SCIENTISTS at Delhi's IndianAgricultural Research Institute (IARI)have identified five wheat varietiesdeveloped in agricultural universitiesand institutes that are resistant todamage by birds, especially parrots.However, these varieties failed atpre-release trials and breeders arenow trying to incorporate the bird-resistant property into other high-yielding wheat varieties, sayornithologist R K Bhatnagar andentomologist Vijai Shankar Singh.
Birds tend to damage crops fromsowing to sprouting and from grain-setting to harvest. Parakeets are a particular nuisance, because unlikeother birds that pick only on thegrains, they prefer to carry the entirewheat cob to their nests. Of 14 parakeet species found in India, 10 cause"excessive depredation", says Bhatnagar.
"They bite off more than they canchew and the damage caused bythem is greater (than that from otherbirds)," agrees Singh. In some cases,parakeets have destroyed upto 80per cent of grain of the best knownhigh-yielding variety of wheat,Kalyansona.
However, Singh and Bhatnagarfound that some wheat varieties fromHimachal Pradesh, Haryana, Delhiand Punjab were extremely "resistant" to the birds and lost onlybetween 2 and 12 per cent of thegrain. Close scrutiny of the structureof these bird-resistant varietiesrevealed that the plants had shortpeduncles - stems between theuppermost leaf and the wheat cob.The scientists postulate that the topleaf obstructs the bird in its attemptto get at the cob.
The length of these stems in thefive bird-resistant varieties isbetween 4 cm. and 8 cm, compared to15 cm in the Kalyansona. The scientists found that other varieties withlarge losses to parakeets also hadlonger peduncles.