Breeding of polyploid heather (Calluna vulgaris)

Calluna vulgaris is an important landscaping plant in Northern Europe. As C. vulgaris is the only species within the genus Calluna, the available gene-pool for breeding is rather narrow and phenotypic variation is limited. Hence, a breeding program for polyploids was set up in order to broaden phenotypic variation in this important ornamental crop. Therefor basic genetic characteristics of polyploid C. vulgaris were analyzed using the progeny of a spontaneously occurring tetraploid genotype. With the help of morphological and molecular marker analysis, it was determined that the autotetraploid plant probably arose from unreduced gametes resulting from first division restitution. Tetraploids displayed tetrasomic inheritance with free combination of homologous and homeologous chromosomes. Triploids were semi-fertile with a high rate of aneuploids in their progeny. As the so-called bud-blooming flower type is a trait of outstanding interest in breeding of C. vulgaris, a strategy for efficient breeding of triploid bud-bloomers was deduced.     

Breeding for earliness in spinach (Spinacia oleracea L.) as based on environmental and genetic factors

Summary One of the most important characters of a spinach cultivar is its earliness. This is determined by the rate of bolting and so by the rate of flower formation, as both coincide almost completely. The rate of flower formation is determined by three factors: Daylength (photoperiodic) requirement. The 7 cultivars tested showed an increased rate of flower formation at longer photoperiods, early cultivars having a higher rate than late cultivars. Rate of growth. By varying the light intensity and temperature, the rate of flower formation appeared to be related to the rate of growth. An increase in the latter is usually accompanied by an increase in the former. So acceleration of growth results in earlier bolting. Balance between growth and development. Indian Thorny and Virtuosa, although having similar daylength requirements and rates of growth, differ in earliness, which is ascribed to a difference in energy distribution over the growth and development processes. Indian Thorny is thought to use more energy for development processes than Virtuosa does.The genetic control of earliness is most likely a polygenic one as rate of growth and balance between growth and development can be expected to be polygenically controlled. This also means that earliness and yield are linked to each other; selection for the one often results in selection for the other. To select for the required earliness without unwanted yield effects, or to increase yield without changing the earliness, selection methods have been described, which are directed to each of the three components individually.Also published as Publication 297 of the Laboratory of Horticulture.     

Methods used for producing polyploid agricultural plants

Samenvatting Methoden ter verkrijging van polyploide landbouwgewassen Verschillende methoden ter verkrijging van polyploiden bij granen en andere gewassen worden beschreven en met elkaar vergeleken.Aanvankelijk gaf een verkorting van de behandelingsduur van drie op anderhalve dag bij de methode vanNavashin Gerassimova voor rogge reeds een belangrijke verbetering, waardoor het aantal tetraploiden, dat per winterseizoen verkregen is, van ongeveer 50 tot ruim 250 werd verhoogd.De beste werkwijze bleek tenslotte een kortdurende behandeling van jonge kiemplanten met colchicine oplossingen van zwakke concentratie tijdens een periode van actieve groei, begunstigd door een iets verhoogde temperatuur. Het aantal tetraploiden, dat op deze wijze verkregen is, bedroeg meer dan 2500 resp. meer dan 1500 per seizoen, het tienvoudige van het volgens de verbeterde methodeNavashin Gerassimova verkregen aantal.Voor rogge en ook voor bieten voldeed het best een behandeling met 0.1 % colchicine gedurende 3 uur bij 27°C.Ook van andere gewassen als gerst, kanariezaad, vlas en boekweit werden volgens de nieuwe methode van colchicinebehandeling grote aantallen tetraploiden verkregen.Een methode werd beschreven voor het onderzoek van cytologische preparaten met behulp van de phase-contrast microscoop.Dit instrument maakt het mogelijk in ongekleurde preparaten van rogge, bieten en andere landbouwgewassen, waarbij colchicinebehandeling is toegepast, na te gaan of het chromosomenaantal verdubbeld is.Bij rogge wordt dit onderzocht aan worteltopcellen van kiemplanten opgekweekt uit het zaad van de met colchicine behandelde planten.Bij bieten komen kerndelingen vooral voor in de zeer jonge blaadjes uit het hart der planten. Zowel blaadjes van de behandelde bietenplanten zelf werden onderzocht, als blaadjes van planten ontstaan uit het zaad van de behandelde planten.Voor het onderzoek van de weefsels worden deze in N. HCl bij 60°C gemacereerd, waardoor zij zacht worden en op een objectglas in een druppel 45 % azijnzuur onder een dekglas uitwrijfbaar zijn, waarbij de celstructuur aanwezig blijft. Is dit geschied, dan is het preparaat klaar voor onderzoek.In bietenpreparaten steken de chromosomen diep zwart tegen het doorzichtige plasma af. In worteltoppreparaten van rogge, waarin de cellen groter zijn en een vrij dicht plasma hebben, is het contrast minder sterk. De chromosomen krijgen hier een donker grijze tint.Bij rogge kan één persoon per dag met de phase-contrast microscoop 150 à 200 planten onderzoeken. Bij bieten, waarvan ook mixoploide planten onderzocht moeten worden, waarbij in één preparaat diploide naast tetraploide cellen voorkomen, kunnen hoogstens 80 à 100 planten per dag onderzocht worden.     

Introgression facilitated by apomixis in polyploid Poas

The Poas have adjusted themselves to contrasting climates from warm temperate to high arctic regions of both the Northern and the Southern Hemispheres. Their bipolar distribution would suggest great geologic age, but they nevertheless have preserved evolutionary youthfulness through polyploidy and apomixis. Transfer of large blocks of heredities between long separated groups of species is accordingly possible without causing disaster to their reproductive mechanism by seed. The Poas have not yet reached the limits of their potential to exchange heredities between species that belong to taxonomically distinct sections, between species of separate continents, and between species of the Northern and the Southern Hemispheres which have remained apart since early geologic periods.Presented at a conference entitled The role of introgressive hybridization in the evolution of crop plants and their wild relatives, held at Versailles on 4th January, 1961 by the Section Wild Species and Primitive Forms of EUCARPIA (European Association for Research on Plant Breeding).     

The present position of spinach breeding

The author gives a review of the present position of spinach breeding. In succession the following sections are treated: Historical data, secondary sex characters, biology of the flower, shortening the time required for a generation, breeding methods, inheritance of some characters, the testing and selection methods and the breeding objectives.     

A technique for identifying polyploid sectors in grass inflorescences

Summary A simple technique for counting mitotic chromosome numbers in ovaries of inflorescences has been developed and applied to grasses. The uses, as outlined, include isolating polyploid inflorescences for hybridization, and as an alternative method to root-tip squashes for chromosome morphology and banding studies.     

Meiotic chromosome and pollen morphological studies of polyploid Cucumis species

summary Meiotic chromosome studies of polyploid Cucumis species revealed the presence of bivalent chromosome configurations in the tetraploid C. aculeatus and C. zeyheri and hexaploid C. figarei, while a maximum of ten quadrivalents were observed in pollen mother cells of a tetraploid species, C. heptadactylus.Allotetraploidy was not accompanied by an increase in the number of pores per pollen grain, but the autotetraploid and hexaploid species showed a relatively high percentage of 4-porate pollen. The pollen fertility of the tetraploid species was normal.Contribution from the Department of Horticulture and Department of Agronomy. Supported by the Colorado State University Experiment Station and published as Scientific Series Paper No 2403.Former Graduate Research Assistant, Department of Horticulture (present address, 1030 Sanders St., Auburn, Alabama 36830 USA) and Professor, Department of Agronomy, respectively.     

Genic microsatellite markers for discrimination of spinach cultivars

A set of simple sequence repeat (SSR or microsatellite) markers was used to discriminate a collection of 33 Spinacia oleracea hybrid cultivars from seven different breeding stations all over the world. All SSR markers were genic microsatellite markers located in coding or non-coding regions of genes of known function. Cluster analysis based on 13 of the SSR markers showed that the spinach hybrids grouped into three clusters. The first two clusters consisted of European spinach types, which were well discriminated according to their origin from different breeding stations. The third cluster was a mixture of Asian as well as European types of spinach. Subclusters in this group did not reflect differences in morphology, earliness or company origin. The data show that genic microsatellites are a powerful tool for discrimination of spinach cultivars.     

1-Methyl cyclopropene extends postharvest life of spinach leaves

Senescence of detached spinach leaves either untreated or treated with 0.1 or 1.0 μL L^?1 1-MCP has been investigated. 1-MCP treated leaves had higher chlorophyll content and photosystem II potential quantum yield (Fv/Fm) and lower solute leakage than untreated leaves after storage in darkness at 23 °C for 6 d, indicating a delay of senescence. Ethylene production was increased in spinach supplemented with 1-MCP after 3 d storage and then declined to the rates of untreated leaves. 1-MCP treated spinach had higher ascorbic acid and glutathione concentrations, and a low oxidised/reduced ratio for both antioxidants. Accumulations of ammonium and protein degradation were reduced by 1-MCP. The results presented here indicate that inhibition of ethylene sensitivity can be successfully used to extend the postharvest life of spinach leaves.     

Examination of the quality of spinach leaves using hyperspectral imaging

The present research is focused on the application of hyperspectral images for the supervision of quality deterioration in ready to use leafy spinach during storage (Spinacia oleracea). Two sets of samples of packed leafy spinach were considered: (a) a first set of samples was stored at 20 °C (E-20) in order to accelerate the degradation process, and these samples were measured the day of reception in the laboratory and after 2 days of storage; (b) a second set of samples was kept at 10 °C (E-10), and the measurements were taken throughout storage, beginning the day of reception and repeating the acquisition of Images 3, 6 and 9 days later. Twenty leaves per test were analyzed. Hyperspectral images were acquired with a push-broom CCD camera equipped with a spectrograph VNIR (400–1000 nm). Calibration set of spectra was extracted from E-20 samples, containing three classes of degradation: class A (optimal quality), class B and class C (maximum deterioration). Reference average spectra were defined for each class. Three models, computed on the calibration set, with a decreasing degree of complexity were compared, according to their ability for segregating leaves at different quality stages (fresh, with incipient and non-visible symptoms of degradation, and degraded): spectral angle mapper distance (SAM), partial least squares discriminant analysis models (PLS-DA), and a non linear index (Leafy Vegetable Evolution, LEVE) combining five wavelengths were included among the previously selected by CovSel procedure. In sets E-10 and E-20, artificial images of the membership degree according to the distance of each pixel to the reference classes, were computed assigning each pixel to the closest reference class. The three methods were able to show the degradation of the leaves with storage time.     

Monitoring of fresh-cut spinach leaves through a multispectral vision system

This paper reports the development of image processing methods for the detection of superficial changes related to quality deterioration in ready-to-use (RTU) leafy spinach during storage. The experiment was performed on spinach leaves stored at 4.5 °C for 21 days (Set 1) and at 10 °C for 9 days (Set 2). Regarding Set 1, 75 units were evaluated beginning at time zero and after 7, 14, and 21 days of storage (treatments t_1.0, t_1.1, t_1.2, and t_1.3, respectively). In the case of Set 2, 24 samples were measured at time zero and after 3, 6, and 9 days (treatments t_2.0, t_2.1, t_2.2, and t_2.3, respectively). Multispectral images were acquired using a 3-CCD camera centered at the infrared (IR), red (R), and blue (B) wavelengths. Opportune combinations of these bands were calculated using virtual images, and a non-supervised classification was performed. A large number of spinach leaves belonging to Set 2 showed injuries due to the effects of in-pack condensation; thus, an image algorithm was developed to separate these defective leaves before applying the classification. For Set 1, Set 2 and all the calculated virtual images, the classification procedure yielded two image-based deterioration reference classes (DRCs): Class A, including the majority of the samples belonging to t_1.0 and t_1.1 (Set 1) and to t_2.0 and t_2.1 (Set 2) treatments and Class B, which comprised mainly the samples belonging to t_1.2 and t_1.3 (Set 1) and to t_2.2 and t_2.3 (Set 2) treatments. An internal validation was performed, and the best classification was obtained with the virtual images based on R and B bands. For each sample, camera classification was evaluated according to reference measurements (visible (VIS) reflectance spectra and CIE L*a*b* coordinates); in all cases, VIS reflectance values corresponded well with storage days, and Classes A and B could be considered homogenous with regards to L* and a* values. Taken together, these results confirmed that a vision system based on R and B spectral ranges could constitute an easy and fast method to detect deteriorating RTU packed spinach leaves under different refrigeration conditions.     

育种人生--记兵团享受政府特殊津贴专家、七师棉花育种家李家胜

清晨的薄雾刚刚散去,初春的棉田里,棉叶上还挂着露珠.这天,李家胜一大早就来到棉花育种试验地里,他抬脚慢慢地跨进棉行,用手轻轻地拨开棉株,弯腰仔细地查看棉花的长势长相,然后在记录本上详细地做着记录.     

浅议航天育种

航天育种较选择育种、杂交育种、辐射育种等育种方法，属新兴的育种技术。自2003年10月“神舟五号”搭载作物种子等以来，人们对此议论增多。现根据我们所掌握的相关情况及近年来的实践作一阐述。     

The importance of photoperiodic response for the breeding of glasshouse spinach

Summary Very quick-growing spinach material has been raised for winter cropping in glasshouses by crossing some glasshouse varieties with an extremely quick-bolting parent and subsequent selection in winter glasshouse crops. The resulting material gave increased leaf production in winter cropping under glass and did not bolt too rapidly.The procedure used was based on the observation that leaf growth is optimal under a daylength corresponding with the critical daylength for bolting. The critical daylength of the current spinach varieties is longer than the daylengths under which winter crops are grown, so the rate of growth is not optimal.This paper also demonstrates how any other growth-accelerating properties than a particular critical daylength can be traced and used for breeding purposes.The importance of this ecological basis for breeding, growing and variety testing is pointed out and exemplified.     

分子辅助育种在能源草育种中的研究进展

综述了能源草的主要研究种类,能源草育种的主要指标,介绍了国内外能源草种质资源收集保存情况,重点介绍了能源草的分子辅助育种研究情况。从分子标记对能源草遗传多样性研究及目标基因寻找,特异连锁标记鉴定及目标基因的QTLs定位,特异基因克隆及基因修饰,基因干扰和转基因技术等方面介绍了能源草分子育种辅助育种情况。同时提出能源草育种需要加大能源草种类的筛选,加大能源草系统收集力度,在常规育种的基础上借鉴其他作物和牧草、草坪草分子辅助育种的方法与成果,加快能源草育种工作。     

Breeding of non-bitter cucumbers

A large number of seedlings of various cucumber varieties have been tested for bitterness. In the American variety Improved Long Green one plant was encountered that was non-bitter. This form of non-bitterness is highly valuable for breeding purposes, because of the possibility to select for non-bitterness at the seedling stage. Non-bitter varieties, as occur in other Cucurbitaceae, were not encountered in the many verieties investigated. Bitterness of cucumber and melon plants seems to be controlled by one dominant gene.Plants can be judged for non-bitterness simply by tasting them, provided that the tasters have previously been tested for sufficient discriminatory power.Non-bitterness of the young seedlings can also be shown by a chemical reaction. To this end a simple method has been developed.     

菠菜对不同施肥模式的响应及其生态化学计量学特征研究?

摘 要：【研究目的】研究不同施肥模式条件下菠菜的产量和品质与其地上部和其施肥模式中N/P、C/N、C/P、P/K相关关系规律,可以反映菠菜对施肥后土壤养分的响应和适应机制,并根据菠菜的响应和适应情况来判断施肥的合理性;【方法】在大田小区试验条件下,研究了菠菜对不同施肥模式的响应及其生态化学计量学特征。试验共分五种处理分别为不施肥对照,有机无机肥配施模式1(含有氨基酸肥料),有机无机肥配施模式2,有机肥施肥模式,无机肥施肥模式;【结果】研究结果表明,有机无机肥配施模式1提高菠菜产量、光合速率、可溶性总糖、蔗糖、游离氨基酸含量、氮素表观利用率和氮吸收效率,且这些指标与其地上部C/N和C/P之间存在显著正相关关系,而与施肥模式中C/N和C/P之间的相关关系不显著但存在正相关趋势。此外,有机无机肥配施模式1降低菠菜地上部硝酸盐含量且与其地上部和施肥模式中N/P、C/N、C/P和P/K之间均不存在相关关系;【结论】这些结果表明在田间条件下,有机无机肥配施模式1促进了菠菜地上部生长,改善了菠菜地上部的品质,是一种科学的施肥措施。