QTLs for Sugar Content of Stalk in Sweet Sorghum(Sorghum bicolor L.Moench)

High sugar content of sorghum stalk is an important factor in the sorghum silage production. To identify the genomic regions controlling sugar content and to develop molecular markers linked to sugar content in sweet sorghum, we used an F2：3 segregating population consisting of 207 individuals derived from a cross between a high sugar content inbred line, Early Folger, and a normal inbred line, N32B, for genetic linkage mapping and quantitative trait locus （QTL） analysis. We constructed a genetic linkage map spanning 983.5 cM based on a total of 327 markers comprising 31 restriction fragment length polymorphism （RFLP） markers, 254 amplified fragment length polymorphism （AFLP） markers, and 42 simple sequence repeat （SSR） markers. In the 20 linkage groups detected, 98.2% of markers aligned to the 10 linkage groups of sorghum. Variations in sugar content at different growth stages and among internodes suggested that the sugar content of middle internodes is stable and suitable for measuring at early dough stage. The broad sense heritability （hB0 of sugar content was 0.64 and 0.62 estimated from the data of F3 families and each parent in 2003 and 2004. We identified one and two QTLs accounting for 22.2 to 25.0% of phenotypic variance using simple interval mapping method in 2003 and 2004, respectively. These two QTLs showed a negative additive effect, and over-dominance effect. A QTL on LG-D was detected in both two years. Above results will be help us to understand the genetic mechanism of sugar content in sorghum and the QTL detected in this study might be useful in the improvement of sugar content by marker-assisted selection.

Sugar beet yield and industrial sugar contents improved by potassium fertilization under scarce and adequate moisture conditions

Sugar beet（Beta vulgaris L.） is an industrial crop, grown worldwide for sugar production. In Pakistan, sugar is mostly extracted from sugarcane, soil and environmental conditions are equally favorable for sugar beet cultivation. Beet sugar contents are higher than sugarcane sugar contents, which can be further increased by potassium（K） fertilization. Total K concentration is higher in Pakistani soils developed from mica minerals, but it does not represent plant available K for sustainable plant growth. A pot experiment was conducted in the wire-house of Institute of Soil and Environmental Sciences at University of Agriculture Faisalabad, Pakistan. K treatments were the following： no K（K_0）, K application at 148 kg ha^（–1）（K_1） and 296 kg ha^（–1）（K_2）. Irrigation levels were used as water sufficient at 60% water holding capacity and water deficient at 40% water holding capacity. The growth, yield and beet quality data were analyzed statistically using LSD. The results revealed that increase in the level of K fertilization at water sufficient level significantly increased plant growth, beet yield and industrial beet sugar content. The response of K fertilization under water deficient condition was also similar, however overall sugar production was less than that in water sufficient conditions. It is concluded from this study that K application could be used not only to enhance plant growth and beet yield but also enhance beet sugar content both under water-deficient as well as water-sufficient conditions.

Manual thinning increases fruit size and sugar content of Citrus reticulata Blanco and affects hormone synthesis and sugar transporter activity

Manual fruit thinning(MFT)in fruit trees has been previously shown to increase fruit size and enhance fruit quality,but the effect of MFT on Ponkan(Citrus reticulata Blanco)and the underlying mechanisms remain poorly understood.In this study,efforts were made to elucidate how MFT influences the fruit quality of Ponkan.The results showed that MFT substantially increased fruit size and elevated fruit total soluble solids in comparison with the fruit from the unthinned trees(used as control).Expression analyses demonstrated that m RNA abundance of three important sugar transporter genes,including CrSUT1,CrSTP1 and CrTMT1,was evidently elevated in the flesh of thinned fruit when compared with those of the control.In addition,MFT prominently up-regulated the transcript levels of various auxin and gibberellin(GA)biosynthesis and signaling genes,including CrYUC6,CrAUX/IAA,CrGA20ox1 and CrGA3ox1.Concurrently,the contents of endogenous IAA and GA3,measured at 90 d after fruit thinning,were notably elevated in the fruit from trees with the thinning treatment relative to the control,although no difference was detected in the two groups before the thinning manipulation.Taken together,these results indicate that manual fruit thinning could greatly improve fruit quality,which may be attributed to promoting fruit expansion due to the increased auxin levels and expediting sugar accumulation through the up-regulation of sugar transporter genes.

Measurement of sugar content in Fuji apples by FT-NIR spectroscopy

To evaluate the potential of FT-NIR spectroscopy and the influence of the distance between the light source/detection probe and the fruit for measuring the sugar content (SC) of Fuji apples, diffuse reflectance spectra were measured in the spectral range from 12500 to 4000 cm^-1 at 0 mm, 2 mm, 4 mm and 6 mm distances. Four calibration models at four distances were established between diffused reflectance spectra and sugar content by partial least squares (PLS) analysis. The correlation coefficients (R) of calibrations ranged from 0.982 to 0.997 with SEC values from 0.138 to 0.453 and the SECV values from 0.74 to 1.58. The best model of original spectra at 0 mm distance yielded high correlation determination of 0.918, a SEC of 0.092, and a SEP of 0.773. The results showed that different light/detection probe-fruit distances influence the apple reflective spectra and SC predictions.

Identification of candidate genes related to soluble sugar contents in soybean seeds using multiple genetic analyses

Soluble sugar content in seeds is an important quality trait of soybean. In this study, 57 quantitative trait loci(QTLs) related to soluble sugar contents in soybean seeds were collected from databases and published papers. After meta-overview-collinearity integrated analysis to refine QTL intervals, eight consensus QTLs were identified. To further verify the consensus QTLs, a population of chromosome segment substitution lines(CSSLs) was analyzed. Two lines containing fragments covering the regions of consensus QTLs and the recurrent parent were selected: one line showed high soluble sugar contents associated with a consensus QTL fragment, and the other line showed low soluble sugar contents. Transcriptome sequencing was conducted for these two lines at the early, middle, and late stages of seed development, which identified 158, 109 and 329 differentially expressed genes, respectively. Based on the analyses of re-sequencing data of the CSSLs and the consensus QTL region, three candidate genes(Glyma.19 G146800, Glyma.19 G122500, and Glyma.19 G128500) were identified in the genetic fragments introduced from wild soybean. Sequence comparisons between the two CSSL parents SN14 and ZYD00006 revealed a single nucleotide polymorphism(SNP) mutation in the coding sequence of Glyma.19 G122500, causing a nonsynonymous mutation in the amino acid sequence that affected the predicted protein structure. A Kompetitive allele-specific PCR(KASP) marker was developed based on this SNP and used to evaluate the CSSLs. These results lay the foundation for further research to identify genes related to soluble sugar contents in soybean seeds and for future soybean breeding.

NIR Hyperspectral Imaging Measurement of Sugar Content in Peach Using PLS Regression

Near infrared （NIR） hyperspectral imaging measurement of sugar content in peach was introauced. NIR spectral images （650～1 000 nm, resolution： 2 nm） of peach samples were captured with developed hyperspectral imaging setup. Partial least square （PLS） regression prediction model was developed to estimate the sugar content in peach; step-wise backward method was utilized to determine optimal wavelength subsets. Experimental results show that the calibration model with optimal wavelength subsets has a correlation coefficient of prediction of 0.97 and a standard error of prediction of 0.19, the prediction accuracy is higher than the calibration model applied over the whole wavelength, which proves that variable selection plays an important role in improving the prediction accuracy of PLS regression model.

Comparison of Sugar Content in Bottled 100% Fruit Juice versus Extracted Juice of Fresh Fruit

This paper presents findings of an experiment for the comparison of sugar concentration in extracted juice of fresh fruit to that of commercially-bottled 100% fruit juice with a “no sugar added” attribute. The goal of the study was to determine if the sugar content of bottled 100% fruit juice with a “no sugar added” label is equivalent to that of extracted juices of fresh fruits. The reported study was performed to address the potential concern that commercially-bottled 100% fruit juices with “no sugar added” may contain higher sugar content than extracted juice of fresh fruit. The fruit juices that were tested included apple, grapefruit, orange, pineapple, pomegranate, red grape and white grape. All bottled juices and fresh fruits were purchased in Toledo, Ohio, USA during the winter of 2012. The fresh fruits were juiced and three samples were tested for sugar concentration using a Brix refractometer. The same testing protocol was also applied to the bottled 100% fruit juice. Application of the Mann-Whitney test on the experimental data demonstrated no statistically significant difference (p > 0.05). The results suggested that the sugar content in the commercially bottled 100% fruit juice with the “no sugar added” label is an accurate representation of sugar content in the freshly-extracted juice of the corresponding fruit.

大豆地方种质资源鲜籽粒可溶性糖含量的全基因组关联分析

【目的】可溶性糖含量是鲜食大豆重要的品质性状之一,研究大豆鲜籽粒可溶性糖含量的遗传变异,深入解析可溶性糖含量的遗传机制,为鲜食大豆种质创新及品质育种提供依据。【方法】利用来自东北大豆生态区、北方大豆生态区、黄淮海大豆生态区和南方大豆生态区的133份大豆地方种质,在2021年连江春季、福清春季和秋季3个环境下对鲜籽粒可溶性糖含量进行表型测定,结合82187个高质量SNP标记,基于混合线性模型MLM(Q+K)对可溶性糖含量进行全基因组关联分析,挖掘可溶性糖含量显著相关的SNP位点,并以显著SNP位点为中心,两端各扩展119.07 kb连锁不平衡衰减距离为候选区间,根据候选区间内基因的注释和组织表达信息预测候选基因。【结果】3个环境下,鲜籽粒可溶性糖含量的变异范围为3.37—33.84 mg·g^(-1),遗传变异系数为24.59%—32.69%,可溶性糖含量遗传率为68.14%。通过全基因组关联分析,连江春季、福清春季和秋季3个环境下分别检测到与鲜籽粒可溶性糖含量显著关联的SNP有6、8和22个,表型变异解释率为12.43%—29.27%,以表型变异解释率较高的9个显著SNP位点所在的候选区间进行搜索,共获得86个基因,结合基因注释和组织表达信息,进一步筛选到9个候选基因,主要涉及转录因子、糖蛋白家族和糖类合成转运等生物学过程。其中,Glyma.01g016500、Glyma.13g042100、Glyma.16g131800和Glyma.16g155300在大豆种子及荚中表达水平较高,可作为大豆鲜籽粒可溶性糖的最具潜力候选基因。【结论】通过全基因组关联分析,检测到36个与鲜籽粒可溶性糖含量显著关联的SNP,进一步筛选出9个候选基因可能参与大豆鲜籽粒可溶性糖含量的调控,其中,Glyma.01g016500、Glyma.13g042100、Glyma.16g131800和Glyma.16g155300可作为调控大豆鲜籽粒可溶性糖含量的关键目标基因。

枸杞SWEET基因家族鉴定及其与可溶性糖含量关系

【目的】糖外排转运蛋白(sugars will eventually be exported transporters,SWEETs)在植物生长发育过程中发挥重要作用,解析SWEETs基因在枸杞果实发育过程中对糖积累作用,为进一步揭示SWEETs基因在枸杞果实发育过程中的作用提供参考。【方法】用生物信息学方法对枸杞SWEET基因(LbaSWEETs)进行全基因组鉴定,并用已发表的转录数据分析LbaSWEETs在果实发育时期的基因表达情况。【结果】枸杞SWEET基因家族共有37个成员,随机分布于10条染色体上,分别编码152~621个氨基酸,蛋白质分子质量为16.87~69.97 kD,等电点为4.96~9.86。亚细胞定位预测位于叶绿体或质膜,大多数含有7个跨膜螺旋。系统进化分析发现,37个LbaSWEETs蛋白可分为4个亚群,每个亚群的基因结构和保守基序组成相似。启动子元件分析表明:Lba-SWEETs基因启动子富含大量激素响应、逆境胁迫和生长发育响应元件。转录组数据和qRT-PCR分析表明:LbaSWEET9和LbaSWEET29基因表达量随果实成熟呈现显著增加。相关性分析结果表明,LbaSWEET9和LbaSWEET29基因表达量与果糖含量呈显著正相关。【结论】LbaSWEET9和LbaSWEET29基因是果糖积累的关键基因。

有机肥对芒果果实糖酸含量与品质的影响

【目的】探明有机肥对芒果果实糖酸含量与品质的影响,为改善和提升芒果果实品质提供理论依据。【方法】以金煌芒为试材,于2020—2022年进行田间试验,设置5个处理,分别为常规施肥(CK)、羊粪有机肥(T_(1))、菜籽饼有机肥(T_(2))、沸力佳生物有机肥(T_(3))和巴迪生物酵素肥(T_(4)),研究不同有机肥对芒果果实不同种类糖和有机酸含量与品质的影响。【结果】与CK相比,有机肥施用后的当年和第2年不同有机肥处理下金煌芒果实的总糖和蔗糖含量均显著升高,T_(1)和T_(2)处理显著提高第2年的葡萄糖和果糖含量,T_(3)处理显著提高第2年的葡萄糖含量,T_(4)处理显著提高当年和第2年的葡萄糖和果糖含量;有机肥施用的2年间T_(1)处理的总酸含量均显著低于CK,而T_(2)处理第1年的总酸含量显著高于CK,第2年总酸含量与CK无显著差异,T_(3)和T_(4)处理的总酸含量在肥料施用的当年和第2年均与CK无显著差异。有机肥对柠檬酸和苹果酸含量的影响与总酸的影响趋势相似;甜酸比在有机肥施用的2年间结果相似,T_(1)和T_(4)处理的甜酸比较CK显著增加,T_(2)和T_(3)处理与CK无显著差异。以T_(1)处理的金煌芒果实糖酸品质最佳。【结论】不同有机肥均提高金煌芒果实总糖与不同种类糖含量,其中,对总糖和蔗糖的影响显著;对总酸含量的影响存在差异,其中,羊粪有机肥对金煌芒果实的品质改善作用最佳。

生物炭与氮肥共施对甘蔗产量和糖分质量的影响

【目的】探求生物炭对大田新植甘蔗生长的效应,从而为甘蔗生产上应用生物炭和制定氮肥高效管理提供理论基础。【方法】试验以甘蔗品种‘GT11’和‘B8’为材料,设置低氮N 120 kg/hm^(2)和高氮N 600 kg/hm^(2)2个氮水平,生物炭C0、C10和C20 t/hm^(2)3个水平,调查测定炭氮配施对甘蔗农艺生长、氮积累量和氮利用率及产量构成因素的影响。【结果】生物炭可适当增加甘蔗出苗率、分蘖率和株高,生物炭虽对产量增加无明显效应,但能够提高甘蔗糖分0.19%~0.82%,从而使产糖量增加了1.93%~10.77%。高炭处理下甘蔗氮累积量增加了0.41%~4.74%,但对氮利用率未起到显著提高作用。【结论】生物炭对新植甘蔗的分蘖、氮累积量及糖度累积起到了一定的促进作用,但这种效应因品种而异,氮在其中的作用大于生物炭的作用。

近红外光谱结合Stacking集成学习的猕猴桃糖度检测研究

利用近红外光谱技术Stacking集成学习对猕猴桃糖度的无损检测。以湖北“云海一号”猕猴桃为研究对象,采用红外分析仪获取了280个样本的光谱数据,包含了4000~10000cm^(-1)范围内的1557个波长数据,使用折射仪测量糖度值。通过蒙特卡洛随机采样结合T检验的奇异样本识别算法筛除异常值样本。利用SPXY算法按照4∶1的比例划分训练集和测试集。使用多元散射校正(MSC)、SG平滑滤波(SG)、趋势校正(DT)、矢量归一化(VN)、标准正态变换(SNV)五种方法对数据进行预处理。使用无信息变量消除法(UVE)、竞争性自适应重加权算法(CARS)和区间变量迭代空间收缩特征选择算法(iVISSA)提取特征波长,使用连续投影算法(SPA)进行二次提取,消除共线性变量。由于单一模型的泛化能力有限,为了扩大建模能力,设计了一种基于Stacking算法的集成学习模型。选择贝叶斯岭回归(BRR)、偏最小二乘回归(PLSR)、支持向量机回归(SVR)以及人工神经网络(ANN)作为基学习器,线性回归(LR)作为元学习器建立集成模型,比较不同组合下集成模型的性能。使用Pearson相关系数分析基学习器与集成模型之间的关系。结果表明:在五种预处理方法之中,矢量归一化的效果最佳。对预处理后的光谱进行特征波长提取,结果显示VN-CARS-PLSR模型效果最好,在测试集上的RP2为0.805,RMSEP为0.498。模型提取了177个特征波长,数据量相比于原始光谱减少了88.6%。通过Stacking算法对基学习器进行融合,对比不同的组合方式,发现PLS+SVR+ANN集成模型预测精度最高,RP2达到了0.853,RMSEP下降至0.433。通过Pearson相关系数分析了基学习器对集成模型性能的影响。研究表明,与单一模型相比,Stacking集成模型能够进行更加全面的建模,具有更高的泛化能力,该方法为猕猴桃糖度品质的无损检测提供了技术支持。

条华蜗牛破厣前后体内总糖含量的变化

【目的】了解条华蜗牛破厣前后体内总糖含量变化规律,为深入研究蜗牛破厣生化机理提供参考。【方法】用蒽酮-硫酸比色法测定了两个体质量组条华蜗牛在破厣、休眠、取食或饥饿等条件下足和内脏的总糖含量。【结果】条华蜗牛破厣后体内含糖量升高,体质量组IV蜗牛足、内脏含糖量都高于相应体质量组I。破厣前蜗牛足内含糖量与破厣后的差异显著(P<0.05),而内脏的差异不显著。休眠蜗牛体内含糖量随休眠天数增加有降低的趋势,除体质量组I蜗牛足内含糖量休眠1 d后(27.62μg/mg)显著高于5 d~15 d外,其他休眠时间之间差异都不显著。蜗牛取食后,足和内脏含糖量变化趋势基本类似,都是取食12 h~24 h后增加,然后有所下降。除体质量组IV足外,取食24 h后都显著高于取食12 h和36 h。活动蜗牛体内含糖量随饥饿时间延长有降低趋势,饥饿36 h后含糖量均显著低于饥饿12 h。【结论】条华蜗牛破厣前后体内总糖含量变化与多个因素有关,总糖量变化规律反映了蜗牛破厣的生理生化特征。

Type 2 Diabetes—Hard to Select a Healthy Choice

Introduction: The use of foods containing high levels of sugar is increasing all the time. This is a risk factor for increased incidence of type 2 diabetes. There are few studies that have investigated the availability of low-sugar müsli products in grocery stores. Purpose: The study aims to identify which types of müsli contain high respectively low levels of sugar, and which brands are involved. Methods: The material consists of both qualitative interviews and observations from five grocery stores: City Gross, Hemköp, Ica Maxi, Stora Coop and Willy’s in Helsingborg, Sweden. The qualitative interviews had a semi-structured character and were recorded. The interviews took approx. 20 minutes and a textual analysis was conducted of the results. Data from observation was analyzed based on brand, nutritional composition and flavors, and also, where low sugar products were placed on store shelves. Results: The grocery stores provided together brands from AXA, Coop, Finax, Frebaco, Garant, ICA, Risenta, Saltå Kvarn och Urtekram, in total 24 müsli products. Of these products, 19 were high in sugar. The observation reveals that müsli products with high sugar content (17 - 29 g per 100 g müsli) are more prominently displayed than those with low sugar content. From the interviews with the store managers, it became clear that it would be valuable to highlight healthy müsli products on the shelves. However, central bureaucracy puts obstacles to such measures. Discussion: The study emphasizes the need for increased visibility of low-sugar products and proposes solutions such as negotiating with responsible person at the head office in Stockholm. Several reviews have shown that if the grocery store raises the prices of unhealthy food, the consumer is willing to purchase healthier müsli and other products. Conclusion: This study shows the need for grocery stores to upgrade healthy müsli products along with advertising to be able to influence customer’s shopping habits. Also, further research is needed how type 2 diabetes is affected by high intakes of food products with high sugar content.

基于高光谱成像技术的涌泉蜜桔糖度最优检测位置

本文旨在探索涌泉蜜桔糖度的最优检测位置和最佳预测模型,以便为蜜桔糖度检测分级提供理论依据。本文利用波长为390.2~981.3 nm的高光谱成像系统对涌泉蜜桔糖度最佳检测位置进行研究,将涌泉蜜桔的花萼、果茎、赤道和全局的光谱信息与其对应部位的糖度结合,建立其预测模型。使用标准正态变量变换(SNV)、多元散射校正(MSC)、基线校准(Baseline)和SG平滑(Savitzkv-Golay)4种预处理方法对不同部位的原始光谱进行预处理,用预处理后的光谱数据建立偏最小二乘回归(PLSR)和最小二乘支持向量机(LSSVM)模型。找出蜜桔不同部位的最佳预处理方式,对经过最佳预处理后的光谱数据采用竞争性自适应重加权算法(CARS)和无信息变量消除法(UVE)进行特征波长筛选。最后,用筛选后的光谱数据建立PLSR和LSSVM模型并进行分析比较。研究结果表明,全局的MSC-CARS-LSSVM模型预测效果最佳,其预测集相关系数Rp=0.955,均方根误差RMSEP=0.395,其次是蜜桔赤道部位的SNV-PLSR模型,其预测集相关系数Rp=0.936,均方根误差RMSEP=0.37。两者预测集相关系数相近,因此可将赤道位置作为蜜桔糖度的最优检测位置。本研究表明根据蜜桔不同部位建立的糖度预测模型的预测效果有所差异,研究最优检测位置和最佳预测模型可以为蜜桔进行糖度检测分级提供理论依据。

气象因素对甘蔗糖分含量的影响及模型构建

利用随机森林和向前逐步选择算法筛选关键气象因素,基于广义加性模型等构建6类甘蔗糖分含量模拟模型,以关键气象因子为自变量模拟甘蔗成熟期的糖分含量,通过模拟值与实测值对比分析,对模拟效果进行评价,并量化关键气象因素对甘蔗糖分含量的影响。结果表明:不同地区、不同时间尺度气象因素对甘蔗糖分含量均有影响,关键气象因素包括气温日较差、最低地温、日照时数、最高气温、平均气压、降水量及平均相对湿度,气温日较差对甘蔗糖分含量的影响呈近似稳定的线性趋势,其余关键气象因素对甘蔗糖分含量的影响呈复杂波动趋势。基于关键气象因素建立模拟甘蔗糖分含量的6种模型,广义加性模型模拟效果最优,拟合R^(2)达0.97,模型验证的绝对误差为0.12个百分点,相对误差为0.86%,均方根误差为0.15。说明模拟值与实测值具有较好的一致性与相关性,模型可实现对广西甘蔗糖分含量的预测,同时,量化关键气象因素对甘蔗糖分含量的影响,也为调控生态系统提供依据。

“华农早”龙眼ד紫娘喜”荔枝F1代果实可溶性糖主要组分的遗传分析

可溶性糖成分及其含量是决定果实品质和风味的重要因素之一。为探讨龙眼荔枝杂交群体果实可溶性糖含量的遗传规律,以“华农早”龙眼、“紫娘喜”荔枝及其杂交F1代68株单株为试材,采用高效液相色谱(HPLC)技术,测定该群体果实可溶性糖组分与含量,并进行杂交群体果实可溶性糖遗传分析。结果表明,龙眼荔枝杂交后代果实可溶性糖主要包括葡萄糖、果糖和蔗糖,其中蔗糖含量最高,均值为67.66 mg/g,占总糖含量的51.79%;葡萄糖与果糖含量接近,分别占总糖含量的22.15%和24.82%。杂交群体的不同糖组分均表现为衰退变异,葡萄糖、果糖和蔗糖含量广泛分离,变异系数分别为25.16%、22.15%和33.69%。蔗糖/单糖0.48~3.05,蔗糖含量与总糖含量之间、总糖含量与甜度值之间均呈极显著正相关。F1代有的单株总糖含量超过170 mg/g,且甜度值超过170,具有高糖特性,为龙眼优质品种创新提供了丰富的材料。

基于全透射可见-近红外光谱的西瓜糖度在线检测研究

糖度是评价西瓜品质的重要指标之一,影响着西瓜的受欢迎程度和销售价格。但体积大、皮厚的自然生物特征为西瓜糖度的快速、无损评估带来了挑战。为探索西瓜糖度快速无损检测,选择230个西瓜作为试验样本,使用自行研制的全透射可见-近红外光谱系统在线采集西瓜光谱数据,在线检测过程中保持光谱连续检测点在西瓜的赤道部位,并分别测量西瓜整果糖度和中心糖度作为理化糖度参考值。首先对样本在线检测过程中产生的多条光谱数据进行均值化处理,并选取波长范围690~1100 nm的光谱数据,使用蒙特卡洛方法剔除其中的异常样本,使用多种预处理方法(SNV、SG平滑等)对光谱数据优化,并采用SPXY算法划分样本校正集和预测集以减小因西瓜内部糖度分布差异造成的影响;基于优化的光谱数据构建了线性PLSR模型和非线性LS-SVM模型预测西瓜中心糖度和整果糖度。结果表明,基于SNV和SG组合法预处理光谱构建的LS-SVM模型预测西瓜整果糖度效果最好,其校正集相关系数R C=0.92,建模均方根误差RMSEC=0.37°Brix;预测集相关系数R P=0.88,预测均方根误差RMSEP=0.40°Brix。进一步使用特征波段挑选算法(CARS、UVE、SPA等)对光谱数据优化,结果显示构建的模型效果更好,其中使用CARS和UVE组合算法选取的特征波长构建LS-SVM模型预测西瓜整果糖度时效果最好,其校正集相关系数R C=0.94,校正均方根误差RMSEC=0.31°Brix;预测集相关系数R P=0.91,预测均方根误差RMSEP=0.37°Brix,且建模变量从1524个特征变量缩减到39个特征变量。该研究为实际生产中西瓜糖度快速无损检测应用提供了参考。

甜菜品种间氮效率差异及其对产质量的影响

【目的】研究不同类型甜菜品种氮素吸收利用差异及其与产质量的关系,以期为生产上氮肥精准施用奠定基础。【方法】采用大田试验方法,以丰产型(‘HI1003’)、标准型(‘IM1162’和‘SX1511’)和高糖型(‘KWS1197’)甜菜品种为试验材料,设置N_(0)(0 kg/hm^(2))、N_(75)(75 kg/hm^(2))和N_(225)(225 kg/hm^(2))施氮处理,测定甜菜不同生育时期干物质量分配、根冠比、氮积累与分配、氮效率和产质量指标。【结果】(1)甜菜生育期氮素吸收利用特征呈单峰曲线变化趋势,在8月9日达到高峰;(2)8月份块根及糖分增长期,N_(0)和N_(75)处理下,丰产和高糖型品种地上部干物质分配较标准型品种增加4.57%~36.77%,标准型品种根冠比变化幅度低于高糖和丰产型品种;(3)N_(75)处理下,高糖型品种收获期氮肥利用率最高,较标准型品种‘SX1511’和‘IM1162’分别增加58.44%和71.26%;N_(225)处理下,氮肥利用率和产量是丰产型品种最高,其产量较标准型品种‘IM1162’和‘SX1511’分别增加10.31%和14.06%。【结论】块根及糖分增长期是氮素调控产质量的关键时期,在该时期进行氮素调控,在发挥品种氮素吸收利用最大效率的同时可实现丰产或高含糖的目标。

句容产区鲜食葡萄外源加糖发酵的酿酒特性及其工艺优化

为探索外源加糖发酵对鲜食葡萄酿酒特性的影响,以句容产区两种主栽鲜食葡萄巨峰和夏黑为原料,采用3种商业酿酒酵母进行加糖发酵试验。首先筛选最适酿酒的鲜食葡萄品种和商业酿酒酵母,然后在酵母接种量、发酵温度、糖度等单因素试验基础上,采用Box-Behnken中心组合设计原理,利用响应面法优化发酵的工艺参数。结果表明:巨峰葡萄和DV10商业酿酒酵母分别为最适的鲜食葡萄品种和酿酒酵母;响应面回归方程与试验结果拟合性好,模型可靠;优化得到的最佳发酵参数为酵母接种量0.10%、发酵温度21.5℃、糖度22.9%,该条件下所得酒液酒精度为11.67%vol。