播期对糯玉米籽粒产量和淀粉热力学特性的影响

以4个糯玉米品种(垦粘1号,苏玉糯2号,苏玉糯5号和渝糯7号)为材料,研究了播期对其籽粒产量与淀粉热力学特性的影响.结果表明:各品种在5月15日播种时受飞虱危害不能正常成熟,能正常成熟时籽粒产量均在4月15日播种时最低,垦粘1号和苏玉糯2号在6月15日播种时最高,苏玉糯5号和渝糯7号则在7月15日播种时最高.播期对淀粉热力学特征值的影响远高于品种间差异(回生值除外).总体上,回生值受播期影响较小,热焓值和峰值指数以3月15日播种时最高,6月15日播种时最低,起始温度、峰值温度和终值温度以4月15日播种时最高,7月15日播种时最低,糊化范围4月15日播种时最低,6月15日播种时最高.不同品种籽粒产量和淀粉热力学特征值对播期的响应有显著基因型差异.碘结合力播期处理的变化趋势与转变温度3个指标相似.相关分析表明,碘结合力与起始温度、峰值温度、终值温度和峰值指数显著正相关,与糊化范围显著负相关.     

鲜食玉米酚类化合物含量及体外功能活性研究

选择‘天紫23’‘西星黄糯6号’和‘京科糯2000’3个不同颜色的代表性品种，探讨鲜食玉米籽粒在鲜食期和完熟期多酚类化合物及体外功能活性的差异。结果表明，鲜食玉米籽粒中的酚酸类物质大多以结合态形式存在，黄酮和花色苷类物质则主要以游离态形式存在，且鲜食期的多酚含量均高于完熟期。鲜食期多酚提取物的羟基自由基清除率、DPPH自由基清除率和总还原能力均显著(P<0.05)高于完熟期，且多数游离酚表现出高于结合酚的抗氧化活性。3个品种鲜食期游离态和结合态酚类物质的α-淀粉酶抑制率分别是完熟期的1.3～1.5倍和1.4～1.8倍，对α-葡萄糖苷酶的抑制率则分别为1.1～1.5倍和1.5～8.1倍。鲜食玉米多酚提取物对胆酸钠的结合能力最高，游离酚和结合酚分别在172.99～219.92μmol/100 mg DW和362.48～417.16μmol/100 mg DW,3个品种鲜食期的胆酸盐结合能力均高于完熟期，结合态多酚表现了更强的胆酸盐结合能力。     

甜菜多倍体品种的重要农艺性状鉴定与评价

对生产上应用的15个多倍体甜菜品种的主要农艺性状进行了研究，方差分析表明它们在根产量、含糖率、产糖量3个性状的表现不同，根产量性状与对照差异不显著；含糖率性状与对照有1个品种达到显著水平，有4个品种达到极显著水平；产糖量性状与对照相比有1个品种达到显著水平，2个品种达到极显著水平。褐斑病性状差异不明显。甜研系列普通多倍体品种的经济性状表现总体上优于其它供试品种：遗传单粒型多倍体品种的各项经济性状指标相对较差。遗传相关性分析表明，除褐斑病级与根产量、含糖率及产糖量呈负相关外，其余3个性状间呈现正相关关系。     

净作和套作条件下大豆籽粒异黄酮积累规律比较

以我国西南地区3个常用大豆品种为材料,比较净作和套作条件对大豆籽粒发育及后熟过程中异黄酮积累规律的影响。结果表明：籽粒成熟期按总异黄酮积累速率可分为初始积累期和快速积累期;受田间小气候影响,套作条件下大豆较晚进入快速积累期;田间采收时,贡选1号品种净作总异黄酮含量极显著高于套作,南豆16和贡秋豆3号净作与套作之间差异不显著。3个品种籽粒后熟期套作条件下总异黄酮的积累量均极显著高于净作,总异黄酮含量套作均显著高于净作;后熟期不同品种异黄酮各组分及总异黄酮的积累量均存在显著差异。本研究发现净套作对3个大豆品种的异黄酮积累动态及总含量均有显著影响,品种间籽粒异黄酮的积累对种植条件的反应不同。相对净作而言,后熟过程更利于套作大豆籽粒异黄酮的进一步积累。     

不同密度条件下旱地胡麻灌浆特性研究--测试文章

在定西干旱生态条件下，以陇亚10号胡麻为材料，研究了密度对籽粒灌浆特性和农艺性状的影响。结果表明：随着种植密度的增大，胡麻分枝数、蒴果数减小，株高波动性变化；胡麻籽粒干物质积累过程呈“S”型曲线，可用Logistic模型进行模拟，相关系数达0.99以上，花后6～31 d籽粒干物质积累速度最大； 胡麻最大灌浆速率、平均灌浆速率和灌浆持续期均受种植密度的影响，处理间平均灌浆速率差异明显，其中以600 万株·hm^-2的平均灌浆速率最高，1 050 万株·hm^-2的平均灌浆速率最低；不同密度处理间百粒重和产量存在显著性差异，600 万株·hm^-2处理的百粒重和籽粒产量最大，显著高于1 200 万株·hm^-2处理。说明在实际生产中要根据不同胡麻品种类型选择最佳的种植密度。     

寒地水稻不同穗型品种穗部性状的比较研究

以33个黑龙江省主栽水稻品种为试验材料,分析出不同穗型品种穗部性状的差异。试验结果表明,寒地水稻不同穗型品种穗部性状之间有显著关系。阐述了单穗重、穗部性状与产量三因素之间的关系,水稻穗部性状之间的每穗粒数、着粒密度、二次枝梗数、二次枝梗粒数、二次枝梗粒率呈极显著的关系。穗部性状对产量的探讨为提高水稻产量提供了一定的科学依据。     

鲜食玉米籽粒发育期间污染真菌分离鉴定及真菌毒素含量分析

为探讨鲜食玉米籽粒发育期间真菌污染和真菌毒素积累情况,选择天紫23、京科糯2000和黑糯6号3?个品种鲜食玉米,在玉米授粉后第0、12、23、35、55天采样对污染真菌进行分离鉴定,并对黄曲霉毒素B1、呕吐毒素和玉米赤霉烯酮含量进行对比分析。结果从3?个品种鲜食玉米中,共分离出1?606?株真菌,经鉴定,隶属13?个属,20?个种;玉米籽粒发育期间主要污染真菌为青霉属（Penicillium）、曲霉属（Aspergillus）、镰刀菌属（Fusarium）、毛霉属（Mucor）和篮状菌属（Talaromyces）,其次是交链孢属（Alternaria）、根霉属（Rhizopus）、帚枝霉属（Sarocladium）、笄霉属（Choanephora）,还有少部分茎点霉（Phoma）、黑孢霉（Nigrospora）、横梗霉（Lichtheimia）和枝孢霉（Cladosporium）;鲜食玉米授粉后23?d（乳熟期）黄曲霉毒素B1、呕吐毒素和玉米赤霉烯酮的含量最低,是食用的最佳时期;污染真菌数量与毒素积累不具备相关性,黑糯6号品种受真菌毒素污染最轻,其次是天紫23和京科糯2000,但测试的鲜食玉米品种真菌毒素含量均远低于国家限量。     

糯玉米新品种"京科糯2000"

一、品种加工特性“京科糯2000”是由北京市农林科学院玉米研究中心选育出的新一代白糯玉米品种。其品质优、产量高,可称为粮、经、饲、果兼用型。1.加工糯玉米食品“京科糯2000”的干子粒产量为600公斤左右,子粒胚乳中含有100%的支链淀粉,在加工中对其干子粒脱皮去胚后,经湿磨制成的糯玉米淀粉,可代替价格昂贵的糯米粉,来制作汤圆、麻糖、年糕等传统食品。2.作为工业原料该品种的优质糯玉米淀粉可作为变性淀粉加工业的原料,目前变性淀粉的用途非常广泛,可作为增稠剂、乳化剂、粘着剂、悬浮剂广泛用于食品、纺织、造纸等工业中,在医药生产中…     

种植密度对两种穗型冬小麦品种籽粒淀粉组成及其糊化特性的影响

在大田试验条件下,研究了不同种植密度对两种穗型冬小麦品种籽粒淀粉积累、组成及其糊化特性的影响.结果表明,两种穗型冬小麦品种淀粉积累随灌浆进程推进呈上升趋势,淀粉积累速率则呈单峰曲线变化,且均在花后21～28 d时积累速率最快.不同种植密度对两种穗型冬小麦品种籽粒淀粉积累及其糊化特性的影响存在差异多穗型品种豫麦49-198以较高密度的B3处理(225×104/hm2)成熟期籽粒淀粉含量最高,直/支比最低;大穗型品种兰考矮早八以最低密度的C1处理(300×104/hm2)籽粒淀粉含量最高.两种穗型品种的多数淀粉糊化参数以高密度或较高密度处理的数值最高,而适宜的种植密度既能改善两种穗型小麦品种的淀粉组成,又有利于提高其粒重与籽粒产量.     

面包小麦品质和产量若干性状的相关性

利用国内外40个面包小麦品种(系)进行了品质和产量若干性状的相关性分析，结果表明，SDS-沉降值与籽粒蛋白质含量、湿面筋含量间呈显著正相关，与比沉降值、伯尔辛值、高分子量麦谷蛋白亚基品质评分之间呈极显著正相关；籽粒蛋白质含量、湿面筋含量与比沉降值、伯尔辛克值、高分子量麦谷蛋白亚基品质评分之间没有相关性。籽粒蛋白质含量、湿面筋含量与株粒重、收获指数、穗粒数呈显著或极显著负相关；SDS-沉降值、伯尔辛克值与株粒重等产量性状间几乎没有相关性；比沉降值与株粒重呈弱的正相关，与收获指数呈显著正相关。讨论认为，在现阶段我国小麦品质育种中，筛选和利用具有优良蛋白质品质，比沉降值高的亲本资源来选育高产优质新品种，具有十分重要的意义。     

燕麦种质资源农艺性状的遗传多样性分析--测试文章

分析了国内外54份燕麦种质资源的遗传多样性,归纳其遗传亲缘关系,为合理利用燕麦品种(系)资源提供理论依据。结果表明：(1) 54份种质资源农艺性状间存在广泛的遗传多样性,5个质量性状(粒色、粒型、穗型、小穗型、抗病性)以抗病性的多样性指数最高,粒色的遗传多样性指数最低;8个数量性状(单株分蘖数、株高、穗长、小穗数、轮层数、单株粒数、单株粒重、千粒重)以单株粒重的遗传多样性指数最高,变异系数最大。(2)聚类分析将54份种质资源的8个数量性状分为4大类群,类群Ⅰ为高秆、大粒型育种目标亲本材料;类群Ⅱ为矮秆育种目标亲本材料,类群Ⅲ的有益性状不明显,为多目标性状育种的亲本材料,类群Ⅳ为增加轮层数、小穗数等育种目标的优良材料。     

Effect of Cd on the growth,dry matter accumulation and grain yield of different rice cultivars

Pot soil experiments showed that there were great variations among six rice cultivars in their tolerance to soil Cd stress, with respect to tillering, plant height, leaf area, dry matter accumulation and grain yield. Some cultivars were highly tolerant of Cd and showed little toxicity under high levels of soil Cd stress (100 mg kg^?1), while others were much more sensitive. Roots were not necessarily more sensitive than above‐ground parts, but the diversities among rice cultivars with regard to the relative changes in dry matter accumulation under soil Cd stress were greater in roots than those observed in straw and grain. The toxicity effects of Cd on rice growth and development lessened as plants grew and matured, indicating that rice plants show adaptation and growth compensation in response to soil Cd stress during prolonged exposure. The relative change in the number of grains per panicle showed a strong positive correlation with relative change in grain yield and, of the four grain yield components measured (panicles per pot; grains per panicle; filled grain percentage; weight per grain), it appeared to be the one most influenced by Cd stress. Thus the reduction of grains per panicle is the main cause of grain yield loss under soil Cd stress. Copyright © 2007 Society of Chemical Industry     

Physico-Chemical Properties of Immature Pods of Japanese Soybean Cultivars

Twelve Japanese cultivars and JS335, the most popular soybean cultivar in India, were grown in the field. Days to arrival of R6 stage (when pods are still green, immature, and tight with fully developed immature green seeds) of these cultivars were recorded. Pods picked at this stage were evaluated for pod yield per plant, pod characteristics (width, presence of hairs) fresh green seed weight and percent moisture content. Fresh green seeds were analyzed for compositional traits viz. protein content, trypsin inhibitor lipoxygenase isozymes, oil content, and polyunsaturated fatty acids (essential fatty acids). Japanese cultivars showed higher fresh green seed weight and pod yield than JS335. On a fresh weight basis, Japanese cultivars exhibited lower protein content but higher oil content than JS335. Most of the Japanese cultivars showed lower trypsin inhibitor content and a varying level of lipoxygenase-I, as well as lipoxygenase-II + III when compared to JS335. Total polyunsaturated fatty acids content in JS335 was higher than some of the Japanese cultivars. The number of pods per plant showed a positive correlation (r = 0.863, p < 0.001) with pod yield per plant. Some of the Japanese cultivars offer great potential for consumption at the green pod stage or as a source for desirable traits.     

Predictive model for grain cracking in terms of rice plant and panicle morphology derived from multivariate analysis

Rice plant and panicle morphology in relation to grain cracking were studied in 17 varieties at four stages of maturity. The data were subjected to principal components analysis in order to identify structure within the data and reduce dimensionality. The first four factors collectively accounted for 72% of the trace. The first factor was dominated by yield and biomass related attributes, and the second with percentage cracked grains and grain moisture-III stage. The projection of varieties onto the planes defined by the first, second, third and fourth factors reflected scattering of varieties over all the quadrants indicating desirable wide variations in the varieties studied, and the results could be generalised. The discussions mainly centred on grain cracking which was primarily influenced by plant height, panicle length, grains/panicle, sequence of grain maturity and the microenvironments—particularly towards the last stages of maturity. Predictive models in terms of the above attributes explained more than 96% of cracking. The role of agronomic practices in controlling grain cracking is discussed. It is indicated that dwarf plants influenced by microenvironment need different panicle morphology and physiological sequence to minimise cracking as compared to tall plants which generally escape the influence of microenvironment.     

Impact of cultivar variation in grain density of rice panicle on grain weight and quality

BACKGROUND: In the last two decades, newly released rice cultivars in southeastern China have been mainly characterised by more grains per cm panicle (GPCP), i.e. a compact panicle. These compact panicle cultivars show high yield potential but inferior quality. Accordingly, experiments were conducted to study the effect of GPCP on grain weight and quality. RESULTS: Two compact panicle and two loose panicle cultivars of japonica rice were used to investigate the effect of GPCP on the variation in grain weight and quality within a panicle. Significant differences in grain quality, including brown rice length, width and length/width ratio, brown rice and head‐milled rice percentages, chalky grain percentage and amylose and protein contents, were found among grains within a panicle. In general, the compact panicle cultivars showed lower grain weight and larger variation in brown rice length, width and length/width ratio, chalky grain percentage and amylose content among grains within a panicle than the loose panicle cultivars. CONCLUSION: GPCP is negatively associated with quality uniformity, and increasing the grain number on top secondary rachises may reduce the variation in grain weight and quality within a panicle. Copyright © 2008 Society of Chemical Industry     

Effect of water deficit on yield and protein content in pearl millet grains

Seventy-two pearl millet genotypes were water stressed at panicle development and grain filling stages. Neither grain yields, yield components, protein percent nor total protein per unit area were affected by water deficit during panicle development but protein content per grain was increased. When plants were water stressed during grain filling, grain yield, grains per unit area and 1000 grain weight were reduced, but grain protein percentage increased. Total protein per unit area was reduced primarily due to lower grain yield. The protein content per grain was unaffected by stress, suggesting that the apparent increase in protein percentage is due to reduced carbohydrate accumulation under stress.     

特大粒甘蓝型油菜籽粒和角果发育形态特征

为进一步了解特大粒甘蓝型油菜种质DL01的大粒机理,以普通籽粒H8为对照,田间调查并比较分析它们的生育期、主花序角果和籽粒在形态、重量、灌浆速率和相对含水量等特征及变化。结果表明,特大籽粒DL01的平均全生育期为207d,比H8长17d,尤其是灌浆期长12d以上;在开花当天,DL01的花梗直径、子房的长度和宽度及重量分别是H8的1.30、1.21、1.39、1.46倍;其最大角果皮光合面积和角果鲜重分别是H8的2.2和3.0倍;单荚胚珠数二者相当,但DL01的着粒数比H8少,最大差异为64%;DL01最大籽粒鲜重（百粒重1.20g）、干重、体积和灌浆速率均是H8的2倍;在含水量方面,在荚角成熟前DL01的果皮含水量比H8略高（3%～5%）,但H8荚果高含水量（〉75%）期只能维持68d,而DL01荚果高含水量（〉80%）期可维持80d;H8籽粒鲜重在47d时达到最高,其含水量为52%,DL01籽粒鲜重在62d时达到最高,其含水量为50%。因此结论是,DL01大粒源自大子房、粗花梗、大的角果皮表面积、低着粒数、高的果皮与籽粒含水量并且灌浆持续时间较长。     

不同贮藏方式对油菜种质资源生活力和农艺性状的影响

为了解在长期库、冰柜和干燥器中贮藏的种质,调查了53份油菜的田间出苗率、主要农艺性状和含油量变化。结果表明储藏11～14年之间的种质田间出苗率平均值都高于储藏19～25年之间的种质,长期库和冰柜中保存的种子出苗率高于干燥器中保存的,表明干燥器不利于种子的长期保存。在长期库、冰柜和干燥器三种保存方式下,11个农艺性状的平均值一致表现为长期库优于冰柜,更优于干燥器;其中全株角果数、单株产量、单株重和分枝高度在三种保存方式下变异较大,变异系数在20%以上;角果宽度和含油量变异较小,变异系数在9%以下,说明不同保存方式不但影响种子活力和田间出苗率,还影响农艺性状。相关分析表明,因保存方式不同,出苗率表现不一致,与之相关的农艺性状也不同;在不同的储藏年限间,出苗率与株高、一次分枝数、全株角果数、主序角果数、单株产量均呈显著正相关。干燥器中保存的种质,因为活力丧失严重,整体出苗率较低,很难判断出苗率与农艺性状间的相关性。