Genetic Analysis Of Oleic Acid And Linolenic Acid And Path Analysis Between Oleic Acid And Some Agronomy And Quality Traits In Brassica Napus L.

Oleic acid, cis-9-octadecenoic acid, is the most important monounsaturated fatty acids. It is reported that high oleic acid content of rapeseed oil (>75%) has huge using value in the edible oil and industry oil. At present, to improve rapeseed oleic acid content while reduce linolenic acid content on the basis of low erucic acid has become one of the important targets in rape breeding. But, researchers still lack system studes about inheritance of oleic acid and linolenic acid in low erucic acid rapeseed, and relationship between high oleic acid and agronomical traits and quality traits.Therefore, this test make the following two aspects of research:1. The research uses gas chromatograph to determine oleic acid and linolenic acid content of single rapeseed of P1,F1, P2, B1, B2, F2 generations derived from the cross of Y520x08T15 which are "double low" high and middle oleic acid rape variety Inheritance of oleic acid and linolenic acid are investigated by applying multi-generation joint analysis method of the major gene plus polygene mixed genetic model of the plant quantitative trait genetic system. The results shown that:1) oleic acid inheritance in the cross of Y520×08T15 is mainly controlled by E model (two major genes with additive-dominance-epistatic effect plus polygene with additive-dominance-epistatic effect). The two major genes have approximately equal additive effect; two major genes'low oleic acid both have part dominance effect to high oleic acid; the second major gene is much higher than the first one about the control of oleic acid inheritance; the heritability of oleic acid is quite high.2) Linolenic acid inheritance in the cross of Y520×08T15 is mainly controlled by D model (one major gene with additive-dominance effect plus polygene with additive-dominance-epistatic effect). The major gene is mainly controlled by additive effect; poly-gene heritability is much higher than major gene heritability.2. Some researches have shown that high oleic acid trait would be associated with some unfavorable agronomical traits, and rapeseed oleic acid content is negatively correlated to seed yield, and so on. To do this study is to find out the relationship between oleic acid content and agronomical traits and quality traits in rapeseed, then guide high oleic acid and low linolenic acid rape breeding. The sample of the path analysis between high oleic acid trait and 8 agronomical traits and quality traits, such as plant height, effective branch number, oil content, linoleic acid and linolenic acid etc, is six generations material of high or middle oleic acid (>65%) in Brassica napus L. The sample size is 208. The plant height, number of effective branch, height of first effective branch and seed number per silique have minute negatively correlated to high oleic acid trait directly or indirectly.1000 seed weight and oil content have tiny positive effect to high oleic acid trait. But, the effects of these six factors are small, that is high oleic acid trait doesn't have abvious adverse effects to main agronomical and yield traits.Linoleic acid is the most important factor which controls the content of oleic acid in rapeseed, and the path coefficient is -0.8444. Linolenic acid is another important factor which controls the content of oleic acid in rapeseed,and the path coefficient is -0.4483.