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Wheat Information Service
Number 78: 24-27 (1994)


Incorporation of stripe rust resistant specific genes into Unnath Kalyansona carrying different gene complexes

R. Asir, V.R.K. Reddy and P. Viswanathan

Cytogenetics Laboratory, Department of Botany, Bharathiar University, Coimbatore - 641 046, India


Summary

The wheat stripe rust resistant specific genes Yr9, Yr11, Yr12, Yr13 and Yr14 were incorporated into Unnath Kalyansona carrying different gene complexes for stem and leaf rusts by simple back cross. In BC2S4 and BC3S4 generations the genotypes with excellent resistant for all three rusts were selected. An increase in grain yield/plant and 1000-grain weight were noticed in the newly constituted lines.

Key words: Stripe rust, gene complexes, Unnath Kalyansona.


Introduction

The wheat yellow rust caused by Puccinia striiformis (Westend f.sp. tritici) is one of the important rust diseases in the wheat growing areas in India (Singh et al., 1990; Brahma et al., 1993; Reddy et al., 1993 a, b). It is confined to the cool climatic area of Indo-gangetic plains, foot hills of Himalaya, Himalayan mountains in North, Nilgiri and Palney hills in South. The high yielding wheat variety Kalyansona released in late 1960's (Rao, 1978) became susceptible to all the three rusts in the middle of 1970's. This variety was improved for stem and leaf rusts after incorporation of Sr24 + Lr24 linked genes from Australian wheat variety TR 360-147/3 Agl4 and Sr26 + Lr24 from Darf/3 Ag/Kite and Sr27 + Lr28 from rye back ground (Kochumadhavan et al.,1988).

All the lines of Unnath Kalyansona are however highly susceptible to stripe rust. The percentage of infection is more in Unnath varieties than the original variety and this may be due to less competition among other rust pathogen for spreading. The present paper reports the results of transfer of five stripe rust resistance genes into Unnath Kalyansona by back cross method.


Materials and methods

Five stocks both spring and winter growth habit of hexaploid wheat carrying genes Yr9 (Verry's), Yr11 (Joss Chambier) Yr12 (Pride), Yr13 (Guardian) and Yr14 (Score W 119) were critically evaluated for eight seasons under natural and artificial epiphytotic conditions at IARI-Regional Station, Wellington, Nilgiris. This location is a 'Hot Spot' and 'Foci' for all the three rusts, therefore the genotype possessing complete rust resistance can be selected under heavy pathogen pressure in natural condition. The rust reactions were recorded by combining severity (Percentage of infection) and response (type of infection). These potentially valued genes were transferred to the imporved Kalyansona by simple back cross method. Intensive plant selections were made in BC2 and BC3 and resistant plants were advanced to BC2S4 and BC3S4. Grain yield/plant (g) and 1000-grain weight (g) were recorded both on recurrent parents and costituted lines.

't' test was applied to test the means.

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