Resistance Breeding in Apple at Dresden-Pillnitz

Resistance breeding in apple has a long tradition at the Institute of Fruit Breeding now Julius Kuehn-institute in Dresden-Pillnitz. The breeding was aimed at the production of multiple resistance cultivars to allow a more sustainable and environmentally friendly production of apple. In the last decades a series of resistant cultivars (Re®-cultivars) bred in Dresden-Pillnitz has been released, ‘Recolor’ and ‘Rekarda’ in 2006. The main topic in the resistance breeding programme was scab resistance and the donor of scab resistance in most cultivars was Malus x floribunda 821. Due to the development of strains that are able to overcome resistance genes inherited by M. x floribunda 821 and due to the fact that single resistance genes can be broken easily, pyramiding of resistance genes is necessary. Besides scab, fire blight and powdery mildew are the main disease for which a pyramiding of genes is aspired in Pillnitz. Biotechnical approaches are necessary for the early detection of pyramided resistance genes in breeding clones. This paper will give an overview of the resistance breeding of apple in Pillnitz and the methods used

Breeding of resistant strawberry cultivars for organic fruit production – Diallel crossing strategies and resistance tests for Botrytis cinerea and Xanthomonas fragariae

Organic strawberry production suffers from high yield losses caused by numerous fungal and bacterial diseases. Two of the most important diseases are the grey mould disease caused by Botrytis cinerea Pers. (teleomorph Botryotinia fuckeliana), and the bacterial angular leaf spot disease caused by Xanthomonas fragariae (Kennedy & King). Beside cultivation methods and organic plant protection measures, the development of resistant cultivars seems to be the most promising strategy in order to improve the productivity in organic strawberry cultivation. Therefore, we established resistance tests to determine resistant and susceptible strawberry cultivars and breeding selections. In a first run, 40 different cultivars and selections were tested for their susceptibility towards B. cinerea by artificial inoculation of fruits and leaves and evaluation of the disease symptoms. Plants of 40 cultivars were tested for susceptibility to X. fragariae by artificial inoculation in the greenhouse. In a diallel crossing approach, 12 commonly cultivated strawberry cultivars have been crossed reciprocally and propagated in a field trial. Important characteristics of the progeny such as ripening time, yield, morphological traits and occurrence of diseases have been evaluated for a period of two consecutive years and lead to the determination of general (GCA) and specific (SCA) combining abilities. Together with the results of the resistance tests we identified a set of genotypes that show resistant characteristics towards B. cinerea and might be suitable for use in organic cultivation systems. Furthermore, they can be used for targeted breeding experiments in the future

Resistenzzüchtung in Dresden-Pillnitz - Der Apfel

The Institute of Fruit Breeding has a long tradition in breeding resistant apple cultivars. Systematic resistance breeding started in the 1930 ties in Müncheberg. Material developed in Müncheberg was transferred in the 1970 ties to the Institute for Fruit Research, the antecessor of the Institute of Fruit Breeding. Based on this material, a couple of multiple resistant cultivars were generated. The time schedule for combining biotic and abiotic resistant traits which demonstrates the long-lasting period necessary for systematic resistance breeding is given. An overview of resistant cultivars of Dresden-Pillnitz and the respective resistant traits is presented. This assortment of cultivars was developed to provide a resistant cultivar for each ripening group and every application in fruit growing. Modern resistance breeding is focused on quality and combination of different resistance genes for each pathogene to achieve durable resistance. Selection is facilitated by genetic markers. Likewise the look for new resistance genes, the analyses of genetics and the development of basic material are main areas of interest. Practical approaches in apple breeding to reach these aims are reported

TEMPRANILLO is a regulator of juvenility in plants

Many plants are incapable of flowering in inductive daylengths during the early juvenile vegetative phase (JVP). Arabidopsis mutants with reduced expression of TEMPRANILLO (TEM), a repressor of FLOWERING LOCUS T (FT) had a shorter JVP than wild-type plants. Reciprocal changes in mRNA expression of TEM and FT were observed in both Arabidopsis and antirrhinum, which correlated with the length of the JVP. FT expression was induced just prior to the end of the JVP and levels of TEM1 mRNA declined rapidly at the time when FT mRNA levels were shown to increase. TEM orthologs were isolated from antirrhinum (AmTEM) and olive (OeTEM) and were expressed most highly during their juvenile phase. AmTEM functionally complemented AtTEM1 in the tem1 mutant and over-expression of AmTEM prolonged the JVP through repression of FT and CONSTANS (CO). We propose that TEM may have a general role in regulating JVP in herbaceous and woody species

Functional evidence on the involvement of the MADS-box gene MdDAM4 in bud dormancy regulation in apple

Over the course of the year, temperate trees experience extremes in temperature and day length. In order to protect themselves from frost damage in winter, they enter a dormant state with no visible growth where all leaves are shed and buds are dormant. Also the young floral tissues need to withstand harsh winter conditions, as temperature fruit trees like apple develop their flower buds in the previous year of fruit development. So far, the genetic control of induction and release of dormancy is not fully understood. However, the transcription factor family of DORMANCY-Associated MADS-box (DAM) genes plays a major role in the control of winter dormancy. One of these genes is MdDAM4. This gene is expressed in the early phase of bud dormancy, but little is known about its function. Six transgenic apple lines were produced to study the function of MdDAM4 in apple. For plant transformation, the binary plasmid vector p9oN-35s-MdDAM4 was used that contains the coding sequence of MdDAM4 driven by the 35S promoter. Transgenicity of the lines was proven by PCR and southern hybridization. Based on siRNA sequencing and phenotypic observations, it was concluded that line M2024 overexpresses MdDAM4 whereas the gene is silenced in all other lines. Phenotyping of the transgenic lines provided evidence that the overexpression of MdDAM4 leads to an earlier induction and a later release of dormancy. Silencing this gene had exactly the opposite effects and thereby led to an increased duration of the vegetation period. Expression experiments revealed genes that were either potentially repressed or activated by MdDAM4. Among the potentially suppressed genes were several homologs of the cytokinin oxidase 5 (CKX5), five LOX homologs, and several expansins, which may indicate a link between MdDAM4 and the control of leaf senescence. Among the potentially activated genes is MdDAM1, which is in line with observed expression patterns during winter dormancy. MdDAM2, which shows little expression during endodormancy also appears to be activated by MdDAM4. Overall, this study provides experimental evidence with transgenic apple trees for MdDAM4 being an important regulator of the onset of bud dormancy in apple

Additive QTLs on three chromosomes control flowering time in woodland strawberry (Fragaria vesca L.)

Flowering time is an important trait that affects survival, reproduction and yield in both wild and cultivated plants. Therefore, many studies have focused on the identification of flowering time quantitative trait locus (QTLs) in different crops, and molecular control of this trait has been extensively investigated in model species. Here we report the mapping of QTLs for flowering time and vegetative traits in a large woodland strawberry mapping population that was phenotyped both under field conditions and in a greenhouse after flower induction in the field. The greenhouse experiment revealed additive QTLs in three linkage groups (LG), two on both LG4 and LG7, and one on LG6 that explain about half of the flowering time variance in the population. Three of the QTLs were newly identified in this study, and one co-localized with the previously characterized FvTFL1 gene. An additional strong QTL corresponding to previously mapped PFRU was detected in both field and greenhouse experiments indicating that gene(s) in this locus can control the timing of flowering in different environments in addition to the duration of flowering and axillary bud differentiation to runners and branch crowns. Several putative flowering time genes were identified in these QTL regions that await functional validation. Our results indicate that a few major QTLs may control flowering time and axillary bud differentiation in strawberries. We suggest that the identification of causal genes in the diploid strawberry may enable fine tuning of flowering time and vegetative growth in the closely related octoploid cultivated strawberry.Peer reviewe

Effect of different feeding intensity on feed intake, live weight gain, various body traits as well as the energy utilization for weight gain in female calves and heifers

In einer Untersuchung mit 80 neugeborenen Kälbern wurden die Auswirkungen unterschiedlicher Fütterungsintensitäten in der Aufzucht von weiblichen Kälbern und Jungrindern der Rasse Deutsche Holstein (Schwarzbunt) auf die Futteraufnahme und das Wachstum untersucht. Im ersten Versuchsabschnitt (bis Woche 14) wurden jeweils 40 Tiere mit Milchaustauscher in niedriger und hoher Intensität versorgt. Darauf folgte bis zur Woche 24 (Abschnitt 2) eine einheitliche Fütterung mit Grassilage und Konzentrat. Von der Woche 25 (Abschnitt 3) bis zur Belegung mit 400 kg Lebendmasse erhielten die als Kälber unterschiedlich behandelten Tiere jeweils Konzentrat in niedriger und hoher Intensität sowie Grassilage zur freien Aufnahme. Die höhere Tränkeintensität bewirkte im Abschnitt 1 eine signifikant größere Trockenmasse(T)-Aufnahme, Lebendmassezunahme (LMZ) und Widerristhöhe sowie einen höheren Energieaufwand für dei LMZ, während sich diese Parameter im Abschnitt 2 nicht unterschieden. Die höhere Konzentratgabe im Abschnitt 3 steigerte unabhängig von der vorherigen Tränkeintensität die T-Aufnahme und den Energieaufwand signifikant. Über den gesamten Versuchsverlauf beeinflusste weder die Tränkeintensität noch die Höhe der Konzentratgabe die T-Aufnahme, das Wachstum und den Energieaufwand, wohingegen die Konzentratgabe die LMZ signifikant positiv beeinflusste.Eighty newborn female Holstein calves were used to assess the influence of feeding intensity during the rearing period of calves and heifers on the feed intake and the growth. Throughout the first period (up to week 14) 40 animals each were provided with low and high amounts of milk replacer. Thereafter until week 24 the animals were fed on the same level with grass silage and concentrates (period 2). From the beginning of week 25 until first mating with about 400 kg of body weight each group was divided again into two subgroups receiving low and high amounts of concentrates and grass silage for ad libitum consumption. The high drinking intensity in period 1 resulted in a significantly higher dry matter intake (DMI), live weight gain (LWG), withers height and energy consumption for LWG, whereas there were no differences in these parameters at the end of period 2. The elevated concentrate level during period 3 significantly increased DMI and energy consumption independent of previous drinking intensity. Throughout the whole experiment neither the drinking intensity, nor the concentrate level did significantly influence the DMI, the growth and the energy consumption, whereas the concentrate level significantly increased the LWG