RICE-wheat production systems occupy 2.2 million hectares of land in the country. Irrigated rice-wheat systems have remained the major source of the marketed surplus grain for feeding the growing population.

Despite increased availability of certified seed, agricultural credit, resource conservation technologies, subsidised fertilisers, water availability, reduced herbicide prices, and release of new high-yielding varieties, better wheat procurement policy and increase in support price, the gain in grain production has stagnated, particularly in wheat in recent years.

In 2007, despite huge production, the country had to import wheat to overcome the shortage. It is the need of the time to look into the reasons. One of the key factors is to identify farming practices and to improve productivity.

Planting schedule along with cultivar selection has important implication to get maximum output of the crop. It not only affects germination, but also crop growth behaviour, number of tillers, number of grains per spike and eventually the grain yield.

The most common practice followed in rice-wheat systems is to establish rice with long-duration, photosensitive, high-quality late-maturing basmati varieties despite its lower yield but high market value, good straw quality, and lower fertiliser requirements.

Late harvest of the preceding rice crop results in delayed planting of wheat. In order to improve the system productivity and get optimum yield, wheat planting should be completed before November 20. Late sowing of the crop can result in reduction of 12-16 kg yield per day after this date.

Late sown crop results in reduced leaf area and chlorophyll content due to rise in temperature that adversely affects photosynthetic activity of plants. As a result of reduced leaf area, the crop intercepts less photo synthetically active radiant energy resulting in reduction in yield.

High temperature at grain filling stage also results in reduced grain yield. It is suggested that in wheat the increase in rate of grain growth, due to higher temperature experienced by late sown crop, does not compensate the loss in grain yield caused by reduced duration of grain growth.

Moreover, late planting results in poor yield and also in efficiency of the inputs applied to the wheat crop. Late planting of wheat also results in poor germination and plant stands.

Lack of uniform performance at sowing from poor quality seed can often mean that crops are of poor quality, especially when environmental conditions are not optimal. To grow successfully seeds must germinate and seedlings emerge, quickly and uniformly throughout the field so that light, water and soil nutrients may be used with maximum efficiency.

Giving crops a good start is therefore of crucial importance. Once sown, seeds spend a great deal of time just absorbing water from the soil. If this time is minimised, seed germination and seedling emergence can be significantly speeded up. The easiest way to do this is to soak seeds in water before sowing.

Seed priming is a technique of seed hydration to improve its performance and is widely used by improving the rate and uniformity of germination and decreasing seed sensitivity to external factors.

This is not a new idea. It has been successfully practiced in many countries including Pakistan.

Soaking seeds overnight in water, on-farm priming and solution of different salts, osmopriming such as CaCl2, KCl and asorbate followed by surface-drying and then sowing in the normal fashion, improves the stand establishment and early vigour of direct-seeded rice, maize, sorghum and chickpea and recently in wheat particularly under saline and late sown conditions.

Rapid establishment and greater vigour also results in faster development, earlier flowering and maturity and higher yield. After priming, the yield increase recorded in maize is 22 per cent, in sorghum 31 per cent, in upland rice 70 per cent and moong bean up to 50 per cent.

Farmers can prime their seeds if they know the safe limits. These safe limits are calculated for each variety so that germination will not continue once seeds are removed from water. Primed seed will only germinate when it takes up additional moisture from the soil after sowing. It is important to note this distinction between priming and pre-germination – sowing pre-germinated seed.

For priming, the seeds are first soaked, which in case of maize is 12-18 hours, sorghum 10 hours, cowpea eight hours, rice 24 hours and wheat 12 hours. Make sure they are not soaked longer than the given time. If they continue to absorb water they will start to germinate and you might loose them.

Dry the soaked seed after taking them out after the specified time either with the help of cloth or placing them in the sun. Sow them the same day. If the seeds cannot be sown the same day because of bad weather or any other reason, the seeds should be stored in a dry place for several days.

Primed seeds result in increased dry matter production at vegetative stage due to continuous gain in plant height, number of tillers and internodes and highest grain yield at reproductive stage is contributed to early initiation of development, faster growth, better establishment of seedling and more tillers.

On-farm priming seems to be an effective and low cost technique for improving the wheat stand establishment and seed performance in a range of growing environments from marginal, slightly saline conditions to high potential, fully irrigated areas.

Participatory promotion of seed priming, where farmers and researchers evaluate together the technology in trials implemented and managed by the farmers themselves, has the potential to make a large impact on the livelihoods of wheat farmers to get maximum gain.