Knob-heterochromatin distribution in Sikkim Primitive strains and Nal-Tel

A striking similarity in knob constellation between Nal-Tel and two Sikkim Primitive strains, viz., Tripura collection No. 2 (T-2) and Muralia, a collection from Pithoragarh of Uttar Pradesh hills bordering Nepal, has been observed.

In strain T-2, there are 11 knob positions at 2L, 4L, 5L, 6S, 6Lb, 6Lc, 7L, 8La, 8Lb, 9S and 9L. Knobs at 2L, 4L, 6S, 7L, 8La, 9S and 9L are larger in size. The knob at 7L was homozygous and very large. Knobs at 5L, 6Lb, 6Lc are smaller in size.

Muralia showed 12 knobs. It has prominently large knobs at 2L, 4L, 5L, 6S, 7L, 8La, 9S and 9L while 6La, 6Lb and 6Lc positions showed smaller knobs. There is also a large chromomere in the long arm of chromosome 6 prior to knob 6La.

T-2 and Muralia share 10 knob positions in common, viz., 2L, 4L, 5L, 6S, 6Lb, 6Lc, M, 8La, 9S and 9L. 1sb and 8Lb are found only in Muralia, and 8Lb was present in T-2 alone.

The Nal-Tel knob number ranged from 8.6-12.2 with a mean of 10. There are 10 common knob forming positions in Sikkim Primitives and Nal-Tel, viz., 2L, 4L, 5L, 6Lb, 6Lc, 7L, 8La, 8Lb, 9S and 9L. It is possible that Nal-Tel, or rather maize belonging to a precursor or derivative of Nal-Tel/Chapalote, was one of the basic materials that was introduced in the North-Eastern Himalayan region.

Sudhansu Dash, J.K.S. Sachan and K. R. Sarkar

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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