scholarly journals Distant hybridization as a method of haploid production in cereals

2019 ◽  
Vol 2 (2) ◽  
pp. 44-52
Author(s):  
T. I. Djatchouk ◽  
V. N. Akinina ◽  
O. V. Khomyakova ◽  
E. V. Кalashnikova
Keyword(s):  
Doubled Haploids ◽  
Chromosome Complement ◽  
Imperata Cylindrica ◽  
Chromosome Engineering ◽  
Distant Hybridization ◽  
Time Period ◽  
Efficient Alternative ◽  
Dh Lines ◽  
Time Required ◽  
Haploid Plants

Elimination of chromosomes is a phenomenon widespread in distant hybrids. It ranges from the loss of one or two chromosomes to elimination of whole chromosome complement of one of the parents. Such elimination leads to the production of haploid plants, which then are treated with colchicine to double the chromosome number and to develop DH‑lines. Homozygosity of doubled haploids serves as a basis for their wide use in plant genetics and breeding. The use of this approach reduces the time required for obtaining homozygous lines by 5 years on the average. It leads to savings in human resources, energy and acreage. The development of the “bulbosum” method for haploid barley production had a strong influence on the chromosome engineering in cereals and its implementation in plant breeding. However, the method developed on that basis could not be used effectively for producing haploids of wheat, triticale, etc. because of Hordeum bulbosum L. pollen sensitivity to genes inhibiting wheat crossability (Kr genes). The crosses with Imperata cylindrica (L.) Raeusch. is an efficient alternative to the widely used wheat × maize and triticale × maize crosses due to abundant pollen supply within a longer time period, significantly higher frequency of embryos formation and haploid plants regeneration.

Haploidy and plant breeding

1981 ◽  
Vol 292 (1062) ◽  
pp. 499-507 ◽  
Keyword(s):  
Plant Breeding ◽  
Doubled Haploids ◽  
Chromosome Complement ◽  
Basic Research ◽  
Breeding Value ◽  
Additive Variance ◽  
Ploidy Levels ◽  
Breeding Programmes ◽  
Dh Lines

A haploid is an organism that looks like a sporophyte, but has the chromosome complement of a reduced gamete. There are several ways in which haploids can occur or be induced in vivo : spontaneously, mostly associated with polyembryony, and through abnormal processes after crosses, like pseudogamy, semigamy, preferential elimination of the chromosomes of one parental species, and androgenesis. In the crops described, haploids are or are near to being used in basic research and plant breeding. The application of haploids in breeding self-pollinated crops is based on their potential for producing fully homozygous lines in one generation, which can be assessed directly in the field. Early generation testing of segregating populations is possible through haploids, because doubled haploids (DH) possess additive variance only. Haploids can also be applied in classical breeding programmes to make these more efficient through improved reliability of selection. The application of haploids in cross-pollinated crops is also based on a rapid production of DH-lines, which can be used as inbred lines for the production of hybrid varieties. By means of haploids all natural barriers to repeated selfing are bypassed. In autotetraploid crops there are two types of haploid. One cycle of haploidization leads to dihaploids; a second cycle produces monohaploids. The significance of dihaploids is in their greatly simplified genetics and breeding and in the possibility of estimation of the breeding value of tetraploid cultivars by assessing their dihaploids. The main drawback of dihaploids is their restriction to two alleles per locus. Also, after doubling, it is impossible to achieve tetra-allelism at many loci, the requirement for maximal performance of autotetraploid cultivars. Tetra-allelism can be obtained when improved dihaploids have a genetically controlled mechanism of forming highly heterozygous restitution gametes with the unreduced number of chromosomes. Monohaploids, after doubling or twice doubling, may lead to fully homozygous diploids and tetraploids. These are important for basic research, but not yet for practical application. Meiotic data of potato homozygotes at three ploidy levels are presented.

scholarly journals Creation of an interspecific hybrid of Capsicum annuum L. and C. frutescens L. using biotechnological approaches

2021 ◽  
pp. 27-33
Author(s):  
E. A. Dzhos ◽  
D. V. Shumilina ◽  
O. N. Pyshnaya ◽  
M. I. Mamedov ◽  
A. A. Baikov ◽  
...  
Keyword(s):  
Interspecific Hybrid ◽  
Microspore Culture ◽  
Doubled Haploids ◽  
Pure Line ◽  
Cultivated Plants ◽  
Hot Pepper ◽  
Distant Hybridization ◽  
New Variety ◽  
Paternal Line ◽  
Haploid Plants

Relevance. Pepper is a common crop both for fresh consumption and for the preparation of spices. Recently, along with the increasing popularity of C. annuum L. pepper, there is increasing interest in other species of this genus, which have a number of breeding and important properties. The most important method of enriching the gene pool of cultivated plants is distant hybridization, through which valuable traits are transferred from wild species to cultivated ones. The development of a new variety is a lengthy process, stretching over several years. In this regard, breeders have faced the challenge of obtaining pure lines to create a pepper hybrid with desired properties by applying modern biotechnological methods that will accelerate this process. One of them is the method of microspore culture, which allows mass production of haploid plants, reducing the time for creating constant parental lines.Material and methods. The aim of the work was to create an interspecific hybrid of hot pepper (C. annuum L. x C. frutescens L.) with high ornamental properties, a complex of economically valuable traits, with good taste qualities. The research was carried out in the film greenhouse of FSBSI FSVC in the Moscow region. The research material was a variety population of hot pepper Capsicum frutescens Cz-544-14, used as a paternal line, which was heterogeneous, and a pure line of C. annuum L. (Pb-551) created by classical breeding.Results. The pepper hybrid F1 Christmas bouquet was created as a result of hybridization of species parental forms obtained by different methods (biotechnological and classical). To accelerate the production of an aligned paternal form of C. frutescens L., the technology of doubled haploids through microspore culture was used. As a result, doubled haploid plants meeting the planned model (compact low habit, purple fruit colouring in technical ripeness and red in biological ripeness) were obtained. The resulting hybrid combined all the necessary economic features: high ornamentality, compactness, bouquet arrangement of fruits, high taste and aroma. Thus, the use of remote interspecific hybridization in the breeding process in combination with biotechnological approaches can accelerate the production of new forms of hot peppers that meet the demands of the market.

Clinical Update: Functional Capacity Evaluations—An Update

1999 ◽  
Vol 4 (5) ◽  
pp. 4-7 ◽  
Author(s):  
Laura Welch
Keyword(s):  
Job Performance ◽  
Functional Capacity ◽  
Injury Risk ◽  
Disability Evaluation ◽  
Time Period ◽  
Submaximal Effort ◽  
Lack Of Sleep ◽  
Overall Performance ◽  
Time Required ◽  
Specific Limitation

Abstract Functional capacity evaluations (FCEs) have become an important component of disability evaluation during the past 10 years to assess an individual's ability to perform the essential or specific functions of a job, both preplacement and during rehabilitation. Evaluating both job performance and physical ability is a complex assessment, and some practitioners are not yet certain that an FCE can achieve these goals. An FCE is useful only if it predicts job performance, and factors that should be assessed include overall performance; consistency of performance across similar areas of the FCE; consistency between observed behaviors during the FCE and limitations or abilities reported by the worker; objective changes (eg, blood pressure and pulse) that are appropriate relative to performance; external factors (illness, lack of sleep, or medication); and a coefficient of variation that can be measured and assessed. FCEs can identify specific movement patterns or weaknesses; measure improvement during rehabilitation; identify a specific limitation that is amenable to accommodation; and identify a worker who appears to be providing a submaximal effort. FCEs are less reliable at predicting injury risk; they cannot tell us much about endurance over a time period longer than the time required for the FCE; and the FCE may measure simple muscular functions when the job requires more complex ones.

scholarly journals The Effect of Tillage Treatments on Soil Temperature at Planting and on Corn (Zea mays L.) Yield

2001 ◽  
pp. 40-44
Author(s):  
Miklós Pakurár ◽  
László Lakatos ◽  
János Nagy
Keyword(s):  
Zea Mays ◽  
Soil Temperature ◽  
Zea Mays L ◽  
Time Period ◽  
Soil Temperatures ◽  
Time Periods ◽  
Time Required ◽  
Corn Hybrid

The effect of soil temperature was evaluated on the yield of the Occitan corn hybrid at a depth of 5 cm. We examined this effect on the time required from planting to emergence for three average durations: five, ten and fifteen days, all calculated from the day of planting. Winter plowing (27 cm), spring plowing (23 cm), disc-till (12 cm) treatments and 120 kg N per hectare fertilizer were applied. As a result of our analysis, we determined the post planting optimum soil temperatures for various time periods. The average soil temperature for a time period of 15 days post planting is the most usable for determining actual yields, followed by ten days, with five days proved to be the least usable (winter plow R2 = 0.86, spring plow R2 = 0.87, disc-till R2 = 0.64).

COMPARAISON ENTRE DES LIGNEES PEDIGREES ET DES LIGNEES HAPLOIDES DOUBLEES CHEZ L’ORGE (HORDEUM VULGARE L.)

1980 ◽  
Vol 60 (1) ◽  
pp. 79-85 ◽  
Author(s):  
PIERRE TURCOTTE ◽  
C. A. ST-PIERRE ◽  
KEH MING HO
Keyword(s):  
Hordeum Vulgare ◽  
Doubled Haploid ◽  
Doubled Haploids ◽  
Block Design ◽  
Pure Line ◽  
Kernel Weight ◽  
Hordeum Vulgare L ◽  
Line Production ◽  
Doubled Haploid Lines ◽  
Time Required

Pedigree and doubled haploid lines from seven crosses of barley (Hordeum vulgare L.) were compared over 2 years. The lines were tested, in a randomized complete block design, in row plots at Ste-Foy in 1977 and in hill plots at Brawley, California in 1978. There are significant differences between the two methods of pure line production for grain yield, 1000-kernel weight, plant height, resistance to lodging and date of maturity. Furthermore, these significant differences between doubled haploid and pedigree lines seem to be tied to wide crosses. After showing that doubled haploids are superior for resistance to lodging, we conclude that the use of doubled haploid lines must be seriously considered in a barley breeding program on the basis of improved selection efficiency and the short time required to get homozygous lines.

Time Required to Achieve Homogeneity of Test Substances Added to Dog Feed

1991 ◽  
Vol 74 (5) ◽  
pp. 857-861
Author(s):  
Philip P Sapienza ◽  
George J Ikeda ◽  
Patricia I Warr ◽  
Richard H Albert
Keyword(s):  
Nicotinic Acid ◽  
Animal Feed ◽  
Mixing Time ◽  
Critical Factor ◽  
Laboratory Animals ◽  
Time Period ◽  
Time Test ◽  
Time Required ◽  
Carrier Animal

Abstract The homogeneity of test substances in a carrier (animal feed) is a critical factor In conducting long-term feeding studies in laboratory animals. A method for determining the adequate amount of mixing to achieve homogeneity by a mixer of the type described has been determined when 2 distinctly different compounds are added to ground dog feed. Nicotinic acid and butylated hydroxyanlsole at a concentration of 1% were separately mixed with the dog feed for 15,30,45,60, and 120 min to determine optimum mixing time. Test portions were taken from 4 different sampling sites at each time period and analyzed in duplicate for the added substance. Four batches were prepared and the results were aggregated. Very little interbatch variability was observed. The variance of the average values from the 4 sampling sites at each time period was calculated and used as a simple, crude, but effective numerical quantity to monitor the approach to homogeneity of the mixture.

scholarly journals Doubled haploids of interspecific hybrids between Brassica napus and Brassica rapa for canola production with valuable breeding traits

OCL ◽  
2020 ◽  
Vol 27 ◽  
pp. 45
Author(s):  
Ainash Daurova ◽  
Dias Daurov ◽  
Dmitriy Volkov ◽  
Kuanysh Zhapar ◽  
Daniyar Raimbek ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Seed Germination ◽  
Brassica Rapa ◽  
Doubled Haploid ◽  
Interspecific Hybrids ◽  
Nutritional Value ◽  
Doubled Haploids ◽  
Doubled Haploid Plants ◽  
Haploid Plants

Doubled haploids (DH) were obtained from two interspecific hybrids between Brassica napus and Brassica rapa. Seeds of doubled haploid plants differed in colour and size. The hybridity of the obtained doubled haploid is shown using genomic in situ hybridization (GISH) analysis. Evaluation of drought tolerance during seed germination on PEG-6000 showed the advantage of doubled haploid plants of interspecific hybrids over the parent cultivars. The oil from seeds of doubled haploid plants showed good nutritional value.

Time Requirement from Pollination to Seed Maturity in Waterhemp (Amaranthus tuberculatus)

Weed Science ◽  
2010 ◽  
Vol 58 (2) ◽  
pp. 167-173 ◽  
Author(s):  
Michael S. Bell ◽  
Patrick J. Tranel
Keyword(s):  
Seed Weight ◽  
Room Temperature ◽  
Coat Color ◽  
Seed Viability ◽  
Time Requirement ◽  
Seed Maturity ◽  
Time Period ◽  
Amaranthus Tuberculatus ◽  
Time Required ◽  
Mature Seeds

Experiments were conducted to determine the amount of time required for waterhemp to produce mature seeds after pollination. Female waterhemp plants were pollinated over a 24-h time period and then isolated from males. Two branches, each containing at least 500 flowers, were harvested from each female at the time of the initial pollination, designated as 0 d after pollination (DAP), as well as at multiple other times after pollination up to 62 DAP. One branch from each harvest was stored at 30 C for 48 h, while the other branch was stored at −20 C for 48 h. Branches were then stored at room temperature until all harvests were complete, at which time seeds from each branch at each time after pollination were collected, weighed, and stratified. Germination tests were then conducted to determine the time at which seeds become viable after pollination. Seeds that had not germinated by the end of the germination tests were subjected to tetrazolium testing for viability. Germination tests were also conducted on nonstratified seeds to investigate changes in seed dormancy that were expected to occur over the amount of time the seeds were allowed to remain on the plants. Seeds stored initially at 30 C postharvest became viable 7 to 9 DAP, whereas seeds stored initially at −20 C postharvest did not become mature until 11 DAP. Seed coat color was white soon after pollination and became dark brown to nearly black by 12 DAP, and seed weight increased until 12 DAP. Tetrazolium tests for seed viability correlated well with the germination tests. Germination tests on nonstratified seeds indicated that dormancy level was initially high in the population used, but began to decrease between 15 and 30 DAP. Results of this study have implications both for waterhemp management and research.

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