Describing and rechristening a popcorn variety of Sikkim as 'Sikkim Primitive' (SP 1 and SP 2), Dr. N. L. Dhawan (MNL 38:69-70, 1964) is credited for arousing great interest in Himalayan maize among the concerned scientists of the world. A project on cytogenetic study of Himalayan germplasm of maize and its cultivated and wild relatives has been taken up by us under the auspices of the Indian Council of Agricultural Research (ICAR). Presently, we have a rich haul of maize germplasm from Sikkim, Nagaland, Meghalaya, Tripura, Mizoram, Manipur and NorthWestern Bengal. The germplasm can be broadly classified into waxy, sugary, floury, flint, dent and popcorn types.
Dr. H. G. Wilkes, who during his visit to our laboratory (1978-79) had the opportunity of studying our collections, has rightly emphasized the importance of studying Indian germplasm (MNL 55:13-15, 1981). We have collected through our personal trips sixteen 'Sikkim Primitive' types from various ethnic groups and different altitudes (4000-7000+ ft) of the North-Eastern Himalayas.
Experiments comprising thirteen primitive types were grown in a replicated trial at a height of 4500 ft in Kumaon Hills to compare the extent of variability among different populations. The data on five randomly selected plants were recorded. The accompanying table gives a general idea about the plant types of different collections.
Various collections of 'Sikkim Primitive' types seem to be derivatives of a single widespread popcorn variety grown and selected by different ethnic groups in remote and isolated pockets of the North-Eastern Himalayas. Tillering habit was not observed in any of the collections. All collections have the unique tendency of bearing ears at the top (Fig. 1). On an average, five ears of almost equal size per plant have been recorded. As many as eight ears have been noted in one of the collections from Tripura (T-26). The increase in the number of ears is associated with the decrease in the number of internodes between the topmost ear and peduncle. Plant types resembling the prototype of wild 'hypothetical maize,' and gynoecious plants have also been recovered from the populations (Fig. 2 and 3).
It is interesting to note that in 'Sikkim Primitives' many of the ears bearing male inflorescences at the tip are all self fertilized. Such ears are completely covered with long husks, and thus silk does not come out of the husk. Apparently there is no indication of inbreeding depression in these populations.
J. K. S. Sachan and K. R. Sarkar
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