Research Article
Yield and Yield Components of Various Wheat Cultivars as Affected by Different Sowing Dates
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Jehan Bakht
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Wajid Ali Shah
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Muhammad Shafi
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Nadia Jabeen
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Wheat is sown in winter months and it has its own definite requirements for temperature and light for emergence, growth and flowering. So, wheat needs to be sown at such an appropriate date that its temperature requirements are fulfilled. Too early sowing produces weak plants with poor root system. And in too early sowing the temperature is above the optimum. Temperature above the optimum leads to irregular germination and the embryo frequently dies and the endosperm may undergo decomposition due to activities of bacteria or fungi. Late planting results in poor tillering and more chance of winter injury. The late planted wheat grows generally slow because of low temperature. Late planted wheat may suffer from rains during April-May, which impaired grain quality. In late planting the wheat variety should be of short duration that may escape from high temperature at the grain filling stage.
Though Pakistan is a major growing country, yet its yield is too low as compared to other countries. Its production is not up to the mark and required standards to bridge the gap between consumption and production. Besides other reasons, one main reason of low productivity is due to deviation from the recommended sowing time of a genotype for a particular set of environment and thus resulting in failure to achieve its maximum productive capacity. Per unit area production can be increased by adopting proper sowing time, seed rate, judicious application of fertilizers, timely irrigation, proper weed control and proper insect pest and disease management. Early planting produce greater number of spikes m-2, heavier grain and highest grain yield ha-1, while late planting affected these characters adversely. Ishaq and Taha (1974) and Khan and Saleem (1986) reported that wheat sown earlier is more profitable when compared with late sown because of more productive tillers. The late sowing resulted in reduced seed weight and low yield in all the wheat cultivars (Zeb et al., 1987). Ansary et al. (1989) reported that delay in sowing suppressed the yield, caused by reduction in the yield contributing traits like, number of tillers, grains spike-1, seed index and grain yield plant-1. The delay in sowing decrease grain yield by 58.2 % and also resulted in lower grain weight and number of grains plant-1 (Razzaq et al., 1986). Rajput and Verma (1994) observed that normal sowing gave higher grain yields than late sowing.
Keeping in view the role of proper sowing in wheat producing the study was initiated with aim to find out the proper time of sowing for different wheat varieties under the agro climatic conditions of Peshawar.
Field experiment to study the yield and yield components of wheat cultivars as affected by different sowing dates was conducted at Malakandhar Research Farms of NWFP. Agricultural University Peshawar, during 1999-2000. The experiment was laid out in randomized complete block design (RCBD) with split plot arrangements. The following treatments were used during the course of experiment:
Sowing dates:
D1 | = | 1st November1999 | D2 | = | 16th November 1999 |
D3 | = | 1st December 1999 | D4 | = | 16th December 1999 |
D5 | = | 1st January 2000 | D6 | = | 16th January 2000. |
Varieties
V1 | = | Tatara-96 | V2 | = | Inqilab-91 |
V3 | = | Bakhtawar-92 | V4 | = | Dera-98 |
The data recorded during the experiment were plant height, days to maturity, grains spike-1, thousand grain weight, grain yield, biological yield and harvest index.
Plant height was recorded by measuring height of five representative plants in each treatment at maturity from base to the tip of the spike. Days to maturity were recorded when 90% plants in each treatment were matured. For 1000 grain weight data, were counted from threshed clean lot of each treatment and then weighed with the help of sensitive electronic balance. For calculating number of grains spike-1, five spikes treatment-1 were randomly selected in each sub plot and then their grains were counted and divided by 5 to get the average grains spike-1. Grain yield, biological yield and harvest index in each subplot was determined and then converted into kg ha-1 according to the following formula:
The data collected during the experiment was analyzed according to RCB design and upon obtaining significant differences, least significant differences (LSD) test was applied (Steel and Torrie, 1980).
Statistical analysis of the data showed (Table 1) that there were significant (P ≤ 0.05) differences in plant height due to different planting dates. While cultivars and interaction between cultivars and sowing dates was not significant. It can be seen from the data (Table 1) that plant height decreased as planting was delayed from 1st November to 16th January. Mean values of the planting dates revealed that maximum plant height (95.50 cm) was attained in plots sown on 1st November, while minimum plant height of 72.00 cm was attained when crop was planted on 16th January. In case of varieties, it was revealed that tatara-96 produced the maximum plant height of 94.16 cm followed by inqilab-91 (91.20 cm), cultivars dera-98 had the lowest plant height of 75.00 cm. Ashiq et al. (1995) reported that the difference in plant height might be due to difference in their genetic makeup. In case of interaction between dates of sowing and cultivars revealed that taller plants (106.00 cm) was attained by tatara-96 when sown on 1st November, followed by those plots sown on 16th November and 1st December with cultivars tatara-96.
Statistical analysis of the data (Table 2) showed that days to maturity was significantly (P ≤ 0.05) affected by different cultivars, sowing dates and their interaction. Days to maturity decreased as planting were delayed from 1st November to 16th January. Maximum days to maturity (169.58) were recorded in those plots, which were planted on 16th November. While minimum days to maturity (109.33) were taken when crop was planted on 16th of January. In case of varieties, tatara-96 or bakhtawar-92 took significantly higher number of days to maturity i.e., 172.67 when planted on 1st November followed by dera-98 and inqilab-91 with 169.33 of 165.67 days to maturity (Table 2). In case of interaction between dates of sowing and cultivars revealed that more days to maturity were taken by cultivars tatara-96 when sown on 1st November. Analysis of the data (Table 3) revealed that grains spike-1 was significantly (P ≤ 0.05) affected by different cultivars, sowing dates and their interaction between cultivars and sowing dates. Mean values of the data indicated that grains spike-1 decreased from 1st November to 16th January. Mean values (Table 3) of the planting dates showed that maximum grains spike-1 (51.00) were recorded in plots sown on 1st November while minimum grains spike-1 of 34.00 was observed when sowing was done on 16th January. In case of varieties, tatara-96 attained maximum grains spike-1 (45.80 grains spike-1). In case of interaction between dates of sowing and cultivars revealed that more grains spike-1 (54.00) was produced by tatara-96 when sown on 1st November (Table 3). Similar results were also reported by Khan and Saleem (1986).
When the effect of varieties on thousand grains weight was taken into an account, it was revealed that tatara-96 gave significantly higher thousand grain weight of 36.65 g followed by inqilab-91 with thousand grain weight of 35.03 g. Similarly dera-98 produced lighter grains. Similar results are also reported by Mahajan (1994). Thousand grain weight was found to be decreased proportionally as the planting was delayed. In case of planting dates, maximum thousand grain weight (46.63 g) was produced when sowing was done on 1st November while 16th January sowing resulted in minimum thousand grain weight. In case of interaction between dates of sowing and cultivars revealed that heavier seed (52.20 g 1000 grains-1) was produced by tatara-96 when sown on 1st November (Table 4).
Table 1: | Effect of different wheat cultivars and date of sowing on plant height (cm) |
Table 2: | Effect of different wheat cultivars and date of sowing on days to maturity |
Table 3: | Effect of different wheat cultivars and date of sowing on grains spike-1 |
Means followed by different letters are significantly different from one another at P ≤ 0.05 |
Table 4: | Effect of different wheat cultivars and date of sowing on thousand grain weight (g) |
Table 5: | Effect of different wheat cultivars and date of sowing on grain yield (kg ha-1) |
Table 6: | Effect of different wheat cultivars and date of sowing on biological yield (kg ha-1) |
Table 7: | Effect of different wheat cultivars and date of sowing on harvest index (%) |
Mean followed by different letters are significantly different from one another at P ≤ 0.05 |
Analysis of the data (Table 5) revealed that different wheat cultivars and sowing dates had a significant (P ≤ 0.05) effect on grain yield, while their interaction was non significant. It can be inferred from the mean value of the data that highest grain yield (3188.00 kg ha-1) was produced when sowing was done on 1st November, while January 16th sowing recorded minimum grain yield (918.01 kg ha-1). Similarly, in case of varieties, tatara-96 produced maximum grain yield (2666.70 kg ha-1), while dera-98 produced minimum grain yield (1954.25 kg ha-1). Similar results are also reported by Jain et al. (1992) and Kumar et al. (1994).
The mean values of the data revealed that biological yield decreased as sowing delayed from 1st November to 16th January (Table 6). Perusal of the mean for planting dates indicated that the highest biological yield of 9861.00 kg ha-1 was produced when sowing was done on 1st November, while the lowest biological yield of 2124.00 kg ha-1was recorded when sowing was done on 16th January. In case of cultivars, tatara-96 produced the highest biological yield, while minimum was produced by dera-98. These results agree with those reported by Rajput and Verma (1994).
Harvest index was significantly (P ≤ 0.05) affected by different varieties and sowing dates while their interaction was non significant (Table 7). Maximum harvest index was observed in those plots, which were sown on November 16th, while minimum was noted in 1st January sowing. In case of varieties, tatara-96 recorded maximum harvest index when compared with other varieties under study. This results agree with Sharma and Smith (1987).
These results leads to the conclusion that wheat cultivar tatara-96 perform better if it is sown on 1st week of November or 3rd week of November. Late sowing either on 1st week of January or 3rd week of January gave minimum production.