6/26/12 MSU Extension 

Photoperiod sensitive sorghuiD for 

bioenergy 

Photoperiod sensitive sorghum is a high-yielding annual crop that shows 

potentialforethanolproduction. 

a 6 n, Michigan State University Extension 

Sorghum is a close relative of corn and has similar growth habits. Sorghum is an annual crop that has been 

used as an emergency livestock feed, particularly when forage supplies are tight. The United States produces 

7.2 million acres of grain and forage sorghum annually. Typically, sorghum will complete its life cycle in one 

growing season starting with planting seed, then vegetative growth, follov.ed by reproductive growth where a 

seed is produced in the tassel and is ready for harvest by fall. 

Photoperiod sensitive (PS) sorghum is derived from breeding t'M:> photoperiod insensitive lines by using 

specific genetic combinations. The benefit of developing the photoperiod sensitive line is that is remains in 

vegetative production for most of the growing season rather than diverting to reproduction, resulting in higher 

biomass yields. 

Photoperiod sensitive sorghum will not initiate floral development until the photoperiod is less than 12 hours 

and 20 minutes per day. From Table 1, on July 1 in Lansing, the sunrise is at 6:04AM and the sunset is 9:20 

PM- that is a photoperiod of 15:16. The day length on September 19 is 12:19. For Lansing, floral 

development 'M>Uidn't occur until September 19. This provides much more time for vegetative growth. 

Table 1. Day length for Lansing by date. Note that the days get shorter as the 

growing season progresses. Photoperiod sensitive sorghum will not flower until 

after September 19, providing for a longer season for vegetative growth, resulting in 

higher biomass yields. 

Date Sunrise Sunset Day 

(AM) (PM) length 

(h:mm) 

1-Jul 6:04 9:20 15:16 

1-Aug 6:30 8:59 14:29 

1-Sep 7:03 8:13 13:10 

19-Sep 7:22 7:41 12:19 

You can find out the day length for your location by going to the Astronomical Applications Department 

msue.anr.msu.edutnewslphotoperiod_sensitive_sorghum_for_bioenergy/ 113 
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Produdion 

Photoperiod sensitive sorghum is planted and ma.naged aimilat to com. Pllotoperiod senlilive IIOfghum elloukl 

be planted on 30-inch rows with population a of 60,000 to 100,000 planta per acre. Fef!Aze Will 100 pounds af 

nilrooen per acre and base P and K application a on aoilteat reaulla. SOI'ghum tend a to be more droughttolerant than com and can be planted on ightet, sandy eoila. Plant into aoil moieture up to 2 inches deap. 

COOl soilS slow emergence and can promote disease d&li elllfHl*!l. control weed a Will pte emergence 

herbicides sucl! as atrazine or metoldllor. There are no option a fot poat-ernergence control fOI' gre.I8M. 

Yield 

Photoperiod aensnl\re sorghum WI1S one or the top )'telders In 201 o reseerd! plots at tile Kelogg Biological 

Station Great Lakes BIOenergy Researd! Plots. Pllotopertod sen81tt\/e SOI'ghum produced 8.5 tons af dry 

matter per acre, the aecond highest )'teldlng Y81tety. Energy SOI'ghum produced 10.9tons or dry matter, 

lnctudlllG the seed. Energy sorghum Is photoperiod lnsen81tt\/e and produces a mature seed head. Typlealy, 

this seed would be ha.nrested ror grain, \loltllllle remainder to be used as biomass rot celkllosle elllanol. 

Photoperiod sensnl\re sorghum reached a height or 15 reetln2010. Not.lllat PS SOI'ghum produced a ~d 

almost double that or S'Michgre.ss and rmcantllus. 

Table a. Yield of four 110rzbam wrieties, sw:itchgra.u and mi.....,nthu.s in ao:to at the 

Kellog Biological Station. Dlta came from raDdomized complete block design 'With 

four replicatiODB. Eaergy 110rzbam yield included the grain. This is data from one 

pow:iDg seasoD. It is recommeaded that multi.·yar data be u.sed whea m•lring 

planting decisiODB. 

12.0 l0.9a 

10.0 

.. 

~ 

u 

<( 8.0 ~ .. 

;: 

.. 6.0 ::iE 

i:" 

0 

"' 

~ 4.0 

2.0 

0.0 

Sweet Forage PS Sorghum Energy Switchgrass Miscanthus 

Sorghum Sorghum Sorghum 

Referenees 
6/26/12 MSU Extension 

National Agriculture Statistics Service, 2007 Census of Agriculture, "Table 33. Specified Crops by Acres 

Harvested: 2007 and 2002". 

Rooney, W. L., J. Blumenthal, et al. {2007). "Designing sorghum as a dedicated bioenergy feedstock." 

Biofuels Bioproducts & Biorefining-Biofpr 1{2): 147-157. 

'l""L" • ,,. ' ............ "J...l: .. l..,.rl MSU ExtensionChttp://www.msue.msu.edul or more information, visit 

http://www.msue.msu.edu Chttp://www.msue.msu.edul ---- --- -- --r-- in your area, visit 

http://expert.msue.msu.edu Chttp://expert.msue.msu.edul r call888-MSUE4MI (888-678-3464). 

msue.anr.msu.edutnewslphotoperiod_sensitive_sorghum_for_bioenergy/ 313