EFFECT OF GIBBERELIC ACID ON VIGOUR OF SORGHUM SEEDS PRODUCED FROM DIFFERENT PLANT POPULATIONS.

Abstract

A field experiment was conducted at the experimental farm ,Dept. of Field Crop Sciences, College ofAgriculture Abu-Ghraib during the spring and fall seasons of 2006 . The aim was to study the seeds vigour ofsorghum Inqath variety resulted from three different plant populations (200,400 and 600) thousand plant per ha .The design of experiment was Randomized Complete Block Design (RCBD) with three replicates . Seedsresulted from these populations were soaked in three concentrations of gibberellic acid (GA3) (100,200 and 300mg .l -1) for 24 hours . The control treatment was soaked in distilled water . Seed vigour tests were conducted asinfluenced by plant population and gibberellic acid according to Complete Randomized Design (CRD) with fourreplicates. In addition , percentage of field emergence and germination rate index were calculated. The resultsshowed that: Seeds resulted from (200) thousand plant per ha gave the highest values of seed germination in thecold test (33.93 % ) and (41%) for spring and fall seasons , respectively. Soaking seeds with (300 mg GA3 .l -1)gave the highest values of seed germination in the cold test (30.75%) and (35.91 %) for spring and fall seasons ,respectively. Soaking seeds with (200) mg per l (GA3) significantly increased the germination index in the springseason only. The combination of interaction between 200×103 plant.ha-1 and 300 mg GA3.l -1 was superior toA