EFFECT OF GAMMA RAYS, ABSCISIC ACID AND PUTRESCINE ON PRODUCTION OF WHEAT PLAN I TS MORE TOLERANT TO SALINITY: ~ B· IN VITRO CALLUS INDUCTION, PLANT REGENERAliION, AND GRAINS PRODUCTION' UNDER SALINE CONDITIONS

In vitro tlssue culture experiment was conducted to e valuate the ext nt of
improvement in salinity tolerance of the sensitive Giza 167 cultivar due l~1 the
previously applied treatments in t he pot experiments during t he first part (A) ~ f the
present investigation. The embryonic calli, plantlets and plants regenerated fro I the
grains produced either by the salt-sensitive untreated and treated plants of Giz 167
cullivar or by the untreated plants of Sakha 8 one. in the second pot expejl'ment
season; 2000·2001 were used to be tested in vitro under the same salinity eve Is
previously applied in the first part of this study. The obtained results from the in vitro
experiments were in full accordance with those obtained in the first part, as repards
the absolute superiority of the regenerated calli, plantlets, and plants from the "lature
grains of the previously treated plants (in the pot experiments) with the weekly
spraying either with 10IJM putrescine or 2 ppm ABA as well as the grains irradiatit n
with 15 KR gamma rays in their growth, chemical composition (In both tissues and
grains), and invertase activity as well as their grain yield (g)fplant and 1000 gtains.
weight which recorded the highest highly significant increments over the respective
values of those produced from the grains of the satt-tolerant Sakha 8 control, al~?, up
to 30% sea water level, nevertheless, without applying any treatments under such In
vitro conditions. This finding strongly Indicating the possibility of transmission at the
phYSiological tolerance to salinity induced by those treatments previously applied in
the pot experiments in the first part with nearly equal extent from the parent tolerant
plants to their regenerations under in vitro conditions, thus enable them to be ad~pted
to the all applied levels of salinity in the media and therefore, could complete th:t life
cycle till harvest and grains production which were highly significantly exceeded that
both controls a Iso up to 30% sea water under in vitro conditions, as d ld u nder pet
experiments conditions in the first part. Therefore, the obtained results strongly
suggested that the tolerance to salinity of the salt-sensltive Giza 167 wheat cu tivar
potted plants and even their regenerated plants under in vitro conditions, can be
improved to a considerable extent, thus could tolerate the irrigation with saline ater
up to 30% sea water and nevertheless, attained their optimal productivity which h ghly
significantly exceed the productivity of the salt-tolerant Sakha 8 cultivar control under
the same 30% salinity level in both cases, if these sensitive plants were weekly
sprayed either with 10 IJM putrescine or 2 ppm ABA or when their grains were
irradiated with 1 5 K R gamma rays before s owing only in the pot experiments, ith
special referring to the putrescine treatment in this concern.