Environmental effects on linseed (Linum usitatissimum L.) yield and growth of flax at different stand densities

The effect of environmental factors and stand density on linseed (Linum usitatissimum L.) yield was investigated by examining yield components and development rates from 4 years of field experiments carried out at Viterbo, Central Italy, in which different seed rates were tested. Spring sowings were carried out using the linseed cultivar ‘Mikael’. Growth analysis using the functional approach and modelling using the SUCROS model for potential production parameterized for linseed were used to carry out a more detailed analysis of environmental effects. Linseed yields varied greatly in response to weather and soil type but showed very little effect of plant density. The crop was able to compensate for reduced stand densities mainly by increasing the number of capsules per plant. All yield components were significantly influenced by weather as represented by the year of sowing. Growth analysis showed that the unit leaf rate had higher values at lower stand densities, suggesting that self-shading at higher densities decreased the efficiency of the foliage. The environmental factors most likely to affect yields were high temperature, due to its effect on development rate, and the consequent shortening of the growing cycle and perhaps water shortage. The foliage duration was more important than the maximum leaf area index. © 1999 Elsevier Science B.V. All rights reserved.