor for the disease rating, which also had the highest heritability (h²= 0.89). Phenotypic correlations between the average head blight rating and relative grain yield traits were moderate (r = 0.42–0.57). In conclusion, an average disease rating provides a quantitative assessment of resistance and is suitable for screening large numbers of genotypes. Relative kernel weight per spike gives a ranking of the genotypes that is very similar to the visual score.     

棕色棉茎尖基因枪遗传转化

为了建立高效的棉花茎尖遗传转化体系,以棕色棉品种新彩棉5号为材料,采用茎尖培养和基因枪遗传转化方法,通过对凝固剂种类、活性炭含量、卡那霉素浓度、渗透处理时间、轰击压力、轰击距离等因素的优化,建立了棕色棉新彩棉5号茎尖基因枪遗传转化技术体系。结果表明,不同凝固剂种类、活性炭含量、卡那霉素浓度、渗透处理时间、轰击压力和轰击距离对棕色棉茎尖转化率有明显影响。最佳的遗传转化体系为:前渗处理4 h,轰击压力7.586 MPa(1100 psi),轰击距离9 cm,轰击后恢复培养4 d,然后在MSB+8 g·L~(-1)琼脂+125mg·L~(-1)卡那霉素筛选培养基中筛选25 d。获得抗性芽后,在添加1 g·L~(-1)活性炭的生根培养基中诱导抗性芽生根,并获得抗性再生植株。通过PCR和q PCR检测,5200个茎尖共获得16株阳性转基因植株,转化率为0.31%。该技术体系的建立为棕色棉的遗传转化奠定了基础,为彩色棉育种提供了新的材料。     

Investigations on Seedling Vigour in Cashew (Anacardium occidentale L.)

Seedlings from 27 open pollinated cas-hew genotypes in two environments with five replications in each location were used to investigate the genetic, the environmental, and the nut size effects on cashew seedling vigour during the 12-week pretransplantation period. Enviromental variances, genotype × environment interactions, and broadsense heritability values for the eight studied traits indicated that emergence percentage (L %) and seedling height (SH) were more reliable indices for seedling vigour, since they were more heritable and less influenced by the environment. Seedlings from large cashew nuts were consistently more vigorous than those from small nuts, probably because of the larger food reserve in the two cotyledons.     

Variance components and heritability of traits related to root: shoot biomass allocation and drought tolerance in wheat

Enhanced root growth in plants is fundamental to improve soil water exploration and drought tolerance. Understanding of the variance components and heritability of root biomass allocation is key to design suitable breeding strategies and to enhance the response to selection. This study aimed to determine variance components and heritability of biomass allocation and related traits in 99 genotypes of wheat (Triticum aestivum L.) and one triticale (X. Triticosecale Wittmack) under drought-stressed and non-stressed conditions in the field and greenhouse using a 10?×?10 alpha lattice design. Days to heading (DTH), days to maturity (DTM), number of tillers (NPT), plant height (PH), spike length (SL), shoot and root biomass (SB, RB), root to shoot ratio (RS), thousand kernel weight (TKW) and yield (GY) were recorded. Analyses of variance, variance components, heritability and genetic correlations were computed. Significant (p?<?0.05) genetic and environmental variation were observed for all the traits except for spike length. Drought stress decreased heritability of RS from 47 to 28% and GY from 55 to 17%. The correlations between RS with PH, NPT, SL, SB and GY were weaker under drought-stress (r?≤???0.50; p?<?0.05) compared to non-stressed conditions, suggesting that lower root biomass allocation under drought stress compromises wheat productivity. The negative association between GY and RS (r?=???0.41 and ??0.33; p?<?0.05), low heritability (<?42%) and high environmental variance (>?70%) for RS observed in this population constitute several bottlenecks for improving yield and root mass simultaneously. However, indirect selection for DTH, PH, RB, and TKW, could help optimize RS and simultaneously improve drought tolerance and yield under drought-stressed conditions.     

Heritability of quantitative traits in segregating common bean families using a Bayesian approach

Genetic parameters for six quantitative traits in the early generation of segregating populations of common beans (Phaseolus vulgaris L.) were evaluated. A Bayesian approach was used for estimating the variance components, breeding values and broad sense heritability of the quantitative traits under analysis. The Markov Chain Monte Carlo method was utilized to analyze the contribution of genes affecting complex traits. Twenty-four F₃ families were evaluated in the field during 2005 in Santa Catarina, southern Brazil. With regard to the grain yield and yield components, the additive variances were relatively similar to the dominance variances. This result is confirmed by the 95% credible set from the posterior distribution. The mean estimates of broad-sense heritability (H²) varied from 11.5% to 64.2%. The heritability estimates of yield and yield components were higher than the estimates for the number of days until flowering and reproductive period. However, for grain yield, the 95% heritability credible set included the heritability estimates from point of crop duration. The predicted genetic gain reached the highest value for the number of pods per plant (10.95%). Days to flowering and reproductive period had the lowest values of genetic advance. One hundred seed-weight, grain yield and seeds per pod exhibited a similar predictable level of genetic gain: GA = 5.73%, 5.81% and 4.77%, respectively. The Bayesian framework provided information that is useful for a breeding program, since it contributes to the understanding of how quantitative traits are genetically controlled.     

Combining ability and gene action controlling yield and yield components in bread wheat (Triticum aestivum L.) under drought‐stressed and nonstressed conditions

This study determined the combining ability and gene action controlling yield and yield‐related traits in wheat under drought‐stressed and nonstressed conditions. Twelve parents possessing Rht‐B1b and Rht‐D1a genes and their 66 half‐diallel crosses were evaluated under field and glasshouse conditions. Plant height (PH), productive tiller number (TN), kernels per spike (KPS), thousand seed weight (TSW) and grain yield (GY) were recorded. Analysis of variance, heritability, correlation and combining ability analyses were performed. Heritability estimates ranged from 53.00% (TN) to 63.07% (KPS). Yield showed positive correlations with all other traits under all test conditions. Significant GCA effects were observed for all traits recorded across test conditions, except for yield in the glasshouse. All Baker's ratios were less than a unit, indicating predominance of nonadditive gene action. Consistently high positive GCA effects were observed on LM02 for GY; LM02 and LM23 for KPS; and LM04 and LM09 for TSW, while LM17 and LM21 had negative effects for PH. Good general and specific combiners will be used for further breeding and selection.     

陆地棉枯萎病抗性的遗传研究

本研究采用最小范数二阶无偏估算法[MINQUE(1 ) ]的统计方法 ,分析加性—显性—母体 (ADM)遗传模型、加性—显性—上位性(ADAA)遗传模型 ,估算陆地棉 8个杂交亲本和F1、F2 代各 2 8个组合的枯萎病抗性遗传效应。结果表明 ,陆地棉枯萎病抗性的遗传无上位性效应 ,有不显著母体效应存在 ,因而采用 ADM模型分析 ,加性方差为 2 8.0 8,显性方差为 7.35,母体方差是 0 .43,分别占表现型方差的 49.9%、1 3.1 %、0 .8% ;广义遗传率为 63.0 % ,狭义遗传率为49.9%。陆地棉枯萎病抗性的遗传主要是加性效应和显性效应 ,以加性效应为主     

Yield Components of Apical and Subapical Ear Contributing to the Grain Yield Responses of Prolific Maize at High and Low Plant Populations

Subapical ears are largely responsible for grain yield variations in prolific maize (Zea mays L.) grown under conditions favourable for the expression of prolificacy trait, but limited information exists on yield components contributing to yield responses. A field experiment was conducted to determine the yield components of apical and subapical ear in prolific maize after various pollination treatments at two plant populations. Hybrid Pioneer 3733 was grown in the perfect stands of 71 428 and 35 714 plants ha^?1. Three pollination treatments were carried out: (i) free pollination; (ii) subapical earshoots were covered to prevent pollination; and (iii) apical earshoots were covered to prevent pollination. Grain yields of free pollinated plants were by 50.1 % larger at low plant population (265 g per plant) than at high plant population (177 g per plant) due to a 45.3 % increase in kernels per plant, whereas 1000‐kernel weight slightly increased by 3.3 %. These increased kernels per plant at low plant population were, in part, the result of kernel increments on apical ear (10.1 %), and mainly associated with kernels from subapical ears that did not occur at high plant population. At low plant population, the total grain yield per plant was reduced by 94 g (35.5 %) after the apical ear was bagged to prevent pollination, but only 52 g (19.6 %) when the subapical ear was bagged. When subapical ear development was stopped at low plant population, grain yield on apical ears increased by only 3.9 % as a result of heavier 1000‐kernel weights, clearly demonstrating limitations in kernel set and size. After grain development on apical ear was prevented, subapical ear enlarged to 80.3 % of maximum apical ear yield because the former had, on average, 2.5 % lighter 1000‐kernel weight and 17.5 % fewer kernels than the latter. Ears did not differ in row number when only apical or subapical ear was developed on plant, whereas subapical ears tended to have fewer rows than apical ears when both were present on the same plant. Our results showed that: (i) plant population affected all yield components on both apical and subapical ear except row number; (ii) the occurrence of subapical ear is triggered by achieving maximum potential kernel set on apical ear; and (iii) subapical ear is inferior in potential grain yield to apical one even when the latter was prevented from pollination.     

Genetic diversity of wheat storage proteins and bread wheat quality

To understand the genetic and biochemical basis of the bread makingquality of wheat varieties, a large experiment was carried out with a set of162 hexaploid bread wheat varieties registered in the French or EuropeanWheat Catalogue. This material was used to analyse their allelic compositionat the twelve main storage protein loci. A large genetic and biochemicaldiversity of the gluten proteins was found. Several gliadin encoding lociexhibited the highest allelic diversity whereas the lowest diversity was foundfor Glu-A1 and Glu-D3 loci encoding some high molecularweight glutenin subunits (HMW-GS) and LMW-GS respectively. Thevarieties were grown in three experimental locations in France. Qualityevaluation was carried out from material harvested in each location usingseven technological tests: grain protein content (Prot), grain hardness(GH), Zeleny sedimentation test (Zel), Pelshenke test (Pel), water solublepentosans (relative viscosity: Vr ), mixograph test (giving 11 parameters)and the alveograph test (dough strength W, tenacity P , extensibility L,swelling G, ratio P/L and the elasticity index Ie). Genetic and locationeffects as well as broad-sense heritability of each of the 22 technologicalparameters were calculated. GH, corresponding to the major Ha gene, Pel,and MtxW (mixograph parameter) had the highest heritability coefficients,alveograph parameters like W, P, the relative viscosity Vr and severalmixograph parameters had medium heritability coefficients whereas Protand L had the lowest. Variance analysis (using GLM procedure) allowed theeffect of the allelic diversity of the storage proteins, on the geneticvariations of each quality parameters, to be estimated. Glu-1 and Glu-3 loci had significant additive effects in the genetic variations of manyparameters. Gliadin alleles encoded at Gli-1 and Gli-2 were alsofound to play significant effect on several quality parameters. The majorpart of the phenotypic variation of the different quality parameters like Zel,Pel, W or mixograph peak time MPT was explained with the GH and allelesencoded at Glu-1 and Glu-3. Allelic variants encoded at Glu3and Gli-2 had similar contribution to the phenotypic variations ofquality parameters and accounted for 4% up to 21% each.     

A new method for evaluation of the resistance to rice kernel cracking based on moisture absorption in brown rice under controlled conditions

We developed and evaluated the effectiveness of a new method to detect differences among rice cultivars in their resistance to kernel cracking. The method induces kernel cracking under laboratory controlled condition by moisture absorption to brown rice. The optimal moisture absorption conditions were determined using two japonica cultivars, ‘Nipponbare’ as a cracking-resistant cultivar and ‘Yamahikari’ as a cracking-susceptible cultivar: 12% initial moisture content of the brown rice, a temperature of 25°C, a duration of 5 h, and only a single absorption treatment. We then evaluated the effectiveness of these conditions using 12 japonica cultivars. The proportion of cracked kernels was significantly correlated with the mean 10-day maximum temperature after heading. In addition, the correlation between the proportions of cracked kernels in the 2 years of the study was higher than that for values obtained using the traditional late harvest method. The new moisture absorption method could stably evaluate the resistance to kernel cracking, and will help breeders to develop future cultivars with less cracking of the kernels.     

三峡库区玉米地方品种配合力分析

为了明确三峡库区玉米地方品种育种潜势,以三峡库区常用的7个玉米自交系为测验种,采用NCⅡ设计,对三峡库区14个玉米地方品种的配合力以及主要性状遗传参数进行了分析。结果表明,‘文峰白玉米’、‘大寨玉米’、‘太阳河白玉米’在单株产量、穗长、穗粗、穗行数、行粒数、百粒重上具有较高的一般配合力。‘文峰白玉米’、‘大寨玉米’在改善株型、提高产量有更为突出的表现。不同性状SCA效应值变幅差异较大,其中单株产量变幅最大,为-25.48%~30.47%。所有性状中,亲本的基因加性效应均对F1性状形成起主导作用;穗长、穗粗、行数等7个性状广义遗传力和狭义遗传力均较高,可在早代进行选择;秃尖长、单株产量的广义遗传力较高,但狭义遗传力较低,不宜过早进行选择。     

水稻条纹病毒和介体灰飞虱抗性的QTL分析

水稻品种Kasalath高抗条纹病毒和介体灰飞虱。为剖析不同抗性类型基因之间的关系，利用回交重组自交系群体Nipponbare/Kasalath//Nipponbare分析了对条纹病毒和介体灰飞虱抗性的数量性状基因座。结果在第11染色体S2260–G257标记区间检测到1个与条纹病毒抗性相关的QTL（qSTV11），LOD值为9.2, 贡献率为35.79%；在第3染色体R1618–C595 和R2170–C1135标记区间各检测到1个与介体灰飞虱抗性相关的QTL (qSBPH3-a, qSBPH3-b)，LOD值和贡献率分别为3.12和2.96, 11.69% 和11.36%,表明条纹病毒和介体灰飞虱抗性由不同基因所控制,而且两者之间不相关。此外，还分别检测到两对与条纹病毒和介体灰飞虱抗性相关的上位性QTL，暗示水稻对条纹病毒和介体灰飞虱的抗性受主效和上位性QTL的共同影响。进一步分析发现SSR标记BJ11-8与qSTV11紧密连锁, 为分子标记辅助选择高抗条纹叶枯病水稻品种提供了基础。     

Genetic variation among European maize inbreds for resistance to the European corn borer and relation to agronomic traits

The univoltine European corn borer (ECB) has become a major limiting factor for maize (Zea mays L.) production in central Europe. The objective of this study was to survey the genetic variation for ECB resistance in European elite maize germplasm. Eighteen flint and 23 dent inbreds were screened under artificial ECB infestation at two locations in 1993 and 1994. Resistance was assessed by damage rating of broken plants, measurement of tunnel length in dissected stalks, and yield reduction in infested plots relative to insecticide-protected control plots. Flint lines showed significantly greater means for damage rating than dent lines with grain yield reduction of 35% and 24%, respectively. Significant genotypic variances among lines and high heritabilities were found for agronomic traits and damage rating. Heritabilities were intermediate for tunnel length and relative grain yield. Significant associations of days to silking, ear dry matter content, and dry matter yield of the whole plant with damage rating and tunnel length suggested a better resistance in late-maturing, high-yielding inbreds. Genotypic correlations of relative grain yield with tunnel length and damage rating ranged between ?0.46 and ?0.72. Partial correlations, eliminating the effect of flowering time, confirmed these associations. Damage rating of stalks is the most suitable trait for evaluation of ECB damage owing to its high heritability and easy recording. Tunnel length below the primary ear is a useful trait for assessing antibiosis because it is not correlated with days to silking. Inbreds with extreme resistance and susceptibility were identified which can be used as parents for establishing breeding and QTL mapping populations.     

Inheritance of yield components and their correlation with yield in cowpea (Vigna unguiculata (L.) Walp.)

Summary The inheritance of yield components was studied in a cross of two varieties of cowpea (Vigna unguiculata), and the relationships among the components and yield were examined in the F₂ of a cross and in a trial of 22 varieties. The main objective was to determine the suitability of using the components as selection criteria for increasing seed yield. All the components appeared to be under polygenic control and transgressive segregation in the F₂ was observed for pod length and number of seeds per pod. Narrow sense heritability estimates ranged from 19.8% for number of pods per plant to 60.3% for pod length. Most of the genotypic correlations between pairs of yield components were significant. Correlation of yield per plant was negative with pod length, but positive with the other components. Number of pods per plant was consistently correlated with yield. However because of low heritability for number of pods per plant, this component may only be used as a preliminary selection criterion while the final selection is based on yield itself.     

Estimation of variance components and heritability of bunch yield and yield components in the oil palm (Elaeis guineensis Jacq.)

In an experiment involving 24 single-cross progenies of oil palm conducted at the Nigerian Institute for Oil Palm Research, 9-year data of fresh-fruit yield and its two components, annual bunch number and single-bunch weight, were recorded. Means of progenies of each of the three traits obtained from 1–9-year records were used in analyses of variance according to a repeated-measures design. The results were then used to estimate variance components due to progenies and progeny × year interactions. These estimates were then used to estimate heritability for yield and yield components based on progeny means, which were assumed to be calculated from 1–9 years of harvests. The results revealed that heritability estimates of fresh-fruit yield and its two yield components were not reliable based on the first-year harvest data. The single-bunch weight had a slower rate of improvement than the other two traits when more years were used for the estimation. Heritability can be expected to be over 80% for fresh-fruit yield and bunch number based on 1-, 3-, and 4-year means, respectively. Six-year data are required for single-bunch weight to reach the same heritability measure.