Rudy A. Fernandez
The Philippine STAR

The country’s now "super-active" hybrid rice technology has climbed a notch higher with the development of supplementary pollinators by Department of Agriculture (DA) researchers.

The devices are a hand-held blower designed by the DA-Philippine Rice Research Institute (PhilRice) and a mechanized supplementary pollinator pieced together by DA-Region 2 (Cagayan Valley) agricultural engineers.

First, some facts about hybrid and inbred rice.

A hybrid rice variety is produced by cross-pollinating two genetically different parents, called R lines (male) and A lines (female). The result is F1 or hybrid seeds.

In the hybrid rice technology, one must always produce new seeds for planting in the next season through cross-pollination. This means that seeds harvested from the hybrid plant cannot be used for replanting because hybrid vigor (heterosis) is lost, resulting in lower yield and non-uniform crop stand.

In the case of the inbred (ordinary) rice variety, its flower contains both male and female organs, hence, it can self-pollinate and produce seeds. Moreover, one can use the grains harvested as seeds for the next planting season.

The tediousness of the hybrid technology, however, can be easily offset by the high yield (as much as 12 tons or 240 cavans per hectare).

Supplementary pollination is an integral part of the hybrid rice technology. Through some methods, the R lines and A lines should be "married".

A common practice is rope pulling, which is done by two persons pulling a rope across two R lines to shake the pollens from the plants and pollinate the A lines. However, rope pulling, aside from being tedious, causes too much sagging and damage to the leaves and panicles (those that hold the grains).

Another is rod shaking, or the shaking of the pollen parent (R lines) with bamboo sticks and pollinate the A lines.

Now comes the PhilRice and DA-Region 2 supplementary pollinators.

As monitored by DOST-PCARRD, field test results showed that by using only half of the maximum air velocity of the PhilRice hand-held blower, field capacity increased by 39 percent compared with rod shaking. Using a portable blower realized a 12 percent yield advantage over rod shaking.

"Maximum fuel consumption is 0.61 liters per hour," reported PCARRD’s Raul Alamban, an agricultural engineer.

The back-pack type mechanized supplementary pollinator developed by DA-Region 2 has been field-tested in Iguig and Enrile in Cagayan. It has a field capacity of 3.5-4.5 ha and pollinating efficiency of 10-15 percent seed set with a corresponding yield increment of 0.5-1.5 t/ha.