Materials and Methods

- Bread wheat varieties as influenced by different nitrogen levels

A field experiment was conducted under the shade of Euclyptus camaldulensis trees to determine the effect of different nitrogen doses on four varieties of wheat viz. Daman-98, Punjab-96, Dera-98, and Inqilab-91 at the agronomic research area of the Faculty of Agriculture, Gomal University, Dera Ismail Khan (NWFP) Pakistan during 2000~2001. The design used was split plot with four replications. The sub-plot size was 2 m×5 m. Nitrogen was applied at the rate of 0 (control), 50, 100, 150 and 200 kg/ha. Half of the nitrogen was applied at the time of sowing, with the remaining half applied during the initial irrigation. A basal 55 kg/ha dose of phosphorus was applied to all treatment plots before sowing. The crop received five irrigations in all. The crop was irrigated first at the time of tillering and formation of adventitious roots followed by a second irrigation at anthesis stage, a third irrigation at milking stage, a fourth irrigation at the time of spike emergence and a last irrigation at dough stage. The amount of each irrigation was four acre inches, so twenty acre inches of water was applied throughout the growing period of wheat. Weedicide namely, “Quatro”, at the rate of 1.8 liter per hectare was sprayed before the tillering stage of wheat to control weeds. Urea and single super phosphate were used as source of nitrogen, and phosphorus, respectively. All other agronomic practices were kept uniform for all treatments.

Parameters observed during the course of study were:

1. Final plant height (cm) at maturity

Twenty tillers were selected at random from each plot at 3 places, their heights were measured in cm and means were taken.

2. Number of plants/m² and spikes/m²

An area of 1 m² was selected at random at 3 places in each plot to count total number of plants and spikes, average was used in the statistical analysis.

3. Spike length (cm) and grains per spike (No.)

Ten spikes were randomly selected from each unit area in each plot. Each spike was measured with scale from the base to the apex to record the spike length in cm. To record the grains per spike, each spike was threshed separately and grains of each spike were counted and averaged.

4. 1000-grain weight (g)

Thousand grains were counted at random from each plot and their weights were taken with a spring balance.

5. Biological yield (t/ha) and grain yield (t/ha)

Whole plots were harvested and tied into bundles. Biological yield was recorded by weighing the bundles of each plot with spring balance.

The bundles were first sun-dried and then threshed by a thresher. The grain weight was recorded in kg and then subsequently converted into t/ha.

6. Grain protein content (%)

Grain protein contents were determined by Microkjeldahl method by taking sample of 500 seeds from each plot and grinding them. The digestion was done by Gunning and Hibherds H₂SO₄ method (Ahmad et al., 2001) and distillation was done by Microkjeldahl apparatus (Jackson, 1962) to determine seed nitrogen contents. Thereafter protein content was calculated by multiplying nitrogen contents in seed with a constant factor of 5.71 (Peter and Young, 1980).

Data recorded were analyzed using ANOVA technique (Steel and Torrie, 1984).