OVERTON – A new variety of arrowleaf clover developed by a Texas A&M researcher shows promise in once again making arrowleaf a viable part of forage production in East Texas and other southern states.

Apache arrowleaf has been shown to be resistant to bean yellow mosaic virus (BYMV), a devastating disease of arrowleaf clover. The development of Apache is the work of Dr. Ray Smith, clover and legume breeder with the Texas Agricultural Experiment Station in Overton.

As early as the 1960s arrowleaf seed was mixed with crimson clover seed and grown widely throughout many southern states, from East Texas to Georgia. By mixing the early- maturing crimson clover and late-maturing arrowleaf, ranchers and farmers could have forage from February through early June. Multiple disease problems, including plant viruses and fungal rot, effectively put a stop to this practice a decade ago. Of the diseases, BYMV was one of the most prevalent and damaging problems.

BYMV didn't affect crimson clover, but it either killed arrowleaf clover, stunted it, or caused it to mature early.

"It left a production gap from when the crimson matured to when warm season grasses came on in June that was never filled," Smith said.

Arrowleaf clovers such as Yuchi, Meeche and Amclo, are affected by BYMV in several ways. Some plants are killed outright by lethal wilt. Others go on to survive but will suffer a variety of symptoms, including misshapen leaves, yellowed leaves or leaves spotted in a yellow mosaic pattern. Of the surviving plants, yields are reduced by as much as 50 percent, but worse, the productive lifespan of the survivors is shortened, leaving months during the spring without forage production.

Apache is resistant to the lethal wilt caused by BYMV and tolerant to the secondary symptoms such as leaf discoloration and stunting.

"It's tolerant to the degree that we expect it to fill the production gap left by susceptible varieties such as Yuchi. Producers should once again be able to rely on a crimson/arrowleaf mixture for forage production from late winter and early spring," said Smith.

Smith began work on a resistant/tolerant arrowleaf clover in the late 1980s. He began with the conventional plant breeding method of growing arrowleaf cultivars in the field and selecting those plants that appeared healthy while those around fell to disease infections.

After several years, it became apparent to Smith that the conventional method wasn't working. The BYMV virus is spread by aphids, and the insect habits meant that some plants were infected while those nearby might not be.

"So we were selecting those plants that both had tolerance to BYMV and those which just happened to dodge the bullet, so to speak," Smith said.

Undaunted, Smith moved to greenhouse trials where he could strictly control the spread of BYMV. Plants were inoculated with a slurry of tissue from BYMV infected plants. In conjunction with the greenhouse trials, Smith continued field trials, but mechanically inoculated those plants with BYMV as well.

The resulting cultivar, which until recently went by the unassuming designation of TX-AL98-1, is resistant to BYMV-induced lethal wilt, tolerant to BYMV-induced dwarfing, and other symptoms such as rough, wrinkled leaves, and yellowed, mosaic patterned leaves.

It shows improved field survival when infected with BYMV and has greater early spring (March) forage production compared to Yuchi, the most commonly grown arrowleaf today. Apache flowers 10 to 14 days earlier than Yuchi, and its total season forage production is greater or equal to Yuchi.

Field trials were also conducted at two sites in Louisiana and one site in Arkansas. In addition, it has been grown in pastures at the Overton Center and by a few participating farmers.

Apache was formally released by the Experiment Station in October. Seed production has been licensed to the East Texas Seed Co.

Seed should be available in good quantities for fall planting.

One of the scheduled tours stops at the upcoming Overton Center Livestock and Forage Field Day today will be at fields overseeded in an Apache/Crimson clover mix.

The Overton Center is located one mile from downtown Overton on Hwy. 3053.