Breeding methods in sorghum

SORGHUM ARUN CHACKO
2019-21-057

Sorghum: ‘4F’ crop—food, fodder, feed and fuel.
• Over half a billion people rely on sorghum as a dietary
mainstay and, given its diversity of uses, as an important
source of income.
• The grain is used mainly for food, prepared in the form of flat
breads and porridges of different kinds.
• Sorghum stover is a vital source of fodder for livestock.
• Sorghum is also used for a wide range of industrial purposes,
including the production of sweet syrups, as a source of starch
for fermentation, and for producing biofuel.
• The durable stalks of the plant are used by the rural poor as a
construction material and as fuel for cooking.

• Sorghum grain is nutritious.
• It has relatively high levels of iron and zinc
(more than 40 ppm and more than 30 ppm,
respectively, and can be used to complement
global food biofortification efforts to reduce
micronutrient malnutrition.

Sorghum Taxonomy
Kingdom Plantae
Sub-kingdom Tracheobionta
Superdivision Spermatophyta
Division Magnoliophyta
Class Liliopsida
Sub-class Commelinidae
Order Cyperales
Family Poaceae (grass)
Tribe Andropogoneae
Sub-tribe Sorghinae
Genus Sorghum
Species Sorghum bicolor

• Chromosome No.: 2n=20
• Common names : Sorghum (Eng.) Jowar (India),
• Origin : North East Africa
• Secondary origin: India
Sorghum
Common wild sorghum Sorghum bicolor ssp. arundinaceum
Grain sorghum Sorghum bicolor ssp.bicolor
Sudan grass Sorghum bicolor ssp.drummondii
Columbus grass Sorghum almum
Johnson grass Sorghum halepense

Historical..
• 1753: Linnaeusdescribed a Sorghum collection under
the name Holcus.
• 1794: Moench distinguished the genus Sorghum from
the genus Holcus.
• 1805: Person suggested the name Sorghum vulgare for
Holcus sorghum (L.).
• 1961: Clayton proposed the name Sorghum bicolor (L.)
Moench as the correct name for cultivated sorghum.

The genus consists of 25 species and has been
split into five sections:
• Eu-Sorghum,
• Chaetosorghum,
• Heterosorghum,
• Para-Sorghum, and
• Stiposorghum.

• Snowden( 1936 ) sub-divided the sorghums
into the sections, sub-sections and series.

Cultivated Sorghum is divided into five distinct
races, namely,
• Bicolor (B),
• Caudatum (C),
• Guinea (G),
• Durra (D),
• Kafir (K).

Diagrammatic representation of spikelets of five basic races.
•
( a ) Bicolor ( b ) Guinea. ( c ) Caudatum. ( d ) Kafir ( e ) Durra

Grain sorghum groups
• Most of the grain sorghums in cultivation are hybrids,
derived from kafir-milo crosses.
The major commercial groups of grain sorghum are
• Durra,
• Shallu,
• Guineense,
• Kafir,
• Kaoliang
• Milo,
• Feterita,
• Hegari.

Progenitor species
• S. arundinaceum,
• S. drummondii,
• S. halepense
• S. propinquum
S. arundinaceum S. Drummondii S. halepense

The species within the Sorghum genus fall into a
primary, secondary, and tertiary gene pool.
• The primary and secondary gene pools consist of
Eu-Sorghum (S. bicolor, S. almum, S. drummondii,
S. halepense, S. propinquum, S. arundinaceum),
• Tertiary gene pool consists of
 Chaetosorghum (S. macrospermum),
 Heterosorghum (S. laxiflorum),
 Para-Sorghum
 Stiposorghum

Cytogenetics
• Sorghum comprises three known ploidy levels:
x=5,10, and 20.
• Important sorghum species are:
• S. bicolor (Linn.) Moench (2n=2x=20),
• S. Propinquun (Kunth) Hitche (2n=2x=20),
• S. halepense (Linn.) Pers. (2n=4x=40).
• Of these three, the most important to crop production is S.
bicolor.
• Grassy species such as S. arundinuceuin, S. verticillijlorum,
and S. aethiopicum, have the same chromosome number
(2n=2x=20) and can be crossed with S. bicolor.
• Sorghum has also been successfully crossed with sugarcane
and corn.

• Cytogenetic male sterility and fertility restoration
systems have been discovered in sorghum and are
used in hybrid sorghum production.
• The CMS in sorghum genotypes was developed by
backcrossing chromosomes of kafir into the
cytoplasm of milo.
• Similarly, genetic male sterility (ms) has been
discovered in sorghum male sterile plants (Msms).

Sorghum bicolor (Linn.). Moench
• The cultivated races are placed in Sorghum
bicolor subsp. bicolor
• S. bicolor is strictly a short-day plant and very
sensitive to photoperiod.
• It is cultivated in harsh conditions, on marginal
land with minimum resources requiring less
water (high water use efficiency, WUE) and
low dosage of fertilizers/nutrients.

Sorghum is grown in three seasons:
1. Kharif season during monsoon i.e. from
June-July to September.
2. Winter season i.e. from September to
February it is 35% of the total sorghum
hectarage at national level.
3. Summer sorghum planted from February
to June under irrigation
• Height generally varies from 40-600
cm.
• It's stem has 7-18 nodes and internodes

Inflorescence
• The inflorescence is a panicle (called arrow) with a central
rachis from which primary branches arise.
• They give rise to secondary and some times tertiary branches
which carry the racemes of spikelets.
Panicle
• A panicle may be shoot, compact or loose and open, 4 to 25
cm or more in length.
• The central axis of panicle the rachis may be striated and it
may be hairy or glabrous.
• The panicle usually grows erect at the apex of the clum, but
may be recurved. It releases 25-100 million pollen grains.

Raceme
• A raceme always consists of one or several
spikelet.
• One spikelet is always sessile (fertile) and the
other pedicellate (sterile), except the terminal
sessile spikelet, which is accompanied by two
pediceled spikelets.
• Raceme may vary in length according to number
of nodes and length of internodes.
• On the pedicellated spikelet, the pedicels vary in
length from 0.5 to 3.0 mm and usually similar to
internodes.

Flower
• Perfect flower consist of two glumes one hairy
lemma, a small palea, small awn, 3 stamens
two lodicules and one pistil.
• Ovary has two styles with feathery stigmas.

Anthesis
• The sorghum
inflorescence usually
begins to flower when the
peduncle has completed
elongation.
• The first flower to open is
either the terminal or the
second flower of the
uppermost panicle branch.

Pollination
• For pollination the emasculated panicle the pollen is collected
in the morning from the desired male parent panicle which is
flowering. Dust the pollen on the emasculated spikelet and
cover is again with pollinated bag.
• Sorghum is predominantly a self pollinating crop and natural
cross pollination varies from 0.6 to 6% depending on the
genotype, panicle type and wind direction and velocity.
• Stigmas exposed before the anthers dehisce are subjected to
cross pollination. Pollination for crossing purposes should start
soon after normal pollen shedding is completed during
morning hours.
• Hand pollination should begin around 09:30 to 10:00 and can
be extended up to 11:30 to 12:30 on a foggy morning.

Pollination
• Hand Emasculation or traditional methods: Remove all the open
spikelets with fine blade scissors preferably in the after noon.
Remove all the three stamens with the help of forceps. Care must be
taken that there is no injury to stigma.
• Hot water treatment: The immature and mature spikelets are
removed from the panicles which have just begun to gloom. The
panicle is then inserted in a sleeve of rubber, which tied lightly
around the panicle and open at the top. The panicle is inserted for
about 10 min. in 480C hot water. After treatment cover the panicle
with bag.
• Male Sterility: Genetic (GMS) and cytogenetic male sterlity (CMS)
are available in sorghum. These types of male sterlity may be used
for the production of hybrid seed on a large scale. Tagging is done as
usual. MSCK 60 (male sterile combine Kafir 60) is a male sterile
variety of sorghum. It contains the Kafir chromosomes and Milo
cytoplasm.

• Removal of anthers from a bisexual flower during emasculation

Fruit
• Fruit of sorghum is caryopsis
(Kernel), naked or covered.
• The individual grains are small-
about 3-4 mm in diameter.
• They vary in colour from pale
yellow through reddish brown
to dark brown depending on the
cultivar

Neelamraju Ganga Prasada Rao
Dr. N.G. P Rao
• Father of Hybrid
Sorghum
• Developed world’s
first sorghum hybrid
CSH-1
• (Coordinated
Sorghum Hybrid)

Breeding Objectives
• High grain yield
• Short duration
• Drought resistant varieties with low HCN content
• Non-lodging
• Good threshability, general attractiveness, large head size,
good head exertion, tillering, and seed set.
• Resistance to pests
• Resistance to disease
• Tolerance to Abiotic Stresses
• Breeding for sweet sorghum
• Striga resistance

High Yield
• Productivity genes are present in durra, roxburghi,
Caudatum and Zera - Zera.
• Direct components: Panicle length and breadth
panicle weight, number of primary branches, number
of seeds / panicle and 100 seed weight.
• Indirect components: Plant height, leaf area index
endosperm texture.
Short Duration
• Fit in multiple cropping programme. Co22 is the
shortest duration having a duration of 70 days.

Breeding drought resistant varieties with low HCN
content in the early stages of growth
• 75% of sorghum is grown under rainfed condition. It is
highly essential to breed varieties, which can with stand
initial as well as terminal drought.
• Further in dry land varieties there will be high HCN
content in the stem during early vegetative phase. This
limits the use of varieties as cattle feed.
• To overcome this it is essential to breed varieties with
low HCN content.
• Low HCN content exhibits partial dominance reaction.
More than one gene is involved in controlling this trait.

• Resistance to Diseases
Sorghum downy mildew, helminthosporium
blight, grain mould, charcoal rot, Ergot and
sugary disease, rust, anthracnose, Zonate leaf
spot, Grey leaf spot, Rough leaf spot, Sooty
stripe.
• Resistance to pests
Shoot fly, stemborer, midge and earhead bug

SORGHUM CONVERSION PROGRAM
• Sorghum genotypes introduced from
tropical climates with short days into
temperate climates with longer
photoperiods almost always mature too late
to produce viable seeds and are too tall to
be harvested with modern machinery.
• Tropical cultivars are convened to
temperate climate adaptation by substituting
two recessive alleles for height for the
dominant counterpart alleles in the tropical
accessions and the recessive ma1 maturity
allele for dominant Ma1 through a
backcross breeding program.

Introduction
• Varieties of milo and kafir sorghum introduced from USA
are used in conversion programme to convert the local long
duration photo sensitive varieties to short duration, non-
photo sensitive lines.
• MSCK 60 A straight introduction to India in 1962 was used
as a female parent to develop experimental hybrids.
• IS 84 and IS 3691 from germplasm collection were used as
restorers of hybrids CSH 1 and CSH 2, respectively.
Selection
• Old varieties like Co1, Co2, Co4 are all selection made
from local land races.

Pure-line Selection
• In this method a large number of plants derived from single,
homozygous, and self-pollinated crop are selected, which are
genetically identical.
• It differs from mass selection where individual selected plants are
subjected to progeny test, and based on the performance of the
progenies, superior progeny producing plants are forwarded and
they are harvested separately without mixing the seeds.
• Base population used for individual plant selection is genetically
variable but homogeneous.
• Progenies of selected plants are evaluated for yield and yield-related
traits and uniformity for agronomic traits. Best progeny line with
higher yield and desired characters is selected. Subsequently their
performance is compared with check varieties to identify best line as
new entry.
• Varieties developed: M-35-1, Sel-3, Yashoda, Maulee

Pedigree Method
• In sorghum each generation is advanced
effectively through panicle-row method and
the selection is practiced till the families are
reduced to suitable size of handling for
comprehensive evaluation trial.
Varieties developed:
• CSV 15 (SPV475 SPV 462),
• CSV 17 (SPV 946 SPV772),
• CSV 20(SPV946 Hh89-246).

Recurrent selection
• Hull (1952) stated, “Recurrent selection was meant to
include reselection generation after generation, with
inbreeding of selects to provide for genetic
recombination.”
• All schemes of recurrent selection have three
principal features:
1) formation of families,
2) testing of families,
3) recombination of the selected families.

Population Improvement
• Mass selection, halfsib family selection, full sib family
selection, and S1 family selection, may be used as
recurrent selection procedures for population
improvement.
• The recurrent selection population is utilized as the
source population for selection of breeding lines
improved for the character under consideration.

Mass selection
• simplest and least expensive recurrent selection
procedure.
• If open pollinated plants are chosen and propagated,
one selection cycle is completed with each generation.
• With open pollination, there is no control of the male
parent, so genetic gain is reduced by one half.
• If plants are selected before flowering and self
pollinated, an additional generation is needed for
recombination of the selected genotypes so that two
generations are required to complete a cycle.

• In half sib family selection, male sterile plants are identified
in the population and pollinated from a random selection of
male fertile plants;
• In full sib family selection, each selected male sterile plant is
pollinated by a single male fertile plant; and in S1 family
selection, selected male fertile plants are bagged and self
pollinated.
• Progenies of the respective selected plants are designated
families.
• Three generations are required to complete a recurrent
selection cycle: selection generation, evaluation generation,
and recombination generation.
• Due to the large genotype × environment interactions,
evaluations should be made at more than one location and in
more than one year.

Backcross breeding
• In sorghum, backcross breeding is applied to transfer
the male sterile (ms) gene into different genetic
backgrounds.
• Nonrestorer lines with good general combining
ability are good choice to convert them into ms lines.
• Transfer of disease and pest resistance through
backcross breeding .

Hybrid Breeding
• In sorghum, hybrid breeding is a three-line system as it involves “A”
ms line, “B” maintainer line, and “R” fertility restorer line.
• “A” line on pollination with the “R” line restores fertility of “A”
lines and develops heterotic fertile F1 seeds.
• Stephens and Holland (1954) demonstrated that milo cytoplasm
interacted with kafir nuclear factors resulting in male sterility.
• Through repeated backcrossing, cytoplasmic genetic ms lines have
been developed by substituting the entire milo genome with that of
kafir.
• Kafir60, msCK60A, provided the initial choice of ms lines in
various sorghum hybrid breeding programs.

“A” Line
• It is the ms line where pollen is nonfunctional and
needs cross-pollination for seed set.
• The CMS system developed by Stephens and Holland
(1954) is referred to as A1 or milo cytoplasm.
• Most of the commercial hybrids developed in sorghum
across the world are based on utilization of single ms
line A1.
• The development of non-milo ms lines is restricted
because the nuclei of new female parent must have
genes that interact with milo cytoplasmic genes to
induce sterility.
• Some of the alternate ms systems are A2, A3, A4, 9E,
A5, and A6.

Milo (A1) and non-milo (A2, A3 & A4) CMS systems in sorghum along with a
fertile panicle.

“B” Line
• It is called as maintainer line as it is used to maintain
the sterile “A” lines B line is isogenic to A line, in the
sense, its genotype is similar to A line except for single
sterility governing (ms) gene.
• B line should be in homozygous state at male sterility
locus (ms ms) to maintain “A” line after crossing Ax B
lines in “A” line maintenance plot.
• Heterozygous condition of male sterility locus in "B"
line (Ms ms) will produce 50% of male fertile F1s in a
cross with "A" line (ms ms) in the "A" line maintenance
plot.
• This will lead to selfed seed production in the hybrid
seed production plots.

“R” Line
• Restorer line is used to restore the fertility in hybrid
after crossing with ms A line in hybrid production
plot.
• Popular R lines such as AKR150, RS585, C43, CB11,
CB33, RS29, Indore 2, AKR354, etc., were
developed by testing their combining ability and
higher yield in hybrid combination with desired A
lines.

Production of Hybrid Seed
• Hybrid seed is produced by crossing AxR lines
in breeder seed production plot .
• In sorghum, generally followed female to male
ratio is 4:2.

Hybridization and selection
a) Inter varietal
• (IS 4283 x Co 21) x CS 3541, Three way cross
derivative Co 25
• (MS 8271 x IS 3691) - Single cross derivative Co26
b) Inter specific
• Co 27 Sorghum. (Co11 x S.halapense)

• The first commercial sorghum hybrid CSH1, an early
duration and dwarf hybrid, was released in 1964 for all
India cultivation using the parental lines bred in the USA
and supplied by the Rockefeller Foundation.
• CSH1: CK 60A x IS 84
• high-yielding open-pollinated varieties (OPVs) CSV 1 to
CSV 35.
• The dual-purpose varieties CSV 15, CSV 20, CSV 23 and
CSV 27 could establish higher grain and fodder yield
potential than the potential hybrids
• Forage sorghum: CSH 7R and CSH 19R

Heterosis breeding :
• Use of CMS lines.
• CSH 5 2077 A x CS 3541
• CoH 4 296 A x TNS 30
Mutation breeding :
• X ray mutant from CSV 5 (148)
• Co21 (699 Tall)
• Co 19 is a natural mutant from Co 2
• The latest multicut forage sorghum variety in India,
CSV 33MF, is an EMS mutant of a forage line, CoFS
29.

Forage Sorghum
• Forage sorghums include sorghum and sudan
grass varieties and hybrids and sorghum –sudan
grass (SSG) hybrids.
• Forage sorghum plants grow 150-360 cm tall and
produce more dry matter yield than grain
sorghum.
• The development of forage sorghum cultivars
with good shoot (tillers) and biomass
regenerability makes them more amenable for
multiple cuts, which is more useful for the cut-
and-carry production in semiarid zones.

Objectives in forage sorghum breeding
• dry matter yield
• leaf spot disease resistance
• shoot fly
• stem borer resistance
• seed setting ability
• quality parameters/sweetness/intake
• low HCN/tannins
• high protein yield
• harvest index (digestibility/biological yield)
• single cut/double cut/triple cut manageability

Marker-Assisted Selection
1. Marker-assisted backcross breeding
2. Marker-assisted gene/QTL pyramiding
3. Marker-assisted recurrent section
4. Genomic selection (GS) using DNA markers

Genetic and genomic resources of sorghum to connect
genotype with phenotype in contrasting environments
• Asterisks denote traits with multiple QTLs that have yet to be characterized and/or fine‐mapped
The Plant Journal, Volume: 97, Issue: 1, Pages: 19-39, First published: 27 September 2018, DOI: (10.1111/tpj.14113)

Sorghum research in India
• Indian Council for Agricultural Research
• Indian Institute of Millets Research (ICAR-IIMR)
(formerly Directorate of Sorghum Research) in
collaboration with All India Co-ordinated Research
Program on sorghum (AICRP on Sorghum) with 21
centers distributed across 10 states of India.
• ICRISAT.

INTSORMIL
• The International Sorghum and Millet
(INTSORMIL) Collaborative Research Support
Program (CRSP, pronounced “crisp”) located at
the University of Nebraska, began in 1979.
• The brown-midrib (bmr) trait in some lines of
sorghum developed by INTSORMIL researchers
provides greater digestibility than normal forage
sorghums.

Breeding methods in sorghum

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