Genetical analysis of some economic traits in flax (Linum usitatissimum L.) [electronic resource].

Includes references.

The main objectives of the present study are to evaluate six different flax genotypes [P₁ (Giza 8), P₂ (Sakha 2), P₃ (Sakha 4), p₄ (Ilona), p₅ (S. 22) and p₆ (Sakha 3)] and their F₁ crosses (including the reciprocal crosses) under three different nitrogen levels (30, 45 and 60 kg Nitrogen/faddan). Data were recorded on days to maturity, seed yield per plant (gm), seed index, straw yield/plant and oil %. The magnitude of both general and specific combining abilities were estimated for all traits, but gene action effects and genetically graphical analysis were done only for the two later traits. The obtained data revealed that the most desirable and/or highest mean performances for all parents and crosses were defined in all traits studied under the three nitrogen levels and their combined data. The mean squares associated with general (G.C.A) and specific (S.CA) combining ability effects were found to be highly significant for most studied traits in the three nitrogen levels and their combined data, this mean the importance role of both (G.C.A) and (S.C.A) effects controlling in the inheritance of all traits, but the first One were the greatest one. Based on the combined data, the best general combiners were detected in the parental cultivar Ilona (P₄) for days to maturity; in sakha 2 (P₂) for straw yield/plant, seed index and seed yield per plant and in S. 22 (P₅) for oil %. Also, based on the combined data of specific combining ability, the most desirable and/or highest values were defined in five crosses (P₃ x p₄, P₃ X p₅, P₂ X P₁, p₄ x p₆ and p₆ x P₄) for straw yield/plant, and in two crosses (P₁ x P₃ and p₄ x P₁) for oil %.The analysis of gene action effects for straw yield/plant and oil % showed that the additive variances (D) and dominance components (H1) were significant for the two traits studied in the three nitrogen fertilizing levels. Also, the ratios of recessive and dominant genes for both traits were markedly differed in each parents under the different nitrogen levels. Degrees of partial dominance, complete dominance and over dominance effects were also sharply differed under the three nitrogen levels for both traits. In general, the third nitrogen level (60 kg N/faddan) gave the highest and/or the most desirable mean performances and different genetic components for most studied traits. 60 and 30 kg N/faddan gave the maximum gain for straw yield and oil %, respectively.

Summary in Arabic.

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