近45年广西寒露风的时空变化特征

为了掌握广西寒露风的演变规律,为晚稻生产提供决策依据,利用广西88个气象站1971—2015年逐日平均气温资料,统计逐年寒露风初日、寒露风日数,采用线性倾向计算、阶段性分析、Morlet小波分析、Mann-Kendall突变检验、相关分析等方法,分析了广西寒露风的时空变化特征。结果表明:(1)近45年广西大部地区寒露风初日呈推迟趋势,南部变化速率大于北部;大部地区寒露风日数呈减少趋势,南部减少速率大于北部。(2)广西寒露风具有较明显的阶段性和突变性特征,突变发生在1998年。(3)寒露风初日、寒露风日数均存在4年、8年左右的周期变化。(4)广西寒露风对气候变暖的响应明显,寒露风初日与9—10月平均气温具有显著的正相关关系,而寒露风日数与9—10月平均气温具有显著的负相关关系。     

玉米种质资源主要品质性状鉴定与评价

对2003—2004年收集、整理的400份玉米种质资源的主要品质性状进行了鉴定评价。结果表明，不同类型的玉米种质资源中地方品种的粗脂肪、粗淀粉性状和自交系粗蛋白、赖氨酸性状具有更大的遗传多样性。通过鉴定，筛选出一批品质性状优异的玉米种质资源．并对现行玉米种质资源品质的评价标准进行了讨论。     

中国甜菜主要种质资源抗病性鉴定与评价

旨在鉴定与评价不同生态区甜菜主要种质资源的抗病性,为种质资源在抗病育种上科学有效利用提供依据。以甜菜3个生态区的313份主要种质资源为试材,在自然发病条件下,按照甜菜的规范标准,调查种质的发病级数,计算病情指数,划分抗性级别。鉴定出高抗甜菜褐斑病种质资源85份、抗病89份,抗甜菜根腐病种质资源11份,抗甜菜丛根病种质资源3份,抗甜菜白粉病种质资源28份。同时鉴定出兼抗2种病害的种质资源,高抗褐斑病兼抗根腐病种质资源5份、抗褐斑病兼抗根腐病种质资源5份、抗褐斑病兼抗丛根病种质资源2份,高抗褐斑病兼抗白粉病种质资源20份。结果表明,中国甜菜种质资源比较匮乏,除抗褐斑病种质资源外,抗根腐病、丛根病和白粉病的资源不但数量少,而且抗性级别低。     

小豆种质资源鉴定与评价

对23份不同来源小豆种质资源的农艺性状、产量、抗病性、抗倒伏性和商品性进行分析、鉴定和评价.结果表明,综合评价较好的品种有0921反-1-4-2-3-1、品红2013-161、0001-17-6-3-1-4-2-1、122-080和THM 2011-28,可在生产上进行示范推广.依据系统聚类分析,可将23份小豆种质资源...     

芜菁种质资源抽薹性状鉴定及评价

为了加快芜菁种质资源育种进程,筛选耐抽薹品种,本试验将46份不同品种芜菁在2℃条件下人工春化30 d后,在25℃光照15 h、20℃黑暗9 h环境中进行常规栽培管理,观察其抽薹情况,筛选出17份极耐抽薹品种,2份极易抽薹品种。其中芜菁品种W05最早抽薹开花,W10和W38两份品种极易抽薹,抽薹率均为100%。利用隶属函数法将所有品种分为五类。由抽薹指标的相关性分析可知,显蕾期与开花期成极显著正相关,叶片数与花薹长呈极显著正相关,蕾薹长与薹高差和抽薹速度呈极显著正相关,薹高差与抽薹天数和抽薹速度呈极显著正相关。利用主成分分析筛选出显蕾期、开花期、抽薹天数和叶片数四个主成分,这四个指标可代表所有抽薹指标85.34%信息。通过综合得分发现,筛选出的四个主成分在不同品种间的表现不同。本试验结果可为芜菁耐抽薹品种的选育提供理论依据。     

具有优异性状的小麦种质资源鉴定与评价

2005年我们为中国农业科学院作物科学研究所国家种质库承担春小麦繁种更新种质资源材料428份任务，经田间种植观察及室内考种，从丰产性、抗病性、抗虫性等主要农艺性状的特征特性进行鉴定。这些资源一部分生产上直接利用，对甘肃省小麦产量的提高起到了很大促进作用，一部分作为亲本在小麦育种中利用，育成了一批高产新品种，为改善甘肃省小麦遗传构成、提高小麦单产和总产做出了积极的贡献。     

超级小麦种质资源农艺性状的鉴定与评价

通过田间观测和室内分析，对来自国外和国内420份超级小麦种质资源在山东泰安市连续二年进行了农艺性状的鉴定和评价。结果表明：在这些小麦种质资源中，单株成穗数、小穗数、穗粒数的变异系数较低，育种时容易选择。性状相关分析表明：随着穗长的增加及穗粒数和千粒重的增加，穗粒重有增加的趋势；随着穗长的增加，株高有增加的趋势；株高的增加有助于穗粒数的增多，但千粒重随之下降。在此基础上筛选出适合泰安生态条件、综合性状好的材料27份，其中抗病好的材料10份，大穗大粒类2份，优质类23份，早熟类12份，矮秆2份，抗寒3份，多穗多粒7份。     

广西籽粒苋资源品质性状的鉴定与评价

广西籽粒苋地方种质资源极其丰富多样,为了给广西籽粒苋育种和生产提供理论依据,以考察收集的61份广西籽粒苋资源为试材,对籽粒的蛋白质、淀粉、脂肪、硒含量等4个主要品质性状进行测定分析和评价。结果表明,蛋白质、淀粉、脂肪、硒平均含量分别为14.59%、41.37%、4.89%、0.056 mg/kg。不同品质性状变异程度不同,其中硒含量变异最大。性状间存在着不同的相关性：蛋白质与淀粉呈极显著正相关、与脂肪呈极显著负相关,脂肪与淀粉呈极显著负相关、与硒呈现显著负相关。不同来源的种质品质性状比较结果表明,百色市地方种质资源的蛋白质、淀粉、脂肪和硒的平均含量明显优于广西其他地市。通过鉴定,筛选出多项品质优异资源4份,双项品质优异资源7份,高蛋白质、高淀粉、高脂肪和富硒含量单项优异资源16份。     

优异甜菜种质资源筛选评价

旨在筛选评价优异的甜菜种质资源,为在育种上科学利用提供可靠信息支撑.本研究对277份甜菜种质资源的块根产量、含糖率、有害性非糖分以及主要病害抗性等8个主要性状的试验数据,按规范标准进行分组划类,分别对各类型种质资源进行筛选与评价.筛选出块根产量52 t/hm2以上的高产型种质资源37份,含糖率17％以上高糖型88份.其...     

白菜类蔬菜种质资源抽薹性状鉴定评价

为筛选耐抽薹白菜类蔬菜种质资源,以233份白菜类蔬菜种质资源为研究对象进行露地栽培,通过对现蕾期和开花期指标进行隶属函数法和系统聚类分析,综合鉴定评价白菜类蔬菜抽薹性状。现蕾期的变异幅度为39.00~181.00天,开花期的变异幅度为46.00~196.00天,变异系数分别达到24.53%和19.80%,表明白菜类蔬菜种质的抽薹性状具有丰富的遗传多样性。采用隶属函数法将233份白菜类蔬菜种质资源划分为5组,其中极耐抽薹种质80份。聚类分析结果表明,在距离系数4.5处233份白菜类蔬菜种质资源被分为5个类群,第Ⅳ类群极耐抽薹类型包括63份种质资源,均属于隶属函数法划分的极耐抽薹等级,说明隶属函数法和聚类分析法均能有效鉴定白菜类蔬菜种质的耐抽薹性。     

A genetic map of sugar beet (Beta vulgaris) based on RAPD markers

Linkage analysis of sugar beet (Beta vulgaris L.) was performed with random amplified polymorphic DNA (RAPD)-markers. From three segregating populations, a combined genetic map was constructed which comprises 85 RAPD, five isozyme, one RFLP marker and the genes for resistance against the nematode Heterodera schachtii Schm., one restorer locus for male sterility and the genes for annuality and hypocotyl colour. For mapping of the two unlinked restorer genes a statistical model was developed based on the maximum-likelihood function.     

An evaluation of single plant randomised field trials of sugar beet (Beta vulgaris L.)

Summary Diploid, monogerm families of sugar beet were grown in transplanted field trials randomised on a single-plant basis. Individual roots were weighed and a range of chemical characters were assessed. There was no significant difference in performance between plants that had members of their own family as nearest neighbours within the row and plants that had randomly assigned neighbours. Good correlations were found between the performance of families in single-plant trials and their performance in conventional plot trials. We conclude that single-plant randomisation could prove useful for genetical studies and for breeding trials particularly when seed or facilities are limited.     

Graft-transmissio of male sterility in sugar beet (Beta vulgaris L.)

Cytoplasmic male sterility in sugar beet was successfully transmitted across the union where male sterile and equivalent O-type plants were reciprocally grafted. Two experiments are described. In the first, 30 pairs of developing flowering stems were exchange-grafted between male-sterile and O-type plants. Fifteen O-type scions exhibited full or partial male sterility when grafted to male-sterile stocks and sterility was observed in progeny from these in eleven cases. In flowers from side shoots of O-types grafted with male-sterile scions eight cases exhibited some male sterility and progeny from four of these retained the sterility. In the second experiment O-type seedlings were grafted to male-sterile seedlings and out of the 22 success-fully raised to flowering, male sterility was exhibited in 12 of them. Male sterility occurred among progeny of all 22, even where the sterility could not be detected in the scions. In six cases where the scion appeared fully male-sterile no pollen was produced in any of the progeny.     

A marker-assisted analysis of bolting tendency in sugar beet (Beta vulgaris L.)

Bolting tendency in sugar beet varies among breeding lines and cultivars. Four crosses were made between breeding lines susceptible and resistant to bolting in order to study the genetic basis of bolting tendency. Bolting percentage in F₂, after 8 weeks of low temperature treatment, varied among the crosses, suggesting a complicated genetic control of bolting tendency. Different segregation ratios were observed, in particular, between families derived from the bolting F₁ plants and those from their non-bolting siblings, the former families showing a significantly higher bolting percentage than the latter. A marker-assisted analysis with seven isozyme loci, Ak1, Gdh2, Idh1, Lap, Mdh1, Pgi2 and Pgm1, revealed that a locus with marked effect on bolting tendency was located near Idh1. Because of a close linkage of Idh1 with B for annuality, the gene tagged by Idh1 appeared to be equivalent or similar to B′ for easy bolting allelic to B as reported by Owen et al. (1940). The results obtained suggest that the B locus may not only have an important role in determining growth habits but also control various degrees of bolting tendency in individual sugar beet plants. A linked pair, Ak1-Lap, and Pgi2 also were found to affect bolting tendency, although their effects varied depending on the crosses and families tested. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of weather variables on sugar beet yield development (Beta vulgaris L.)

There is much data on the impact of weather variables on the growth of sugar beet from studies conducted under controlled conditions or single field experiments, but these data are of only limited validity for other sites or larger areas. The aim of the present study was to quantify the influence of weather conditions on the growth of sugar beet for the further development of simulation models, based on data representative of sugar beet cultivation in Germany. For this purpose, 27 field trials were conducted in 2000–2001 in commercial fields with variable climatic and soil conditions. From the end of May until the end of the season, beets were harvested manually every 4 weeks, the dry matter yield of leaves and taproot was determined and their growth rates were calculated. Temperature, solar radiation, rainfall and humidity were recorded daily for each site and the potential evapotranspiration and climatic water balance were estimated. The soil water content to a depth of 0.9 m was determined at every harvest date.Several functions were developed to describe the growth of sugar beet as affected by the given meteorological variables. From sowing to the end of June, the dry matter accumulation of both leaves and taproot was strongly enhanced by increasing temperature and during this period leaf dry matter increased linearly with thermal time. After reaching 700 °C d, the taproot dry matter accumulated exponentially with thermal time. The optimum mean daily air temperature for taproot growth was approximately 18 °C. Higher temperature occurring in July and August decreased final taproot yield, but by the end of the season, growth was independent of temperature. High solar radiation advanced growth during the first 65 days after sowing and again in October.Neither the water input by rainfall and irrigation nor the climatic water balance adequately described the growth of the leaves or taproot, but it was shown that the increase in taproot dry matter during July and August depended on the amount of available water in the soil. The maximum sugar yield that can theoretically be achieved in Germany and comparable agroclimatic regions was calculated as 24 t ha⁻¹. The present data reliable for a large agroclimatic region in Europe are of significant value as input for simulation models.     

A gene complex for annual habit in sugar beet (Beta vulgaris L.)

Annual habit in sugar beet has been shown to be controlled by a dominant gene, B, which induces bolting under long days without the cold requirement usually essential for biennial cultivars. The induction of bolting by B, however, is often influenced by both environmental and genetic factors. We studied the genetic basis for bolting suppression, caused by delayed planting, in lines derived from a cross between annual and biennial lines. The F₂ progeny of a late-bolting F₁ plant yielded an unexpected segregation ratio of annuality from monogenic inheritance when planted in late May, there being an excess of non-bolting biennials, although the expected segregation was observed in the late April sowing. Bolting suppression was caused by restricted daylengths due to delayed planting because the segregation was normal under artificially induced long days. The analysis with Idh1, an isozyme marker proximal to B, demonstrated that heterozygous B plants were more susceptible to bolting suppression due to delayed planting than homozygous B plants. The results suggest that bolting suppression was controlled by a number of genes responsible for long daylength requirement, one of which was closely linked to B and formed a gene complex for annuality. The annual habit was controlled singly by B under long days but modified by the genes for long daylength requirement under restricted daylengths. This revised version was published online in July 2006 with corrections to the Cover Date.     

Selection for sugar yield in sugar beet, Beta vulgaris, using different selection indices

In sugar beet breeding, sugar yield is mainly influenced by root yield and sugar content. In this short communication several indices to select for both traits simultaneously are compared in order to find the best one. The indices are correlated with the base index of Williams (1962) from independent experiments. The indices differ in the amount of information necessary for the calculation of their weights. Three different series of each eight sites gave similar results. The optimum index using all information from phenotypic and genotypic variances and covariances, did not perform best. Sugar content with its higher herit ability must have a larger weight than root yield. Heritabilities as index weights performed best, but two other indices using heritabilities and phenotypic but no genetic covariances also performed well.     

Correlation between polyovules and number of pistil lobes (stigmatic rays) in sugar beet (Beta vulgaris L.)

The polyovules phenomenon in sugar beet has the same importance for breeding as multigermity, because only mono-ovulic monogerm plants can be used for mechanized cultivation. The polyovules trait was investigated in two Japanese lines, mono-ovulic line NK-219-O and polyovulic line NK-183-cms. Plants of the former had three pistil lobes (stigmatic rays) in each flower, a single ovule per ovary, a single seed in the mature fruit and a single seedling germinated in subsequent tests. Plants of the latter had 5–6 pistil lobes in each flower, 2–3 ovules per ovary, double-seeds and double-seedlings. The correlations between a Pistil Lobes Index (PLI) and thenumber of ovules per ovary, percentage of double-seeds inan X-ray test, and percentage of double-seedlings in germination tests were 0.885, 0.838, and 0.749, respectivelyindicating close associations. These results are important both in sugar beet breeding for indirect selection to eliminate the undesirable polyovules trait and for botanicalinvestigations of the relationship among different parts of the gynoecium.     

Combined linkage maps and QTLs in sugar beet (Beta vulgaris L.) from different populations

The construction of genetic maps is an expensive and time-consuming process. The breeder is therefore interested in using maps developed from other mapping populations but this is only possible if the genetic structure is similar for the chromosomal regions of interest. In this paper, maps of three populations of sugar beet (Beta vulgaris L.) with common polymorphic marker loci are compared. Maps were constructed with MAPMAKER 3.0 and JOINMAP 2.0. Both mapping programs gave, in general, the same order for common markers. However, the number of common markers was too low to construct a combined map for all chromosomes. For one population, in contrast to the other two, the map constructed with MAPMAKER 3.0 was much longer than that constructed with JOINMAP 2.0. For two of these populations yield traits were also available from different environments. For quantitative trait loci (QTL) analysis of the yield data, the packages MAPMAKER/QTL 1.1 and PLABQTL were used. No QTL common for the two populations could be detected. The program and the version used strongly influenced the estimated positions of QTLs. There was also a strong interaction with environments.