Chinese cabbage(Brassica campestris L. ssp. pekinensis) and radish(Raphanus sativus L.) are the most important vegetables in Korea. Different lines of leaf mustard (B. juncea(L.) Czern & Coss.) are known to possess high level of tolerance to extreme temperatures and resistance to certain diseases which are desired in improving cultivars of Chinese cabbage and radish.
Therefore, interspecific and intergeneric crosses of leaf mustard with two cultivars each of Chinese cabbage and radish were made in order to examine the possibility of introgressing the desirable characters into Chinese cabbage or radish from leaf mustard, synthesizing new vegetable crops or producing matroclinous homozygous plants through pseudogamy.
Silique set from reciprocal pollinations between leaf mustard and Chinese cabbage was generally very high with an average of 94%, indicating the absence of any pre-zygotic physiological barrier. About 50% of in vitro cultured embryos from reciprocal crosses developed into normal seedlings. The embryo-derived callus or plant organs, when subcultured, formed multiple shoots and roots, resulting in whole plants.
There was a significant reciprocal difference in silique set from the intergeneric crosses between leaf mustard and radish, that is, the average silique set was 86.6% from the crosses where leaf mustard was used as female parents and radish as male parents, while it was only 25.0% from the crosses in the opposite direction. Genotypic effect of radish on the silique set was also noticed in the reciprocal crosses. Percent normal seedling development from embryo culture, which was 35% on the average, was a little higher from the crosses where leaf mustard was used as female parents and radish as male parents than from the crosses in the opposite direction. The embryo-derived callus or plant organs, when subcultured, regenerated into whole plants.
Therefore, it is concluded that embryo culture and subculture of embryo-derived callus or organs can be effectively used for production of hybrid plants or matroclinous homozygous plants from interspecific or intergeneric crosses of leaf mustard with Chinese cabbage or radish.
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