A cytogenetic study of monosomics in Brassica napus L.

1985 ◽  
Vol 27 (6) ◽  
pp. 683-688 ◽  
Author(s):  
Zhegong Fan ◽  
William Tap

Two types of monosomic plants of Brassica napus L. were discovered among the backcross progenies of crosses between Diplotaxis muralis L. and B. napus and between Brassica juncea L. and B. napus. These monosomics were designated mono-1 and mono-2, respectively. Morphologically the monosomic plants were virtually indistinguishable from their sib disomic plants. Seed production on both mono-1 and mono-2 plants was normal. Cytological examination revealed that most pollen mother cells (85%) of mono-1 plants formed 18 bivalents plus one univalent at diakinesis, while the remainder (15%) formed 17 bivalents plus a trivalent. The univaltn in mono-1 was submetacentric and its two arms were always stained more lightly than the centromeric region. Later meiotic stages in mono-1 plants appeared normal. The plants of mono-1 produced two types of pollen grains which were different in size. Both the large and small pollen grains of mono-1 were deeply stained with an I2–KI solution. Meiotic behavior of mono-2 plants was similar to that of mono-1 plants, but the frequency of trivalent formation was higher (62%). The univalent in mono-2 was longer than the two chromosomes it paired with to form a trivalent. Pollen produced on mono-2 plants was uniform in size and comparable to that of the normal disomics.Key words: Brassica napus, Brassica juncea, Diplotaxis muralis, aneuploidy, monosomics.

1985 ◽  
Vol 27 (4) ◽  
pp. 467-471 ◽  
Author(s):  
Z. Fan ◽  
W. Tai ◽  
B. R. Stefansson

Male sterility was investigated in backcross populations from hybrids between Diplotaxis muralis and Brassica napus using the former as the female parent. The F1 was male sterile and low frequencies (less than 20%) of male sterile plants were obtained from subsequent backcross generations. The data did not fit any Mendelian genetic ratios. Cytological examination of pollen mother cells from 52 plants of these backcross populations indicated the presence of an extra chromosome in all 22 male sterile plants and the normal chromosome number (2n = 38) in the remaining 30 fertile plants. Thus an extra chromosome which is derived from Diplotaxis muralis appears to be the sole cause of male sterility in these backcross populations.Key words: male sterility, Brassica napus, Diplotaxis muralis.


Author(s):  
Г.П. ЧЕКРЫГА ◽  
К.Н. НИЦИЕВСКАЯ ◽  
О.Б. ЮДИНА

Разработка систем качества потребляемых населением продуктов из меда невозможна без оценки флористического богатства региона. Цель настоящего исследования – установление ботанического происхождения меда по пыльцевому анализу, а также бонитета медоносной растительности юга Западной Сибири. Объектом исследования были 92 образца меда сбора 2019 года, полученные с пасек, расположенных в разных почвенно-климатических зонах региона. Для анализа из образца массой 200 г стеклянной палочкой мед наносили на предметное стекло в количестве одной естественной капли, закрывали покровным стеклом и под микроскопом при увеличении 400 исследовали морфологическое строение пыльцевых зерен. После идентификации пыльцевых зерен при увеличении 100 подсчитывали количество зерен каждого найденного морфологического типа. Затем вычисляли среднее арифметическое значение результатов пяти параллельных исследований в 5 каплях, определяли сумму средних арифметических значений общего количества подсчитанных пыльцевых зерен каждого идентифицированного типа и вычисляли частоту встречаемости. Ботаническое происхождение меда определяли исходя из процентного количества пыльцевых зерен в меде: при количестве пыльцевых зерен одного морфологического типа, превышающем 45%, образец считали монофлерным, от 44 до 15% – составной частью смешанного меда (полифлерным), от 14 до 0% – фиксировали присутствие, но не принимали в расчет. Установлено, что при получении монофлерных медов медоносные пчелы предпочитают растения: дягиль сибирский (Archangellica decurens Idb.), дудник лесной (Angelica silvestris L.), донник желтый, (Melilotus officinalis L.), донник белый, (Melilotus albus Medic.), рапс (Brássica nápus L.), синяк обыкновенный (Echium vulgare L.). По наличию пыльцевых зерен в образцах меда установлено, что 82,02% видов медоносных растений являются дикорастущими, 17,08% введены в культуру и используются для получения продуктов питания, кормов, как припасечные растения. Выявлена связь почвенно-климатических зон с видовым приоритетом пыльцевых зерен растений в образцах меда. Для всего региона это дикорастущие виды – дягиль сибирский и дудник лесной, с которых получено максимальное количество монофлерных медов – 42,42%. The development of quality systems for honey products consumed by the population is impossible without an assessment of the floral wealth of the region. The purpose of this study is to establish the botanical origin of honey by pollen analysis, as well as the bonitet of honey-bearing vegetation in the south of Western Siberia. The object of the study was 92 samples of honey collected in 2019, obtained from apiaries located in different soil and climatic zones of the region. For the analysis, honey in the amount of one natural drop was applied with a glass stick to a slide, covered with a cover glass. The morphological structure of pollen grains was examined under a microscope at a magnification of 400. After identification of pollen grains at an increase of 100, the number of grains of each morphological type found was counted. Then the arithmetic mean of the results of five parallel determinations in 5 drops was calculated, the sum of the arithmetic mean values of the total number of counted pollen grains of each identified type was determined, and the frequency of occurrence was calculated. The botanical origin of honey was determined based on the percentage of pollen grains present: when the number of pollen grains of the same morphological type exceeds 45%, the sample was considered monoflower, from 44 to 15% – a component of mixed honey (polyflower), from 14 to 0% – the presence was recorded, but not taken into account. It was found that when obtaining monofleral honey, honey bees prefer plants: siberian angelica (Archangellica decurens Idb.), wood angelica (Angelica silvestris L.), yellow melilotus (Melilotus officinalis L.), white melilotus (Melilotus albus Medic.), rapeseed (Brássica nápus L.), common bruise (Echium vulgare L.). Based on the presence of pollen grains in honey samples, it was found that 82,02% of honey plant species are wild, 17,08% are introduced into culture and are used for food, feed, and as supply plants. The connection of soil-climatic zones with the specific priority of pollen grains of plants in honey is revealed. For the entire region, these are wild species – siberian angelica and forest angelica, from which the maximum amount of monoflower honey is obtained – 42,42%.


2021 ◽  
Vol 937 (3) ◽  
pp. 032114
Author(s):  
O A Serdyuk ◽  
V S Trubina ◽  
L A Gorlova

Abstract The purpose of the research was a comparative evaluation of the disease affection of spring and winter forms of Brassica napus and Brassica juncea on the central zone of the Krasnodar region. Phytosanitary monitoring of diseases was carried out from the seedling stage. In 2011-2020, there were identified the diseases affecting winter and spring crops Brassica napus and Brassica juncea to the same extent: the occurrence frequency of downy mildew and powdery mildew was high, of Alternaria blight – from medium to high, of phytoplasma and bacterial blight – low. Differences are established for Sclerotinia disease, Phoma rot, Fusarium blight, white rust, gray rot. The occurrence frequency of Sclerotinia disease on winter form of Brassica napus and Brassica juncea varied in research years from low to medium, of Phoma rot – from medium to high; on spring forms, these diseases were noted in certain years with the low frequency. Fusarium blight affected only sowings of spring forms of Brassica napus and Brassica juncea with medium and high frequency, except for 2018-2019, when it was low. White rust affected only spring from of Brassica napus, gray rot – only winter forms of Brassica napus and Brassica juncea in certain years with the low frequency.


Rodriguésia ◽  
2021 ◽  
Vol 72 ◽  
Author(s):  
Kamila Bernardi Izoton ◽  
Luciana Dias Thomaz ◽  
Mário Luís Garbin ◽  
Patrícia Maria Oliveira Pierre

Abstract The genus Schinus (Anacardiaceae) comprises 30 species found in Peru, Bolivia, Chile, Paraguay, Uruguay, Argentina and Brazil. Schinus terebinthifolia (Brazilian pepper tree) is socioeconomically important in the Brazilian state of Espírito Santo. Dried fruit is used as a pepper-like spice and natural populations are exploited. Studies on the meiotic behavior and pollen stainability from an ecological and evolutionary point of view are essential, since they can promote future sustainable management strategies for this species. The objective was to evaluate meiotic behavior and characteristics of pollen grains of individuals from a natural population of S. terebinthifolia localized in the municipality of Vitória, Espírito Santo state, Brazil. Young anthers were squashed in 1% acetocarmine dye to obtain the pollen mother cells. The pollen stainability with 1% acetocarmine, Lugol’s iodine solution and Sudan IV and pollen shape were used to assess the pollen potential viability, cytochemistry and morphology. All individuals had a gametic number of n = 7, a regular meiotic behavior and so the somatic number is 2n = 2x = 14 chromosomes. Median pollen stainability was 94%. Pollen grains are dispersed as monads, 3 - colporate and subspheroidal. The exine has striate-reticulate ornamentation. Pollen grains are starch positive and lipid negative. This is the first report of the occurrence of diploidy for the species. The high pollen stainability is the result of the occurrence of regular meiosis. The presence of starch as pollen reserve can increase the resistance of pollen grains to hostile environments in this species.


Genome ◽  
1988 ◽  
Vol 30 (3) ◽  
pp. 450-457 ◽  
Author(s):  
William Tai ◽  
H. Ikonen

Twenty five polyhaploid plants (2n = 2x = 19, genome formula AC) of Brassica napus (2n = 4x = 38, AACC) were cytogenetically studied. Seven of these were found among field populations and the rest were derived through anther culture of B. napus cv. Regent. Meiotic behaviour at diakinesis and metaphase I revealed nine bivalents and one univalent in more than 40% of the more than 400 pollen mother cells analyzed. However, when the chromosome number of the polyhaploids was doubled using colchicine, 19 bivalents were observed. These doubled plants (2n = 4x = 38, AACC) also had normal behaviour identical to a regular B. napus at other meiotic stages. Quadrivalent associations were observed when the chromosome numbers were doubled to the octaploid level (2n = 8x = 72, AAAACCCC). It is suggested that A and C are homoeologous genomes. If homologous partners are present, chromosomes would pair within the same genome to form bivalents as occurred in the allotetraploids and to form quadrivalents as occurred in the allooctaploids. However, when a homologous partner is not available, the homoeologous chromosomes would then pair to form bivalents in those polyhaploids.Key words: Brassica napus, polyhaploids, genome relationship, meiotic behaviour, homoeologous pairing.


1981 ◽  
Vol 96 (2) ◽  
pp. 321-326 ◽  
Author(s):  
D. Eisikowitch

SUMMARYThe self-fertile cultivar of swede rape (Brassica napus) Maris Haplona does not usually autopollinate. The entomophilie pollen grains cannot be transferred by wind alone; anthers when flicked by insects or artificially under dry conditions behave like catapults raising a cloud of pollen grains.Variability in the concentration of sugar in its two types of nectaries (within a single flower) may increase the range of visiting insects. All visiting insects, including honey bees, carried out pollination; it is suggested that beehives should be placed in fields of oil-seed rape in order to increase pollination.


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