A Plant Growth Study of 18 Flax (Linum usitatissimum, L.) Genotypes

Flax is an important oilseed cop in the United States. Limitations on seed yield have been a major concern of researchers trying to develop high yielding flax cultivators. Dybing stated that comparative studies of physiological and biochemical factors could provide necessary insight into the cause of these limitations. Comstock concluded that there was sufficient genetic variability in the Flax World Collection to meet any breeding objective. Lay et al. considered the question of what physiological parameters could be measured to identify high yielding genotypes, and when in the life cycle of a plant those parameters could be influencing seed yield significantly. Morphological characteristics such as degree of branchiness and canopy width have been reported to be poorly associated with seed yield of flax. Inconsistent associations between seed yield and foliage distribution or CO2 exchange rates have also been reported by Dybig. He further observed that foliage weight ratio was positively associated with seed yield for later flowering cultivars and so was boll number at full bloom stage. Lay et al. found no significant differences between low and high yield cultivars for foliage parameters such as leaf area index (LAI) and specific leaf weight (SLW) and concluded that direct relationships between photosynthesis and see yield were difficult to demonstrate. Plant growth analysis approach was adopted in the present study with the following objectives: (a) describe partitioning of plant growth throughout the life cycle of 18 flax cultivars differing in seed yield, (b) provide data on seed yield and its components in flax and (c) identify any possible relationships which might exist between plant growth components and seed yield