International Journal of Horticulture, 2017,Vol.7, No. 23, 205-218
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Figure 1 Growth curves for different seed weights: 2nd interim cut
The longitudinal growth curves of yam yield with interim detachment of yam at the time of second growth
recording are shown for different seed weights in Figure 1. This is same as Figure 1 of Dasgupta (2017a). There
are 8 plants of 500 g seed weight, 13 plants of 650 g seed weight, and 10 plants of 800 g seed weight subjected to
interim yam cut at the time of second growth recording. Second interim cut of yam along with final harvest on
maturity from replantation of stem structure, with a few attached roots in the same pit produced higher yield in
total. Further analysis of the data has to be made for plants with second interim cut. In general, curves with seed
weight 800 g are seen above other curves. 800 g seed weight corresponds to higher yield in harsh and extreme
agro-climatic environment. For seed weight 500 g, sharp upturn of all longitudinal growth curves is observed
beyond a time from sprouting till the end, indicating possibility of these curves crossing the other growth curves
from below over time, if lifetime of plants with seed weight 500 g could be extended further.
Figure 2 Mean growth curves for different seed weights: 2nd interim cut
Consider a fixed seed weight and the relevant plants with yam cut at the time of second interim growth recording.
For each plant alive, growth recordings are available at two interim time points of uprooting, along with initial
and final weight at mature stage harvesting.
y
co-ordinate of curves in Figure 1, with different time points
x
for
which yield data from first interim, second interim, final harvest are available in records are considered. For such
fixed time
x
from the above set, mean of
y
values lying in the curves, obtained from linear interpolation, provides
an estimate of mean response at that time point. The mean values joined by lines provide a raw estimate of mean
response curve for a particular seed weight in Figure 2. Mean curves for different seed weights are of use to
compute proliferation rates. Seed weight 800 g corresponds to the highest yield. Mean curve of yield for seed
weight 650 g and 800 g seem a bit erratic towards end due to scarcity of observations therein at far end. Mean
curve corresponding to seed weight 500 g has upward slope from 87 days onward, approximately after 3 months;
the growth rate goes on increasing to a steeper level especially after 125 days and continues till the end of
lifetime. If the plants with seed weight 500 g are properly nourished after a time gap from sprouting, then there is
a possibility of higher yield from these plants.
