HETEROSIS AND COMBINING ABILITY STUDIES IN DIALLEL CROSSES OF MAIZE (Zea mays L.)
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Date
2020-09-30
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CSKHPKV. Palampur
Abstract
The present investigation was carried out on experimental materials derived through
crossing eight inbred lines in half diallel mating design. The experimental material consisted of 8
parental inbreds, their 28 crosses and four checks viz., Palam Sankar Makka-2, Vivek Hybrid-45,
Bio-9544 and DKC 7074 were evaluated in RBD at two environments representing different
agroclimatic and ecological conditions of North-Western Himalayas i.e. SAREC, Kangra and
HAREC, Bajaura during Kharif, 2019. Analysis of variance indicated sufficient amount of
variability in the experimental material for all the traits across the environments except shelling
(%) in E1. Bartlett‟s test indicated that error variance was homogeneous only for days to 50%
pollen shed and silking, days to 75% brown husk, ear circumference (cm), 1000-grain weight (g)
and grain yield (q/ha). The pooled analysis revealed significant differences between the
environments for all the traits except days to 50% silking. Per se performance of parents and
crosses revealed that environment E1 took less number of days to 50% pollen shed and silking
except for days to 50% silking for crosses, whereas, environment E2 took less number of days to
75% brown husk. Plant height was observed more in E1 as compared to E2. Mean performance of
grain yield and its contributing traits viz., number of kernel rows per ear, number of kernels per
row, ear length, ear circumference and 1000-grain weight for parents and crosses observed more
in E2 than E1. Analysis of variance for combining ability revealed significant GCA and SCA for
most of the traits indicated the preponderance of additive and non-additive gene actions for the
inheritance of the traits. Estimates of σ2SCA were higher as compared to the estimates of σ2GCA
in both the environments and in pooled over environment as well, except for the days to 75%
brown husk in E1 indicated preponderance of non-additive gene action. In pooled analysis, mean
squares due to environment, GCA, SCA, GCA × environment and SCA × environment were
significant for all the traits except for days to 50% silking in environment and GCA × environment
for days to 75% brown husk. Significant mean sum of squares for GCA × environment and SCA ×
environment were observed for days to 50% pollen shed and silking, ear circumference, 1000-
grain weight and grain yield. The magnitude of interaction in case of GCA observed higher for
days to 50% pollen shed and silking, 1000-grain weight (g) and grain yield (q/ha) than SCA. The
inbred line P1 in E2, pooled over environment and P6 in E1 were found good general combiner for
most of the traits and may be utilized as potential parental inbred lines for development of high
yielding single cross maize hybrids. Based on high per se performance, SCA effects, standard
heterosis (%), days to 75% brown husk and diseases resistance to TLB and BLSB in both the
environments under natural conditions and for TLB under artificial conditions, the crosses P1 × P4
and P2 × P4 in E1, E2 as well as pooled over environment identified as the potential hybrids may
be commercially exploited after critical evaluation for its superiority in performance and with
stability across the locations over years