Natural and induced variation in tissue culture

Abstract

Tissue culture, variation, clone plant breeding, mutagens. SUMMARY This literature review suggests a novel approach to intra-clonal plant improvement which will utilize both the natural and induced variation associated with clonally propagated plants through various in vitro and in vivo procedures. Many plants obtained in this manner will be of single-cell origin and, hence, of pure mutant type avoiding the traditional chimerism phenomena of mutation breeding studies. While such a system of plant breeding is not intended to replace conventional breeding methods for most crops, it may have special use for the plant breeder who is working with crops which are unique, highly-adapted, or in which the sexual apparatus is disturbed.

Cytological analysis in embryogenic callus cultures and regenerated plants of Papaver somniferum L. (opium poppy).

“…The fact that embryogenic callus in the present study maintained uniformly a diploid state for the first four months of its culture and developed chromosome abonormalities only thereafter indicates that the variability is not already present in the original explant but has been induced in the cultures by various physical and chemical factors of the culture system. D'Amato (1978), Skirvin (1978) and Constantin (1981) have reported that the regenerated plants in many species exhibit numerical chromosome instability similar to that obtained in Table 3. Comparative meiosis on cultured and non-cultured plants of P. somniferum cultures.…”

Production of mitotic abnormalities by magnesium sulphate in Vicia faba L.

“…It is well known that magnesium sulphate is a constituent of different nutrient media like the Murashige and Skoog's medium, White's medium, Nagata and Takebe's medium and Nitsch's medium. It has been reported frequently that plant tissues and cells display a high degree of instability under in vitro cultures (D'Amato 1978, Skirvin 1978, Constantin 1981. A number of factors have been found to contribute to chromosome instability in in vitro cultures.…”

Chromosomal behaviour in callus culture of Zea mays L.

“…In cultured cells, changes in chromosome number are not only the sole criteria for chromosomal instability, but there are also deviation in chromosome structure and basic karyotype (Partanen 1963, D'Amato 1977, Sunderland 1977, Skirvin 1978. Occurrence of chromosomal fragments in the metaphase cells suggests possible deletion in the complement (Fig.…”