MSc

An investigation on "Screening of tomato somaclones for resistance to Tomato Leaf
Curl Virus" was undertaken in the Department of Olericulture, College of Horticulture
during 2000 - 2002 to standardize the explants of L.esculentum var. 'Sakthi' and; to
standardize the media for callus induction, organogenesis and shoot induction in tomato and
to screen the somaclones of bacterial wilt resistant 'Sakthi' and L. pimpinellifolium for
resistance to Tomato Leaf Curl Virus.
The leaf segments exhibited high callus index in the MS medium supplemented with
NAA (2 mgl") and BA (1 mgl', 2 mgl' and Jrngl") for 'Sakthi' and L. pimpinellifolium.
The basal medium containing NAA (1 mgl") and kinetin (4 mgl") gave maximum callusing
in internodal segments of' Sakthi'. In the case of nodal segments MS medium supplemented
with NAA (1 mgl") and BA (4 and 5 mgl") recorded early callusing and highest callus
index in both' Sakthi' and L. pimpinellifolium.
The percent morphogenic capacity was highest in internodal calli (95%) followed by
leaf segment calli (88.8%) in 'Sakthi' when basal medium supplemented with NAA (2 mgl
!) and BA (3 mgl").
In 'Sakthi' the highest percent root growth and maximum number of root hairs was
obtained in MS medium with IBA (1 rngl"). In L. pimpinellifolium percent root growth was
maximum in the medium containing IBA (0.5 mgl") and IAA (1.5 mgl").
Screening of somaclones of 'Sakthi ' and L. pimpinellifolium for resistance to TLCV
disease, transmitted by white fly Bemisia tabaci has revealed that two somaclones of
'Sakthi' were free from the disease and five plants exhibited mild symptoms. Two
somaclones yielded higher than control and another two plants were free from fruit cracking.



The somaclones of L. pimpinellifolium were free from TLCV disease. However the
resistance to the disease improvement in horticultural traits can be confirmed only in
subsequent generations.