Intra and interlocus interactions between alcobaça (alc), crimson (og c ), and high pigment (hp) loci in tomato Lycopersicon esculentum Mill.

The ripening mutant allele alcobaça (alc/alc) may be deployed to extend shelf life in tomatoes, but has reportedly negative effects on fruit colour development. Colour enhancing mutants crimson (og ^c /og ^c) and high pigment (hp/hp) could potentially overcome this limitation, but a detailed account of their interactions with alc is not available. In this paper, we report on intra-allelic (additive and dominant) interactions within these 3 loci, and on their possible interallelic (epistatic) interactions. Eight near-isogenic (NIL) tomato lines in background Flora-Dade were obtained, representing all possible 2ⁿhomozygous combinations in the n = 3 loci. The 8 NIL were crossed in all possible combinations (reciprocals excluded), to obtain 28 hybrids that were heterozygous in at least one locus. The 36 treatments (= 8NIL + 28 hybrids) were grown in a randomized complete block design with 4replications, and the following traits were evaluated: total yield, average fruit mass, fruit firmness at harvest (= breakerstage) and 6 days after harvest (d.a.h)., % coloured fruit surface, fruit lycopene and beta-carotene contents, fruit % soluble solids and solids/acidity ratio, internal and external fruit colour. The loci alcobaça, crimson and high pigment or their epistatic interactions had significant influence on the expression of all traits measured. Epistatic effects were responsible for most of the variation among genotypes (with a minimum of 48.1%of the total sum of squares for % coloured fruit surface and a maximum of 82.8% for total yield). External fruit colour was defficient in all alc/alc genotypes, and their commercial use is impaired, in spite of improvements in fruit internal and external colour brought about by deployment of specific genotypic constitutions in lociog ^c and hp. Some but not all alc ⁺ /alc genotypes were firmer and showed improved fruit quality over the normal Flora-Dade (alc ⁺ /alc ⁺ og ^c+ /og ^c+ hp ⁺ /hp ⁺) background. The following genotypic combinations represented good compromises between yield, long shelf life and fruit quality traits: alc ⁺ /alc og ^c+ /og ^c hp ⁺ /hp, alc ⁺ /alc og ^c /og ^c hp ⁺ /hp ⁺ and alc ⁺/alc og ^c+/og ^c+ hp ⁺ /hp     

Response to early generation selection for grain yield and harvest index in bread wheat (T, aestivum L.)

The availability of a reliable selection criterion for the identification of the most productive genotypes in early generations represents a crucial point in many breeding programs. The findings reported in the literature concerning the effectiveness of early generation testing for grain yield (GY) or harvest index (HI) are contradictory. In this work, we measured the response to selection for GY and HI applied in different generations, from F₂ to F₆ in nine segregating populations previously screened in F₂ by means of visual selection. Genetic variability for HI and GY was found in most of the segregating populations. However, GY of spaced plants in F₆ and F₃ generations was weakly correlated with yield of F₄ and successive generations grown at normal seed density. HI was of limited value as an indicator of yield potential.     

Prediction of Various Effects of Harvest Date in Sugar Beet Growing

One crucial decision in sugar beet growing is determining harvest date. This paper focuses on some aspects associated with harvest date which have to be included in a decision support system for sugar beet growing.
Firstly, a module was created for dirt and crown tare, mainly based on lutum (or clay) and soil moisture contents. An independent test of the module showed poor results, because fine tuning of harvest machinery has an overriding effect. Secondly, the variation in weather conditions during autumn in Wageningen over a period of 38 years was analysed. The ranges of future root and sugar production appeared to be so wide that early predictions of the day on which the sugar quota are exceeded will not be very reliable. Thirdly, risks of severe frost or heavy rainfall in autumn were assessed, based on the same 38 year data set. The risk of frost damage to unharvested beets proved to be negligible when the crop was harvested before November 10, as advised by the sugar industry.
The work described in this study makes the model PIEteR (a field specific bio-economic production model for sugar beet, developed for decision support at field and farm level) more applicable by using its potential to analyse the effects of different years and quota options.     

紫花醉鱼草(Buddleja fallowiana Balf.f.et W.W.Smith)种子萌发条件的研究

紫花醉鱼草是主要分布于云南西北部海拔 2 70 0～ 380 0 m的一种野生观赏灌木 ,其种子长圆形 ,褐色 ,周围有翅 ,大小约 0 .5 mm× 0 .5 mm,千粒重 0 .0 5 5 g。在 2 0℃及 2 5℃的发芽温度下第 15 d的发芽率分别为 94%和 98% :在抑制紫花醉鱼草种子发芽的 30℃的温度下 ,180 0 lx～ 30 0 0 lx的人工光照和每日光照 16～ 2 0 h能促进种子萌发。在 2 5℃的发芽适温下 ,照光能使紫花醉鱼草种子萌发提前 1～ 3d。低温高海拔的生境和其种子萌发对高温与光照的需求 ,可能是紫花醉鱼草在自然环境中不能自然繁殖成为蔓延性杂草的原因之一。     

Harvest index versus grain/straw-ratio. Theoretical comments and experimental results on the comparison of variation

Summary The variation of the two parameters, harvest index and grain/straw-ratio, has been theoretically compared by applying the relative measure coefficient of variation. The harvest index exhibits a clear superiority (= lower variation) compared to the grain/straw-ratio.Applications to ten European winter oilseed rape cultivars and lines are in an excellent agreement with the theoretical findings.     

农林高等院校创新型人才的素质要求及培养路径探讨

培养创新型人才是时代的必然要求,也是高校育人的根本任务和建设创新型国家的关键。阐述了农林院校创新型人才内涵、基本特征和培养的紧迫性,探讨了农林院校创新型人才素质要求及培养路径,对农林院校创新型人才的培养具有一定的借鉴作用。     

收获期对不同生育期高油大豆油分及产量的影响

利用不同生育期高油大豆品种的收获期试验,来研究收获期对不同生育期高油大豆品种油分及产量的影响。采用分期收获的方法对6个不同生育期高油大豆品种进行处理,利用近红外谷物品质分析仪进行油分分析,DPS数据处理系统进行数据处理。试验表明,收获期对大豆油分含量和产量有显著的影响。从初熟期开始,随着收获期的延迟,各品种油分含量呈先上升后下降有规律的变化趋势,6个品种的油分含量变化幅度为0.37-0.87个百分点,每个品种都有一个最佳的收获时期以获得最高的油分含量,但油分含量变化情况和品种的生育期相关性不大,是由品种本身的遗传特性决定的。播期对产量也有较明显的影响作用,四个生育期相对较长的品种黑农44、垦农19、合丰48号和合丰47号产量变化较大,达到了极显著水平,而两个早熟品种的产量变化较小,不显著,产量变化总体趋势是晚熟品种＞中熟品种＞早熟品种。不同生育期的高油品种适期收获能获得较高的油分和产量。     

新收获小麦在储藏过程中品质变化的研究

新收获小麦具有明显的后熟期,进入储藏过程,后熟期完成,其品质逐步提高。研究影响新收获小麦在储藏过程中品质变化的几个常见指标,如小麦的物理结构、酶、脂类物质、蛋白质、碳水化合物、发芽率、电导率等,以及这些指标与新收获小麦储藏时间的关系。     

养分优化管理促进间作小麦高产群体的构建

华北平原上最近出现的、既能保障粮食安全又可提高农民收入的小麦/西瓜/玉米间作体系备受农民欢迎,但是该体系普遍存在施肥不合理,养分盈余严重的问题。因此,本研究通过单因素随机区组设计的田间试验,探讨养分优化对该体系间作小麦群体动态和产量形成的影响,为建立间作小麦高产高效技术体系提供科学依据。本试验共设置了2个施肥处理,即：农户传统施肥(Con处理)和养分优化施肥(Opt处理),在4个农户的地块进行,共8个试验小区。从小麦返青期开始,监测间作小麦在两种施肥方式下,边行和内行的分蘖数动态变化;从小麦抽穗期开始,每隔3天,监测两个处理间作小麦边行和内行的抽穗数、扬花数的动态及收获期的生物量、产量及其构成要素。研究结果表明,通过养分的优化管理,显著增加了间作小麦的有效分蘖数、抽穗数、扬花数,提高了小麦的成穗率;同时,养分优化管理也增强间作小麦的边行优势,其小麦产量同传统相比,增产11.8%,收获指数增加16.7%。因此,通过养分优化可提高间作小麦边行的收获指数,促进间作小麦高产群体的建成,边行优势的增强,有助于间作优势的提高。     

采收期和贮藏温度对上饶早梨保鲜效果的影响

以"天桂梨"为试材,研究不同采收期和采后贮藏温度对上饶早梨保鲜效果的影响。结果表明,上饶早梨适宜的采收期为盛花期后102 d,采后适宜的贮藏温度为2℃,该条件可有效延缓上饶早梨果实贮藏期间硬度的下降,降低果实的呼吸强度和VC损失,延缓货架期果实的褐变和腐烂,提高食用品质。