Studies on Heterosis, Combining Ability and Stability in Sweet Corn (Zea mays L. Ssp. saccharata)
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Date
2020-12-28
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MPUT, UDAIPUR
Abstract
An investigation was conducted to estimate the extent of average heterosis,
heterobeltiosis and standard heterosis, general and specific combinig ability effects of
parents and sweet corn hybrids, respectively as well as genotype x environment
interactions and stability parameters for green cob yield and contributing characters.
Fifteen elite sweet corn inbred lines were crossed with three diverse testers in line x
tester fashion to develop forty five sweet corn hybrids. These forty five sweet corn
hybrids along with eighteen parents and three standard checks Madhuri, Priya and
Sugar-75 were evaluated in three different environments viz., E1 (at Instructional
Farm, RCA, Udaipur, during Kharif 2019), E2 (at ARS, Banswara, during Kharif
2019) and E3 (at Instructional Farm, RCA, Udaipur, during Rabi 2019-20). The
material was planted in RBD with three replications in each of the environments. Ten
plants were selected on random basis for recording the observations for twenty yield
attributing characters.
Analysis of variance on pooled basis revealed presence of significant
differences in mean sum of squares due to environment, genotypes, parents and parent
v/s crosses for all the characters. Except for protein content, the mean sum of squares
due to crosses was found to be significant for all the characters. The mean sum of
squares due to genotype x environment and crosses x environment were found to be
significant for all the characters except for moisture per cent of green grain and
protein content. The mean sum of squares due to environment x parents were found to
be non-significant only for moisture per cent and TSS content of green grain and
protein content. The mean sum of squares due to environment x parents v/s crosses
were found to be significant for all the characters except for ear length, ear girth,
number of grain rows ear-1, moisture per cent of green grain, green cob yield and
protein content On the basis of per se performance and significant estimates of economic
heterosis over the three environments for green cob yield (kg ha-1), five best sweet
corn hybrids were identified viz., L7 x T1, L3 x T1, L9 x T1, L7 x T2 and L7 x T3. Among
the best five hybrids, the sweet corn hybrids L7 x T1 and L3 x T1 exhibited high per
se performance and significant economic heterosis over the best check Sugar-75 over
the three environments for green cob yield, green fodder yield, green cob weight
plant-1 and TSS content of green grain.
For green cob yield and green cob weight/ plant, lines L2, L3, L7, L8, L11, L12
and L13 were identified as good general combiners on the basis of general combining
ability estimates over the three environments. Similarly, for green fodder yield, lines
L1, L2, L3, L4, L7, L11, L12 and L13, for TSS content of green grain, lines L1, L5, L7,
L10, L11, L13 and L14 and for protein content, line L12 were identified as superior
general combiners over the three environments on the basis of general combining
ability analysis.
Among the testers, T1 was identified as good general combiner for green cob
yield, green cob weight plant-1 and TSS content of green grain on the basis of general
combining ability estimates over the three environments. Similarly testers T1 and T2
were reported as superior combiners for green fodder yield on the basis of general
combining ability analysis in pooled environments.
Out of 45 sweet corn hybrids, the five best crosses which possessed
significantly positive specific combining ability effects for green cob yield on pooled
basis were L5 x T2, L15 x T3, L10 x T1, L6 x T3, and L9 x T1, among which L5 x T2, L10
x T1 and L9 x T1 exhibited positively significant standard heterosis over the best check
Sugar-75.
Apart from green cob yield, the sweet corn hybrid L5 x T2 exhibited positively
perceptible specific combining ability effects for characters number of leaves plant-1,
length of leaf, number of ears plant-1, ear length, ear girth, number of grain rows ear-1,
number of grains row-1, 100 fresh seed weight, green cob weight plant-1, green fodder
yield and TSS content of green grain. On the basis of specific combining ability
effects, among the selected best five hybrids, sweet corn hybrids L5 x T2 and L6 x T3
were best for green cob yield, green fodder yield and green cob weight plant-1 while
the hybrid L10 x T1 was best for green cob yield, green cob weight plant-1 and TSS
content of green grain Among all the sweet corn hybrids, L12 x T1 was identified as stable performer
in various environments (bi=1) with higher mean than the population mean for green
cob yield. For unfavorable environments (bi<1), the sweet corn hybrids L7 x T1 and L9
x T1 and within favorable environments (bi>1), hybrids L7 x T3 and L10 x T1 revealed
stable performances with high mean value for green cob yield as well as positively
significant standard heterosis over the best check Sugar-75 on pooled basis. For TSS
content of green grain, sweet corn hybrids L1 x T1 and L11 x T1 showed non
significant deviations from regression (S2di) and regression coefficient equivalent to
unity (bi=1) with greater mean than the population mean, thus signifying their
predictable performances and stability for different environments for sweetness.
These parents and sweet corn hybrids can be used in future breeding programmes and
further multi location testing programmes, respectively
Description
Studies on Heterosis, Combining Ability and Stability in Sweet Corn (Zea mays L. Ssp. saccharata)
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Citation
Chouhan D. and Dubey R.B.