For any particular species, breeding methods are largely conditioned by the stage of evolution and development of that species as a crop plant. Continued selection and isolation by man are likely to have influenced the amount of genetic variability, the mating system and the type of gene action, all of which are interdependent and together determine the applicability of any particular breeding method . Forage grasses and legumes have a relatively short history as intensively cultivated crops, and an even shorter history of directed artificial selection . As a consequence, in all the common species, there exists in the wild or semi-wild state a wide diversity of natural adaptations to climatic and edaphic conditions and to biotic systems . These vast resources of genetic variability placed the first breeders of forage crops in a fortunate position vis a vis their counterparts in crops which had achieved a narrow genetic base either by virtue of a long history of cultivation and selection (e .g. cereals) or, through recent introduction on too narrow a scale (e.g . rubber). Rapid improvement was possible and was achieved in forage crops by the application of sound ecological principles to the discovery and exploitation of naturally occurring ecotypes . While some advance may still be possible in this way, we now have to consider the best means of more rigorously tailoring genetic material to the demands of increasingly sophisticated farm systems .

The genetic basis of present breeding methods in forage crops

Selection at the seedling stage in forage grass breeding would be extremely useful if seedling traits are highly heritable and correlated to desired agronomic traits. Objectives of this study were to determine the response to selection for high shoot weight and divergent selection for seedling tiller number in big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.) seedlings and obtain estimates of realized heritability for these traits. Base populations were breeding populations of 'Pawnee' big bluestem and 'Pathfinder' switchgrass. Divergent selection for single or multiple (three or more) tiller(s) 6 to 8 wk after planting in a greenhouse produced four populations [big bluestem high seedling weight, multiple tiller (BBMT); big bluestem high seedling weight, single tiller (BBST); switchgrass high seedling weight, multiple tiller (SWMT); and switchgrass high seedling weight, single tiller (SWST)], which were planted in isolated polycross nurseries. Seed from polycross nurseries was used to conduct a second cycle of selection. Populations were evaluated in greenhouse studies for fresh weight and tiller number of seedlings. Seedling fresh weight was increased in BBST and SWST Cycle 2 populations, and divergent selection for tiller number resulted in populations significantly different from the base population. Realized heritability estimates for seedling tiller number in big bluestem and switchgrass were 0.26 and 0.23, respectively. The effect of genetic modification of seedling tiller number and shoot weight on establishment under Held conditions and on mature plant phenotypes will need to be determined.

/pdf/divergent-selection-for-seedling-tiller-number-in-big-3ueznjpt8b.pdf

Divergent Selection for Seedling Tiller Number in Big Bluestem and Switchgrass

Selection for yield under spaced plant conditions was carried out for three generations in five lines of Lolium perenne derived from natural populations and of known genetic organisation, and for two generations from within the bred variety S.23. Evaluation of all selected generations under comparable spacing conditions revealed that overall a slow positive response to selection had been achieved. The magnitude and direction differed for the several lines and was inconsistent. The variable response was accounted for by low heritability, genotype x year interaction and the small population size with high intensity of selection imposed.

Selection for yield in Lolium perenne. I. Selection and performance under spaced plant conditions

The mean performance and the amount of genetic variance were studied for ear emergence and forage yield in replicated clonal trials of a Norwegian variety of Lolium perenne L., and its induced autotetraploid C2-population. Induction of tetraploidy did not alter the dry matter production of euploids, but resulted in earlier ear emergence. Aneuploidy had a severe effect upon forage yield, but did not change the earliness. The genetic variation for date of ear emergence was significantly smaller in the euploid class of the C2-population than in the diploid source population. No significant difference in genetic variance for productivity was detected between the two populations. Diallel crosses involving 15 randomly selected parental clones at each ploidy level were used to gain information on the nature of the genetic variation. The pattern of variation for ear emergence was mainly an additive system together with an important degree of maternal control. In autotetraploids also a significant aon-additive variance was detected. Considering forage yield of diploids the items for GCA, SCA and maternal effects were all highly significant. The dominance ratios furthermore suggested a high degree of dominance, but not overdominance. In autotetraploids, on the other hand, the items for SCA were non-significant for all cuts except for the first.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1601-5223.1977.tb01392.x

Genetic variation in diploid and autotetraploid populations of Lolium perenne L.

The mean performance and the amount of genetic variation were studied for ear emergence and forage yield in replicated clonal trials of a Norwegian variety of Festuca pratensis, Huds., and its induced autotetraploid C2-population. Induction of tefraploidy resulted in earlier ear emergence and reduced dry matter production of euploids. Aneuploidy had a severe effect upon forage yield, but did not alter the earliness. The genetic variation for date of ear emergence was twice as large in the diploid source population as in the euploid class of the C2-population, while the opposite was true for forage yield. To gain information on the nature of the genetic variation for these two characters as well as for plant height, diallel crosses involving 14 randomly selected parental clones at each ploidy level were used. GCA was the only significant source of genetic variance for date of ear emergence in diploids. In autotetraploids also extra-nuclear factors participated. At both ploidy levels the heritable differences in plant height were determined by nuclear genes exhibiting both additive and non-additive gene action. Considering forage yield, the items for GCA, SCA and reciprocal effects were significant in diploids as well as in tetraploids. Estimates of average degree of dominance for yield and height suggested non-additive to be as important as additive variance at both levels of ploidy.

Genetic variation in diploid and autotetraploid populations of Festuca pratensis

Progenies from a five genotype diallel cross in Lolium perenne L. were studied to assess the pattern of genetic control for seed weight, a number of seedling characters, and two adult plant characters.Variation in seed weight was largely determined by the maternal parent, but some control by the pollen parent was apparent. Gene action was additive, but some specific genetic effects were also present, suggesting possible interaction between the haploid pollen genome with a diploid ovular genome in the triploid endosperm, or alternatively between the developing seed and the female parent plant.Of the seedling characters (total germination, rate of germination, rate of leaf and tiller production, length of fifth leaf, and seedling dry matter production) only length of fifth leaf showed any additive variation which might be easily exploited.Adult plant production showed considerable variation which interacts with the season of assessment. However, the relative order of merit remained the same and only the mag...

Genetic control of variation in a selected population of Lolium perenne L.

Dry pea (Pisum sativum L.) is a cool-season food legume rich in protein (20–25%). With increasing health and ecosystem awareness, organic plant-based protein demand has increased; however, the protein quality of organic dry pea has not been well studied. This study determined the genetic variation of individual amino acids (AAs), total AAs (liberated), total protein, and in vitro protein digestibility of commercial dry pea cultivars grown in organic on-farm fields to inform the development of protein-biofortified cultivars. Twenty-five dry pea cultivars were grown in two USDA-certified organic on-farm locations in South Carolina (SC), USA, for two years (two locations in 2019 and one in 2020). The concentrations of most individual AAs (15 of 17) and the total AA concentration significantly varied with dry pea cultivar. In vitro protein digestibility was not affected by the cultivar. Seed total AA and protein for dry pea ranged from 11.8 to 22.2 and 12.6 to 27.6 g/100 g, respectively, with heritability estimates of 0.19 to 0.25. In vitro protein digestibility and protein digestibility corrected AA score (PDCAAS) ranged from 83 to 95% and 0.18 to 0.64, respectively. Heritability estimates for individual AAs ranged from 0.08 to 0.42; principal component (PCA) analysis showed five significant AA clusters. Cultivar Fiddle had significantly higher total AA (19.6 g/100 g) and digestibility (88.5%) than all other cultivars. CDC Amarillo and Jetset were significantly higher in cystine (Cys), and CDC Inca and CDC Striker were significantly higher in methionine (Met) than other cultivars; CDC Spectrum was the best option in terms of high levels of both Cys and Met. Lysine (Lys) concentration did not vary with cultivar. A 100 g serving of organic dry pea provides a significant portion of the recommended daily allowance of six essential AAs (14–189%) and daily protein (22–48%) for an average adult weighing 72 kg. Overall, this study shows organic dry pea has excellent protein quality, significant amounts of sulfur-containing AAs and Lys, and good protein digestibility, and thus has good potential for future plant-based food production. Further genetic studies are warranted with genetically diverse panels to identify candidate genes and target parents to develop nutritionally superior cultivars for organic protein production.

/pdf/organic-dry-pea-pisum-sativum-l-a-sustainable-alternative-3ts2002x.pdf

Organic dry pea (Pisum sativum L.): A sustainable alternative pulse-based protein for human health

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

T. Lawrence

Author Tools

Chat about Author

Papers

Genetic control of variation in a selected population of Lolium perenne L.

Organic dry pea (Pisum sativum L.): A sustainable alternative pulse-based protein for human health