Late blight resistance gene from Solanum ruiz-ceballosii is located on potato chromosome X and linked to violet flower colour

<p>Abstract</p> <p>Background</p> <p><it>Phytophthora infestans </it>(Mont.) de Bary, the causal organism of late blight, is economically the most important pathogen of potato and resistance against it has been one of the primary goals of potato breeding. Some potentially durable, broad-spectrum resistance genes against this disease have been described recently. However, to obtain durable resistance in potato cultivars more genes are needed to be identified to realize strategies such as gene pyramiding or use of genotype mixtures based on diverse genes.</p> <p>Results</p> <p>A major resistance gene, <it>Rpi-rzc1</it>, against <it>P. infestans </it>originating from <it>Solanum ruiz-ceballosii </it>was mapped to potato chromosome X using Diversity Array Technology (DArT) and sequence-specific PCR markers. The gene provided high level of resistance in both detached leaflet and tuber slice tests. It was linked, at a distance of 3.4 cM, to violet flower colour most likely controlled by the previously described <it>F </it>locus. The marker-trait association with the closest marker, violet flower colour, explained 87.1% and 85.7% of variance, respectively, for mean detached leaflet and tuber slice resistance. A genetic linkage map that consisted of 1,603 DArT markers and 48 reference sequence-specific PCR markers of known chromosomal localization with a total map length of 1204.8 cM was constructed.</p> <p>Conclusions</p> <p>The <it>Rpi-rzc1 </it>gene described here can be used for breeding potatoes resistant to <it>P. infestans </it>and the breeding process can be expedited using the molecular markers and the phenotypic marker, violet flower colour, identified in this study. Knowledge of the chromosomal localization of <it>Rpi-rzc1 </it>can be useful for design of gene pyramids. The genetic linkage map constructed in this study contained 1,149 newly mapped DArT markers and will be a valuable resource for future mapping projects using this technology in the <it>Solanum </it>genus.</p

Cryopreservation of Plant Tissues in Poland: Research Contributions, Current Status, and Applications

Cryopreservation of vegetatively propagated plant material is an increasingly widely used method for the efficient and safe storage of germplasm resources around the world. In Poland, there are currently four cryobanks in use for long-term plant protection programs. However, plant tissues propagated in vitro constitute only a small portion of the accessions stored in them. To date, cryogenic storage techniques have been developed and adopted in this country for ornamental plants (roses, chrysanthemums, and geophytes), crop species (potato and garlic), forest tree species (the genera Quercus and Fraxinus), and some ferns. Polish researchers have used suspension cultures of Gentiana spp. and shoot tips of Lamprocapnos spectabilis to improve cryopreservation knowledge. A better understanding of the benefits of cryopreservation and its widespread implementation in plant biodiversity conservation programs is required. The objective of this review is to provide a concise synthesis of the scientific contributions, current status, and applications of cryogenic techniques for the conservation of in vitro culture-derived plant tissues in Poland. First, the results contributing to research that has been achieved using cell suspensions and advances related to the use of nanoparticles and plant extracts to improve cryopreservation efficiency are discussed. Then, the applications and advances in cryopreservation of ornamental plants (roses, radiomutants, plant chimeras, Lamprocapnos spp., and geophytes), crop species (potato and garlic), forest trees, and ferns are summarized

Bottle necks in breeding late blight resistant potato

The resistance to late blight (LB) is considered as a factor of major importance among resistances to potato pathogens. For four last decades more work has been done on potato resistant to Phytophthora infestans than on breeding for resistance to any other potato disease. Many sources of resistance have been known to breeders for many decades, but the results of their utilization are still disappointing. The difficulties in breeding for LB resistance were assessed by 39 participants of the survey organized for the Global Initiative on Late Blight (Zimnoch-Guzowska and Flis 2002), who indicated several major factors hampering progress in this area. The following factors found to be the most important bottle necks are discussed in the paper: (i) identification and utilization of new sources of resistance, not sufficient agronomic value of the used resistance sources; (ii) combination of earliness with LB resistance; (iii) complexity of genetic determination of LB resistance; (iv) combination of foliage and tuber resistance; (v) screening methods applied for resistance evaluation; (vi) cost of selection for resistance; (vii) lack of molecular markers (MAS) applicable to selection for LB resistance.   limitations, Phytophthora infestans, potato, resistance breedin

Exploitation of biotechnology by Polish plant breeding

W ramach koordynacji projektu badawczego zamawianego PBZ-MNiSW-2/3/2006 pt. „Nowe metody genetyki molekularnej i genomiki służące doskonaleniu odmian roślin uprawnych” przeprowadzono badania ankietowe wśród krajowych ośrodków hodowli roślin na temat wykorzystania biotechnologii w procesie hodowlanym roślin uprawnych. W badaniach wzięło udział 18 krajowych ośrodków hodowli roślin. Ankieta obejmowała 14 rozbudowanych pytań, ukazujących obecny stan wykorzystania biotechnologii w hodowli twórczej, trudności w uzyskaniu oczekiwanego postępu hodowlanego, znacznie pożądanych kierunków hodowli w poszczególnych gatunkach, obecne i przyszłe zastosowanie markerów molekularnych, zainteresowanie firm hodowlanych w szkoleniu własnego personelu, celowości prowadzenia programu hodowli wstępnej przez wyspecjalizowane ośrodki oraz korzystania z usług biotechnologicznych oferowanych hodowcom.Survey on application of biotechnology in the breeding process of cultivated plants was organized in the frame of coordination of the PBZ-MNiSW-2/3/2006 project entitled: “New methods of molecular genetics and genomics served to variety improvement in cultivated plants”. All of the eighteen invited domestic breeding centers took part in the survey. Fourteen extended questions were focused on current status of biotechnology application to plant breeding, difficulties in achieving expected breeding progress, importance of desired directions in breeding of respective plant species, use of molecular markers — currently and in the future, interest of breeding companies in training of their own staff, necessity of pre-breeding program realization by specialized centers and use of biotechnological services offered to breeders

The use of estimates of heritability and genetic variances in selection for chip colour between potato populations

The objective of this research was to examine the expected responses to selection for colour of chips (= crisps) produced directly from tubers stored at 4-6°C for three months in three potato populations. Population 1 was obtained from crossing cv. Lady Claire with parental line M-62774, Population 2 was derived from crossing cv. Snowden with parental line M-62724. Both populations originated from crosses between cold chipping parents. Population 3 was produced by intermating cold chipping parent (cv. Snowden) with good chipping parent (M-62805) that requires the reconditioning treatment. Fifty-eight to sixty random clones for each population plus four parents and four control cultivars were planted in 2003 and 2004 at M³ochów Research Center of Plant Breeding and Acclimatization Institute. A considerable genotypic variation in chip colour after cold storage has been found within three hybrid populations. Heritability estimates were moderate, ranging from 0.42 to 0.53, and each of these populations exhibited good potential advance by selection for chip colour after cold storage

Effect of deep freezing of Phytophtora infestans on their survival and pathogenicity

The maintenance of Phytophthora infestans cultures isolates from blighted potato, frozen in liquid nitrogen, was studied in two experiments. The effects of deep freezing and acclimatization pre-treatment at different temperatures on culture survival and stability of virulence and aggressiveness were evaluated. The best survival of cultures maintained for three months in liquid nitrogen was expressed, when cultures were acclimatized before freezing at 7˚C. The survival of frozen cultures was significantly worse in comparison with control combinations stored on rye-agar and rye-agar under paraffin oil for short time (in experiment I – 40 days, in experiment II – three months). The virulence spectrum of frozen cultures after thawing was more narrow than that one observed before culture freezing. However this virulence spectrum did not differ significantly from virulence range of control cultures. The level of aggressiveness of culture stored in liquid nitrogen did not differ significantly from control cultures as well. The virulence spectrum and aggressiveness level of cultures frozen in liquid nitrogen were significantly higher after two passages of thawed cultures on potato tissues than after single passage

Multivariate analysis of phenotypic diversity in the tetraploid × diploid hybrid progenies of potatoes

Osiemdziesiąt rodów ziemniaka uzyskanych z czterech interploidalnych krzyżowań 4x-2x zostało ocenione na 12 cech użytkowych, w tym morfologii bulw, w Instytucie Hodowli i Aklimatyzacji Roślin, Oddział Młochów w latach 2008–2009. Celem badań była ocena genotypowej różnorodności wśród rodów ziemniaka i uzyskanie wglądu w strukturę wielocechowej zmienności. Analiza składowych głównych (PCA) wyodrębniła pięć składowych głównych, które wyjaśniały 78,4% łącznej wariancji wśród rodów ziemniaka. Wykazana przez analizę PCA genotypowa różnorodność potomstwa 4x-2x daje szansę na wyselekcjonowanie wartościowych tetraploidalnych rodów zarówno na jadalny, jak i przetwórczy kierunek użytkowania. Spośród wyodrębnionych pięciu składowych głównych pierwsze trzy były najważniejsze. Pierwsza składowa (29,9% zmienności) była głównie skorelowana z regularnością kształtu, głębokością oczek i ciemnieniem enzymatycznym. Druga składowa, tłumacząca 16% łącznej zmienności była dodatnio skorelowana z plonem bulw, średnią masą bulwy i spłaszczeniem bulw. Trzecia składowa, wyjaśniająca 13,2% łącznej zmienności była pozytywnie skorelowana z zawartością skrobi i barwą chipsów.Eighty potato clones derived from interploid crosses 4x-2x were evaluated for 12 tuber morphological and agronomic traits at the Plant Breeding and Acclimatization Institute — National Research Institute, Research Center Młochów during 2008–2009. The objective of the research was to assess the genotypic diversity among potato clones and to gain insight into the structure of multivariable variation. The principal component analysis (PCA) distinguished five principle components which explained 78.4% of the total variance among potato clones. The demonstrated genotypic diversity of 4x-2x progenies gives the chance for selecting valuable tetraploid clones for both table and processing use. Out of five PCs, the first three were the most important. The first PC (29.9% of total variance) was mostly correlated with shape regularity, depth of eyes and enzymatic browning. The second PC, that explained 16.2% of the total variance, was positively correlated with tuber yield, mean tuber weight and tuber flatness. The third PC explaining 13.2% of the total variance was positively correlated with starch content and chip colour

The structure of multivariable phenotypic variation in potato progenies derived from tetraploid × diploid crosses

W IHAR, Oddział Młochów w latach 2008–2009, dla osiemdziesięciu rodów ziemniaka z czterech krzyżowań tetraploid × diploid przeprowadzono oceny pod kątem 12 cech użytkowych i jakościowych. Celem badań była ocena struktury wielocechowej zmienności. Eksploracyjna analiza czynnikowa (EFA) pozwoliła na wyodrębnienie 5 czynników odpowiedzialnych za 68% obserwowanej łącznej zmienności rodów. Wartości własne analizowanej macierzy korelacji dla tych czynników były większe od 1. Pierwszy czynnik (21,7% zmienności) był utworzony przez cechy odpowiedzialne za ogólny wygląd bulw (regularność kształtu, głębokość oczek, frekwencja bulw z wtórnym wzrostem). Drugi czynnik (15,5% zmienności), zwany czynnikiem plonotwórczym był skorelowany z plonem bulw, średnim ciężarem bulwy i stopniem spłaszczenia bulw. Trzeci czynnik (12,2% zmienności) określał przydatność do przetwórstwa i był skorelowany z dwoma wiodącymi cechami technologicznymi — zawartością skrobi i barwą chipsów. Czwarty czynnik (9,9% zmienności) został zinterpretowany jako wydłużenie bulw (korelacja z typem kształtu, frekwencją bulw spiczastych). Piąty czynnik (8,5% zmienności) był utworzony przez cechę wyglądu bulw. Wielowymiarowa struktura tej zmienności daje szansę na wyselekcjonowanie wartościowych tetraploidalnych rodów ziemniaka do użytkowania jadalnego, przetwórstwa spożywczego (chipsy, susze) oraz przetwórstwa na skrobię.In IHAR, Research Center Młochów during 2008–2009, eighty potato clones derived from the four tetraploid × diploid crosses were evaluated for 12 agronomic and tuber quality traits. The research objective was to examine the structure of multivariable variation. The first five axes of exploratory factor analysis (EFA) extracted 68% of the total variance among clones. Eigenvalues of the analyzed correlation matrix for these factors were above 1. The first factor (21.7% of total variance) was created by traits responsible for general appearance of tubers (shape regularity, depth of eyes, the frequency of tubers with the symptoms of secondary growth). The second factor (15.6% of total variance) was called a performance factor and was correlated with tuber yield, mean tuber weight and tuber flatness. The third factor (12.2% of total variance) called a suitability for processing was correlated with the two key processing traits: starch content and chip colour. The fourth factor (9.9% of total variance) was interpreted as tuber elongation since it was correlated with type of shape and the frequency of tubers with pointed ends. The fifth factor (8.5% of total variance) was correlated with the skin appearance. Multivariate structure of this variance gives a chance for selecting of valuable potato clones for: table use, processing into chips or dry-products and starch processing

Resistance of Phytophthora infestans in three Solanum nigrum F3 families

Solanum nigrum is a self-pollinating, hexaploid weed and one of a few Solanaceae species native to Europe. It used to be described as a non-host  for Phytophthora infestans. However, now it is known that, like its distant relatives: potato (Solanum tuberosum L.) and tomato (Solanum lycopersicum L.), S. nigrum can suffer from potato late blight caused by this pathogen. Both susceptible and resistant S. nigrum genotypes  have been previously identified and inheritance of resistance originating from one accession has been described based on population of F2 plants and 15 F3 lines. The goal of this study was to evaluate resistance of three families of F3 lines, originating from crosses between  a susceptible and three different  resistant  S. nigrum accessions  followed  by two self-pollinations.  Parental  acces- sions were tested for the spectrum of late blight resistance against 48 P. infestans isolates. The three families consisted of 106, 96 and 115 F3 lines, respectively, and from each line 20 plants were tested for resistance to P. infestans. Laboratory  detached leaf assays were  performed in two dates and two replications  of three leaves  each.  Segregation  of the trait  within the line  allowed  us  to distinguish hetero- and homozygous lines. In one F3 family, the ratio of resistant homozygotes: heterozygotes: susceptible  homozygotes  was 1:2:1, indicating  that  a single  gene is  most likely  underlying  the late blight resistance in this case. In the other two, observed segregations of the trait significantly deviated from this model suggesting more complex inheritance patterns