Effect of nitrogen on maturity of cotton by using node above white flower
2003
Iqbal, M. (Cotton Research Station, Multan (Pakistan)) | Chang, M.A. | Iqbal, M.Z. | Muhammad-ul-Hassan
Due to indeterminate growth habit of cotton plant (G. hirsutum L.) maturation is affected by many environmental and cultural factors. An easy and reliable measure of progression towards maturity that can be attained during crop development is needed for both production and research programme. The node above white flower (NAWF) technique was used to monitor the growth, development and maturity of three varieties viz; MNH552, MNH554 and AC-134 under five nitrogen level (N1=0, N2=75, N3=125, N4=175 and N5 250 kg ha-1). The objective of this study was to evaluate physiological cut out date (NAWF-5) as a measure of maturity by comparing it with percent first pick, days taken to first flower and days taken to open first boll and to evaluate the effect of nitrogen on maturity related traits and seed cotton yields. Within each test, sequential node above white flower counts were used to determine physiological cutout date (days taken to NAWF-5), percent first pick was determined by sequential harvest. The days taken to first flowers and days taken to open first boll were recorded from planting date to open first white flower and boll open. Significant variation was found within each nitrogen level for all of the maturity measurements and seed cotton yield except between N4 and N5, The days taken to NAWF-5 was closely related to percent first pick, days taken to first flower, days taken to open first boll and seed cotton yield. It was also concluded that excess of nitrogen application increase the potential for rank growth, risk of nitrogen losses through soil run-off or leaching. From the result of present study it was also indicated that application of nitrogen fertilizer above 175 kg ha-1 did not extend the flowering period and also did not increase seed cotton yield significantly. Days to NAWF-5 could be used for monitoring cotton plant after flowering, earliness determination, detecting fruiting problems during growth season and for all management decisions (Nitrogen fertilizer application etc)
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