The few days required to induce Zea diploperennis to flower in Minnesota
--Carlson, LA

In late April of 1994 65 Zea diploperennis plants, P.I. No. 441931, were planted in isolation in St. Paul, Minnesota. Sixty-three were induced to flower by covering them with 30 gallon galvanized trash barrels from 7:00 pm until 7:30 am for a variable number of nights. Again in 1995 volunteer plants from the shattered seeds were exposed to short days for various numbers of days. The volunteer plants from this 250 square meter plot exceeded 100 plants.
No. of plants No. of long nights to produce silking No. of days to flower No. of silking locations
1 3 none none
1 5 55 days-tassel only none
1 7 41 days-tassel only none
7 9 36 5
2 11 25 6
5 13 23 7
10 15 17 4
7 17 17 11

Constant observations plus data would suggest tropical maize, at least Zea diploperennis, can be induced to flower by covering with barrels for only 11, 12, or 13 days.

In a separate experiment 23 plants were identified at time of first silkings. Days to shattering of seed from the ear were recorded. Shattering was assumed when the top one or two seeds would disarticulate with a soft bending of the seed from the ear. Experience indicated it only takes one or two days from a ripe color until disarticulation takes place.
No. of plants Days to disarticulation No. of seeds collected
2 25 45
4 28 48
7 25 25
10 27 106

The seed of Zea diploperennis in Minnesota reached physiological maturity in 27 days during the weather conditions of August 1995. 

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors

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