Hay Yields of Intermediate Wheatgrass Cultivars
By John D. Berdahl, Forage Geneticist, Northern Great Plains Research Laboratory, Mandan, ND

Yield data in Table 1 are from a test that was dormant-seeded on summer fallow at the Central Grasslands Research Extension Center on November 21, 1989. Stand establishment in the following year was excellent. Individual plots in this study consisted of five 20-foot rows spaced 14 inches apart. Intermediate wheatgrass has moderate spread form rhizomes, and a single row of Russian wildrye was seeded between each plot to keep each entry separate. Plots were replicated four times. No fertilizer or herbicides were applied for the duration of the test. Plots were cut once each year, similar to management from haying, and regrowth was not grazed. Good stands were maintained, but nitrogen deficiency was apparent 4 years after the plots were established.

Reliant and Oahe were not statistically different in hay yields and were the highest yielding entries in this test (Table 1). In other tests, Manska typically has averaged 10 to 15% less than Reliant in hay yields. Manska produces more tillers with finer stems than other current intermediate wheatgrass cultivars, and has produced high average daily gains in grazing tests with yearling steers. Stands of intermediate wheatgrass pastures thin out under heavy grazing pressure, and it is necessary to allow pastures to recover in the fall. Intermediate wheatgrass has produced sustained high yields in grass-alfalfa mixtures used for hay. Reliant averages about 2 days later in heading date than other intermediate wheatgrass cultivars, and its maturity matches the late-bud stage of alfalfa better than other cultivars. Reliant produces higher hay yields than smooth bromegrass, and it more closely matches alfalfa maturity.

In earlier tests conducted at CGREC, NewHy, a cultivar developed from a cross between quackgrass and bluebunch wheatgrass, and Regar meadow bromegrass have been compared with intermediate wheatgrass in tests at the Central Grasslands Research Extension Center. NewHy, developed at Logan, Utah, and Regar, developed at Aberdeen, Idaho, have both persisted well under hay management. Hay yields of both grasses have averaged about 65% of intermediate wheatgrass (average yields of Reliant, Manska, and Oahe). NewHy has salt tolerance similar to tall wheatgrass but has better forage quality and regrowth potential. NewHy has only mildly spreading rhizomes in contrast to the overly aggressive spread of quackgrass, one of its parents. NewHy would be a good choice for pasture or hay on ground that has moderate salinity problems. Regar meadow bromegrass, a bunchgrass that is distinctly different from smooth bromegrass, has excellent regrowth potential when rainfall is adequate and has higher forage quality than intermediate wheatgrass. Yields of meadow bromegrass have been relatively low in dry years.

Table 1. Dry matter yields of intermediate wheatgrass cultivars at Central Grasslands Research Extension Center.
Cultivar	1991	1992	1993	1994	1996*	5-yr Average	Relative Yield
	-------------------------------lb/acre------------------------------						%
Reliant	4542	8000	7576	4340	2377	5367	100
Manska	3218	6549	5600	2870	1808	4009	75
Mandan 759	3762	7224	6035	3767	2078	4573	85
Oahe	4248	7937	6982	3181	2150	4900	91
Slate	3666	7038	5798	3921	2118	4508	84
Greenleaf	2841	6043	5831	3243	1839	3959	74
Chief	3650	6909	5486	2620	1784	4090	76
Clarke	4249	7786	4670	3255	1862	4364	81
Average	3772	7186	5997	3400	2002	4471
5% lsd	651	777	1666	1056	462	624
*Data for 1995 was not available