BREEDING EFFORTS FOR DEVELOPMENT OF CANOLA GRADE MUST ARD VARIETY IN FIELD MUSTARD tBrassica rapa)

Abstract

Abstract Brassica rapa in the main oilseed crop in Bangladesh and development of canola grade B. rapa variety is a priority research in Bangladesh. The present research was under taken with a long term goal to develop canola grade B. rapa variety in Bangladesh. Six Canadian canola grade double zero genotypes of B. rapa were crossed with four Bangladeshi popular varieties e.g. Tori-7, Maghi, BARI Sharisa 14 and BARI Sharisa 17 to develop 24 F, hybrid populations. For transferring the low erucic trait from Canadian lines to Bangladeshi cultivars, backcrosses were also performed. The F, hybrids were evaluated for their saturated and unsaturated fatty acid compositions and yield contributing traits. The analysis of variance showed highly significant variation among the F, and BC,F I populations. Among the 24 hybrids, the lines Gl, G7, G14, G14, G16, G17, G18 and G19 were selected as promising lines as these lines had higher values of the yield and yield contributing traits. These F I lines were selected and advanced to F2 generation through self-fertilization and were also used in backcross breeding to develop BC 1F I. Among the hybrids, the desired negative heterosis effects for early maturity (90-95 days) were found in the hybrids G4, G5, G6, G7, G13 and G17, while the hybrids G 17, G 18, G 19, G20 showed the highest significant heterosis for yield, and the hybrids G 17 and G18 had the highest harvest index. The results suggested elite recombinant lines of early maturity and high yielding could possible be obtained from the segregants of these hybrid lines. The fatty acid compositions analysis unraveled that the hybrids viz. G3, G4, G5, G9, G12, 017, 020 and G23 had lower erucic acid «20-22%), but higher oleic (32-34%) and higher linoleic acid (22-24%), linolenic acid (9-11 %) contents suggested that these lines could possible produce low erucic acid plus high oleic linoleic, and linolenic acids in the segregating generations. Interestingly, some intercrossed F2 lines were found having low erucic acid «2%), but higher oleic acid (>50%) with early maturity (90-94 day) suggesting the breeding lines were very promising. Thus, the selected promising breeding lines could be utilized for developing early matured and high yielding having low erucic acid and high mono- and polyunsaturated fatty acid compositions. Keywords: short duration, canola-grade, breeding lines, high oleic acid, Brassica rapa