Introgression of novel genetic variation in Brassica carinata

摘要

Brassica carinata (BBCC, 2n=34) has still to emerge as a major oilseed crop owing to poor agronomic attriutes like long duration, low oil content and hard to thresh siliqua. Interspecific hybridization followed by selection in selfed and backcross progenies was employed to introgress useful variability into B. carinata cv PC 5 from two related digenomics viz. B. napus (AACC, 2n=38) and B. juncea (AABB, 2n=36). Hybridity of B. napus×B. carinata and B. juncea×B. carinata crosses was confirmed through cytological and molecular analysis. Forty six F3, BC2 and BC1 F2 B. carinata type prrogenies werre identified on the basis of morphology and high pollen grain stainability. Almost all these progenies had high bivalent frequency (16-17 Ⅱ) indicating their relative genomic stability. Morphological and seed quality evaluation of these progenies indicated significant variation for key economic traits. Individual plants / progenies with low erucic acid ( 11.8% in BNC 2 vs. 45.5% in PC 5), high oil content (41.5% in BJC1 vs. 34.5%in PC 5), early maturity (157 days vs. 168 days in PC 5) and short stature (140 cm vs. 231 cm in PC 5) were selected. Diversity analysis (UPGMA) on the basis of morphological variation grouped 42 of the 46 progenies,with B. carinata cv. PC5 at a taxonomic distance of 1.09 inferring enlarged genetic base. At molecular (RAPD) level also 17 of the selected 21 progenies grouped with B. carinata cv. PC5 at a similarity coefficient of 0.63, confirming broadly the clustering based on morphological diversity. The use of identified variability in breeding programmes is likely to help in the development of early maturing, canola quality B. carinata cultivars having high oil content and desired morphotype. Increasing oil content to 41.5 per cent was a significant achievement of the study.