RA 00015.pdf - OAR@ICRISAT

Relationship Among Plant Type,
Population, and Planting Pattern
Farmers' cultivars and landraces of millet include
a wide variety of plant types and are grown
in a wide range of planting geometries and plant
populations. We have initiated studies to determine
if there are interactions among plant
type and planting system; if so, they might be
important in variety selection and testing. In one
such study three cultivars, of contrasting height
and tillering habit, were grown at a range of plant
populations from 3 to 25 plants per square meter
in wide rows, narrow rows, and with all plants
equally spaced.
Population seemed to have no effect on grain
yields, as all genotypes demonstrated a remarkable
ability to adjust to changing crop competition.
Individual plant yields increased sixfold
as population declined from 25 plants/m 2 to 3
plants/m 2 . The yield per plant was unaffected by
planting pattern at high populations, but was less
in the equidistant planting at the low populations.
These results suggest that population
per se, over a broad range, is not a determinant of
millet yields, at least where fertility is adequate.
Planting pattern, in contrast, had a highly
significant effect on yield, which was independent
of both genotype and of plant population. Grain
yields were significantly different in the order of
wide rows > narrow rows > equidistant planting
(Fig 24). The yield differences were due to
increases in dry weight of individual tillers, and
to leaf area, grain number, and grain yield (tiller
numbers per unit area were constant), emphasizing
the role of tiller productivity in maximizing
yield.
These studies are now being expanded to
include hill-planting systems, various fertility
levels, and a wider range of cultivars.
Millet Genotype Evaluation
Analysis was completed on the large-scale experiment
of 1976 in which relationships between
yield, yield components, and length of the major
growth stages were evaluated. Results were analyzed
separately for the entire set of 50 genotypes,
as well as for smaller subsets representing
the high-tillering Indian hybrid type and the
lower-tillering West African type. Differences in
grain yield between the two subgroups were not
statistically significant, but there were significant
differences in tiller number per plant, seed number
per plant, and harvest index (Indian types
were superior); and in grain number per panicle
and length of the GS 2 stage (West African types
were superior).
The relative contributions of different yield
components in each group were assessed in a
multiple linear regression model of yield on
panicle number per plant, grain number per
panicle, and grain size (100-seed weight). Over the
entire set, seed number and grain size accounted
fdr 45 and 42 percent, respectively, of the
variation in yield, with panicle number account-
3 500
3 000
2 500
2000
1500
Equidistant
37.5-cm
row
Seeding configuration
cv 700250
cv HB 3
cv K 599
L.S.D.
(0.05)
75-cm
row
Figure 24. Grain yield of three pearl millet cultivars
as affected by geometry of
planting. Mean data from a series of
five planting populations ranging from
3 to 25 plants/m 2 .
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