Somaclonal genetics of rice, Oryza sativa L.

Abstract

The inheritance and variations of some traits of more than 2,000 somatic cell derived plants of rice (Oryza sativa L.) were investigated in the second and third generations (T2 and T3) of regenerated plants (somaclones). The percentages of multiploids occurring in somaclones ranged from 0-13.3 in nine varieties (or hybrids) of 'Hsien' (indica) group, but no multiploid was found in nine varieties (or hybrid) of 'Keng' (japonica) group. A dwarf mutant with the height of only 20 cm was isolated in the T2 of 'Tai-Zhong-Yu 39'. Genetic analysis indicated that it was controlled by a single recessive gene. The frequencies of chlorophyll mutations probably controlled by cytoplasmic genes decreased gradually with the advance of generations. The variations of five quantitative traits - plant height, grain weight, etc. - in 950 T2 pedigree lines of four varieties were also studied. Only 24.4% of the lines were normal in all the traits studied. Variation frequencies of different traits were from 11.5% to 39.5%. And there was an obvious tendency for the plant height to become shorter, number of productive tillers to increase and 1,000 grain weight to be lighter, whatever the variety studied. Traits were uniform within each of more than 90% of all T2 lines studied. What is more interesting, variations phenotyped in T2 proved to breed true. Causes of somaclonal variations are discussed, as well as their potentials in breeding.

Transmissible reproductive changes following physiological adaptation to salinity in Sorghum bicolor

“…An induced decrease in plant height, fertility and seed size has been observed after plant regeneration from callus culture in wheat (Larkin et al, 1984;Maddock & Semple, 1986), Sorghum {Bhaskaran et al, ]9S7;Caietal., 1990), rice (Fukui, 1983;Sun ei al., 1983) and maize (Zehrf/fl/., 1987). Some of the induced changes described were stable for many generations (Sun et al, 1983;Larkin et al, 1984;Maddock & Semple, 1986;Bhaskaran et al, 1987). The level of somaclonal variation was increased after the adaptation of the callus to salinity (McCoy, 1987).…”

In Vitro Culture of Hybrid Indica Rice Combined with Mutagenesis

“…In rice, several investigators (NISHI et al 1968, HENKE et al 1978, OoNO 1978. SUN ZONG-XIU 1983) have reported the occurrence and inheritance of somaclonal variation, although this variation has not yet been incorporated in any breeding programme.…”

Tissue culture and somaclonal variation of Cuphea viscosissima Jacq accessions

“…. Tissue culture-induced variation occurs at high frequencies Lôrz and Scowcroft, 1983;Zong-Xiu et al, 1983), is stable and heritable, and occurs for both monogenic and polygenic traits (Bingham and McCoy, 1986;Zong-Xiu et al, 1983). Somaclonal variation has been reported to occur for traits that are useful in crop improvement such as yield, maturity and disease resistance (Daub, 1986;.…”