I - --ii

Table I
The timing of reproductive induction and physiological maturity in winter-sown chickpeas, 1980-81.
Days Date DD Acc. Photo- Leaf Days Date DD Acc. Acc E o
Site of from period of from from
G-I I G-I Hr.Min. No. 1-M M I-M I-M
ILC 482
Jirdirezs 67 15/2/81 520 10.52' 7th 99 25/5/81 1401 430.4
Tel Hadya 70 18/2/81 563 11.00' 6th 96 25/5/81 1337 528.0
Brida 69 17/2/81 444 10.56' 6th 94 22/5/81 1320 469.8
Khanasser* 55 18/2/81 401 11.00' 4th 97 26/5/81 1468 588.1
Mean 65.3 482 10.57' 96.5
ILC 72
Jindiress 80 1/3/81 644 11.24' 8th 95 4/6/81 1506 466.3
Tel Hadya 79 28/2/81 655 11.21' 9th 93 1/6/81 1403 585.0
Brida 82 3/3/81 566 11.26' 8th 98 9/6/81 1610 637.1
Mean 80.3 622 11.24' 95.3
G = Germination, I = Initiation, DD Acc. = Degree Day Accumulation (Mean air temperature
in °C), M = Physiological maturity.
* = Additional information obtained from associated rotation trial
Canopy Development and Drymatter Production
143
Crop drymatter production is directly dependent upon the amount of radiant
energy intercepted by the crop canopy. Considerable variations were observed at
all sites within the peak values achieved by the active crop photosynthetic
surface (green area index, Table 2). In this regard the densely planted ILC 72
treatment consistently developed its canopy faster, and to a greater extent, than
standard density plantings of either cultivar. At the standard density the spreading
cultivar (ILC 482) generally achieved higher values than the erect cultivar
ILC 72. However, it was only at Jindiress that the green area index values were
sufficient to achieve an effective canopy cover. Green area index values need to
be greater than four if the canopies are to approach full closure.
Maximum drymatter production values (Table 2) reflect the trends in canopy
development previously outlined. However, the differences in proportion betwcen
maximum green area index and maximum drymatter production values
foc Jindioss (max. DMP = approx. 1.67 max GAI) and [or Brida suggest that a
reduction in the efficiency of conversion of intercepted radiation into dry matter
may have occurred. This possibility can ony be confirmed by a more sophisticated
analysis which is currently ongoing, but for which results are as yet
unavailable.