irst case of haploidy in higher plants was reported in Datura stramonium T $ : ~ ~ ~ ~ ~ ~ ~ et al. 1922). Subsequently, haploid sporophytes have been discovered in many plant species; STADLER and RANDOLPH first reported haploidy in maize (1929 unpublished, cited by RANDOLPH 1932). Numerous investigations have been conducted on the occurrence of spontaneous and induced haploids in a number of s...

An Escherichia coli Hfr strain in which three negative chromosomal alleles (leu(-), arg(-), and mtl(-)) were closely linked to three positive alleles (ara(+), rha(+), and xyl(+), respectively) was employed in matings with a Salmonella typhosa recipient. The detected expression of the negative E. coli alleles in S. typhosa hybrids selected for receipt of an associated positive E. coli marker was...

With two copies of every gene, a diploid organism is able to mask recessive deleterious mutations. In this paper we present the analysis of a two-locus model designed to determine when the masking of deleterious alleles favors the evolution of a dominant diploid phase in organisms that alternate between haploid and diploid phases ("alternation of generations"). It is hypothesized that diploidy ...

Doubled haploidy methodology is commonly used in many agronomically important crops to speed the development of new cultivars. There are a number of advantages in using haploidy technology in both practical application (varietal development, mutagenesis, transformation) and basic research (genomics, biochemical, and physiological studies). Haploid plants are commonly produced using one of four ...

Haploid plants are very important in various realms of research disciplines such as plant biotechnology, molecular genetics and traditional plant breeding. They provide useful information regarding recombination and genetic control of chromosomal pairing. Haploidy expedites the breeding process thereby increasing the crop yield. Researchers have been working on the haploidy approach for more th...

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