MORPHOLOGICAL VARIATION IN PLANTS REGENERATED FROM LONG-TERM CALLUS CULTURE OF PEA

PNL Volume 17 1985 RESEARCH REPORTS

MORPHOLOGICAL VARIATION IN PLANTS REGENERATED FROM LONG-TERM CALLUS

CULTURE OF PEA

Ezhova, T. A., A. M. Bagrova, and S. A. Gostimski

Moscow State University, USSR

Pea callus tissue was derived from apices of var. 'Ranny zeleny-33'

using the method of Gamborg, et al. (1). In these conditions a friable,

light-green, rapidly growing morphogenetic callus was obtained. The

callus was transferred to fresh medium every 1-1/2 to 2 months over a

two-year period. To secure a large number of shoots, two-year-old

callus was placed into 250 ml Erlenmeyer flasks either on the same

medium or on a medium with added benzylaminopurine content (2 mg/1). To

avoid getting adventitious shoots from the same meristematic zones, 3-5

cm long shoots were taken from flasks along with the pieces of callus

from which they had been derived.

Shoot tips were grafted in the greenhouse. From about 200 shoots

grafted, seeds were obtained from 70 Regenerants (R_o).

Some of the grafted regenerants had shortened internodes and

altered leaf and flower morphology.

Seeds from the grafted regenerants (from 1 to 15 seeds from each

regenerant) were planted in the field. Segregation of a chlorotica

mutant was observed in one of 65 lines (4 green : 1 chi plants).

Another line segrated for a waxless mutant (2 normal : 1 waxy plants).

It is likely that other mutations had occurred but , because the popula-

tion sizes were small, they remained undetected. Therefore analysis of

the R₂ generation is required.

The most interesting results were obtained while studying some

physiological and quantitative characters. In 70-80% of the R₁ Lines

the following changes were found: more robust habit as compared with the

initial variety (IL); dark green leaves unlike the light green leaves of

the IL; oblong leaflets as compared with oval; earlier or later flo-

wering time.

For example, 85.5% of the plants of var. Ranny zeleny formed theit

first flower on node 10 (14.5% on nodes 9 and 11). Among the R₁ regene-

rants only 27% of the plants flowered at node 10, while the rest (73%)

flowered at nodes 8, 9, 11, 12 and 13 (Fig. la, b).

We have not seen direct correlations among these changed charac

ters. For instance, some plants with more vigorous habit were late flo-

wering lines and some were early.

The same changes that occurred in R1 also were present in R2 and

there was no segregation of the changed characters among the plants and

the families belonging to the same line. For example, all the plant

among three families of line No. 1 had statistically significant differ-

ences (P > 0.999) in the length/width ratio of the leaflets. Thus the

change in leaflet shape (from oval in the IL to oblong) was an inherited

difference (Table 1).

The study of flowering time of nine lines of the R2, general ion has

shown that five lines flowered more frequently on node 9 (from 8 to 10,

very rarely on node 11), and four lines flowered at node l3 (from 11 to

14) (Fig. 1 c, d). These data indicate that variability of flowering

time among R1 lines did not result from physiological and epigenetical

events, but had genetic basis.

Studies of karyotypes in callus tissues, pollen fertility, and

meiosis in regenerants, which is to be reported, demonstrated that the

variability of regenerants was not caused by changes in ploidy or by

large chromosomal aberrations.



	PNL Volume 17 1985 RESEARCH REPORTS 9

	1. Gamborg, 0.L., F. Constabel, and J.P. Shyluk. 1974. Physiol. Plant. 30:125-128.





	Fig. 1. Distribution of number of nodes to first flower in the initial line (Ranny zeleny) and in R1 and R2 regenerants. n = total number of plants.