Germination Aspects of Itchgrass (Rottboellia cochinchinensis)

Itchgrass (Rottboellia cochinchinensis), is native to India and it is found in several regions of the world. It is feared by farmers because of its difficult control and progress. The aim of this work was to study the factors that affect the germination of this weed's seeds. The methods of overcoming dormancy evaluated were: 1 - mechanical scarification, 2 - chemical scarification, 3 - treatment pre-sowing, 4 - chemical treatment, 5 - hormonal treatment, 6 - untreated seeds. The effects of temperature (5, 10, 15, 20, 25, 30, 35 and 40 degrees C), photoperiod (6, 8, 10, 12, 14 and 16 hours of light), the quality of light (white, red, red bell, yellow, green, blue and absence of light), availability of water (0.0, -0.2, -0.3, -0.4, -0.5, -0, 6, -1.2, -2.4 MPa), viability of its seeds when stored under cold, dry and natural conditions were studied. All bioassays were carried out in camera for thirty germination days, with the treatments arranged in a completely randomized design in four repetitions. The seeds had high germination index under our climatic conditions, without dormancy and were not photoblastic. The water deficit from water availability is essential for germination, with optimum temperature of 25 degrees C. The newly-collected seeds are not viable for the germination study, presenting reduction in germination when stored under cold and dry conditions, showing that cold may be an agent of dormancy induction.