Rosa Dumalis Research Articles

Changes in colour and sugar content in rose hips (Rosa dumalis L. and R. rubiginosa L.) during ripening

SummaryRose hips constitute a recently domesticated small fruit crop. In the last few years, interest in this crop has increased considerably due to its nutritive and health promoting values. Changes in CIE colour co-ordinates L*, a* and b*, glucose, fructose and sucrose contents , fruit weight, percentages of fruit flesh and dry matter, and °Brix values were determined during the ripening period in two species, Rosa dumalis and R. rubiginosa. In both species, colour changes during ripening were characterised by a large increase in a* (redness) for the first three harvest dates, whereas L* and b* (yellowness) decreased during the whole study (rose hips became darker and less yellow). Glucose was the major sugar, followed by fructose, both increasing significantly in R. rubiginosa until the beginning of October. By contrast, a maximum was reached by mid-September for R. dumalis. °Brix values increased in both species during the first 3 weeks of September, then levelled-out. In both species, changes in calculated hue (visible colour) were related to changes in total sugar content and °Brix value. It should, therefore, be possible to use colour as an indicator of optimum harvesting time.

Screening of fungal diseases in offspring from crosses between Rosa sections Caninae and Cinnamomeae

Roses constitute one of the most important ornamental plant crops. Recently an increasing interest has been noted also for the fruits; rose hips. Plant breeding of dogroses (section Caninae) is complicated by their unique meiosis with an unequal distribution of chromosomes, which results in strongly matroclinal offspring. Disease resistance was evaluated for blackspot, leaf spot, powdery mildew and rust in 649 field-grown offspring from eleven families. One genotype of Rosa dumalis and two of R. rubiginosa were used as pistillate parents and six selected genotypes derived from open pollination of ‘Uralskij Champion’ were used as pollinate parents. Blackspot was the most serious disease, followed by leaf spot, whereas powdery mildew and rust were rare. Significant differences between families with different staminate parents were found for blackspot, leaf spot and powdery mildew, indicating the possibility to select for resistance to these diseases in seedlings from crosses involving section Caninae in spite of the Canina meiosis.

Exogenous IBA and Inoculation with Agrobacterium rubi Stimulate Adventitious Root Formation on Hardwood Stem Cuttings of Two Rose Genotypes

During Fall and Winter 1999-2000 and 2000-2001, a study was conducted to evaluate the effects of exogenous IBA application (0, 2000, or 4000 ppm) and inoculation with Agrobacterium rubi (strains A1, A16, or A18) alone or in combination with each bacterial strain on rooting of hardwood stem cuttings of two rose selections (ERS 14, Rosa canina, and ERS 15, Rosa dumalis). Treatments of hardwood stem cuttings with IBA, bacteria alone and in combination with IBA were found to promote rooting. The highest rooting percentage was obtained among ERS 14 cuttings when treated with 4000 ppm IBA plus A. rubi A16. However, optimal rooting of ERS 15 was obtained when treated with 2000 ppm IBA plus A. rubi A18. Better rooting was observed in thornless ERS 15 genotype than in thorny ERS 14 genotype in both years. Chemical name used: 1H, indole-3-butyric acid (IBA).

Variation Among and Within Dogrose Taxa ( Rosa sect. caninae ) in Fruit Weight, Percentages of Fruit Flesh and Dry Matter, and Vitamin C Content

Important fruit traits were screened in a plant breeding program concerning a newly domesticated crop in Sweden of rose hips. The taxa Rosa dumalis subsp. coriifolia , R . dumalis subsp. dumalis , R . rubiginosa and R . villosa subsp. mollis, collected from 23 localities in Scandinavia, were investigated for fruit weight, percentage of fruit flesh, percentage of dry matter and vitamin C content. R . dumalis subsp. coriifolia, R . dumalis subsp. dumalis and R . villosa subsp. mollis had significantly larger fruits and a higher percentage of fruit flesh than R . rubiginosa. Analysis of intraspecific variation showed that R. dumalis subsp . coriifolia was the most variable taxon, followed by R . dumalis subsp. dumalis and R . villosa subsp. mollis , whereas R. rubiginosa showed the most restricted variability. A highly significant positive correlation was found between fruit weight and percentage fruit flesh which in turn showed a moderate negative correlation with percentage dry matter.

Evidence of apomixis in hemisexual dogroses, Rosa section Caninae

All members of Rosa section Caninae, dogroses are polyploid and characterized by their unbalanced meiosis, which in most cases leads to a pronounced morphological influence from the maternal parent. In a previous investigation on a pair of reciprocal crosses between two species in this section, Rosa dumalis and R. rubiginosa (2n=35), nine offspring plants (approximately 10%) did not receive any of the 21 RAPD markers present in the respective pollen parent. This was interpreted as a possible occurrence of apomixis. These nine plants have now been subjected to a further study with additional markers. Thirteen new RAPD markers showed the same result as in the previous investigation: none of the nine plants inherited any of the pollen donor markers. The reproducibility of the RAPD markers was checked by mixing DNA samples to obtain a series of artificial hybrids between the two parent plants. Twelve RAPD markers gave the expected result, whereas one marker appeared only 50% of the time. In addition, pollen viability, mean number of seeds per hip, mean seed weight, and mean weight of fruit flesh per hip have been studied on the four progeny groups: R. dumalis×R. rubiginosa plants which received pollen donor markers (PM plants), R. dumalis×R. rubiginosa plants which did not receive any pollen donor markers (NPM plants), R. rubiginosa×R. dumalis PM plants and R. rubiginosa×R. dumalis NPM plants. A canonical discriminant analysis based on these four reproductive characters separated the four progeny groups. There were significant differences between the two PM groups in all investigated characters, and also between the PM and the NPM groups in pollen viability. The result from the RAPD markers together with the differences in pollen viability between the PM and NPM progeny groups is taken as an indication that apomixis occurs within the Caninae section.

KUŞBURNU TİPLERİNİN DONA DAYANIMLARI ÜZERİNDE BİR ARAŞTIRMA

OZET : Bu arastirma 1996-1998 yillarinda Erzurum'da yurutulmustur. Arastirmada materyal olarak, daha once Erzurum'da yurutulen seleksiyon calismasi sonucu secilen ve Rosa canina turune ait olan 25-Mrk-14 (dikenli) ve Rosa dumalis turune ait 25-Mrk-15 (dikensiz) nolu kusburnu tipleri kullanilmistir. Kasim-mart aylari arasindaki dinlenme doneminde, kusburnu tiplerinin 1 yillik surgunleri alinarak -30 0 C'de 0, 8, 16 ve 24 saat sure ile suni don testine tabi tutulmuslardir. Deneme aylari boyunca tiplerin tomurcuklarinda seker ve nisasta analizleri yapilarak bunlarin mevsimsel degisimleri tespit edilmistir. Arastirma sonunda dona dayanim yonunden uygulama saatleri, aylar ve tipler arasinda farklilik ortaya cikmis, dikensiz tip dikenliye gore soguga daha az dayanikli bulunmustur. Her iki tipte de dona dayanim ocak ve subat aylarinda yuksek, kasim ve mart aylarinda ise dusuk olarak belirlenmistir. Diger yandan tiplerin cesitli seker icerikleri (toplam seker, sakkaroz) kasim ayindan mart ayina kadar artis gostermis ancak mart ayinda bu degerlerde dusus oldugu gozlenmistir. Anahtar kelimeler : Kusburnu, soguga dayaniklilik, karbonhidratlar A RESEARCH ON THE FROST RESISTANCE OF SOME ROSE HIP TYPES SUMMARY : This research was carried out during the 1996-1998 in Erzurum. The material used in this study were thorny 25-Mrk-14 ( Rosa canina ) and thorniness 25-Mrk-15 ( Rosa dumalis ) rose hip types which were selected from previous studied performed in Erzurum. Samples of one year old twigs were collected and exposed to the artificial freezing test at -30 o C periodically from november to march. Throughout the experiments, several biochemical analysis on the buds of the rose hip types, including total sugar, starch and the others were done once a month. Our results showed that there was a significant differences between thorny and thorniness types of rose in term of resistance to freezing, according to hours of treatment and month of samples taken. The thorniness type was less resistant than thorny type in term of frost resistance. Frost resistance in both of rose hip types were found much more higher in january and february than november and december. On the other hand, the sugar ingredients of rose hip types increased from november to february, but decreased in march. Key words : Rose hip, frost resistance, carbohydrates

Different levels of morphometric variation in three heterogamous dogrose species (Rosa sect.Caninae, Rosaceae)

Difficulties in delimiting well-defined entities in the dogroses (Rosa sect.Caninae) has resulted in very variable taxonomic treatments. The present study was undertaken to provide a background for taxonomy as well as plant breeding. Morphometric diversity was analysed on seedlings obtained from field collections in South Sweden of three species,Rosa dumalis, R. rubiginosa andR. villosa. A canonical variates analysis showed that the three species are relatively distinct whereas two subspecies ofR. dumalis were less well discriminated. Analyses of variance demonstrated that intraspecific variation is pronounced inR. dumalis and, to a lesser extent, inR. villosa.

Determination of pollen viability and <i>in vitro</i> pollen germination of <i>Rosa dumalis</i> and <i>Rosa villosa</i>

Pollen quantity, viability and germination of four genotypes of Rosa dumalis and R. villosa were investigated. The number of anthers per flower were 90.3 in genotype 4 (Rosa villosa) and 116.4 in genotype 1 (Rosa dumalis). Genotype 1 showed the highest pollen viability on the basis of both TTC and IKI tests. Â Key words: Dogrose, Pollen germination, Pollen viability, Rosa spp. DOI = 10.3329/bjb.v36i2.1511 Bangladesh J. Bot. 36(2): 185-187, 2007 (December)