Showing papers on "Plant breeding published in 1975"

High frequencies of haploid production in wheat (Triticum aestivum) by chromosome elimination

Abstract: THE production of haploid plants from hybrids, followed by chromosome doubling, provides the plant breeder with a means of accelerating the development of desirable true breeding lines. This could be advantageous in breeding programmes particularly among some of the cereals where many generations, taking many years, may be required before an acceptable pure line variety can be obtained.

Male sterility in wheat plants deficient in copper

Abstract: IN higher plants, copper deficiency affects the reproductive phase more than the vegetative. Yields of grain may be markedly reduced or nil without much effect on yield of vegetative parts1–3. Failure to produce seed may be caused by lack of sufficient photosynthate production or translocation, or to the absence of fertilised embryos. Although soluble carbohydrates were low in copper-deficient wheat leaves, the evidence reported here points to the non-viability of pollen as the primary cause of failure to set grain. Possible mechanisms for the induction of male sterility by copper deficiency are proposed, and its potential for use in plant breeding is discussed.

Protein‐screening am Weizen‐ und Ackerbohnen‐Sortiment in Gatersleben

Abstract: Actually and in future times plant proteins will constitute the main and primary source of proteins in animal feeding and human alimentation. Therefore, the main efforts to resolve the world nutrition problems are focused on the increase of the protein production and the improvement of the nutritional quality of plant seed proteins. In this regard plant breeding occupies one of the most important strategic positions. With the aim of selecting forms with elevated grain protein content and improved protein quality the systematic screening of collections of wild forms and cultivated cereals and leguminoses constitutes a pre-requisite of successful breeding work in relation to the above-mentioned task. In 1970 the Central Institute of Genetics and Investigation of Cultivated Plants at Gatersleben, GDR, belonging to the Academy of Sciences, started a systematic protein screening with about 10000 wheat, 6500 barley and 450 broad bean specimens, which are parts of the World Collection of Cultivated Plants at this institute. Protein determination was performed by the traditional KJELDAHL-method. Limiting amino acids, essentially lysin from cereal grains, were estimated by automatic ion exchange technique. The annual analytic capacity amounted to 6000 to 8000 samples. First results and problems of wheat- and broad bean-screening are reported in the present publication.

Genetic Engineering as a Key to Water-Use Efficiency

Abstract: Eslick, R. F. and Hockett, E. A., 1974. Genetic engineering as a key to water-use efficiency. Agric. Meteoroi., 14: 13–23. Most of the present breeding systems are locked into certain germ plasm sources and the chance development of cultivars with greater water-use efficiency is very small. Extensive germ plasm pools containing genes for greater water-use efficiency exist, but heavy selection pressure is necessary to identify these genes. Plant breeders need to determine the plant characteristics contributing to water-use efficiency. Tests for these characteristics need to be simple and rapid. The four general methods of developing isogenic pairs (lines homozygous for AA and aa) are: through point mutations; by backcrossing A or a into an adapted cultivar; by crossing AA and aa and selfing Aa; and by crossing AA and aa and bulking homozygous F2 and F3 lines. The first two methods result in isogenic pairs in a “specific” genetic background and the second two in isogenic pairs in an “average„ genetic background. Genes on chromosome segments adjacent to the isogenic pair being tested may greatly influence the results obtained. Care should be used in interpreting data since the worth of a gene may be completely obscured by pleiotropic effects or compensating effects of the background containing the isogenic pairs. The purpose of this paper is to discuss two areas of plant breeding that are related to the general topic of this symposium. One area is concerned with the present status of and approaches to plant breeding and the probabilities of plant breeders detecting genes contributing to water-use efficiency. The second area is concerned with the use of isogenic analysis to detect genes associated with water-use efficiency. This presentation will draw on general information concerning plant breeding and more specifically on our experiences with barley. This is not intended to be a comprehensive review of the literature. Primarily, this discussion is directed to those that are not plant breeders.

Effects of Defoliation on Grain Yield and Other Characters of Sorghum

Abstract: Three late varieties were evaluated for reaction to leaf removal at two-week intervals after heading. Defoliations performed up to the eighth week after heading significantly reduced 1000-seed weight in Alemaya 70. However, in the other two varieties, the seeds developed to the same weight as those from undefoliated plants, only if the leaves were left on the plants for at least ten weeks after heading