Abstract: The study was conducted to evaluate the appropriate sowing time of newly evolved wheat varieties/cultivars under Bahawalpur conditions. The study included 6 sowing dates started form Ist November up to 15th January of year 1999-2000 to 2000-2001 with equal intervals of fifteen days and five varieties/cultivars viz., 2236, 2098, 2219 punjnad-1 with inqlab, 91 as standard one. Regardless of varieties/cultivars the best results were obtained when wheat was sown after Ist and before 15th November of year 1999 to 2000. However wheat variety punjnad-1 gave significantly higher weights in a wide range of sowing period i.e., Ist to 30th November. The highest mean grain yield of 5315 kg ha-1 was obtained when crop was sown on 15th November (D2) followed by 5268 kg ha-1 for sowing on Ist November (D1).
Intoduction
Wheat (Triticum aestivum L.) is the main food crop of Pakistan, which is grown on an area of 8.463 million hectares with an annual production of 21.078 million tones of grins, giving an average yield of 2.491 tones per hectare during the year 1999-2000 (Anonymous, 2002). This yield of wheat is far below than the potential yield, Despite all out efforts made in this direction, yield of wheat is a result of many contributing factors, among these the time of sowing of wheat crop at its appropriate time is most important. Late sowing beyond certain limits lowers the grain yield significantly. Weights were reduced by delayed sowing. Randhawa et al. (1981) reported that short duration wheat varieties Sonalika and WG-377 yielded highest when sown on Nov. 15. They also reported that number of tillers and 1000- grain weight were reduced by delayed sowing. Ali et al. (1982) concluded that yield of all the cultivars were similar in spite of differences in yield components. They further observed that 1000- grain weight was maximum for Blue silver (41.6 gm) and the minimum for SA-75 (35.1 gm) while harvest index was higher in SA-75 than in other cultivars. They also concluded that delayed sowing reduced stand density, number of grains per ear and grain yield. Kalyan et al. (1985) said that the wheat crop sown on 21 Nov. resulted in 6.9 tones ha-1 and 18% higher yield in both the year, respectively than those sown on 6 Dec. Phadnawis and Saini (1992) reported that grain yield decreased from 166.28 gm m-2 with delay in sowing dates from 2 Nov. to 17 Feb. Grain yield positively correlated with total grain number m-2 mean grain weight and number of ears m-2. Raj et al. (1992) concluded that grain yield of wheat cultivar WH-283 was decreased from delaying after Nov . 28. Dabre et al. (1993) observed that the highest grain yield were obtained from on Nov. 15. It was suggested that increasing the seeding rate where sowing is delayed may check any yield decrease. Lathwal and Thakral (1999) concluding that plant height, grain yield, straw yield and harvest index decreased with the delay in sowing. An increase of 48 and 39% in grain yield was observed from 5 and 15th November sowing compared with 5th December. Kumar et al. (2000) observed that wheat growth was better when sown on 20th November than on 1st November or 10th December, although there was little grain yield difference between the two dates in November. Wheat cv. WH 542 gave higher yield than HD 2329 and WH 533.
Keeping in view all these , this study was conducted to find out the appropriate sowing time for newly evolved wheat varieties/ cultivars under irrigated conditions of Bahawalpur, Pakistan.
Materials and Methods
The study was carried out at Regional Agricultural Research Institute Bahawalpur, Pakistan during the year 1999-2000 to find out the appropriate sowing time of newly evolved wheat varieties/ cultivars for maximum grain yield. The trial was laid out in Split Plot design, and a plot size of 2.4 X 6 m-2 having varieties in main plots and sowing dates in sub-plots. Standard dose of NPK involved the following levels of two factors:
Factor 1
Varieties/ cultivars
| V1 | = | Inqlab-91 |
| V2 | = | 2098 |
| V3 | = | 2219 |
| V4 | = | 2236 |
| V5 | = | Punjnad –1 |
Factor 2
Sowing dates
| D1 | = | 1st November of year = 1999 to 2000 |
| D2 | = | 15th November of year = 1999 to 2000 |
| D3 | = | 30th November of year = 1999 to 2000 |
| D4 | = | 15th December of year = 1999 to 2000 |
| D5 | = | 30th December of year = 1999 to 2000 |
| D6 | = | 15th January of year = 2000 to 2001 |
The observations were recorded for grain yield and yield components. Data collected were analysed statistically using least significant difference test at 5 % level of probability (Steel and Torrie, 1984).
Results and Discussion
Wheat grain yield (kg ha-1)
The analysis of variance Table 1 showed that significant
differences among wheat varieties/cultivars for all the characteristics at different
sowing dates. Data Table 1 revealed superiority of Punjnad
1 over others and among sowing dates, (D2) 15th Nov. and (D1) 1st Nov. were
the best for all growth parameters and consequently the grain yield. The highest
mean grain yield of 5315 kg ha-1 was obtained when crop was sown
on 15th Nov. (D2) followed by 5268 kg ha-1 for sowing on lst Nov.(D1).
As far as variety was concerned Punjnad-1 gave reasonably higher grain yield
in all the cases even up to 15th Dec (D4). Similar findings were reported by
Kalyan et al. (1985), Phadnawis and Saini (1992), Raj et al. (1992)
and Dabre et al. (1993).
No. of fertile tillers
The maximum number of fertile tillers were attained on 15th Nov. (D2) for
all varieties/cultivars followed non significantly by Ist Nov. (D1). Before
or after these dates, this growth parameter was decreased significantly (Table
2). Similar findings were reported by Randhawa et al. (1981).
| Table 1: | Wheat grain yield (kg ha-1) of different wheat varieties (V) at different sowing dates (D) of year 1999-2000 to 2000-2001 |
| Table 2: | Number of fertile tillers (m-2) of different wheat varieties (V) at different sowing dates (D) of year 1999-2000 to 2000-2001 |
| Table 3: | 1000-grain weight (g) different wheat varieties (V) at different sowing dates (D) of year 1999-2000 to 2000-2001 |
Phadnawis and Saini (1992). The interaction between wheat varieties/cultivars and sowing dates was also significant, however mean values for all the varieties/cultivars were statistically same for this yield component. On the basis of two years results it was concluded that sowing of wheat crop form Ist Nov. (D1) to 30th Nov. (D3) resulted in a significantly higher values as compared to rest of sowing dates.
1000-grain weight (g)
The maximum 1000-grain weight was attained in 15th Nov.(D2) for all the
varieries/cultivaes followed non significantly by lst Nov. (D1). Table3.
After these dates the growth parameter was decreased significantly. Similar
findings were reported by Randhawa et al. (1981), Phadnawis and Saini
(1992). Regardless of the sowing time, all the varieties/cultivars were statistically
at par for 1000-grain weight.