The effects of timing of N application and plant growth regulators on morphogenesis and yield formation in wheat
2001
Zhang, G. | Chen, J. | Bull, D.A.
The influence of timing of N application and PGRs on wheat morphogenesis and yield formation was studied under non-lodging condition. N treatments consisted of three different proportions applied at sowing, 3-leaf stage, stem elongation stage and booting stage, respectively. PGR treatments were 30 ppm uniconazole (S3307), 30 ppm gibberellic acid (GA3) and a mixture of S3307 and GA3. S3307 increased tillering, but had no obvious effect on the final number of ears per plant. The combined application of S3307 and GA3increased ears per plant. S3307 significantly reduced plant height and the length of two basal internodes, the area of two topmost leaves, number of florets per spike, shoot and grain weight per plant in all N treatments, particularly in N treatment 6040 (see below), but increased dry weight per unit length of two basal internodes. It is suggested that application of plant growth retardant such as S3307 may reduce grain yield by inhibiting formation and development of both source (leaf area) and sink (floret) under little or no lodging condition. When applied together, GA3 modified some inhibition of growth by S3307. The timing of N application had significant influence on most of the characters studied. The N treatment 6040, in which 60% of total N fertiliser was applied at sowing and 40% at stem elongation, produced the greatest ear number per plant, florets and grains per ear, the largest area of the two topmost leaves, and the highest grain yield, indicating that more N application at stem elongation was favourable to high yield formation.
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