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Results and
discussion
Results on hybrid necrosis on different cross combinations are
summerised in Table
1. All the plants
in a cross between D 525-2 and Spica were necrotic whereas in D 525-2
x Kalyan Sona cross were non-necrotic. This derivative when tested
against 14 different Australian wheat leaf rust cultures, was found
to carry Lr13 along with Lr23 (Saini 1987). The
dominant complementary necrotic gene Ne2 is linked with
Lr13 with a linkage distance 33.17 plus or minus 4.12 mu
(McIntosh 1983; Anand et al. 1991). The cross between Spica and D
525-2 showed necrosis due to the presence of Ne1 in Spica and
Lr13- Ne2 in D 525-2. The crosses of D 3237-5 and D 3542-6
with Spica were non-necrotic but with Kalyan Sona were necrotic.
These observations indicate that hexaploid derivative D 525-2 carries
dominant necrotic gene Ne2 whereas D 3237-5 and D 3542-6 carry
Ne1.
All the three derivatives confer seedling and adult plant
resistance against different leaf rust races of wheat prevalent in
India (Cupta et al.1991,1992), therefore, their characterization for
necrotic genes Ne1 and Ne2 would help breeders to use
them effectively in their wheat breeding programmes.
References
Anand D, Saini RG, Gupta AK and Shiwani (1991) Linkage distance
between the wheat leaf rust resistance gene Lr13 and a gene
for hybrid necrosis Ne2m,. J Genet & Breed 45:
245-246.
Gupta S, Gupta AK and Saini RG (1991) Transfer of leaf rust
resistance from durum wheats CPAN 6051 and CPAN 6073 to Triticum
aestivum. Wheat Inf Service 73: 8-10.
Gupta Sanjiv, Gupta AK and Saini RG (1992) Transfer, expression and
inheritance of resistance to leaf rust from Triticum durum to
Triticum aestivum. SABRAO J 23(2): 119-125.
Hermsen JGTh (1963) The genetic basis of hybrid necrosis in wheat.
Genetica 33: 245-287.
McIntosh RA (1983) A catalogue of gene symbols for wheat. Proc 6th
Intn Wheat Genet Symp Kyoto Japan pp 1197-1254.
Nishikawa K (1967) Identification and distribution of necrosis and
chlorosis genes in tetraploid wheat. Seiken Ziho 19: 37-42.
Saini RG (1987) Genetics and breeding for rust resistance in wheat.
Project Report University of Sydney Australia pp 54.
Zeven AC (1981) Eight supplementary list of wheat varieties
classified according to their genotype for hybrid necrosis. Euphytica
30: 521-539.
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