COMBINING ABILITY STUDIES IN NEW PROMISING HYBRIDS IN RICE (Oryza sativa L.)
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Date
2015
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PROFESSOR JAYSHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
Abstract
The present investigation entitled “Combining ability studies in new
promising hybrids in rice (oryza sativa L.)” was carried out at R.A.R.S, Polasa,
Jagtial.With the aim to identify promising hybrids. The main objectives of the
investigation were to study the combining ability of parents and the crosses to identify
superior parents and hybrids. Besides magnitude of heterosis, heterobeltiosis and
standard heterosis, were also estimated. The study also aimed to asses the physical grain
quality traits of the hybrids and identification of hybrids with gall midge resistance.
Four CMS lines were crossed with nine testers and the resultant 36 crosses along
with the parents and two checks viz., Samrat and 27P31 were evaluated for combining
ability (Line x Tester design), heterosis and grain quality traits at R.A.R.S, Polasa,
Jagtial during kharif, 2014.
Combining ability effects were studied and heterosis was estimated for the various
characters like days to 50% flowering, plant height, panicle length, number of productive
tillers per plant, number of tillers per plant, spikelet fertility, 1000 grain weight,
incidence of gall midge, kernel length, kernel breadth, L/B ratio, hulling percentage,
milling percentage and head rice recovery.
The analysis of variance for yield contributing and physical grain quality
characters revealed significant difference among the treatments for all the characters
under study. In case of replications, for most of the characters, there were no significant
differences except for, panicle length, incidence of gall midge, hulling and milling percentage, which signifies that the differences were mainly due to the genotypes. So,
further study of these genotypes for combining ability can be continued.
The gca effects of the parents revealed that the lines viz., CMS 46A and CMS
11A and the testers viz., JGL-20779, JGL-18047, JGL-20171 were promising general
combiners for single plant yield.Based on significant sca effects, six cross combinations
viz., CMS 46A x JGL-20779, CMS 11A x JGL-20779, CMS 11A x JGL-21820, CMS
46A x JGL-18222, CMS 46A x JGL-21820 and JMS-1 x JGL-20779 appeared
promising for grain yield.
The physical grain quality traits like kernel length, kernel breadth, L/B ratio,
hulling and milling percentage, head rice recovery, was studied and it was found that
among the lines, CMS 46A line had maximum hulling, milling and head rice recovery.
Among the testers, JGL-20779 recorded maximum hulling, milling, head rice recovery
percentage. Among the crosses CMS 23A x JGL-20171 was the best hybrid for hulling,
milling, and head rice recovery percentage.
Heterosis for single plant yield was mainly because of simultaneous manifestation
of heterosis for yield component traits. Of the 36 hybrids studied, the significant
positive standard heterosis over the best check Samrat, was observed in three hybrids,
These hybrids are, CMS 46A x JGL-20779(15.30), CMS 11A x JGL-20779 (13.88),
CMS 11A x JGL-21820(11.03).
The best hybrid identified was CMS 46A x JGL-20779, which had highest single
plant yield of (32.4 g/plant), short duration (123 days) and L/B ratio (3.19) which
indicates the fitness of the grain, highly preferred by consumers of Telangana. Further,
it showed lower susceptible reaction to gall midge at Jagtial.
Another hybrid CMS 11A x JGL- 21820 with short duration (125 days) gall midge
resistance and higher single plant yield (31.2 g/plant) and L/B ratio is (2.36) also
appeared to be promising.
Another hybrid CMS 23A x JGL-21820 with short duration (121 days) gall midge
resistance and higher single plant yield (27.7 g/plant) and L/B ratio is (2.67) also
appeared to be promising.
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Keywords
hybrids, rice, yields, grain, developmental stages, heterosis, planting, biological phenomena, genes, crossing over