CHANGES IN PHOTOSYNTHETIC PIGMENT OF WHEAT(TRITICUM AESTIVUM L. VAR. BARI GOM-25) AS AFFECTED BY NAA AND N-FERTILIZER

Abstract

A field experiment was conducted to investigate the changes in
photosynthetic pigment of BARI Gom-25 as affected by foliar spray of NAA and
N-fertilizers. The experiment consisted of seven different concentrations of NAA
(NAA0 = 0, NAA1 = 10, NAA2 = 20, NAA3 = 30, NAA4 = 40, NAA5 = 50 and NAA6 =
60 ppm) and five N-levels (F0=0, F1=25, F2=50, F3=75 and F4=100% of the
recommended dose) and their 35 combination treatments. Results revealed that
foliar application of 40 ppm NAA (NAA4) produced higher chlorophyll a content
at all stages (tillering, flowering and grain filling) and were significantly higher
than control at tilling and flowering stages. Chlorophyll b and carotenoid
contents did not show any general trend to NAA at any stage except at tilling
stage. Application of 50% of the recommended N-fertilizer (F2) produced
significantly maximum photosynthetic pigment contents at tilling stage whereas,
at flowering stage the same results were obtained from 100% of the
recommended N-fertilizers (F4) but with few exceptions. At grain filling stage,
photosynthetic pigment did not show any general trend to N-fertilizer
application. Findings on combined effects indicated that 20 and 30 ppm NAA in
combination with 50% N-fertilizer (NAA2F2 and NAA3F2) had produced
significantly maximum chlorophyll a content at tilling stage. However, at
flowering stage the highest chlorophyll a content was noted from NAA2F4
treatment (20 ppm NAA in combination with 100% N-fertilizer). Findings also
revealed that combined application of NAA and N-fertilizer had not resulted any
general trend on chlorophyll b and carotenoid contents in most of the cases
where the maximum value in photosynthetic pigment was found depending on
the concentrations of NAA, fertilizer dose and plant growth stages.