RESULTS AND DISCUSSION
 Significant differences due to location were found for most
traits except for 500 kernel weight and modification (not shown)
(Table 1). Isabela was the more productive environment.
 Very few differences among varieties were found (Tables 2 and
3). Number of moldy kernels varied significantly among varieties
with White H.E. o2 being most susceptible to infection and local
variety Diente de Caballo the least susceptible. Although the
Puerto Rican varieties were less ear rot susceptible and taller than
modified o2 varieties, in general the modified varieties per-
formed well. Percent and degree of modification did not vary
among varieties, with all varieties showing excellent levels of
edosperm modification (Table 3). It appears that the o2 modifiers
are relatively stable over different environments. Our results show


 Table 1: Location means of agronomic traits averaged over seven corn
 varieties planted in March (Lajas) and May (Isabela), 1983.

 Location
 Trait Lajas Isabela X LSD
 Earworm (percent of
 ear damaged)1 6.3 0.1 3.2 0.99
 No. of moldy kernels
 per ear1 3.8 8.3 6.1 1.12
 Plant height (cm) 150 189 170 6..54
 Ear height (cm) 67 83 75 3.09
 Ear length (cm)1 12.6 14.1 13.3 .54
 Ear diameter (cm)1 4.2 5.1 4.6 0.55
 Days to 50% anthesis 61 55 57.6 1.03
 Yield (kg ha-1)2 3054 3888 3472 427.6
 500 kernel weight (g)1 122.6 132.9 126.9 4.65 (n.s.)
 1Averaged over all subplot treatments.
 2Averaged over check and benomyl treated subplots.
 n.s. = No significant differences among locations according to F-test.
 LSD = Least significant difference at 0( = 0.05.


Table 2: Means of various agronomic traits over two
 varieties *


 Variety

Diente de caballo2

Mayorbela

White HE-o2

Amarillo Dentado

Tuxpefo-1 QPM

Pool-23-QPM

Amarillo Dentado QPM

Amarillo Cristalino QPM


that those varieties with a high percent modification also have in-
dividual kernels with a high degree of modification. It will not be
necessary to select directly for endosperm modification in a selec-
tion program aimed at improving adaptation of these materials in
Puerto Rico. Very poorly modified families should nevertheless
be eliminated in a selection program.
 No variety by location (i.e., genotype by environment) interac-
tions were found for any trait (not shown). This means that
varieties responded similarly at both locations for all traits
although location means were often different. This would nor-
mally suggest that testing at one location would be sufficient
when testing these traits and varieties. However, lack of a variety
by location interaction may be due in part to lack of sufficient
precision in determining possible differences between varieties.


 Table 3: Percent and degree of endosperm modification in two normal and
 six modified c2 corn varieties averaged over two locations 1


 Variety Percent Modification Degree of Modification3
 Diente de Caballo2 96.7 3.7a
 Mayorbela 100 5.0
 White H.E. 02 95.8 4.1
 Amarillo Dentado 99.5 3.9
 Tuxpefo-1 QPM 98.1 4.0
 Pool 23 99.4 4.1
 Amarillo Dentado QPM 98.4 4.0
 Amarillo Cristalino 100 4.2
 Mean 98.7 4.2


 iValues are means over two locations (Lajas and Isabela) and three subplot
 treatments.
 2Mean over three treatments at Lajas only.
 3Ratings from 0 to 5 (opaque to normal).


locations for six modified o2 and two normal corn


 500
Moldy Insect Days to Plant Ear Ear Ear Grain kernel
;ernels damage 50% height height length diameter yield weight
(no.) (%) anthesis (cm) (cm) (cm) (cm) (kg/ha) (g)

 2.4 6.1 64 194 100 13.3 4.6 3030 172.3

 4.6 3.5 56 182 91 14.4 3.9 3963 137.6

 10.5 3.5 59 177 79 14.3 5.3 3652 124.9

 5.2 2.9 58 173 76 13.4 4.9 3583 125.7

 6.9 3.0 58 158 64 13.2 4.6 3372 130.6

 4.8 2.5 58 165 71 12.9 4.8 3139 122.6

 3.5 2.8 58 165 70 12.4 4.7 3378 125.3

 7.0 4.1 57 168 71 12.8 4.3 3215 121.7


X 6.1 3.2 58 170 75 13.3 4.6 3472 126.9

LSD 1.8 2.1 1.9 12.2 4.5 .98 1.0 800.0 8.7
 (n.s.) (n.s.) (n.s.) (n.s.)

 Values are means from Lajas and Isabela, Puerto Rico with the exception of Diente de Caballo. Averaged
 over subplots as indicated in Table 1.
 Mean from Lajas only. These menias are not included in the overall mean.
 n.s. = No significant differences among varieties according to F-test.
 LSD = Least significant difference at rd = 0.05.


PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY-VOL. XX


k


78