Abstract:
The experiment was conducted at the experimental tieid of Sher-e-Bangla
Agricultural University, Dhaka during the period from October. 2006 to March 2007
to screen some tomato varieties/genotypes for their resistance to whitefly, J3emisia
uthacE Gennadius. Incidence and abundance of whitefly as well as Tomato yellow leaf
curl virus (TYLCV) disease and several morphological traits of the tomato varieties
were studied to identify resistance source(s) among nine released tomato varieties.
Out of nine tomato varieties. 13AR1-2 showed the most preferred host followed by
RARI-S, whereas BINA-3. I3ARI-7 and BINA-1 performed as least preferred host for
whitefly, Bnnisia jahaci in terms of adult whitefly incidence. Considering the
TYLCV infection transmitted by whitefly, 110110 of' them were found to be free
from TYLCV infection. Disease incidence varied from 22.57 to 53.04%.
Only three tomato varieties were resistant, which include BARI-2 (Ratan),
DART-S and BARI-9. The varieties BARI-3, I3ARI-7 and BINA-) and B1NA-2
were found as moderately resistant to TYLCV infection and the varieties BINA-3 and
BINA-4 were found as moderately susceptible. In this study. the incidence of TYLCV
infected leaves and plants were not directly proportional to the density of vector
(whitefly) population, but were related either with the proportion of the
virulif'erous whitefly rather than total number of whitefly or the
morphological and or physiological properties of the host plant.
Considering mean whitefly infestation, cumulative TYLCV infection and comparative
yield of different tomato varieties, it was observed that the tomato BARI-2 had
significantly the highest whitefly infestation (25.95 per plant) and but with the lowest
TYLCV infection (22.57%) and the highest yield (73.00 t/ha) On the other hand,
flower per bunch, the maximum number (99 33 and 5.67) were produced by the
variety BINA-2, which was statistically similar with the variety BARI-2 (79.33 and
5.33). The number of fruits was not positively related to the yield exce
BINA-2 showed significantly the second lowest whutefly infestation (16.90 per plant)
and second highest TYLCV infection (46.7 1%) and yielded the highest (73.24 t/ha).
The variety BARI-7 showed significantly maximum height (2904 cm) per plant but
produced lowest yield (54.98 t/ha), whereas BARI-2. (265.5 cm) and BINA-2 (250.3
cm) showed third highest height as well as produced significantly highest yield (73.00
and 73.24 t/ha, respectively). In consideration of number of branch and leaves per
plant, the maximum numbers (13.78 and 86.77 respectively) were produced by the
variety BARI-2. In terms of the number of flower bunch per plant and number of
flower per bunch, the maximum number (99 33 and 5.67) were produced by the
variety BINA-2, which was statistically similar with the variety BARI-2 (79.33 and
5.33). The number of fruits was not positively related to the yield except few cases.
The increase in yield per hectare due to the increase of single fruit weight was
justifiable.
Description:
A THESIS
Submitted to
Sher-e-Bangla Agricultural University, Dhaka
In the partial fulfillment of the requirements
for the degree of
MASTER OF SCiENCE (MS)
IN
ENTOMOLOGY
SEMESTER: JAN VARY-JUNE, 2007