mass selection
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2021 ◽  
Vol 04 (04) ◽  
pp. 13-26
Author(s):  
Bal Krishna Joshi ◽  

Indigenous seeds are grown by the farmers over the years with a strong influence from local natural factors. Such seeds have a higher level of intrapopulation variations and the capacity of buffering the adverse factors. Understanding indigenous seeds along with their diversity are useful to diversify their uses, to assess conservation status, to know the factors making farming areas red zone, and to improve their performance. Selection is the simplest and most common method for the improvement of crop varieties. The variation must be created and maintained to impose selection. Different types of selection can be considered depending on the mode of reproduction of crops. Response to selection and correlated response are estimated to make the selection process more effective. Many different selection approaches can target either developing monomorphic or polymorphic varieties. There are five selection units and can be applied in five crop stages. Farmers’ criteria need to be considered during selection process. Based on the genotypic classes, there are three types of selection namely stabilizing selection, directional selection, and disruptive selection. The most simple and common selection methods are pure lines, mass selection, and class-bulking selection. Orthodox seeds in short, medium, and long-term storage facilities are conserved as a seed bank. Major types are household seed banks, community seed banks, national seeds, natural seed banks, and global seed banks. A seed bank is for assuring the availability of crop diversity for research, study, and production. The common works in seed banks are diversity collection, regeneration, characterization, multiplication, and distribution along with online database management.


2021 ◽  
Vol 49 (4) ◽  
pp. 12555
Author(s):  
Gai YUHONG ◽  
Adnan RASHEED ◽  
Zhao ZHOU ◽  
John J. GARDINER ◽  
Muhammad ILYAS ◽  
...  

The soybean is one of the most significant legume crops around the globe and serves as a source of dietary components for humans and animals. It has a higher percentage of protein compared to any other crop. Soybean yield and quality have been affected by many environmental factors.  The genetic mechanism of yield and quality is still not clearly understood. Hence there is still a need to investigate the major potent factors to shed light on the mechanism behind yield and quality traits in soybean. Recently, a lot of significant work, including novel QTL, genes, and CRISPR-based genome editing in soybeans, has been done, which opened new doors of hope. The current review has presented detailed work done previously. We have also discussed the role of different breeding techniques in the conventional way of soybean improvement. The genetic factors regulating yield, quality, and disease resistance could be further cloned and transferred into elite cultivars to attain higher output in the current situation of changing environment. The integrated use of several techniques, like CRISPR/Cas9, next-generation sequencing, omics approaches, would be a fruitful way to improve soybean yield and quality. Besides this, hybridization, mass selection, pure line selection, backcross breeding, and pedigree selection should be adopted to develop novel soybean cultivars. This review concluded that soybean yield and quality improvement could be enhanced by exploring its genetic mechanism using several molecular and conventional methods.  


2021 ◽  
Vol 32 (Issue 2) ◽  
pp. 32-39
Author(s):  
C.J. Bermejo ◽  
F. Maglia ◽  
T. Palacios ◽  
M.A. Espósito ◽  
F. Cazzola ◽  
...  

Lentil (Lens culinaris Medik.) is a self-pollinating diploid (2n=2x=14) species belonging to the Fabaceae family. It is one of the oldest crops known, with 8,000 to 9,000 years of history and it is among the earliest domesticates from the Near East Fertile Crescent. The seeds have high nutritional value. This crop is an interesting substitute to wheat in cereal rotations but its importance is low due to a lack of suitable varieties with local adaptation. Some of the major problems that Argentinian lentil breeders face are the narrow genetic base of the current cultivated germplasm and its low yield potential. A lentil breeding program was initiated in 2004 to develop new varieties with adaptation to prevalent conditions in growing areas of Argentina. Germplasm was obtained from ICARDA (International Center for Agricultural Research in the Dry Areas) and local producers. Conventional breeding methods using hybridization and selection are being carried out to develop improved varieties, broad the genetic base, and isolate superior recombinant inbred lines. Two new varieties have been obtained, one of the macrosperm type (Boyerito FCA) and the other of the microsperm type (Tacuarita FCA) through the application of mass selection in F2 populations from the cross of selected materials. This program complements traditional breeding methods with biotechnological techniques such as transgenesis, use of molecular markers, in vitro embryo culture combined with the SSD method to shorten the breeding time, and digital phenotyping. Key words: Lentil, conventional methodologies, in vitro embryo culture, biotechnology techniques, digital phenotyping.


2021 ◽  
pp. 36-41
Author(s):  
M. S. Kornilova ◽  
D. P. Kurunina ◽  
G. V. Varivoda

Relevance. The soil and climatic conditions of the Lower Trans-Volga region are considered favorable for melon growing and make it possible to obtain high-quality products. The purpose of the research was to create new competitive varieties and hybrids of melon and pumpkin.Materials and methods. The object of the research is new varieties of melon and butternut pumpkin created at the Bykovskaya melon breeding experimental station. Melon cultivar Osen and pumpkin cv. Zhemchuzhina were used as standards. The methods of creation are intervarietal hybridization, individual and mass selection. During the growing season, appropriate observations and counts were carried out.Results. As a result of many years of breeding work at the Bykovskaya cucurbits selection experimental station, a melon cultivar 251 and a pumpkin cultivar 509 have been created. both producers and consumers. Therefore, the obtained varieties were evaluated for taste, yield, resistance to biological and abiofactors of the environment, dry matter content, fruit size, fruit and pulp color. During the comparative assessment of the accessions, it was determined that the new varieties of melon and pumpkin exceed the standards in terms of the main economically valuable traits. The average yield during the study, in the melon cultivar 251, exceeded the standard by 47.8%. In the pumpkin cultivar, the average yield for three years of research exceeded the standard by 69.6%. In terms of taste, the new melon variety was at the level of the standard, the cv. Osen. A variety of butternut pumpkin exceeded the standard in all quality indicators. The susceptibility to powdery mildew in the melon cultivar varied depending on the year of research. The melon sample showed resistance to anthracnose higher than the standard by 16.4 and 18.6%, over the years of study. In the pumpkin cultivar, resistance to powdery mildew and anthracnose was higher than the standard, on average by 34.9% to powdery mildew and by 28.6% to anthracnose. Thus, new varieties of melon and pumpkin meet the modern requirements of the industrial melon industry, are resistant to environmental stress factors, common diseases, and have economically valuable traits.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kim K. L. Bellamy ◽  
Frode Lingaas ◽  
Per Madsen

Abstract Background Distichiasis is a presumed inherited eyelid disease, characterized by misplaced eyelashes. The effect on eye health and animal welfare varies between individuals; most mild cases show no clinical signs, but some affected animals develop painful corneal disease. In this study, we investigated the prevalence and heritability of distichiasis in the Norwegian population of Havanese dogs. Results A total of 1156 Havanese were included in the study. Out of these, 168 were affected with distichiasis, making the prevalence in our sample 14.5% (95% CI 12.5–16.6%). There was no sex predisposition. Most affected individuals were graded “mildly affected”. The estimates generally showed high heritabilities, which varied between 0.276 (linear model) and 0.720 (Bayesian threshold model). The linear estimates, after conversion to the underlying scale (h2l = 0.664–0.674), corresponds well to the results of the Bayesian models. Conclusions The estimated heritability of distichiasis in Havanese is high and the prevalence is moderate. The high heritability indicate that a significant selection response could be obtained by simple mass selection. To secure good animal welfare, it’s important to control the number of affected individuals and especially the severely affected.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ali Ammarellou ◽  
Valiollah Mozaffarian

AbstractFolk medicine such as herbal and natural products have been used for centuries in every culture throughout the world. The Chenopodiaceae family with more than 1500 species is dispersed worldwide. The Iranian wild spinach (Blitum virgatum L.) is an important traditional medicinal plant used for antiviral diseases such as pneumonia and other respiratory track infections. This plant is a mountainous herb and is growing upper than 3000 m. We performed a mass selection plant breeding program on wild populations of this Iranian wild spinach during 2013–2020. Based on experimental and field characteristics this plant was identified as B. virgatum, |abbaricum|, and related characteristics were prepared with reference to the International Union for the Protection of New Varieties of Plants (UPOV). Mass selection program resulted from an adapted population named as medicinal spinach (MSP) population. To compare the mineral content of the mass-selected population with cultivated spinach (Spinacia oleracea L. |Varamin 88|), both plants were planted in pots and fields under similar conditions. In five leaves stage, plant samples were taken from both leaf and crown sections and used for experimental analysis. Atomic absorption spectroscopy was used to determine the mineral content including iron (Fe), zinc (Z), manganese (Mn), and copper (Cu). Our results showed the selected medicinal spinach population (MSP) with about 509 ppm iron was an important iron-rich population with about 3.5–4 times more than the amount of iron in cultivated spinach in the same conditions. Because iron is an important essential element for blood production, respiration process, energy metabolisms, synthesis of collagen, and some neurotransmitters are needed for proper immune function, so the supply of absorbable adequate iron is very important. The reasons such as the prevalence of the COVID-19 pandemic, which affects the amount of exchangeable oxygen in the lungs and historical local evidences of the use of this plant (MSP) for pneumonia, could open new horizons for focusing on studies related to the use of ancestral human experiences in addition to scientifically modern research.


2021 ◽  
Author(s):  
Tim K. Esser ◽  
Jan Boehning ◽  
Paul Fremdling ◽  
Mark T. Agasid ◽  
Adam Costin ◽  
...  

Electron cryomicroscopy (cryo-EM) and single-particle analysis (SPA) have revolutionized structure determination of homogeneous proteins. However, obtaining high-resolution structures from heterogeneous samples remains a major challenge, as the various protein states embedded in thin films of vitreous ice may be classified incorrectly, resulting in detrimental averaging of features. Here we present native electrospray ion-beam deposition (native ES-IBD) for the preparation of extremely high-purity cryo-EM samples, based on mass selection in vacuum. Folded protein ions are generated by native electrospray ionization, mass-filtered, and gently deposited on cryo-EM grids, and subsequently frozen in liquid nitrogen. We demonstrate homogeneous coverage of ice-free cryo-EM grids with mass-selected proteins and protein assemblies. SPA reveals that they remain structurally intact, but variations in secondary and tertiary structure are currently limiting information in 2D classes and 3D EM density maps. Our results show the potential of native ES-IBD to increase the scope and throughput of cryo-EM structure determination.


2021 ◽  
pp. 48-59
Author(s):  
V. Gurbyk ◽  
◽  
O. Striletsky ◽  
H. Kurinenko ◽  
V. Tkachuk ◽  
...  

Purpose. To evaluate the reproductive indicators and exterior characteristics of the breeding brood stock of the Galician carp group at the original farms, namely farms "Korop" and "Dzherelo", State Enterprise "Lviv Experimental Station". Methodology. The study was conducted according to generally accepted methods in fish farming and breeding using statistical processing and data analysis. The productive features of the Galician carp were improved by the method of mass selection and directional selection. The tasks of the selection were to obtain a breeding stock of the Galician group, which will ensure the production of offspring with high individual weight in the first year of life. Findings. The age of maturity in brood Galician carp was 3-4 years in males and 4-5 years in females. After pituitary stimulation in the conditions of industrial reproduction, a positive reaction of the brood fish was established, which exceeded 92%. When forming breeding stocks of Galician carp in the first year of life, the intensity of selection was 15%. Directional selection on the basis of average individual weight started on the second year of life. The intensity of selection of age-1+ Galician carp group was 50%, then this parameter exceeded 85%. Reproduction of the Galician carp group occurred in spawning ponds and in industrial conditions. Working fertility of females was 1256.0 ± 132.80 thousand eggs, relative fertility - 127.5 ± 5.52 thousand eggs/kg, which was quite high in comparison with the Ukrainian framed carp. During the reproduction of Galician carp in ponds, the yield of three-day-old larvae from one nest amounted to 241 thousand individuals. According to the obtained data, based on the exterior indicators, the Galician carp group is characterized by a high-backed physique and fleshy structure, which is preserved throughout life. In view of the conducted study, the Galician carp group fully complies with the requirements of the Regulation on approbation of selection achievements in animal husbandry and can be submitted to the relevant authorities for consideration and approval as an intrabreed type of Ukrainian framed and scaly carp breeds. Originality. The analysis of reproductive indicators of the breeding brood stock of Galician carp will serve as a basis for the presentation of this group in the status of intrabreed type and its approval as a selection achievement. Practical value. The obtained results will contribute to the expansion of the Galician carp group both in the aquaculture of Ukraine and abroad. Breeding brood material as an object of selection will be involved in work with framed carp mixes. Key words: breeding, carp, inventory, grading, crossbreeding, organization of spawning, reproduction.


2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Tristan Kistler ◽  
Benjamin Basso ◽  
Florence Phocas

Abstract Background Efficient breeding programs are difficult to implement in honeybees due to their biological specificities (polyandry and haplo-diploidy) and complexity of the traits of interest, with performances being measured at the colony scale and resulting from the joint effects of tens of thousands of workers (called direct effects) and of the queen (called maternal effects). We implemented a Monte Carlo simulation program of a breeding plan designed specifically for Apis mellifera’s populations to assess the impact of polyandry versus monoandry on colony performance, inbreeding level and genetic gain depending on the individual selection strategy considered, i.e. complete mass selection or within-family (maternal lines) selection. We simulated several scenarios with different parameter setups by varying initial genetic variances and correlations between direct and maternal effects, the selection strategy and the polyandry level. Selection was performed on colony phenotypes. Results All scenarios showed strong increases in direct breeding values of queens after 20 years of selection. Monoandry led to significantly higher direct than maternal genetic gains, especially when a negative correlation between direct and maternal effects was simulated. However, the relative increase in these genetic gains depended also on their initial genetic variability and on the selection strategy. When polyandry was simulated, the results were very similar with either 8 or 16 drones mated to each queen. Across scenarios, polyandrous mating resulted in equivalent or higher gains in performance than monoandrous mating, but with considerably lower inbreeding rates. Mass selection conferred a ~ 20% increase in performance compared to within-family selection, but was also accompanied by a strong increase in inbreeding levels (25 to 50% higher). Conclusions Our study is the first to compare the long-term effects of polyandrous versus monoandrous mating in honeybee breeding. The latter is an emergent strategy to improve specific traits, such as resistance to varroa, which can be difficult or expensive to phenotype. However, if used during several generations in a closed population, monoandrous mating increases the inbreeding level of queens much more than polyandrous mating, which is a strong limitation of this strategy.


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