EVALUATION AND DEVELOPMENT OF MAINTAINER GENE POOL IN RICE FOR DEVELOPMENT OF IMPROVED HYBRIDS
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Date
2007
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ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
Abstract
The present investigation was carried out during Kharif 2006 and Rabi 2007 to
morphologically characterize maintainer lines, to analyze variance for different characters
and to analyze combining ability and study heterosis and heterobeltiosis of the different
characters of ten selected maintainer lines and their 45 direct hybrids. The experiment
was conducted at the Directorate of Rice Research, Rajendranagar, Hyderabad. During
the Kharif season, the selection of superior maintainer lines from a maintainer collection
available at the Directorate was made and the crosses were made among the selected ten
lines in half diallel fashion. The evaluation of F1s with parental lines was taken up during
the Rabi 2007 season in a randomized block design with three replications. Observations
were recorded for fifteen characters viz. days to 50% flowering, plant height, panicle
exsertion, spikelet opening, stigma exsertion, number of productive tillers, culms
strength, panicle length, number of filled grains, filled grain %, grain yield, 1000-grain
weight, leaf senescence, grain type and phenotypic acceptability.
The gca/sca variance for all the characters studied was less than one indicating
that they are predominantly governed by non-additive gene actions. However, grains
length and breadth ratio and days to 50 % flowering showed the least magnitude of the
predominance of non-additive gene actions while panicle exertion rate, stigma exertion
rate and filled grains per panicle showed the highest magnitude of the non-additive gene
action. From the gca effects IR68897B was good general combiner for six characters viz.
plant height, productive tillers plant-1, panicle length, filled grains panicle-1, yield plant-1
and 1000-seed weight. The parental lines APMS6B, IR79128B and IR79156B were good
general combiners for three characters each. From the specific combining ability results
IR68897B x IR79156B was good specific combiner for seven characters viz. days to 50
% flowering, stigma exsertion %, productive tillers per plant, panicle length, filled grains
panicle-1, filled grain % and grain yield plant-1. For heterosis over mid parent APMS6B x
PMS17B was good heterotic combination for 7 characters viz. days to 50 % flowering,
plant height, productive tillers plant-1, panicle length, filled grains panicle-1, filled grain %
and grain yield plant-1. For heterobeltiosis DRR2B x IR67684B was good heterotic
combination for 6 characters viz. plant height, panicle exsertion %, stigma exsertion,
panicle length, filled grains panicle-1 and grain yield plant-1.
According to overall studies based on specific combining ability, heterosis and
heterobeltiosis the following five crosses viz. IR58025B x IR79156B, IR68897B x
IR79156B, IR68897B x IR69628B, APMS6B x PMS17B and DRR2B x IR67684B could
be given consideration for selection of desirable maintainers from F2 generation onwards.
This study provided information as well as the material for improvement of
maintainer line gene pool in rice for development of improved hybrids
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Keywords
EVALUATION, DEVELOPMENT, MAINTAINER, GENE, POOL, RICE, DEVELOPMENT, IMPROVED, HYBRIDS