Combining ability analysis for yield and maturity traits in elite inbred lines of maize
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Date
2006
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Publisher
SKUAST-K
Abstract
The present investigation was carried out to generate information on crossing ability
(general and specific), gene action and heterosis. Fifteen S2 maize lines (used as females) were
crossed to three testers (two broad genetic based and one inbred) to generate forty five line x tester
progenies. These lines x testers progenies along with 18 parents (15 lines + 3 testers) were
evaluated in randomized block design during Kharif season of 2005 at K.D. Research Station of
SKUAST-K. Data were recorded on competitive plants except for maturity traits where the data
were recorded on whole plot basis. The mean/medium values were used for statistical analysis and
estimation of genetic parameters.
Analysis of variance and estimates of the components of genetic
variance revealed that significant differences existed among the lines
and lines x testers progenies for all the traits. The variance due to gca
and sca was also significant for all the traits except days taken to 50%
anthesis and ear girth in respect of gca. The estimation of variance due
to dominance deviations ( ˆ 2 )
s D was high in magnitude than additive
genetic variance ( ˆ 2 )
s A for all the traits. The average degree of
dominance ranged from 1.74 (kernel rows ear-1) to 3.86 (ear height).
Narrow sense heritability was very low and ranged from 6.04 (ear
height) to 25.93 (100 grain weight). Significant and desirable gca for
maturity traits viz., anthesis and silking was recorded in the lines 132C
and 139B and for husk browning in the lines 146B and 106B. The lines
132C and 106B revealed significant and desirable gca for shorter plant
height and lower ear placement. Among yield component traits the
highest significant and desirable gca was recorded in the lines 147C
(ear length), 106C (ear girth), 139 B (kernel rows ear-1), 139A (kernels
row-1) and 106 C-2 (100 grain weight). For grain yield the maximum
significant and desirable gca was recorded in the lines 139A, 151A and
142A. None of the cross combinations revealed significant and
desirable sca for all the traits. The most promising crosses that revealed
significant and highest sca for grain yield were 139A x 153A, 106C-2
x C6,106 C-1 x Super-1 and 106 C-1 x 153A. The maximum
contribution of different traits towards the performance of crosses
came from the lines (35.9%-68.65%) and from lines x testers (31.10%
- 60.15%). The contribution from testers was low (0.24% - 24.46%).
Significant and desirable heterosis was observed for all the traits. The
cross 132C x C6 was observed to possess earliness. The maximum
heterosis for grain yield was observed in the crosses 139A x 153A,
142A x C6 and 106C-1 x 153A to the extent of 77.08, 39.58 and 35.42
per cent, respectively.
Description
M.Sc Thesis submitted to SKUAST Kashmir
Keywords
Combining ability, yield and maturity trait, elite inbre, Genetic and Plant Breeding