Indian Society of Genetics & Plant Breeding


Modified backcross breeding method for rapid conversion of field corn line to shrunken2 (sh2) gene-based sweet corn line

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The non-availability of superior and diverse inbred parents
is one of the major bottlenecks to develop high yielding
sweet corn hybrids. The sh2,one of the promising recessive
mutant alleles, has been used in sweet corn development
however its transfer to superior field corn lines may require
extra inbreeding to identify heterozygous carrier plants.
The use of molecular markers linked with sh2 requires a
well-equipped laboratory and skilled person to carry the
marker assisted backcross breeding (MABB). Considering
the above constraints, a modified backcross breeding
method was used taking advantage of shrunken kernel of
sweet corn for foreground selection coupled with
phenotypic comparison with recurrent parent (RP). The
BC1F1plants were grown and plants having high phenotypic
similarity with RP were selfed as well as backcrossed as
pollen parent. The BC2F1 kernels of BC1F1 plants having
high similarity with RP and segregation in BC1F2 kernels
were harvested. The BC2F1 plants phenotypically most
similar to recomment parameter (RP) were selfed and the
shrunken kernels were selected from the segregating BC2F2.
The shrunken kernels were homozygous (sh2sh2) at Sh2
locus, which were validated upon inbreeding based on nonsegregating kernels in BC2F3. The modified backcross
method used is rapid, cost effective and can be used by
maize breeder with limited resources for conversion as well
diversification of sweet corn germplasm.

Keywords: Sweet corn, inbred, Shrunken2, foreground selection, modified backcross breeding


Year: 2019
Volume: 79
Issue: 1
Article DOI:
Print ISSN: 0019-5200
Online ISSN: 0975-6906



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