LONGEVITY OF PEARL-MILLET (PENNISETUM-GLAUCUM) SEEDS HARVESTED AT DIFFERENT STAGES OF MATURITY

The storage potential of seeds harvested at weekly intervals after controlled pollination was studied in three diverse cytoplasmic male sterile pearl millet (Pennisetum glaucum) lines. In the first experiment in 1989, a comparison of p50 (time for viability to decline to 50% during storage) among seeds of the line DSA 105A harvested 14, 21, 28, 35 and 42 days after pollination (DAP), and then stored at 35-degrees-C with 15% moisture content or 40-degrees-C with 13% moisture content, showed that those harvested 35 DAP had the greatest longevity. In the second experiment in 1990, a comparison of p50 within the lines 5141A and L67A harvested 28, 35 and 42 DAP, and then stored at 40-degrees-C with 13% moisture content, showed that seeds of both lines harvested 42 DAP had the greatest longevity. In both the seasons, and in all three lines, maximum seed longevity (p50) was attained one week after physiological maturity (defined as the end of the grain filling period), which is therefore the optimum time of harvest to obtain good quality seeds for conservation.