Germination behaviour of Acacia catechu Willd. seeds in relation to bruchid insect infestation and scarification.
The present study was carried out to know the insect-pests damage to the seed of Acacia catechu, their incidence and impact on germination. In addition, seed scarification techniques have also been studied to enhance the germination potential and to explore the possibility of utilizing insect infested seed having some leftover endosperm. Maximum seed infestation (16:6%) was recorded at Dolan (Distt Solan) followed by Bhakhra (15.8%) in district Bilaspur and minimum in district Hamirpur at loction Nagrera (0.6%) followed by Wahad (0.8%) of district Una. The maximum pod infestation (48%) was observed at Bhakhra followed by Delgi (29%) of district Solan. The lowest pod infestation was observed in district Bilaspur at locations Kharota (3%) and Ghumarwin (4%). The average seed (10.5%) and pod (16.5%) infestation was maximum in seed zones falling between 600 to 900 m amsl, however, the insect incidence was low in areas lying above 900 m amsl (seed 3.2%, pod 14.3%) and below 600 m amsl (seed 3.5%, pod 14.8%). Insect attack on seed was also found to increase the fungal incidence in seeds. Maximum fungal incidence (85%) was observed in badly damaged seeds followed by partially damaged (45%) and healthy (23%) seeds. A higher germination (49%) was recorded in partially insect damaged seeds than in healthy (42%) and badly damaged (6%) seeds, owing to the increased permeability of seed through partial seed rupture by bruchids. The maximum seed germination (79%) was recorded when healthy seeds were scarified with hot water (40-50°C) for 2 hours. This treatment also reduced the fungal incidence in seed.