HORMONAL REGULATION OF TILLERING IN SORGUM (SORGHUM BICOLOR L. MOENCH) AND ITS INFLUENC ON GRAIN YIELD AND ITS COMPONENTS

A. Jadoo, Kh.; L. Alowan, Afrah

	HORMONAL REGULATION OF TILLERING IN SORGUM (SORGHUM BICOLOR L. MOENCH) AND ITS INFLUENC ON GRAIN YIELD AND ITS COMPONENTS
The Iraqi Journal of Agricultural Science
Article 1, Volume 46, Issue 3, 2015, Pages 300-311
Authors
Kh. A. Jadoo; Afrah L. Alowan
Abstract
A field experiment was carried out at the Experimental Farm, Department of Field Crop, College of Agriculture-University of Baghdad during the spring and fall seasons of 2013. The aim was to investigate the possibility of hormonal regulation of tillering in sorghum and its relationship with grain yield and its components. Split-plot design with arrangement was used with three replicates where three sorghum cultivars (Inqath, Rabeh and Abu Al sabeen) occupied the main plots and seed soaking treatments with Gibberellic acid and Ethephon occupied the sub- plots . Seed soaking treatments were (T2 = 300, T3 = 600 and T4= 900 mg.L-1) of gibberellic acid and (T5= 500, T6 =1000 and T7= 500 mg.L-1) of ethephon besides two control treatments: un-soaked seeds (T0) and seeds soaked with only water (T1). The contribution percentages of the main stems and tillers in both grain and biological yields were significantly different in these varieties in both seasons. The highest contribution percentages of the main stem in the grain yield were (90.50 and 80.94 %) for Abu Al sabeen with the lowest percentages (9.94 and 13.06 %) of tillers in both seasons, respectively. By contrast, the contribution percentages of the main stems of Rabeh variety were less (84.57 and 84.94 %) which increased the contribution of tillers to 14.7 and 15.06 % in both seasons, respectively. However, seeds soaking treatments reduced the contribution of the main stems in the grain yield but increased it for the tillers. Ethephon treatment (T5) gave the lowest contribution percentages of the main stem (59.99 and 62.74 %) and the highest of the tillers (40.14 and 37.91 %) in the grain yield in both seasons, respectively compared with the GA3 treatments (T3 and T4 )which gave the highest percentages of the main stems (100 and 100 %) with no contribution of tillers in both seasons, respectively. This led to the highest grain yield (6.78 and 6.30 t.ha-1) for ethephon treatment (T5) compared with 4.61, 4.37 and 4.84, 4.53 t.ha-1 for GA3 treatments (T3 and T4 ) in both seasons, respectively. The control treatments (T0 and T1 ) and the highest concentration of ethephon (T7) gave the lowest grain yield (3.31, 3.82, 3.35, 3.92, 3.48 and 3.54 t.ha-1) in both seasons, respectively. These results suggest that there was a possibility to increase the grain yield of sorghum via the hormonal regulation of tillering in favor of increasing their contribution in the final grain yield.
Keywords
Main stem; Tillers; fertile tiller; ethephon

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