Denomination: 'I181664'
Botanical Name: Zea mays
Applicant/Holder: DEKALB Genetics Corporation
3100 Sycamore Road
Dekalb, Illinois
United States of America
Breeder: R. Mark Lawson, DEKALB Genetics Corporation, Dekalb, United States of America
Agent in Canada: Monsanto Canada Inc.
1288 Glanworth Drive
London, Ontario
N6N 1H1
Tel: 519-644-1767
Application Date: 2001-08-21
Application Number: 01-2809
Grant of Rights Date: 2004-03-03
Certificate Number: 1752
Date rights revoked: 2017-03-03

Variety Description

Variety used for comparison: '3AZA1'

Summary: Principal ear insertion of 'I181664' is higher than that of '3AZA1'. 'I181664' has no anthocyanin colouration of the glume ring, glume tip and body whereas it is weak in '3AZA1'. The attitude of the lateral branches of the tassel of 'I181664' are erect to semi-erect whereas they are semi-erect to horizontal in '3AZA1'.


'I181664' is an inbred corn variety. At inflorescence emergence, the angle of the leaf with the stalk is semi-erect (30-40 ). After male flowering, the leaf blade is medium to wide with no anthocyanin colouration of the sheath. There are few leaves per stem (11 - 13) with no anthocyanin colouration of the stem nodes and internodes.

Tassel emergence and male flowering of 'I181664' is early to mid-season. The intensity of anthocyanin colouration on the ring at the base of the glumes, at the tips and on the bodies of the glumes and on the anthers is absent. At the end of male flowering, the main axis above the lowest side branch is medium to long and long above the upper side branch. Density of the branches on the main axis of the tassel is sparse to intermediate. There are few (3-10) erect to semi-erect lateral branches with a medium size angle (30-60 ) between the main axis and the lateral branches.

The silks have no anthocyanin colouration one to two days after emergence and two to three days after emergence. The shank or peduncle is long to very long.

The percentage of plants with ear wings is very low. The ear of 'I181664' is cylindrical-conical in shape with a medium-sized diameter in the middle-third of the ear (including kernels) and a small to medium diameter at mid-cob (excluding kernels). There are a medium number of rows (13-14) of kernels. Anthocyanin colouration of cob glumes is present. The wedge-shaped kernels of 'I181664' are a flint/dent type and yellow-orange in colour on the dorsal side. The kernel tip is yellow.

Origin & Breeding History: 'I181664' was derived from the cross '3AVB3' x '3AZA1' made in the summer of 1994. Seed was grown ear-to-row from 1994 to 1998. In the summer of 1997, corn inbred 'I181664' was coded and reproduced by self-pollination for the past two seasons. Selection criteria included yield in hybrid combination, earliness and high test weight.

Tests & Trials: Tests and trials for 'I181664' were conducted at London, Ontario in 2001 and 2002. The trials consisted of two replicates with two rows per replicate. The rows were 4.5 meters long with approximately 22 plants per row.

Comparison tables for 'I181664' with reference variety '3AZA1'

Plant height (cm)

  'I181664' '3AZA1'
mean 184.5 180.9
std. deviation 9.3 11.27

Height of principle ear insertion (cm)

  'I181664' '3AZA1'
mean 59.8 44.35
std. deviation 7.14 8.06

Number of days from emergence to 50% of plants in silk

  'I181664' '3AZA1'
mean 76.5 78.5
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