Physiology and molecular biology of Miscanthus genotypes grown under U.K. conditions
Miscanthus is found in many different environments in the wild and thus may
have a broad genetic base which could be exploited by a genetic improvement
programme. Miscanthus sinensis is found in higher and colder latitudes than
Miscanthus sacchariflorus, which is usually found closer to sea level. However, M
sacchariflorus achieves taller canopy height and is later in maturing. Therefore, for
United Kingdom (U.K.) conditions the combination of the lower temperature adapted
traits of M sinensis with the higher productive potential of M sacchariflorus is
required. No previous work has been performed on the effect of the altitude at which
plants are collected on their adaptation to U.K. conditions. Therefore, the aim of the
current study was to differentiate by physiological and molecular methods between
and within the genotypes of Miscanthus sampled from different altitudes in Japan.
Physiological analysis was undertaken, in the field, over 3 seasons in order to
determine which parameters could be used as predictors of productivity. In the second
growth season a modified method was used to measure leaf extension rate (CliftonBrown,
1997) and this was found to correlate positively to annual production when
measured during the vegetative phase of growth. Results also confirmed that
genotypes with a flowering date in September and October were more productive
since the length of the vegetative growth stage was increased. Considerable variation
was found to be present both between, as well as within, the genotypes and ecotypes
of Miscanthus studied, which could be exploited in an improvement programme.
Further analysis was also carried out at the genetic level using the AFLP
fingerprinting technique; this confirmed the results obtained using the physiological
parameters. However, no clear link could be found between the altitude at which the
plant was collected and the traits exhibited. It was found that late flowering M.
sinensis outperfonned M. sacchariflorus genotypes primarily because of differences
between stem densities. The results obtained show that a Miscanthus breeding
programme for U.K. conditions is feasible as considerable variation in productivity
related traits is present at the genetic as well as the physiological level.