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ESTIMATION OF GENETIC DIVERGENCE, COMBINING ABILITY AND STABILITY FOR GREEN COB YIELD AND ITS COMPONENTS IN SWEET CORN ( Zea mays L. saccharata)

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Title ESTIMATION OF GENETIC DIVERGENCE, COMBINING ABILITY AND STABILITY FOR GREEN COB YIELD AND ITS COMPONENTS IN SWEET CORN ( Zea mays L. saccharata)
 
Creator SESHU, G
 
Contributor BRAHMESWARA RAO, M.V.
 
Subject yields, grain, wheats, inorganic acid salts, developmental stages, rice, crops, nutrients, fertilizers, farmyard manure
 
Description breeding design to explore the fullest range of heterosis and to realize
good recombinant lines. Based on genetic divergence studies, the genotypes 6019-3 (P10) and
6039 (P6) from cluster I, 6055-1 (P1) from cluster II, 6051-2 (P9) from cluster III, 6075-1
(P7) from cluster IV, SC-10-3 (P5), SC-14-2 (P2), SC-17-4 (P3) from cluster V and 6016-2
(P4) from cluster VI and 6069-2 (P8) from cluster VIII were selected for hybridization
programme as they were expected to produce high heterotic crosses.
Ten divergent parents were crossed in diallel fashion excluding reciprocals during
kharif, 2011 at College Farm, College of Agriculture, Rajendranagar, Hyderabad. The
resulting 45 crosses along with parents and two standard checks viz., Sugar-75 and Madhuri
were evaluated in Randomized Block Design replicated thrice during rabi, 2011-12 at three
locations viz., Rajendranagar, Karimnagar and Kampasagar.
The pooled analysis of variance for combining ability revealed significant differences
due to environments, parents, hybrids and various interactions indicating the existence of
wider variability in the material studied. The ratios of GCA/SCA variances revealed that non
additive gene action was predominant in the inheritance of all the characters.
Combining ability analysis revealed that among the parents, P1, P2, P4 and P6 were
found to be good general combiners for earliness. The parents, P4, P7, P5 and P8 recorded
significant positive gca effects for green cob yield, these inbreds may be utilized in
population improvement or in the development of synthetics and composites. The hybrids,
P3XP9, P5XP8 and P1XP8 were found to be good specific combiners for earliness. While the
hybrids, P5XP8, P5XP6, P1XP10, P2XP6 and P6XP10 which recorded positively significant
sca effects for green cob yield per hectare. Hence, considered as good specific combiners,
therefore, these hybrids could be recommended for heterosis breeding.
Estimates of heterosis, heterobeltiosis and standard heterosis were variable among
crosses in desirable direction and some of them turned out to be best specific crosses.
Heterosis for green cob yield per hectare is mainly because of simultaneous manifestation of
heterosis for yield component traits. The highest standard heterosis for green cob yield per
hectare over better check Sugar-75, was recorded for hybrids, P5XP8, P4XP8, P5XP6, P4XP5
and P3XP7 along with per se, average heterosis, heterobeltiosis and with high sca effects.
These hybrids may be further exploited in multiplication evaluation before releasing them for
commercial cultivation.
In pooled analysis high narrow sense heritability estimates were recorded for days to
maturity, days to 50 per cent tasseling, days to 50 per cent silking, green cob yield per plant.
Thus, these traits are predominantly under the control of additive gene action and hence these
characters can be improved by selection.
On the whole based on the overall performance among the parents, P4, P1 and P2 and
among hybrids, P5XP8, P4XP8 and P5XP6 are found to be the best for yield and yield
attributes in the present investigation.
Results of stability analysis revealed that the hybrids, P5XP8, P4XP8, P5XP6,
P4XP5, P3XP7, P4XP10, P1XP10, P6XP10, P5XP7 and P7XP8 are identified as stable and
best performing hybrids for green cob yield per hectare, for sugar content, the hybrids P1 X
P6, P1 X P4, P8 X P10, P8 X P9, P2 X P9, P6 X P10, P2 X P4, P3 X P8 and P2 X P3 and for
other traits. Hence, suitable for wider environments. P3 X P7 for green cob yield per hectare
and P6 X P8 for sugar content performed well in better environment. Three hybrids, P4XP10,
P6XP7 and P9XP10, performed well for sugar content in poor environmental condition.
Study of correlations revealed that green cob yield per hectare was positively
correlated with that 100-seed weight, cob girth, cob length, number of kernels per row, plant
height, number of kernel rows per ear, ear height and negatively correlated with days to 50
per cent tasseling, days to 50 per cent silking and days to maturity.
Keeping in view of the above facts, by considering all factors like per se performance,
sca effect, standard heterosis, relative heterosis, heterobeltiosis and stability, the most
promising hybrids identified were P5XP8, P4XP8 and P5XP6. These hybrids may be
further tested over locations, seasons and years before recommending for commercial release.
 
Date 2016-06-14T11:51:11Z
2016-06-14T11:51:11Z
2013
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67338
 
Language en
 
Relation D9323;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY