Linkage of Two Mutant Genes for Multinoded Character with Marker Loci on Barley Chromosomes 5 and 7

Ganesh Prasad and S. B. Tomer
Department of Agricultural Botany
S. D. J. Post Graduate College Chandesar
Azamgarh 276128, U. P. India. "R"

The multinoded mutants of the present study were induced by chemical mutagens in a 6-rowed hulled barley cultivar DL36. Their general characteristics and inheritance were reported by Prasad and Tripathi (1985). One of these mutants was designated as multinoded branched (mnb) which produced 16 internodes and the other was designated as multinoded dwarf (mnd) which produced 10- 11 internodes with the average of 10.5. These mutants were monogenic recessive. They were crossed with the stocks carrying genetic markers. Linkage studies were made from F₂ data.

The gene for multinoded branched (mnb) was found to be linked with the genetic markers black lemma and pericarp (B) and third outer glume (trd) in the 5th linkage group. Recombination values of mnb with B and trd were 41.41 + 3.41 and 35.26 + 5.30 per cent, respectively. This mutant gene was located in the long arm of chromosome 5 at right side of the trd locus, distal to the centromere (Fig. 1).

Multinoded dwarf (mnd) gene showed linkage with smooth awn (r) and third inner glume (tg) in the 7th linkage group. Recombination values of mnd with r and tg were 39.00 + 4.76 and 30.57 + 6.59 per cent, respectively. It was located in the long arm of chromosome 7 at right to r and tg loci, distal to centromere (Fig. 2).

Several types of multinoded mutants have been reported in barley. Walker et al., (1958) described a many noded dwarf mutant which was associated with the chromosome 7 and showed 31.8 + 8.4 per cent recombination with the gene for short haired reachila (s). Two other many noded dwarf mutants (m and m2) were found associated with the chromosome 2 (Lebaron 1959). There may be several loci governing different types of multinoded character and they may be distributed on different chromosomes.

References:

Lebaron, F. C. 1959. An inheritance and linkage study of 19 factor pairs in barley. M. S. Thesis, Utah State Univ.

Prasad, K. G. and Tripathi, D. K. 1985. Induced multinoded mutants in barley. BGN 15:10-12.

Walker, G. R. W., Kasha, K. and Miller, R. A. 1958. Re- combination studies in barley. Proc. Genet. Soo. Can. III (2):41-43.

Fig. 1.Location of the mutant gene multinoded branched (mnb) on chromosome 5 of barley on the basis of cross over values (c=Centromere; s=Short arm; L=Long arm; B=Black Lemma and pericarp; trd Third outer glume).

Fig. 2.Location of the mutant gene multinoded dwarf (mnd) on chromosome 7 of barley on the basis of cross over values (c=Centromere; s=Short arm; L=Long arm; s=Short haired rachilla; Smooth awn; tg=Third inner glume).

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