Theory and application of open-pollination and polycross in forage grass breeding

The basic moments of a process of obtaining apple tetraploids as donors of diploid gametes for apple breeding with polyploidy using are demonstrated. In industrial terms, triploids are of the greatest importance. The manifested effect of heterosis leads to the improvement of many characteristics - higher resistance to diseases, pests and adverse environmental conditions, greater autogamy than in diploids, less pronounced periodicity of fruiting, larger fruits and a convenient crown for harvesting. Triploids are developed as a result of crosses 2n × 3n or 2n × 4n. Tetraploids are necessary for more successful apple breeding with polyploidy using. For industry they are not of great importance but they are of interest as donors of diploid non-reduced gametes and allow to make the selection process more directional. One of the methods of experimental polyploidy is the induction of polyploids using mutagenes. The germs were treated with colchicines at concentrations 0.1% - 0.4% during 24 and 48 hours. According to the morphology the obtained plants were divided into five groups. Colchicine concentrations 0.3% and 0.4% during 48 hours of the treatment had a disastrous impact on the development of germs. As a result of the cytological analysis, tetraploids and chimeras were revealed, which were obtained from the seeds from the open pollination of Orlik and Svezhest (treatment variants – 0,1% colchicines solution and 24 and 48 hours of exposition), as well as from the seeds obtained as a result of the Svezhest × Bolotovskoye crossing. Tetraploids had a normal growth but they differed in large leaves, while chimeras were of low size with normal leaves and internodes.

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High‐yielding forage grass cultivars increase root biomass and soil organic carbon stocks compared with mixed‐species permanent pasture in temperate soil

European Journal of Soil Science ◽

10.1111/ejss.13160 ◽

2021 ◽

Author(s):

A. S. Gregory ◽

A. Joynes ◽

E. R. Dixon ◽

D. A. Beaumont ◽

P. J. Murray ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Root Biomass ◽

Carbon Stocks ◽

Forage Grass ◽

Mixed Species ◽

Permanent Pasture ◽

Soil Organic Carbon Stocks ◽

Temperate Soil

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Flow Cytometry-Based Determination of Ploidy from Dried Leaf Specimens in Genomically Complex Collections of the Tropical Forage Grass Urochloa s. l.

Genes ◽

10.3390/genes12070957 ◽

2021 ◽

Vol 12 (7) ◽

pp. 957

Author(s):

Paulina Tomaszewska ◽

Till K. Pellny ◽

Luis M. Hernández ◽

Rowan A. C. Mitchell ◽

Valheria Castiblanco ◽

...

Keyword(s):

Flow Cytometry ◽

Germplasm Collection ◽

Forage Grass ◽

Breeding Programs ◽

Robust Identification ◽

Ploidy Levels ◽

Sustainable Improvement ◽

Tropical Forage ◽

Relative Differences

Urochloa (including Brachiaria, Megathyrus and some Panicum) tropical grasses are native to Africa and are now, after selection and breeding, planted worldwide, particularly in South America, as important forages with huge potential for further sustainable improvement and conservation of grasslands. We aimed to develop an optimized approach to determine ploidy of germplasm collection of this tropical forage grass group using dried leaf material, including approaches to collect, dry and preserve plant samples for flow cytometry analysis. Our methods enable robust identification of ploidy levels (coefficient of variation of G0/G1 peaks, CV, typically <5%). Ploidy of some 348 forage grass accessions (ploidy range from 2x to 9x), from international genetic resource collections, showing variation in basic chromosome numbers and reproduction modes (apomixis and sexual), were determined using our defined standard protocol. Two major Urochloa agamic complexes are used in the current breeding programs at CIAT and EMBRAPA: the ’brizantha’ and ’humidicola’ agamic complexes are variable, with multiple ploidy levels. Some U. brizantha accessions have odd level of ploidy (5x), and the relative differences in fluorescence values of the peak positions between adjacent cytotypes is reduced, thus more precise examination of this species is required. Ploidy measurement of U. humidicola revealed aneuploidy.

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Fruit Tree-Based Agroforestry Systems for Smallholder Farmers in Northwest Vietnam—A Quantitative and Qualitative Assessment

Land ◽

10.3390/land9110451 ◽

2020 ◽

Vol 9 (11) ◽

pp. 451

Author(s):

Van Hung Do ◽

Nguyen La ◽

Rachmat Mulia ◽

Göran Bergkvist ◽

A. Sigrun Dahlin ◽

...

Keyword(s):

Management Practices ◽

Smallholder Farmers ◽

Knowledge Exchange ◽

Fruit Trees ◽

Agroforestry Systems ◽

Fruit Tree ◽

Rapid Expansion ◽

Qualitative Assessment ◽

Forage Grass ◽

High Investment

Rapid expansion of unsustainable farming practices in upland areas of Southeast Asia threatens food security and the environment. This study assessed alternative agroforestry systems for sustainable land management and livelihood improvement in northwest Vietnam. The performance of fruit tree-based agroforestry was compared with that of sole cropping, and farmers’ perspectives on agroforestry were documented. After seven years, longan (Dimocarpus longan Lour.)-maize-forage grass and son tra (Docynia indica (Wall.) Decne)-forage grass systems had generated 2.4- and 3.5-fold higher average annual income than sole maize and sole son tra, respectively. Sole longan gave no net profit, due to high investment costs. After some years, competition developed between the crop, grass, and tree components, e.g., for nitrogen, and the farmers interviewed reported a need to adapt management practices to optimise spacing and pruning. They also reported that agroforestry enhanced ecosystem services by controlling surface runoff and erosion, increasing soil fertility and improving resilience to extreme weather. Thus, agroforestry practices with fruit trees can be more profitable than sole-crop cultivation within a few years. Integration of seasonal and fast-growing perennial plants (e.g., grass) is essential to ensure quick returns. Wider adoption needs initial incentives or loans, knowledge exchange, and market links.

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