In mutation breeding with EMS, turmeric single bud chips were used. Near LD50, many sprouts started withering. But due to care in handling like helping the pseudostem to open, helping the leaves unfold in budlings, helped more budlings to survive. Further, some of sprouts withered and died due to deleterious mutations, but new sprout arose from the bud, in the nodes (generally in the opposite to original sprout). These new sprouts were given extra care to survive, by placing them at proper position in the protrays.
1. Helping pseudostem to open freely.
2. Helping budlings to open leaves freely while germinating so that budling can establish.
3. Allowing the new sprout to grow in withered budlings, by placing the new sprout at geotropically advantageous position.
All these measures helped to achieve recovery of more mutant population.
Any opinion on the utility of this method in mutation breeding.
Mutation breeding through radiation is a way of variability creation in different crops usually those are not propagated by seeds or those are not able to produce true seeds with proper germination ability. Sometimes mutation breeding resulted better if it is given below the injury level or below the lethal dose. In Bangladesh mutation on Ginger with 5Crad Gamma radiation found better than its higher or below doses. If the dose is higher new bud may die, damaged or unable to germinate. If any shoots germinate from out side of the radiation imposed area may not have any change. However it may need keen observation and should allow time to see the result.
Thanks a lot.
Good morning Giridhar
I never work with turmeric but worked with mutation breeding in rice using EMS (0,2v/v) and it showed efficient in callus mutation to survive a not selective herbicide. I used this paper with base. Maybe it can help you.
The best regards, Liane
Dear Giridhar Kalidasu I'll answer on the base of that I've understood. Although you don't provide any data about the treatment method (time of treatment, were completely immersed the discs in mutagenic treatment?...), once you reached a DL50 (how did you determined it?), most of tissues in direct contact with EMS would died (as much as 50%). However, depending of duration of treatment probably some internal latent buds weren't affected by treatment: that's why likely sprouting from "dead" materials could be occurred. In this case, probably no-effects of mutagen occur. Anyway, keep checking these buds for variations regarding control. I hope it helps you.
The method is: 1. Selection of rhizomes without any active, growing buds. 2. Disbudding of any buds/differentiating buds in the selected rhizomes. 3. Cutting the rhizomes in to single node rhizome pieces. 4. Treating with any chemical mutagen for 45 min by soaking. The treatment is at LD50 and higher dose, which was arrived earlier on whole rhizomes and planting in the main field.
The rhizome is a modified stem. The intercalary meristems differentiate in to growing plant through production of pseudostem and roots. Normally, the intercalary meristem at the nodes of rhizomes remain undifferentiated and dormant. But, as the rhizome tries to germinate due to sowing or due to changes in air humidity or any other induction, like injury, the meristem differentiates in to a bud, further grows in to pseudostem. Finally, becomes a plant with roots and pseudostem, produces mother and other order rhizomes. If the meristem gets activated and differentiates after the mutagenic treatment, possibly we are going to find a mutant, that too a solid one. If the meristem is active and already at some differentiation, we may find a chimera. In the current method, we allowed most intercalary meristem to become active and differentiate after the mutagenic treatment. The plant thus originated might be, mostly a solid mutant (depends) and possibility of recovery mutants increased. The deleterious mutations, which after developing in to pseudostem caused death, however, the turning of buds in the cocopeat allowed a group of cells in the intercalary meristem to differentiate and produce a budling, which, if not of deleterious nature survive. The care in the protrays, which has reduced the serious environmental stress during early growth of mutated plants, has probably helped in survival of more mutants, to grow as individual plants. It seems plants have extreme ability to deal with mutations, provided good amount of care is taken. However, extremely deleterious mutations such as (albino), might have withered in protrays, however, turning of buds in the protrays allowed other cells of intercalary meristem to take over and generate a complete plant. The plants have been transplanted in the field a week ago and mostly they are good. I request all other to comment on this and help me understand the issue better.
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