STUDY OF GENE ACTION FOR GRAIN QUALITY, PHYSIOLOGICAL AND YIELD TRAITS IN RICE (Ovza sativa L.)
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Date
2009
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Publisher
Acharya N G Ranga Agricultural University, Guntur
Abstract
ABSTRACT
In 21 cr0sse.s obtained from seven parent diallel, nature of gene action and
extent of heterosis were studied for six yield components, five physiological and
eleven grain qualit) characters along with yield during rahi 2006-07, kharif2007 - . . and rabi 2007 -08. Gene effects were estimated from six generations of two crosses
Genetic parameters like GCV, PCV, heritability and genetic advance were
estimated. Combining ability analysis, generation mean analysis, character
association, path coefficient analysis and selection indices were also carried out.
The phenotypic coefficient of variation was higher than the genotypic
coefficient of variation. indicating the profound influence of environment on the
expression of characters. The estimates of genetic parameters exhibited higher
heritability and genetic advance for all the characters except for ear bearing
tillerslplant and panicle length. Thus improvement can be sought by straight
selection for these characters. . '.. '
Gca effects were greater than sca effects, non-additive gene action primarily
governed almost all the yield components, physiological and quality characters as
the sca variance is greater than the gca variance.
The estimates of heterosis and heterobeltiosis were variable among crosses in
desirable direction and some of them turned out to be best specific crosses. Samba
mahsurilprabhat (Ear bearing tillers), samba mahsuril Jagtial samba (1000 grain
weight) Samba mahsuri/ Nellore mahsuri (harvest index), Nellore mahsuril Viljetha
(head rice recovery). Indra/vi.ietha (LIB ratio) Indralvijetha and Samba mahsurit
Polasa prabha (kernel elongation ratio), Samba Mahsurillndra (amylose content),
Samba mahsuril lndra (protein content) and IndraIPrabhat ( Iron and Zinc contents)
were best specific crosses and exhibited maximum heterosis. These can be used in
recombination breeding to spot true breeding progenies. - . Among the parents, Prabhat was good general combiners for most of the
yield contributing characters viz.. panicle length. number of seeds per panicle and
1000 grain weight and Prabhat for ear bearing tillerslplant. Samba mahsuri for
harvest index and lndra for biological yield were good general combiners among
physiological traits. lndra contributed maximum for hulling whereas samba
mahsuri contributed highest towards milling trait and important cooking quality trait
elongation ratio. Among nutritional quality traits Samba mahsuri and Nellore
rnahsuri contributed maxim~rm with intermediate gelatinization temperature and
amylose content whereas Nellore mahsuri for protein content. I
Additive variance was available for selection in the crosses for Ear bearing
tillers (Samba mahsurit Polasa prabha), head rice recovery (Samba mahsuri1Polasa
prabha), kernel elongation ratio (Samba mahsuril Nellore mahsuri), Specific leaf
weight (Samba mahsuril Polasa prabha and Samba mahsuril Nellore mahsuri)
protein content (Samba mahsurimellore mahsuri and Samba mahsuri/Polasa prabha)
and grain yield (Samba mahsuri/Polasa prabha' and Sarnaba mahsuri/ Nellore
mahsuri). -. - --
For character association Ear bearing tillers, panicle length and 1000
grain weight among the yield component; harvest index, biological yield and flag
leaf lU content among physiological traits exhibited positive significant correlation
with yield. I J~~lling percent, milling percent and protein content exhibited positive
association with yield in case of quality traits. Protein content exhibited negative
association with elongation ratio suggesting that, superfine rices are to be upgraded
regarding protein content.
All the characters under study except days to 50% flowering, panicle length
and specific leaf weight exhibited positive direct effect on yield. Keeping in view
the significant association along with positive direct effects; Ear bearing tillers,
1000 grain weight, harvest index, biological yield, flag leaf N content, hulling
percent, milling percent and protein content can be considered for isolating good
genotypes.
The association of flag leaf Nitrogen content with days to 59% flowering,
plant height, ear bearing tillers, panicle length, number of seeds per panicle, 1000
grain weight. biological yield, hulling percent, milling percent, LIB ratio, protein
content, Zinc and yield per plant indicates its significance.
Description
D.ADILAKSHMI