The role of initial seed vigour status in the expression of invigoration effect of wet and dry seed treatments in French bean (Phaseolus vulgaris L.)

The deterioration of high vigour (HV) French bean (Phaseolus vulgaris L. cv. Pusa Parvati) seed during storage could be significantly slowed down by pre-treatment of the seed with powdered plant materials such as dried leaves of bitter gourd (Momordica charantia L.) and amrul (Oxalis corniculata L.) at the rate of 2 and 2.5 g per kg of seed, respectively, and pharmaceutical formulations namely, 'aspro', a commonly used aspirin-containing formulation (56.5% aspirin with 43.5% paracetamol) and 'celin', an ascorbic acid (vitamin C)-containing formulation at 0.2 and 0.5 g per kg of seed, respectively as well as by the common bleaching powder (active ingredient chlorine released from calcium hypochlorite) at 3 g powder per kg of seed. The vigour status of seed interacted with the different treatments to give differential response in respect of post-storage germinability and seedling vigour. The high vigour (HV) seed lot proved more responsive to the dry treatments than the medium vigour (MV) seeds. On the other hand, in low vigour (LV) seeds, the dry treatments did not show any promotion of germinability and seedling vigour. The wet treatment, moisture equilibration-drying (humidification-drying treatment), was very effective in the medium vigour seed lot, but not in high and low vigour seeds. The dry treatments given to high vigour or the wet treatment to medium vigour seeds resulted in better post-ageing performance which would indicate that the beneficial treatments reduced degradative reactions responsible for the loss of seed vigour and viability.