Research Article
Response of Wheat Cultivars to Varying Seeding Rates under Rainfed Conditions
Not Available
Amanullah Jan
Not Available
Ijaz Ahmad Khan
Not Available
Muhammad Azim Khan
Not Available
Ihsanullah
Not Available
Wheat (Triticum aestivum L.) belongs to family Gramineae. It is a major source of food for a large section of the population of the world and is applying about 73 % of the calories and proteins of the average diet (Heyne, 1987). Wheat is the most important crop produced in Pakistan. It is a staple and indispensable food article of the people of Pakistan and occupies more land than any other crop. Although Pakistan is one of the top ten producers of wheat throughout the world yet, the wheat yield per unit area is still for below its potential yield. Apart from other factors causing low yield, optimum seed rate and suitable cultivars play an important role in achieving its potential yield. Planting wheat at optimum rate and selection of suitable variety are very important for economic yield. Greater plant population can be obtained from higher seed rate, but would give poor growth and development of the crop, which will ultimately have adverse effect on the number of productive tillers, number of grains per ear, length of ear, 1000 grain weight and finally the grain yield.
Similarly, varietal performance of different cultivars is not similar at all locations. Several reports address the importance of seed rates and cultivars in obtaining greater yield. Abo-Shataia et al. (2001) concluded that as sowing rates increased the yield of wheat crop increased. The results of Barriga and Pihan (1980) showed that 80, 120, 160 and 200 kg ha-1 seed rate gave significant increased number of spikes m-2 but significant decrease in number of grains/spike. High seed rate resulting in lodging and hence low yield are the similar results reported by Ciha (1983). Shaheena et al. (1987) reported that plant density did not significantly effected 1000 grain weight. The results of Schoonwinkel et al. (1991), showed that seed rate of 75 and 100 kg ha-1 consistently produced greater grain yield than 50 kg ha-1. The experiment was designed with the aim to select the optimum seed rate and high yielding varieties for rainfed conditions.
Field studies on response of wheat cultivars to varying seeding rates under rainfed conditions was conducted during 1998-99 at the Agriculture Research farm of NWFP Agricultural University, Peshawar, Pakistan. The experiment was laid out in Randomized Complete Block Design. Four seeding rates (40, 80, 120 and 160 kg ha-1) and three cultivars (Khattakwal, Suleman-96 and Tatara-96) were sown on 30th October.
Data were recorded on plant height (cm), lodging index (lodging data was recorded at the scale of 0.2 = no lodging and 9.0 = complete lodging) (Freez and Bacon, 1990). Grains spike-1, number of spikes m-2, 1000 grain weight (g), biomass yield (kg ha-1) and grain yield (kg ha-1).
Results and Discussion
Plant height (cm): Statistical analysis of the data (Table 1) revealed that plant height of the varieties was significantly affected by seed rates. Variety Khattakwal had significantly highest plant height of 125.31 cm while Tatara-96 had the lowest plant height (99.16 cm). The significant difference in plant height at the similar seed rate and same environmental condition might be due to the inherited characteristics of the varieties. Seeding rate had significant effect on plant height; increasing seed rate from 40 to 160 kg ha-1 a trend of increase in plant height was noticed. The increase in plant height with increase in seed rate may be due to greater competition for light. The results are in agreement with the findings of Marwat et al. (1989) and Nazir et al. (1987).
Lodging index: Cultivars, seed rate and their interaction had significant effect on lodging index (Table 2). Among cultivars highest lodging (7.0) was noticed for Khattakwal. As seeding rate increased lodging index was also increased. Highest lodging was recorded for 160 kg ha-1 seed rate while a seed rate of 40 kg ha-1 had lowest lodging %age. The effect of seed rate on lodging in case of variety Khattakwal is very clear. Increasing the seed rate, lodging in Khattakwal significantly increased. The results are in greater analogy with the findings of Freez and Bacon (1990).
Number of grains spike-1: Cultivars and seed rates had significant effect on the number of grains/spike as well as their interaction (Table 3). Among the cultivars, Khattakwal had lowest grains spike-1 (26.51). Seed rate 40 kg ha-1 produced more (41.99) grains spike-1, while lowest of 35.04 grains spike-1 was found at 160 kg ha-1. Number of grains spike-1 decreased as seeding rate increased. These results are supported by Wright et al. (1991) and Barriga and Pihan (1980).
Number of spikes m-2: Statistical analysis of the data showed that seed rates and its interaction with cultivars had significant effect on the number of spikes m-2, while cultivars have no significant effect (Table 4). The higher number of spikes m-2 was 215.3 for seed rate of 160 kg ha-1. The number of spikes m-2 decreased as seeding rate decreased. The highest of spikes m-2 at highest seed rate are in line with those reported by Velloses et al. (1988) and Wright et al. (1991).
Table 1: | Plant height (cm) of wheat cultivars at four seed rates |
Table 2: | Lodging index of wheat cultivars at four seed rates |
LSD value at 5 % level of significance for cultivars = 0.2868 | |
LSD value at 5 % level of significance for seed rates = 0.33123.428LSD value at 5 % level of significance for interaction = 0.5736 |
Table 3: | Number of grains spike-1 of three wheat cultivars at four seed rates |
Table 4: | Number of spikes m-2 of wheat cultivars at four seed rates |
Table 5: | 1000 grains weight (gm) of wheat cultivars at four seed rates |
Table 6: | Grain yield (kg ha-1) of wheat cultivars at four seed rates |
Table 7: | Biomass yield (kg ha-1) of wheat cultivars at four seed rates |
Table 8: | Loose smut attack subplot-1 of three wheat cultivars at four seed rates |
1000 grains weight (g): Cultivars, seed rates and their interaction had significant effect on 1000 grains weight. Suleman-96 produced heaviest grain weight of 1000 grains (42.61), while Khattakwal had lowest 1000 grain weight of 30.77 g (Table 5). The lowest of 36.88 g was produced at the seed rate of 160 kg ha-1 although it was at par with 120 kg ha-1 while highest at lowest seed rate (40 kg ha-1). Highest 1000 grain weight at lowest seed rate is the similar result reported by Aziz (1997). He concluded that seed rate and different wheat varieties significantly affected 1000 grain weight.
Grain yield (kg ha-1): Statistical analysis of the data (Table 6) showed that cultivars, seed rates and interaction had significant effect on the grain yield of the three cultivars. Suleman-96 yielded 2708 kg ha-1 followed by Tatara-96 (2500 kg ha-1), while Khattakwal produced the lowest yield of 1233 kg ha-1. As for as the seed rate are concerned, increasing seed rate there was a significant increase in grain yield. Interaction of seed rates and cultivars showed that Tatara-96 and Suleman-96 produced 3567 and 3367 kg ha-1, respectively at seed rate of 160 kg ha-1. Similar results were reported by Nazir et al. (1987).
Biomass yield (kg ha-1): Khattakwal gave heaviest biomass yield of 7617 kg ha-1 followed by Suleman-96 which produced 7410 kg ha-1 biomass, while the lightest biomass (6548 kg ha-1) was produced by Tatara-96 (Table 7). In case of seed rates the heaviest biomass yield (8466 kg ha-1) was obtained at 160 kg ha-1 seed rate followed by 120 kg ha-1 seed rate, which produced 7786 kg ha-1 biomass yield, while the lightest biomass yield (5807 kg ha-1) was obtained at 40 kg ha-1 seed rate. While the interaction of Khattakwal at seed rate of 160 kg ha-1 and Tatara-96 at seed rate of 160 produced the highest biomass yield of 8533 kg ha-1 and 8467 kg ha-1, respectively. While the lightest biomass (4377 kg ha-1) was obtained in Tatara-96 sown at 40 kg ha-1 seed rate. The results obtained are in agreement with Hassan (1999).
Number of loose smut effected spikes plot-1: Highest numbers of spikes were affected by loose smut in Suleman-96 with (37 spikes/plot) followed by Khattakwal. Whereas no spike was effected in case of Tatara-96. Among the means of seed rates 160 kg ha-1 produced more effected spikes (20.58) spikes and minimumwere affected in case of lowest seed rate of 40 kg ha-1 (Table 8). It is suggested that Suleman-96 and Khattakwal should be treated with fungicides necessarily to minimize loose smut losses in wheat production.
The present study showed that a seed rate of 160 kg ha-1 is probably the optimum seed rate in the prevailing conditions. Variety Suleman96 out yielded despite of the loose smut attack. Application of fungicides to seed can further increase yield per unit area.