PHOSPHORUS COATING ON PEARL MILLET SEED IN LOW P ALFISOL IMPROVES PLANT ESTABLISHMENT AND INCREASES STOVER MORE THAN SEED YIELD

摘要

Phosphorus (P) is one of the main limiting nutrients in the semi-arid regions where pearl millet is grown; its deficiency leads to poor seedling establishment and eventually poor crop yield. Experiments were carried out in pots and field-like conditions to evaluate the effect of seed priming and seed coating with P on the shoot biomass at two and four weeks after sowing (WAS), and on the panicle and stover yield at maturity of three hybrid varieties of pearl millet in low P Alfisol. Overall, seed priming did not increase shoot biomass at two and four WAS. In pots, seed coating at a rate of approximately 400 g P ha(-1) increased vegetative biomass over 400% at early stages, and panicle yield by about 50%, over the non-coated treatment, with genotypic variation in the magnitude of the response. In field-like conditions, seed coating restored stover biomass to 85-100% of that in the non-limiting P treatment, whereas the panicle yield remained 25-35% lower than in the non-limiting P treatment, but still 45-65% higher than the non-coated treatment. P deficiency delayed the time to flowering by 20-24 days compared to the non-limiting P treatment, but plants in the seed coating treatment reduced that gap by 10-14 days. Seed P coating treatment appears a valid option to promote pearl millet seedling establishment and then to boost yield under low soil P conditions. The maintenance of an effect of seed coating on panicle yield in pots suggests a positive early effect on developmental processes before panicle initiation.