Sorghum Sudan Genetics Explained

What is sorghum sudangrass?

Sorghum sudan is a hybrid cross between sudangrass and sorghum. The result is a high tonnage, tall, wide leafed product that works in a variety of different forage situations. Sorghum sudan breeding has developed quite a bit over the past 50 years to the point where now you can buy very specific products with very specific traits that fit your needs. 

But let’s be honest, all those traits acronyms like BMR, PPS, MS can get confusing. And how do you know which traits you really want to have for your operation and which ones maybe you don’t need. Here we’ll break down and explain the different sorghum sudan traits as well as highlight some of our favorite products. 

Traits

BMR or brown mid-rib: As opposed to a conventional mid-rib the BMR trait offers higher digestibility due to a lower lignin content. Lower lignin means that the rumen in an animal can produce more energy from the same amount of forage. This trait is critical if you are trying to add weight to your livestock.

AT or aphid tolerance: Aphid tolerance indicates that a plant will not show signs of being affected by aphids even when the aphids are present. This is especially important in areas where aphids pose a large threat to forage crops

MS or male sterile: Male sterile plants do not produce pollen and therefore will not develop any volunteer seed that could come up in the next season. It’s important to note that even if a plant is male sterile it CAN still be pollinated from a neighboring field. This trait is helpful when the planted field will be used for row crop production the following year or for organic producers. Additionally, this trait allows the sugars to stay down in the leaves and stem because it doesn’t have to use any setting seed. A higher sugar content later in the season means more energy for your livestock.

PPS or photoperiod sensitive: The photoperiod sensitive trait is a native trait to sorghum sudans though it’s been bred out of most products due to the staggering height. This trait, however, works great in a single cut situation where tonnage is the main goal. While it does have a slightly lower sugar content compared to other sorghum sudan products, it will not set seed until daylength drops below 12 ½ hours. This means the plant puts all its energy into developing massive amounts of tonnage before it reaches full maturity.

Brachytic Dwarf: The brachytic dwarf trait gives the resulting plant a shorter stature while maintaining the high yields of its taller counterparts. But how can a 4-6 foot plant produce the same amount of biomass as an 8-10 foot plant? The secret is in the internode length, the length between the leaves. The word brachytic means that the internode length is shorter, essentially just making the leaves develop closer together. This trait is helpful if lodging is a concern. A shorter plant is also ideal in grazing situations so the livestock can reach the majority of the plant without trampling it down. 

Products

Super Cover

      Traits: none, conventional

      Pros: inexpensive, fast growing, good hay production, smaller stem compared to other sorghum sudans

      Cons: lower digestibility, not ideal for weight gain

      Best Use: maintenance level grazing forage, works well in super diverse summer mixes

Cattle Cover

      Traits: BMR

      Pros: excellent forage, small stem, wider leaf at the same population as planting other products, high sugar content, 6-7 feet tall, Zach Louk’s personal favorite

      Cons: longer maturity, reaches mid bloom at 70 days

      Best Use: fits almost everything, bale, chop, graze, baleage, fresh chop, stockpile forage for winter, very easy to dry down

Endurance 

      Traits: BMR, Brachytic Dwarf, AT

      Pros: huge leaves especially in lower populations, quick growing, blooms in 63 days, great standability, very high digestibility, great hay, shorter stature while maintaining yield

      Cons: not male sterile, may produce volunteer seed

      Best Use: in a diverse mix where it won’t shade out other plants, where standability is a primary concern

SolarMaxx

     Traits: PPS, MS, AT

      Pros: very high tonnage, extremely water efficient

      Cons: not as digestible as a BMR, slower growing

      Best Use: single cut situations, dry/low rainfall environments

Short King 

      Traits: BMR, PPS, MS, AT

      Pros: excellent forage quality, not specifically a dwarf type but shorter than typical PPS varieties, a Green Cover favorite

      Cons: not a true dwarf variety

      Best Use: mix with a BMR millet for a season long grazing forage, excellent for grazing or harvested forage

What about millets?

When thinking about which warm season grass is right for you it’s important to consider millets as well. Millets work great in a mix with sorghum sudan and other warm season species and they also fit some particular niches where sorghum sudans do not thrive. 

Soil Types: While sorghum sudans work well in dark, heavy clay soils, they generally do not like high pH, salty or sandy soils. These lower quality soils, however, are a great fit for millets. Millets also have an extremely deep and fibrous root system that helps break up compaction deep into the soil profile and scavenges nutrients such as nitrates, bringing them back up to the soil surface. Millets break down relatively quickly compared to other warm season grasses so the nutrients stored in the plant will be readily available for the next crop. 

Protein Content: Millets generally have much higher protein content compared to sorghum sudans. They can range anywhere from 16-24% on a dry matter basis. This makes them a great product to plant with sorghum sudan as the sorghum sudan will provide high energy and the millet will bring in the protein. 

Prussic Acid: Prussic acid is a volatile toxic acid produced in sorghum products when the plant freezes. During the fall, sorghum sudan products should be avoided for at least 10-14 days to allow the prussic acid to leave the plant. After that the sorghum sudan can be grazed safely again. Sometimes, however, it’s not practical to have to remove an entire herd of livestock off a specific pasture for 2 weeks to wait for the sorghum sudan to be safe again. In these cases millet is a great alternative because it does not produce the toxin after a freeze. 

Tillering: Millets are excellent at filling in gaps in a field because of their tillering capabilities. If you have a field that needs a little more cover, consider millet to help fill in the bare spots, while still providing an excellent forage. 

One of our favorite millets is the Exceed BMR Pearl Millet. With the BMR trait this millet maintains excellent digestibility and grows 4-5 feet tall, about half the height of traditional hybrid millets. Try mixing this millet with a sorghum sudan and maybe some cowpeas, sunflowers, and buckwheat for an excellent summer grazing mix. 

As always, our team is dedicated to helping you make the best cover crop decision for your situation. If you’re still not sure which product would work best for you, give us a call today at 402-469-6784 and we can find a solution for you.