USE OF CELL AND MOLECULAR GENETIC MANIPULATION TO IMPROVE PASTURE PLANTS

1988 ◽  
pp. 67-72
Author(s):  
D.W.R. White
Keyword(s):  
Cell Culture ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Nutritional Quality ◽  
Rust Resistance ◽  
Herbicide Tolerance ◽  
Pest Resistance ◽  
Crown Rust ◽  
Wide Range ◽  
Pasture Plants

Cell culture and genetic engineering techniques can be used to develop improved pasture plants. To utilise these methods we have developed procedures for regenerating plants from tissue cultures of perennial ryegrass and white clover. In both, the plant genotype influences regeneration capacity. There was significant genetic variation among regenerated perennial ryegrass plants in a wide range of characteristics. Most of the regenerants were resIstant to crown rust and this trait was highly heritable. This rust resistance is being used to breed a new ryegrass cultivar. A system for introducing cloned genes into white clover is described. This capability is bemg used to incorporate genes with the potential to improve nutritional quality and pest resistance. Other possibilities for engineering genetic improvements in white clover, genes conferring herbicide tolerance and resistance to white clover mosaic virus, are briefly outlined. Keywords: Lolium perenne, Trifolium repens, cell culture, somaclonal variation, crown rust resistance, transformation, cloned genes, nutritional quality, proteinase inhibitors, Bt toxins, pest resistance, WCMV viral cross-protection, herbicide tolerance, Agrobacterium, Bacillus thuringenisis.

The effects of a wide range of nitrogen application rates on the yields from a perennial ryegrass sward with and without white clover

1970 ◽  
Vol 74 (2) ◽  
pp. 227-240 ◽  
Author(s):  
D. Reid
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Nitrogen Fertilizer ◽  
Crude Protein ◽  
Dry Matter ◽  
Growth Curves ◽  
Nitrogen Rate ◽  
Wide Range ◽  
Grass Sward ◽  
Nitrogen Rates

SUMMARYA series of twenty-one nitrogen fertilizer rates ranging from 0 to 800 lb nitrogen/acre (897 kg/ha)/annum was applied on a pure S. 23 perennial ryegrass sward and on an S. 23 ryegrass sward containing S. 100 white clover. Total yields of herbage dry matter and crude protein from both swards at all the nitrogen rates were determined each year by cutting the herbage five times at approximately the same stage of growth on each occasion. Four-parameter growth curves relating herbage yield to nitrogen rate were fitted to the data, and are presented for the first 3 years of the experiment. On the pure-grass sward the response of dry-matter yield to nitrogen rate was almost linear between the 0 and 300 lb nitrogen/acre (336 kg/ha) rates, then it decreased steadily, becoming non-significant about the 500 lb/acre (560 kg/ha) rate. In contrast the response of crude-protein yield was virtually linear from the 0 to the 600–700 lb nitrogen/acre (673–785 kg/ha) rates. The inclusion of white clover in the sward increased the yields of dry matter and crude protein at the low nitrogen rates, but decreased the responses, with the result that the yields and responses of the grass + clover sward were not significantly different from those of the pure-grass sward at nitrogen rates above about 300 lb/ acre (336 kg/ha). In terms of profitability at present fertilizer prices the optimum nitrogen rate for dry-matter production on both swards was estimated to be 400–450 lb/ acre (448–504 kg/ha), whereas that for crude-protein production was greater than 600 lb/acre (673 kg/ha). The value of clover in a sward receiving nitrogen fertilizer is discussed.

Evaluation of resistance to five isolates of Puccinia coronata f. sp. lolii in 19 perennial ryegrass cultivars

1997 ◽  
Vol 48 (2) ◽  
pp. 191 ◽  
Author(s):  
R. G. Clarke ◽  
O. N. Villalta ◽  
G. Hepworth
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Rust Resistance ◽  
South Australia ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
Breeding Lines ◽  
The Many ◽  
Test Plants ◽  
Differential Test

This paper seeks to provide information on the differences in resistance to Puccinia coronata f. sp. lolii of the many perennial ryegrass (Lolium perenne) cultivars available in Australia, and on the variation in resistance to this pathogen within these cultivars. This information will help farmers to select crown rust resistant cultivars suited to their area, and indicate to perennial ryegrass breeders the diversity of crown rust resistance within the cultivars and lines screened. Twenty genotypes of 14 cultivars and 5 advanced breeding lines of perennial ryegrass were screened for their reaction to 5 isolates of P. coronata f. sp. lolii. The isolates were collected from South Australia, southern Queensland, and 3 separate regions of Victoria. Tasdale, Victorian, Martlet, Tasmanian No. 1, and D1 were significantly (P < 0�05) more susceptible to crown rust than all other cultivars and lines. Embassy, D4, and D16 were the most resistant of the 19 cultivars and lines screened. Within all cultivars and lines there was significant (P P. coronata f. sp. lolii . This type of screening for genotype reaction could enable differential test plants to be selected for determining the presence of P. coronata f. sp. lolii pathotypes, an area that requires further research.

scholarly journals Mapping and Comparative Analysis of QTL for Crown Rust Resistance in an Italian × Perennial Ryegrass Population

2007 ◽  
Vol 97 (6) ◽  
pp. 767-776 ◽  
Author(s):  
S. Sim ◽  
K. Diesburg ◽  
M. Casler ◽  
G. Jung
Keyword(s):  
Perennial Ryegrass ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Oryza Sativa L ◽  
Lignin Biosynthesis ◽  
Crown Rust ◽  
Italian Ryegrass ◽  
Grass Species ◽  
Resistant Parent ◽  
Crown Rust Resistance

Crown rust (Puccinia coronata f. sp. lolli) is a serious fungal foliar disease of perennial ryegrass (Lolium perenne L.) and Italian ryegrass (L. multiflorum Lam.), which are important forage and turf species. A number of quantitative trait loci (QTL) for crown rust resistance previously were identified in perennial ryegrass under growth chamber or greenhouse conditions. In this study, we conducted a QTL mapping for crown rust resistance in a three-generation Italian × perennial ryegrass interspecific population under natural field conditions at two locations over 2 years. Through a comparative mapping analysis, we also investigated the syntenic relationships of previously known crown rust resistance genes in other ryegrass germplasms and oat, and genetic linkage between crown rust resistance QTL and three lignin genes: LpOMT1, LpCAD2, and LpCCR1. The interspecific mapping population of 156 progeny was developed from a cross between two Italian × perennial ryegrass hybrids, MFA and MFB. Because highly susceptible reactions to crown rust were observed from all perennial ryegrass clones, including two grandparental clones and eight clones from different pedigrees tested in this study, two grandparent clones from Italian ryegrass cv. Floregon appeared to be a source of the resistance. Two QTL on linkage groups (LGs) 2 and 7 in the resistant parent MFA map were detected consistently regardless of year and location. The others, specific to year and location, were located on LGs 3 and 6 in the susceptible parent MFB map. The QTL on LG2 was likely to correspond to those previously reported in three unrelated perennial ryegrass mapping populations; however, the other QTL on LGs 3, 6, and 7 were not. The QTL on LG7 was closely located in the syntenic genomic region where genes Pca cluster, Pcq2, Pc38, and Prq1b resistant to crown rust (P. coronata f. sp. avenae) in oat (Avena sativa L.) were previously identified. Similarly, the QTL on LG3 was found in a syntenic region with oat genes resistant to crown rust isolates PC54 and PC59. This indicates that the ortholoci for resistance genes to different formae speciales of crown rust might be present between two distantly related grass species, ryegrass and oat. In addition, we mapped four restriction fragment length polymorphism loci for three key ryegrass lignin genes encoding caffeic acid-O-methyltransferase, cinnamyl alcohol dehydrogenase, and cinnamoyl CoA-reductase on LG7. These loci were within a range of 8 to 17 centimorgans from the QTL on LG7, suggesting no tight linkage between them. The putative ortholoci for those lignin biosynthesis genes were identified on segments of rice (Oryza sativa L.) chromosomes 6 and 8, which are the counterparts of ryegrass LG7. Results from the current study facilitate understanding of crown rust resistance and its relationship with lignin biosynthesis, and also will benefit ryegrass breeders for improving crown rust resistance through marker-assisted selection.

scholarly journals SOMACLONAL VARIATION IN RESISTANCE OF PERENNIAL RYEGRASS TO CROWN RUST

1988 ◽  
pp. 93-96
Author(s):  
R.A. Skipp ◽  
D.W.R. White
Keyword(s):  
Tissue Culture ◽  
Perennial Ryegrass ◽  
Rust Resistance ◽  
Callus Cultures ◽  
Crown Rust ◽  
Plant Diseases ◽  
Puccinia Coronata ◽  
Parental Genotype ◽  
Vegetative Tissue ◽  
Screening Experiments

Resistance of perennial ryegrass plants regenerated from tissue culture (somaclones) to crown rust (Puccinia coronata) was assessed in growth cabinet/glasshouse experiments. Somaclones regenerated from callus cultures initiated from the vegetative tissue of three different somaclonal parent plants were tested for resistance to crown rust collected from Palmerston North and Linwln. Most plants tested were highty resistant and their leaves developed small pale yellow flecks but showed little or no sporulation. However, a few large pustules did develop on leaves of some of the somaclones. Screening experiments with rust cultures initiated from each of three single pustules showed that somaclones varied in their reaction to crown rust. Within each group of somadones derived from a particular parent some were more susceptible. and some more resistant, than the parental genotype. Two of the somaclones obtained from one of the parent plants had very fine leaves similar to those of turf perennial ryegrass plants. Somactoning may provide an efficient technique for plant breeders to improve the crown rust resistance of both pasture and turf perennial ryegrasses. Keyword% Puccinia coronata, Lolium perenne, somaclones. tissue cutture, plant breeding, plant diseases.

scholarly journals Identification of genomic loci associated with crown rust resistance in perennial ryegrass (Lolium perenne L.) divergently selected populations

Plant Science ◽  
2013 ◽  
Vol 208 ◽  
pp. 34-41 ◽  
Author(s):  
Gintaras Brazauskas ◽  
Yongzhong Xing ◽  
Bruno Studer ◽  
Britt Schejbel ◽  
Ursula Frei ◽  
...  
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Rust Resistance ◽  
Crown Rust ◽  
Lolium Perenne L ◽  
Crown Rust Resistance

N transfer from white clover to perennial ryegrass, via exudation of nitrogenous compounds

Agronomie ◽  
2003 ◽  
Vol 23 (5-6) ◽  
pp. 503-510 ◽  
Author(s):  
Florence Paynel ◽  
Jean Bernard Cliquet
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
N Transfer ◽  
Nitrogenous Compounds
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