A Database for Triticeae and Avena
NATIONAL WHEAT RESEARCH PROGRAM
M. R. Bhatta.
Crop Season. Weather conditions during wheat season
were fairly dry and cool, which favored excellent growth of wheat
in the irrigated area of Terai. However, in the hills, moisture
stress was severe because of insufficient rains resulting poor
yields. Week-long, westerly dry winds during the peak grain-filling
period in the Terai reduced kernel weight to some extent.
Area and production. Wheat crop occupied an area of
640,802 hectares, the total production was 1,086,470 metric tons,
and the average productivity was 1,695 kg/ha during the 1998-99
wheat season. Wheat area, production, and productivity increased
by 0.12 %, 5.4 %, and 5.3 %, respectively, compared to the 1997-98
wheat season. Wheat yields have increased steadily since 1995-96,
and the present national average yield is 1.695 tons/ha.
Wheat varietal diversification in the country. Since
the inception of National Wheat Research Program in 1972, a number
of wheat cultivars with different genetic background have been
released, and many of them have been accepted widely by the farmers.
Newly released wheat varieties are more tolerant to the foliar-blight
complex of diseases, the number one factor limiting wheat production
in the terai of Nepal. Bhrikuti (pedigree: CMT/COC75/3/ PLO//FURY/ANA)
has become very popular among wheat growers because of its high
yield potential and disease resistance. Other varieties currently
popular are Nepal 297, BL 1022, Rohini, UP 262, and Annapurna-1.
The major objectives of the wheat-improvement program are to
develop wheat cultivars that fit well into the rice-wheat pattern
with high yield potential; resistance to multiple diseases (leaf
and stripe rusts, foliar blight, and loose smut); tolerance to
postanthesis heat and drought stress; and sterility.
Wheat-breeding activities during 1998-99 included regular hybridization
work involving selected parents for specific purposes; screening
and selection on segregating generation lines; multilocation evaluation
of advanced genotypes in the form of screening nurseries; and
yield trials, along with farmers' field trials. Varietal maintenance
produces nucleus and breeder seeds of currently popular varieties.
New wheat cultivar released. BL 1473 (NL 297/NL352)
was released for the Terai areas under timely sown and late-sown,
irrigated conditions. BL 1473 is resistant to leaf and stripe
rusts and moderately resistant to Helminthosporium leaf blight,
is very similar to Sonalika in maturity, and has bold amber grains.
The rice-wheat cropping system is the most predominant one
and occupies nearly 0.5 x 106 ha. Roughly, more than 84 % of the
wheat area is sown after rice. Mid-November is the optimum planting
time for wheat, and a delay in planting has become the main yield-limiting
factor, because the management efficiency (fertilizers and irrigation)
is reduced greatly. Causes of late planting of wheat include an
excess/depletion of soil moisture and a long turnaround time.
Research into making timely planting of wheat possible and increasing
production with reduced cost of production is in progress.
Relay seeding. The prerequisite for relay seeding is
excess soil moisture at planting, so fields are irrigated if soil
moisture is depleted. Wheat seeding is done 3-5 days before the
rice harvest. The harvested rice plants are spread uniformly to
cover the entire plot and let dry for about a week. Relay planting
lessens bird damage, protects soaked seed from drying, and conserves
soil moisture. On-station and on-farm research conducted since
1990 revealed its superiority over conventional practices and
found relay seeding suitable for poorly drained, heavy-textured
soils where normal land preparation is very difficult. Covering
seeds for about 1 week with harvested rice plants improved wheat
yield. Yields were better, and 1,000-kernel weight and net benefits
also were improved. Relay seeding could be an alternative technology
to change nontraditional wheat fields (rice-fallow) to the rice-wheat
Surface seeding. This method is similar to relay seeding
in all respects except that the wheat is seeded after harvest
of the rice crop. Leaving longer stubble improved the crop stand
and grain yield. An increase in N use efficiency was found when
equal amounts of N were applied 20 and 30 days after seeding.
A severe infestation of weeds was observed when N was applied
before 10 days after seeding. Improvement in 1,000-kernel weight
contributed to higher yields.
Surface seeding onto saturated soil. This type of seeding
is a reduced-tillage method, where the field is plowed once or
twice and then leveled, irrigated, and drained immediately. Soaked
or dry wheat seed treated with fresh cowdung were planted late
in the afternoon This technology was compared with surface seeding
and the conventional practice of wheat establishment. Similar
to surface seeding, this method is statistically superior to the
conventional practice in grain yield. Because the seed sticks
to the soil surface at planting, emergence is excellent and uniform.
Weed intensity was minimized, and even rat damage was reduced
considerably. Improvement in 1,000-kernel weight was observed.
Disease situation. Because of the dry season, incidence
of Helminthosporium leaf blight and leaf rust were low compared
to previous years. Annapurna-1 (Lr26) had a 30S/MS to 60S leaf
rust severity, Sonalika had 20S, and Bhrikuti (Lr34+Lr26) had
10MS severity in the disease screening nurseries. Yellow rust
severity also was low because of dry weather; varieties with Yr9
showed a 50S to 60S severity.