A few of these experimental lines have been tested in previous years. Several variety trials produced averages of more than 10,000 pounds per acre, with some experimental and commercial cultivars producing well over 11,000 pounds per acre. The following section summarizes the averages for each group of tests. Research also indicates growers should reduce nitrogen applications 20-30 pounds per acre in Londax®-treated fields.

Very early maturity

Twenty-one experimental cultivars and nine commercially available cultivars that reach 50 percent heading within 90 days were tested at four locations.

Overall, the highest ranking cultivar was the experimental long-grain variety 88-Y-774 at 10,200 pounds per acre. However, it did not perform well in the San Joaquin County trial, indicating a sensitivity to cool temperatures.

Two experimental cultivars that did perform well in San Joaquin County were 87-Y-125, a long grain, and 87-Y-760, a short grain; each averaged nearly 10,000 pounds per acre.

The highest yielding, very early commercial cultivars were M-103 and Calmochi-101. M-202, an early cultivar that performed well everywhere but San Joaquin County, ranked eighth.

Early maturity

Twenty-three experimental lines and nine commercially available varieties that reach 50 percent heading in 90 to 97 days were tested at four locations.

The highest ranking commercial cultivars were M-202 and M-201, yielding an average of 9,500 pounds per acre. S-201 and L-202 ranked 14th and 18th, respectively, with yields of more than 8,800 pounds per acre. M-203 ranked last at 7,750 pounds per acre, probably the result of its lodging sensitivity.

An experimental cultivar, 88-Y-271, ranked highest in three of the four early trials, yielding an average 10,210 pounds per acre.

Intermediate and late maturity

Project leader Jim Hill makes a point during the annual Rice Field Day in September 1989

Four commercially available standard cultivars were compared, to 20 experimental cultivars; all require more than 97 days to reach 50 percent heading at the Rice Experiment Station.

Commercial varieties A-301, M-401, M-7 and M-302 ranked 15th, 17th, 21st and 22nd respectively. All yielded more than 8,400 pounds per acre at three locations. At Biggs, however, the average was significantly higher-nearly 10,300 pounds.

Top-ranked experimental cultivar 87-Y-488 yielded 9,380 pounds per acre. It ranked third in tests during 1988.

Short and medium grain

Twenty-one experimental lines and four commercial varieties common to all test sites were compared for agronomic performance at Biggs and a field in Colusa County.

M-202 ranked highest of the commercial cultivars at 10,110 pounds per acre. At the Colusa site, however, it yielded more than 11,000 pounds per acre, as did three experimental cultivars.

S-101, S-201 and M-103 all produced more than 9,000 pounds per acre.

Fertility Management

(study was conducted jointly with Rice Experiment Station researchers, led by Director D. Marlin Brandon.)

Researchers also found in a comparison with Basagran® and MCPA that Londax® reduces nitrogen needs by 20-30 pounds per acre. Because the herbicide virtually eliminated weed competition throughout the season, more nitrogen was available to the rice plants.