Indian Society of Genetics & Plant Breeding

Heterosis for seed yield and its relationship with genetic divergence in grasspea (Lathyrus sativus L.)

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Heterosis has been a phenomenon of great interest for
Plant Breeders and its utilization has led to the
considerable yield improvement in crop plants. Keeping
in view, the present investigation was conducted to study
the nature and extent of genetic diversity available in this
crop under northwestern Himalayas. Twenty-four
landraces were collected from different agroclimatlc
locations and raised In Randomized Complete Block Design
with three replications in the experimental farm of Himachal
Pradesh Krishi Vishvavidyalaya, Palampur, during rab;
1994-95. To study the relationship between heterosis over
the better parent and genetic divergence, five genetically
diversed parents (LSP-1, LSP-2, LSP·3, LSP-4 and LSP-5)
were crossed In a half-diallel fashion. All the fifteen
populations were raised in randomised complete block
design with three replications during rab; 1995·96. The
observations on plant height, number of branches, days
to flower, days to podding, days to maturity, pods/plant,
seeds/pod, 100-seed weight, seed yield/plot and seed
neurotoxin content were recorded at appropriate stages.
The seeds were analyzed biochemically as per the standard
procedure. The analysis of variance revealed the presence
of considerable genetic variability for all characters except
for days to maturity. Using Tocher's procedure, twenty
four lines could be grouped into five clusters, three of
which contained only a single line each. Cluster I
contained the maximum number of 19 lines. LSP-19
(white flower) and LSP-20 (pink flower) clustered with blue
flowered lines. Likewise, LSP-20 (lowest ODAP) clustered
with other high ODAP lines including LSP-11 (highest
ODAP) which suggested that the flower color and ODAP
content were not the cause for genetic diversification In
Lathyrus sat;vus L. The study revealed an appreciable
heterotic response over better parent in desired direction
for a number of characters. A highest positive and
significant heterosis for seed yield (28.7%) was exhibited
by the cross LSp·2 x LSP-5 followed by the crosses
LSP-3 x LSP-5 (23.0%) and LSP-2 x LSP-3 (16.7%). The
cross LSp·2 x LSP-5 also recorded highest heterosis
(53.6%) for pods/plant. An examination of the clustering
behavior of fifteen populations revealed that seven clusters
could be formed, two of which contained only single
member each. The cross LSP-2 x LSP-5 though, showed
highest heterosis for seed yield yet, its parents did not
record maximum divergence. On the other hand, the cross LSP-2 x LSP-3 showed maximum divergence (148.0)
between its parental clusters, but, indicated considerable
heterotic response for seed yield.

Keywords: Grasspea, Lathyrus sativus, heterosis, multivariate D2-statistic


Year: 2003
Volume: 63
Issue: 1
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906



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