Sw. Bang et al., PRODUCTION OF INTERGENERIC HYBRIDS BETWEEN RAPHANUS AND SINAPIS AND THE CYTOGENETICS OF THEIR PROGENIES, Ikushugaku Zasshi, 46(1), 1996, pp. 45-51
Reciprocal crosses were made to analyze the intergeneric crossability
and to obtain intergeneric hybrids between Raphanus sativus and four S
inapis species (S, abba, S, arvensis, S, pubescens and S, turgida). Po
llen germination in the pistil and development of hybrid embryos depen
ded on the direction of each cross. The crossability was relatively hi
gher when Sinapis species were used as pistillate parents, whereas S.
pubescens was compatible with R, sativus only when used as pollen pare
nt, By embryo rescue technique and/or conventional method, hybrid plan
ts were produced in all intergeneric crosses between een R, sativus an
d four species of Sinapis except for the cross of S, pubescens x R. sa
tivus due to strong pre-fertilization barriers. When Sinapis species w
ere used as pistillate parents, 172 F-1 hybrid plants were obtained th
rough ovary culture followed by embryo culture. Using R, sativus as pi
stillate parent, 12 F-1 hybrid plants were obtained by embryo culture.
Exceptionally a few F-1 hybrid plants were obtained from the cross of
R, sativus x S. pubescens through ovary culture followed by embryo cu
lture. In the cross of S. turgida x R, sativus, a number of seeds harv
ested by conventional method developed to F-1 hybrid plants. These res
ults indicate the effectiveness of selective application of embryo res
cue techniques for the production of hybrids in distant crosses depend
ing on the characteristics of crossability between the two parent spec
eis. In the cross of Sinapis species x R, sativus, 20 F-1 hybrid plant
s exhibited the (0-1)(III) +(0-7)(II) + (4-18)(I) chromosome associati
on type at MI. Eight F-1 hybrid plants in the reciprocal cross exhibit
ed (0-5)(II) + (8-18)(I) at MI. The occurrence of trivalents and more
frequently of bivalents could be attributed in part to allosyndesis. N
o differential level in chromosome association in the reciprocal hybri
ds could be detected. Hybrid plants in the present study could become
promising materials for the breeding of alloplasmic lines, alien-chrom
osome addition lines and novel amphidiploids between genus Raphanus an
d Sinapis.