Journal of Applied Horticulture. 2003: 5(2): 81-84

In vitro establishment of tolerant clones of banana against race-1 Fusarium oxysporum f. sp. cubense

Saravanan, T; Muthusamy, M; Marimuthu, T

Agricultural Research Station, Tamil Nadu Agricultural University, Kovilpatti - 628 501, India.

A study was conducted to develop gamma radiation-induced resistant clones of banana (Musa sp.) cv. Rasthali against F. oxysporum f.sp. cubense race-1. Shoot buds of Rasthali irradiated with 20, 40, 60, 80 and 100 Gy by using Co60 in a gamma chamber were used for in vitro culture establishment and to develop resistant clones. Shoot buds irradiated with 40 Gy had the maximum shoots per culture and percentage of culture establishment. Other doses of gamma radiation inhibited the culture establishment when compared to the untreated control. The shoots irradiated with 40 Gy were used to develop resistant clones against toxins of race 1. To standardize the concentration of the culture filtrate of the pathogen for the tolerant clone selection, the multiple bud clumps were cultured on MS medium supplemented with 2-15% crude culture filtrates. The growth of multiple bud clumps was completely inhibited on the medium containing 10% culture filtrate. In the successive selection, the rate of survival of the plantlets increased from 6.5 to 56.4% in the medium containing 10% culture filtrate. Approximately 50% symptomless plantlets were obtained from 40 Gy-irradiated and survived plantlets under greenhouse conditions. The activity of peroxidase enzyme was higher in the tolerant plantlets, and a 4-fold increased in the enzyme activity was recorded at 21 days after inoculation of the pathogen.