THE INFLUENCE OF SEED PRIMING WITH P & Zn SOLUTIONS AND ITS OPTIMIZATION WITH RESPECT TO RATE AND DURATION ON YIELD OF CEREALS

Abstract

Benefits of seed priming can be best achieved if seed are primed in proper concentration of nutrient for optimum duration. A series of experiments were conducted in laboratory, greenhouse and field during 2008-2011 at The University of Agriculture, Peshawar to study the effect of P and Zn seed priming on germination, emergence and yield of cereals (wheat and maize). Laboratory experiments were conducted to determine the optimal duration and maximal concentration of zinc (Zn) and phosphorus (P) for priming wheat and maize seed. The seeds were soaked with water through a range of durations (0, 3, 6, 12, 18, 24, 30, 36, 42 and 48 h) and tested for germination. Seed soaked for 18 h resulted in higher mean germination and final germination whereas less time to 50% germination. In subsequent experiments, seeds were primed for 18 h in various concentrations of Zn (0.01%, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2.0%, 2.5%, 3.0% and 3.5%) and P (0.1%, 0.5%, 1%, 2%, 3% and 5%) along with dry and water soaked seeds as control treatment. Less time to 50% germination and higher mean and total germination was noted for seed primed with 0.1% and 0.5% P (wheat and maize); and 0.05% and 0.1% Zn (wheat) or 0.1% and 0.5% Zn solutions (maize). Chemical analysis of the Zn- and P-primed seed of wheat and maize revealed that increasing Zn and P concentration in the priming solution caused an increase in the Zn and P concentration of the primed seed, respectively. The two maximal concentrations of Zn and P were further evaluated in subsequent pot experiment in glasshouse. Results of the pot experiment revealed that lower time to 50% emergence and higher total emergence was recorded for seed primed in 0.05% Zn (wheat) or 0.1% Zn (maize) and 0.1% P (both crops). Seedlings resulted from seed primed with high concentration of P and Zn had more P and Zn, respectively. The field experiment consisted of three priming treatments i.e. NP (no primed seeds), ZnP ( wheat seed primed in 0.05% Zn and maize in 0.1% Zn) and PP (wheat and maize seed primed in 0.1% P); two levels of P (45 and 90 kg ha-1 for wheat whereas 30 and 60 kg ha-1 for maize) and two levels of Zn (10 and 15 kg ha-1 for both crops) as soil fertilization. Dry and water soaked seeds were used as control treatment. Urea and SSP were applied to provide N and P, respectively. Results showed that priming significantly affected emergence and yield parameters. Lower days to 50% emergence and higher emergence m-2, plant height, number of tillers m-2, number of spikes/cobs m-2, grains per spike/cob, thousand grain weight, grain yield and dry matter yield were recorded for seed primed in 0.05% Zn (wheat) or 0.1% Zn (maize) along with 90 kg P ha-1 (wheat) or 60 kg P ha-1 (maize) and 15 kg Zn ha-1 as soil application followed by seed primed in 0.1% P along with the same amount of fertilizer application. Phosphorus and zinc concentration in wheat and maize seedling, leaf and grain were significantly affected by different combination of priming and soil application of fertilizer. This simple, low-cost, low-risk and easily adoptable technology is expected to possibly reduce, to some extent, fertilizer and irrigation water requirements of the crop and significantly increase grain yield which will largely benefit economy of the resource-poor farmers and the country.