MSc

The investigations on "Development of yellow vein mosaic virus (YVMV)
resistant hybrids in okra (Abelmosehus eseulentus (L.) Moench)" was undertaken at
the Department of Olericulture, College of Horticulture, Thrissur during the period of
2000-2001.
Fifteen lines viz., AE-198, AE-202, AE-210, AE-211, AE-214, AE-219,
AE-238, AE-260, AE-264, AE-265, AE-275, AE-279, AE-280, AE-282 and AE-287
were crossed with two testers AE-285 and AE-190 (Parbhani Kranti) in line x tester
mating design to produce 30 hybrids. These F I hybrids along with the parents were
evaluated for several quantitative, fruit quality, qualitative characters and resistance to
yellow vein mosaic virus. Among them, a parent AE-238 and two hybrids AE-238 x
AE-190 and AE-265 x AE-190 were disease free in field screening, grafting and
vector transmission studies.
The general combining ability of the parents, specific combining ability of
the hybrids and heterosis (relative heterosis, heterobeltiosis and standard heterosis)
were estimated. The best general combiners were AE-202, AE-264 and AE-190 which
showed significant high gea effects for most of the traits among the traits studied.
Based on the per se and gea effects, the parents AE-264, AE-214 and AE-190 were
found as best for crossing.
Based on the per se performance, sea effects and heterosis on all the three
bases, the hybrids AE-264 x AE-285 for plant height, AE-279 x AE-190 for internodal
length, AE-219 x AE-190 for number of primary branches, AE-219 x AE-190 for
petiole length, AE-264 x AE-285 for days to flowering, AE-202 x AE-285 for duration

of flowering, AE-202 x AE-285 for first fruiting node, AE-264 x AE-190 for fruit
length, AE-279 x AE-285 for fruit girth, AE-219 x AE-190 for number of fruits per
plant, AE-202 x AE-285 for crop duration, AE-2l9 x AE-190 for yield per plant,
AE-238 x AE-190 for mucilage content, AE-238 x AE-285 for calcium content,
AE-279 x AE-190 for vitamin A content and AE-214 x AE-190 for magnesium
content excelled other hybrids.
Based on per se performance, sea effects and heterosis, hybrids AE-219 x
AE-190, AE-264 x AE-285 and AE-265 x AE-190 were selected as top ranking
hybrids. Among them AE-265 x AE-190 was not shown disease symptoms in field
screening, grafting and vector transmission studies. So it was to be concluded as best
hybrid having YVMV resistance.
Reddish green colour of leaf base, green colour of leaf vein, deeply lobed
nature of leaves, purple throat on both sides of corolla, slightly prickly nature of fruit,
light green colour of fruit and five ridged nature of fruit were dominant. Yellowish
with red colour on both sides of corolla in flower is incompletely dominant.
Resistance to YVMV may be complex in nature probably involving major and minor
genes with acting modifiers. Further studies are required to confirm it.