PhD

Investigations on “Bacterial wilt resistance and yield in brinjal (Solanummelongena L.)” was undertaken in the Department of Olericulture, College of Horticulture, Vellanikkara during 1993 – ’96.
Preliminary evaluation of seventy eight brinjal accessions during Kharif 1994 revealed considerable variation for most of the economic characters. Twenty four accessions/varieties selected based on productivity, resistance to bacterial wilt, crop duration, fruit and plant characters from the preliminary evaluation were subjected to detailed evaluation during March – November, 1995. In the long duration accessions, the non – prickly SM 141 has yielded as high as 6.4 kg/plant with maximum number of fruits (113.5) having maximum weight (128.27 g). Among short duration accessions maximum yield was recorded in white fruited Swetha (3.9 kg/plant). The study revealed the necessity for differential spacing depending on the duration and spread of the plant.
In addition to the already available bacterial wilt (Pseudomonas solanacearum) resistant varieties viz., Surya, Swetha, ArkaKeshav, ArkaNidhi, BB 44 some more varieties/accessions viz., Annapurna, Composite 2, TGR, SM 71, SM 116 and SM 141 were found resistant under artificial inoculation. The contents of total phenol and O.D. Phenol was higher in the resistant varieties than the susceptible ones. The anatomical studies revealed well developed secondary xylem with small compact cortical cells in the resistant variety compared to the susceptible variety.
The nine F1 hybrids differing in size, shape and colour of fruits were compared with their parents during summer 1996. Two F1 hybrids viz., the long stout and deep purple fruited ArkaKeshav x SM 71 and oval and deep purple fruited Surya x SM 116 had surpassed the standard parent by 337.62 per cent and 290.04 per cent respectively in productivity. Both the hybrids having bacterial wilt resistance, desired plant habit and attractive fruit characters can be progressed further. In general the F1 hybrids had more vigour and tolerated infestation of jassids better than the parents.
In Kerala the cultivation of brinjal during summer is limited mainly due to heavy incidence of jassids. In the present study varietal variation was observed for resistance to jassids (Amrascabiguttulabiguttula). The long trichomes with high density contributing to a matting effect on the leaf surface may be responsible for the jassid tolerance in varieties like Pusa Kranti and BB 7. These jassid resistant but wilt susceptible varieties yielded 2417.2 per cent and 186.0 per cent respectively more over the intact plants after grafting onto Solanumtorvum. The present study revealed the scope of cultivating jassid resistant varieties viz., Pusa Kranti and BB 7, though highly susceptible to bacterial wilt during the summer months in the state.