Project Leader and Principal UC
Cooperative Extension, UC Davis
Objective of the varietal testing program is to determine the adaptability
of improved experimental lines of rice from the breeding program to the
various production areas of California. New varieties are released only
after they have been proven satisfactory in statewide tests. This project
also assists other projects and cooperates with local farm advisor studies
of importance to rice growers.
M-401, the new variety released in 1981, showed an average yield of 9,780
pounds per acre.
Twenty new very early experimental lines (heading in less than 90 days at
Biggs) were compared with M-101, M9, Earlirose, and S-201. Eleven of the 12
highest yielding lines were short-grain types. Many of these were two to
seven days earlier than S-201, which was the leader in average yields. Two
medium-grain types averaged 600 pounds per acre more than M9 and 1,100 pounds more than M-101.
One is as early as M-101.
The rice panicle is formed at ground level about 30 days before heading.
Top: First signs of developing panicle. (250x) Bottom: Rice panicle about
five days later. (100x)
Nineteen early lines (heading in 90 to 99 days at Biggs) were compared with
standard varieties S-201, L-201, M9, Calmochi-202 and the tall variety S6.
Twenty of the 23 short-statured lines in this test produced yields superior
to M9, indicating that further yield increases are still possible. In these
trials, S-201 and L-201 ranked third and eighth, respectively.
Twenty-four late varieties and experimental lines were tested in four
locations. All of these reached 50 percent heading at Biggs in more than 105
days. M-401, the new variety released in 1981, showed an average yield of
9,780 pounds per acre. Fifteen of the experimental lines were better than
A trial was conducted in the Sutter Basin to determine the potential of a
number of very early varieties for double cropping after wheat. From a June
11 planting date, the average yield of all 24 lines was 7,880 pounds per
acre, with some cultivars yielding 8,300 pounds per acre. Several other
experiments were conducted cooperatively with farm advisors and other
project leaders, including studies on nitrogen and zinc
fertilization practices, relative grain versus straw production, calcium
peroxide seed coating, and a cooperative effort on sample collecting and
field monitoring with Chevron's experimental Bolero program.
Table 1. Characteristics of Publicly Developed Rice
||Replaced Colusa, wide adaptation but only moderate
resistance to blanking. Has irregular maturity. Replaced by S-201.
Foundation seed no longer available.
||Very high yield potential, replaced S6; more resistance
to blanking than S6; maturity like S6.
||Earliest variety; excellent seedling vigor; good
resistance to blanking best suited for special
conditions such as cold areas and/or late planting dates; head rice can
be low, so harvest as near to 25% moisture as
possible to enhance head yield. May not yield as well as
other varieties at normal planting dates.
||Very high yield potential in warmer areas; not adapted
to colder areas or to very early seeding
because of poor seedling vigor; mixed maturity
of seeds on panicles. Somewhat difficult to thresh cleanly
- special harvest adjustment may be necessary. May be more
susceptible to sheath blight.
||Same maturity but with improved yield potential compared
to M9; 2-3 inches shorter than M9 with greater
resistance to lodging. Intended as a
replacement for M9.
||High yield potential, replaced M5;
good seedling vigor and resistance to blanking, can be seeded 10 days
later than optimum date for late varieties, or earlier to spread harvest
season; straw strength not as good as M7. Foundation seed no longer
||Replaced M-301; has better straw
strength; more translucent grains; is about 2 days later; has good
seedling vigor and resistance to blanking. Can be seeded 7 or 8 days
later than late varieties to spread harvest season.
||High yield potential; good seedling
vigor and resistance to blanking; very good straw strength.
||High yield potential; good seedling
vigor and resistance to blanking; rough hulls and leaves; long awns in
||Intended as a premium quality rice
and not as a replacement for M7. Has high yield potential; 3 days
earlier than M7 but lodges more and is more sensitive to blanking.
Sensitive to early draining and over fertilization.
||Very high yield potential in warmer
areas; not adapted to colder areas; injury by Ordram® has been observed
at rates greater than 3 a.i. lbs/acre; threshes readily at low cylinder
speeds. Harvest at moisture content as near to 25% as possible to
enhance head yield; matures in 7 to 10 fewer days after heading than do
short- or medium-grain varieties.
||A sweet rice replacing Calmochi-201.
Similar to S-201 in growth characteristics but 2 days later. Has smaller
seeds. Yield much greater and lodges less than Calmochi-201, but yields
not as high as S-201.
varieties with short height have replaced rapidly the tall varieties.
Proper management of the short-stature varieties to obtain high yield
includes: (1) managing water depth and other factors to obtain a dense
stand; (2) good weed control; (3) nitrogen fertilization of 20 to 40
units higher than has been used for tall varieties; and (4) draining as
late as possible before harvest.
and Calmochi varieties should not be grown unless arrangements have been
made first with a marketing agency.
THE CALIFORNIA COOPERATIVE RICE RESEARCH FOUNDATION AND THE UNIVERSITY
OF CALIFORNIA COOPERATIVE EXTENSION