Ij. Ekanayake et Jh. Dodds, IN-VITRO TESTING FOR THE EFFECTS OF SALT STRESS ON GROWTH AND SURVIVAL OF SWEET-POTATO, Scientia horticulturae, 55(3-4), 1993, pp. 239-248
Field screening in saline sites to select salt-tolerant genotypes of s
weet potato (Ipomoea batatas (L.) Lam. ) is complicated owing to the l
arge spatial variations in the soil salinity level, differential ontog
enic reactions of the plant to salinity and a large genotype X environ
ment interaction. Testing micro-propagated plantlets in in-vitro salin
e media can overcome some of these in-vivo problems of variability and
repeatability. A series of laboratory experiments was conducted to te
st the hypothesis that a vigorous plantlet surviving in a saline mediu
m would be tolerant owing to a higher competitive ability and a lower
growth retardation. The results showed significant variations among th
e existing cultivated Ipomoea germplasm and some breeding lines for sa
lt tolerance based on plant growth characters, percentage of survival
and fibrous root formation. In-vitro techniques were shown to be usefu
l in identifying relatively salt-tolerant genotypes. In-vitro clonal b
ehavior in a saline medium and the thick root yield potential in salin
e field sites need further study.