Genetic parameters and heterosis in rubber (Hevea brasiliensis Muell. Arg.). 3. Variability and hybrid vigour for yield and certain yield attributes - Licy J; Nazeer M A; Panikkar A O N; Premakumari D; Saraswathyamma C K; Sethuraj M R; Varghese Y A (Golden Jubilee Symposium, Horticultural Research - Changing Scenario, May 24-28, 1993, Bangalore, India, 1993)