ABSTRACT
The improvement in quality traits of lettuce (Lactuca sativa) leaves using
somatic hybridization techniques via protoplasts fusion is the main focus of
this study. Somatic hybridization between two cultivars of lettuce, Evola and
Red Leaf Amboni green and red, respectively, were carried out at Plant Science
Laboratory, University of Nottingham, UK during 2006-7 to test the culture of
fused protoplasts via polyethylene glycol (PEG) and electro fusion on four
types of media i.e. liquid B5 based medium (T1), embedding of liquid B5
medium over agarose (equal volume ratio) (T2), embedding of solid B5 medium
over agarose (equal volume ratio) (T3), embedding of liquid B5 medium over
MS0.8 medium supplement with 0.5mg/l NAA and 0.04mg/l BAP (T4) under five
replications. The treatment T4 in each replication gave significant result for
fused protoplasts via chemical and electro- fusion in terms of micro and macro
colonies (5 to 73 average micro colonies in petri dishes) culture while other
treatments have damaged the protoplast. In all replications under T4 a large
number of micro colonies and macro colonies were observed and tested for
viability via Flourescein diacetate (FDA) test. All macro colonies show 100%
viable colonies for regeneration. It has also been observed that electro fusion
shows 40.51% protoplast fusion frequency over PEG. Based on the results, it
can be concluded that selection of lettuce genotypes on the basis of seed
viability using somatic hybridization techniques via protoplast fusion (both
methods of fusion) cultured under optimum medium for improvement of lettuce
quality could be an important tool in in vitro techniques.
KEYWORDS: Lactuca sativa; cultivars; somatic hybridization; protoplasts
fusion; growing media; Great Britain.