Potentials of protoplast fusion in plant breeding programmes

1988 ◽  
Vol 12 (2) ◽  
pp. 163-172 ◽  
Author(s):  
K. Glimelius
Keyword(s):  
Plant Breeding ◽  
Protoplast Fusion ◽  
Breeding Programmes

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 Winter wheat in England and Wales, 1923–1995: what do indices of genetic diversity reveal?

2003 ◽  
Vol 1 (1) ◽  
pp. 43-57 ◽  
Author(s):  
C. S. Srinivasan ◽  
Colin Thirtle ◽  
Paolo Palladino
Keyword(s):  
Genetic Diversity ◽  
Winter Wheat ◽  
Plant Breeding ◽  
Genetic Resources ◽  
Wheat Crop ◽  
England And Wales ◽  
Genealogical Relationship ◽  
Breeding Programmes ◽  
Winter Wheat Crop ◽  
The Stability

AbstractGenealogical data have been used very widely to construct indices with which to examine the contribution of plant breeding programmes to the maintenance and enhancement of genetic resources. In this paper we use such indices to examine changes in the genetic diversity of the winter wheat crop in England and Wales between 1923 and 1995. We find that, except for one period characterized by the dominance of imported varieties, the genetic diversity of the winter wheat crop has been remarkably stable. This agrees with many studies of plant breeding programmes elsewhere. However, underlying the stability of the winter wheat crop is accelerating varietal turnover without any significant diversification of the genetic resources used. Moreover, the changes we observe are more directly attributable to changes in the varietal shares of the area under winter wheat than to the genealogical relationship between the varieties sown. We argue, therefore, that while genealogical indices reflect how well plant breeders have retained and exploited the resources with which they started, these indices suffer from a critical limitation. They do not reflect the proportion of the available range of genetic resources which has been effectively utilized in the breeding programme: complex crosses of a given set of varieties can yield high indices, and yet disguise the loss (or non-utilization) of a large proportion of the available genetic diversity.

Variability in hot pepper for phytochemicals offers promising tools in plant-breeding programmes

2010 ◽  
Vol 60 (3) ◽  
pp. 227-234
Author(s):  
Supradip Saha ◽  
N.K. Hedau ◽  
S. Kumar ◽  
V. Mahajan ◽  
H.S. Gupta
Keyword(s):  
Plant Breeding ◽  
Hot Pepper ◽  
Breeding Programmes

Plant breeding technologies relevant to developing countries

1993 ◽  
Vol 16 ◽  
pp. 37-46 ◽  
Author(s):  
S. Ceccarelli
Keyword(s):  
Developing Countries ◽  
Plant Breeding ◽  
New Technologies ◽  
Small Ruminants ◽  
Quality Characteristics ◽  
Agricultural Systems ◽  
Marginal Areas ◽  
Breeding Programmes ◽  
Straw Quality ◽  
Sustainable Agricultural Systems

AbstractThe relevance of new and traditional plant breeding technologies is discussed with particular reference to the improvement of sustainable agricultural systems in difficult environments. The focus of the paper is on barley, a crop which is grown as animal food, mostly for small ruminants, on about 17 million ha in developing countries. Barley is also a typical low-input crop being grown largely in agriculturally marginal areas by risk-averse farmers. Differences in straw quality characteristics between varieties of some crops are discussed in relation to their utilization in breeding programmes using either conventional or new technologies. A greater interaction between animal scientists and plant breeders is needed to define appropriate techniques to screen for straw quality. This is considered to be essential to incorporate straw quality characteristics in breeding programmes.

Long-term collaboration between farmers’ organizations and plant breeding programmes

2019 ◽  
pp. 29-48 ◽  
Author(s):  
Eva Weltzien ◽  
Fred Rattunde ◽  
Mamourou Sidibe ◽  
Kirsten vom Brocke ◽  
Abdoulaye Diallo ◽  
...  
Keyword(s):  
Plant Breeding ◽  
Breeding Programmes

Plant breeding and improvement of the cotton plant

1980 ◽  
Vol 10 (4) ◽  
pp. 152-158
Author(s):  
G A Niles
Keyword(s):  
Plant Breeding ◽  
Cotton Plant ◽  
Insect Pests ◽  
Unit Area ◽  
Cotton Breeding ◽  
Economic Profit ◽  
Breeding Research ◽  
Breeding Programmes

Cotton breeding research is directed to the development of cultivars that can be grown with maximum economic profit. Yield is a function of bolls per unit area, seed per boll and lint per seed, and its improvement depends on favourable alternatives to one or more of these components. Some breeding programmes place emphasis on fibre and spinning characteristics, while resistance to disease and insect pests and adaptation to mechanized harvesting are increasingly important objectives.

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