Indian Journal of Genetics and Plant Breeding (The)
Year : 1981, Volume : 41, Issue : 1
First page : ( 124) Last page : ( 129)
Print ISSN : 0019-5200. Online ISSN : 0975-6906.

Studies on multilines in wheat-II. progression of yellow rust in mixtures of isogenic lines in varying proportions

Gill K. S., Nanda G. S., Aujla S. S., Singh Gurdev, Sharma Y. R.

Plant Breeding Department, Punjab Agricultural University, Ludhiana, India

Summary

A study has been conducted on the progression of yellow rust of wheat on the mixtures of varying ratios of six component lines of a multiline of Kalyansona cultivar. The components involved were, two highly susceptible two moderately resistant and two highly resistant. Fifteen possible mixtures were each developed in three (50:50, 75:25 and 25:75) ratios. A total of 52 combinations (45 mixtures as above, six pure cultures and one multiline among all the six components mixed in equal proportions) were grown at the Punjab Agricultural University, Ludhiana. A race mixture of 13,14,14A, 20, 20A, 38 and I was sprayed with the one week interval. Data for yellow rust were recorded according to the modified Cobb's scale four times with one week interval from each other. For plotting graph a coefficient was obtained by multiplying the severity and prevalence of rust.

The results indicated that the development of rust was slow in mixtures as compared to the pure cultures even when the seed of the most susceptible parents were mechanically mixed and grown. In case of the two moderately resistant parents a 50:50 ratio was the best for checking the rust development. Compared with the multiline the rust development was not more in mixtures when 25 to 50 per cent population was susceptible. Rust development in the mixtures did not occur when the original parents were highly resistant irrespective of the ratio of the mixture.

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