Phenotypic variations in plant progenies of interspecific crosses involving Brassica juncea / B. carinata

摘要

With the aim of transferring fungal disease resistance in Indian mustard, eight hybrids were generated, throughin vitro ovule culture/in vitro germination of seeds, using two brown seeded Brassica juncea genotypes; RESBJ-830 and RESBJ-837 as female parents, and the yellow seeded B. carinata variety Kiran as male donor. The hybrids showed intermediate morphological characteristics with pronounced male donor specific features; such as presence of red dots at the tip of the anthers (RA) and purple color (PC) at the junction of petioles, shoots, mid rib and green pods. Complete to partial pollen sterility was observed in the F2 and BC1 generations. A significant difference was observed in the seed coat color between the progenies of hybrids derived from the two B. juncea genotypes. While the F2 seeds derived from RESBJ-830 were brown seeded, those from RESBJ-837 were yellow seeded, and both segregated in a ratio of 2 (Brown): 1 (Yellow) in BC1 generation. Most of the plants in the F2 generation resembled either the male parent B. carinata or were intermediate in morphology with about equal frequency, and only one plant resembled B. juncea. The BC1 generation had a high percentage of plants resembling B. juncea (40%), followed by intermediate (37%), and B. carinata plant type (21%). A significant variation for branching pattem, leaf and floral morphology, inflorescence and siliquae arrangement was recorded in both F2 and BC1 generations. The B. juncea type plants in these generations resembled the female parent in most of the morphological traits except for length of the main shoot that was short in F2 plants and long like the female parent in BC1 plants. The variations observed for the presence of RA (85%) and PC (30%) in F2 plants, were reduced to 40% and 17%, respectively, in BC1 generation. An apetalous phenotype was also identified in both generations. The subsequent BC1F2 and BC2 generations recovered B. juncea type brown/yellow seeded plants with the latter in higher percentage in BC2 generation. The characteristic feature of the male donor, RA and PC, and short main shoot with distantly placed siliquae were observed only in plants derived from RESBJ-830. The genetic stability of the above-mentioned phenotypic traits and disease response to fungal diseases in advanced generations were evaluated.