Phosphorus nutrition of linseed (Linum usitatissimum L.) as affected by nitrogen supply: effects on vegetative development and yield components

Abstract

Abstract The effects of phosphorus (P) and nitrogen (N) supplies on the growth and yield components of linseed cv. Glenelg were studied in a glasshouse experiment using controlled P and N supplies that ranged from deficient to more than adequate for maximum growth. The main effect of constant P stress on yield components was a reduction in the number of capsules per plant as a result of reduced numbers of tillers and fruiting branches per plant. Phosphorus-stressed plants required longer to reach seed maturity than plants which received high P. Phosphorus supply had little effect on either single-seed weight or seed oil concentration, and had no significant effect on the number of seeds per capsule. Nitrogen stress did not affect the timing of maturity or single-seed weight or the number of seeds per capsule; however, it reduced the number of capsules per plant and slightly increased seed oil concentration. The onset of P stress at the start of flowering reduced capsule number by 20%, and seed and oil yields by 16%. The onset of P stress at half-seed-fill of the main stem capsules had no effect on seed or oil yields. The relief of P stress at the start of flowering resulted in a recovery of seed and oil yields to about 80% of the values for unstressed plants. Seeds contained over 80% of the total shoot P at maturity. Seed and oil yields could be predicted with reasonable precision from the dry matter or P content of the whole shoot as early as flower buds visible, and this could provide the basis of an oil yield prediction model for linseed.