Sweet Sorghum: Breeding and Bioproducts - Industrial Crops: Breeding for BioEnergy and Bioproducts - page 13

Fig. 1.1 Comparison of
grain sorghum (front) and
sweet sorghum crop (rear)
at flowering
Pedigree Method
Pedigree breeding method is the most commonly used method of breeding in
sorghum where the selection begins in the F 2 generation targeting superior plants
which are expected to produce the best progenies. Hybrids between diverse parents
segregate for a large number of genes, and every F 2 individual is genetically
different from other individuals. The population size becomes crucial for the
success of recovering desirable genotypes, when several genes are involved. In
this method (Fig. 1.1 ), superior individual plants are selected in successive segre-
gating generations from the selected families, and a complete record of parent
progeny relationship is maintained. Identifying a potentially good cross is essential
since the best F 1 plants produce better yielding F 4 progenies. The selection in
segregating generations should be based on (1) performance of the families of the
selected cross on the whole and (2) the individual plants performance within the
selected family. Selection for many of the per se selection criteria encompassing
various traits like tallness, stem thickness, and juice yield can be rapidly applied in
the first two or three segregating generations since crosses between elite lines
produce a high proportion of progeny with desirable per se values. Once the
promising lines have been identified, they can be test crossed onto male-sterile
lines for checking fertility restoration and may be classified as B or R lines. Lines
with high biomass yield and other desirable agronomic characters can be released as
varieties. The pedigree method has been utilized to create new recombinants,
transfer of few to many genes governing resistances to various insects, diseases,
cold tolerance, etc. in sorghum. In India, the important sweet sorghum genotypes
released through pedigree method of selection are SSV 74, SSV 84, CSV 19 SS, and
CSV 24SS [ 45 ].