Variations in chlorosis and potential usefulness of alloplasmic Brassica rapa with the cytoplasm of male sterile Brassica juncea

摘要

To select superior seed parents for vegetable hybrid seed production, we conducted interspecific crosses between male sterile Brassica juncea (2n=36, AABB) and eight inbred lines of Brassica rapa (2n=20, AA). Alloplasmic lines of B.rapa with the cytoplasm of B.juncea were developed from B.junceaxB.rapa hybrids by repeated backcrossing using B.rapa as the recurrent male parent until the BC3 generation. Seed fertility, male sterility and chlorophyll content were investigated in these plants cultivated under four different temperature conditions (5, 10, 12 and 20 degrees C). At 10 degrees C, the alloplasmic lines of B.rapa with the cytoplasm of B.juncea were male sterile with partly chlorotic leaves. The alloplasmic B.rapa had lower chlorophyll a, chlorophyll b and carotenoid contents than those of the original B.rapa. The leaves recovered from chlorosis when the plants were cultivated at 20 degrees C. An alloplasmic line of B.rapa (A6) is available as a seed parent for vegetable hybrid seed production and contributes seed fertility, slight chlorosis and stable male sterility