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New FD4 and FD5 Varieties

New FD4 and FD5 Varieties

Fall Dormancy (FD) is often the first characteristic that alfalfa growers consider when deciding which variety to grow. What options do you have as you consider planting a new variety this spring? Alfalfa Partners is introducing two new FD varieties that up the ante and should be considered for planting this spring.

SW4515 – FD4 Alfalfa

SW4515 has great yield potential and high resistance (HR) to stem nematode. It has excellent overall disease resistance and is highly resistant to all six major alfalfa pests and diseases, including Bacterial Wilt, Verticillium Wilt, Fusarium Wilt, Anthracnose, Phytophthora Root Rot and Aphanomyces Race 1, as well as Race 2.

This variety is resistant to spotted and pea aphid and shows good resistance to lodging. It has a broad-based parentage with germplasm from lodging resistance breeding lines. Overall, SW4515 shows solid overall agronomic characteristics with a disease resistance index (DRI) of 35/35 with very good winterhardiness.

“SW4515 is a nice replacement for SW4107,” said Robin Newell, Alfalfa Partners Director of Alfalfa Product Marketing. “It’s going to go everywhere that SW4107 would work and has the added advantage that this variety has high resistance to stem nematodes. That means we can take SW4515 into irrigated areas with surface water that may have tail waters coming off upstream fields and carrying those stem nematodes into the field.”

SW4515 is a very uniform variety that responds well to an aggressive cutting schedule and can be planted in fields with variable soil types. To learn more about SW4515, go to https://alfalfapartners.com/sw4515/.

SW5615 – FD5 Alfalfa

If you’re looking for a variety that has excellent fall growth but also has superior yields all year long, consider SW5615. This FD5 variety has a strong performance record in research trials across a wide geography. The combination of excellent winter survival and strong disease resistance gives this variety a leg up on stand persistence.

SW5615 is highly resistant to all major alfalfa diseases with a 35/35 DRI, including multi-race Aphanomyces. SW5615 is also highly resistant to stem nematode.

“This is also an excellent replacement for Pioneer 55v50 and SW5213,” Newell explained. “You have more yield, better forage quality, stem nematode resistance, and much more. You have the whole package with SW5615. On top of all that, SW5615 is one of the best winter hardy varieties that we have in our lineup. It can’t be beat and is a super choice for the whole northern half of the United States.”

In short, SW5615 is a superb choice for overall yield, forage quality and stand persistence. To learn more about this FD 5 variety, go to https://alfalfapartners.com/sw5615/.

More About Fall Dormancy

What exactly is fall dormancy and how do we separate varieties using this gauge? Fall dormancy is simply a measure of fall growth. As autumn days bring shorter day lengths, alfalfa plants begin to slow their vegetative growth, pushing more carbohydrates into storage in the taproot to prepare for winter. But there is a wide spectrum in this response, with some varieties having almost no slowing of fall growth (non-dormant), and others slowing considerably as autumn day length shortens (fall dormant), and some in between (semi-dormant).

Consider varieties in a target range of fall dormancies that can be best suited to your growing environment. Fall dormancy rating 3-5 (fall dormant) are highly suited to the northern half of the United States and areas that experience soil freezing during winter. Fall dormancies of 6-7 (semi-dormant) have more fall growth and less tolerance to freezing. Semi-dormant varieties are often preferred in areas with little or no soil freezing yet with sustained wet winter soil conditions making harvest difficult and no desire for sustained winter growth. Non-dormants are well-suited to areas where winter growth can be sustained with warm daytime temperatures, with a desire for continuing harvest during winter months.

Learn more about fall dormancy at https://alfalfapartners.com/fall-dormancy-classification-of-alfalfa-explained/.