Training Manual Development Of Cultivars And Seed ... - icrisat

• Each raceme always consists of one or several spikelets; one spikelet is always sessile and the
other pedicellate, except for the terminal sessile spikelet, which is accompanied by two pedicellate
spikelets.
• Sessile spikelets (seed-bearing) (Fig. 3) consist of:
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an outer glume (convex or boat-shaped) and an inner glume (flattened); glume texture,
size, and thickness are variable. The seed is enclosed by the glume or protrudes from it
depending on the race of sorghum.
two lemmas consisting of delicate white tissue; the lower one is oblong or elliptical, equal
in size to the glume; the upper one is shorter and ovate, and may be awned.
two lodicules, much reduced, useful in flower opening.
a palea, much reduced, of little interest.
two pistils/stigmas, attached to a short, stout style extending to the ovary.
three thread-like stamens, attached to the anthers.
• Pedicellate spikelets:
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much narrower than the sessile spikelets, lanceolate in shape.
male or neuter, but may very rarely have a rudimentary ovary.
lemmas are much reduced in size.
the upper lemma rarely has an awn, depending on the genotype.
• Flowering (opening or protruding of anthers and stigmas) begins at the tip of the panicle and
proceeds toward the bottom. It usually takes 4-12 days for all the florets to flower.
• Seed or caryopsis:
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spherical in shape or somewhat flattened on one side, depending on the race (Fig. 4).
pericarp color varies (red, brown, white, yellow, cream-colored).
testa may also be colored (dark red to brown).
endosperm may be white or yellow (carotenoid pigments that have a relatively low vitamin
A activity).
Flower Opening/Anthesis—A Discussion
Anthesis refers to the period of flower opening during which the spikelets are open, the anthers are
extended, and the pollen sacs burst to release pollen.
Flowering of sorghum inflorescence normally starts as soon as the peduncle completes its
elongation (House 1985). Blooming of the spikelets progresses from the tip to the bottom of the panicle
in a fairly regular manner, with the spikelets in the same horizontal plane across the panicle opening at
the same time.
Flowering of the inflorescence may be spread over a period of 4-13 days depending on the
cultivar, panicle size, temperature, and humidity. In cooler weather (Dec/Jan at ICRISAT Asia Center,
Patancheru), completion of panicle flowering takes about 10-13 days. The two lodicules at the base of
the floret first swell and exert pressure on the glumes, forcing them to open in about 10 min. This usually
happens between 0200 and 0800.
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