350 
Journal of Agricultural Research 
Vol. XIV, No. 9 
Citrandarin ( C . nobilis , King of Siam orange, X Poncirus trifoliala). (CPB 40210, 
40303, 40315* seedlings), I, II. 
The plants (7 to 15 inches) have been in fair shape during the experiments and some 
new growth has developed. Citrus-canker appeared at the punctures, but spread 
very slowly on the healthy leaves, so that only a few spots developed on each plant. 
This hybrid shows some resistance to canker and is about as resistant as the Satsuma 
orange. 
The few spots (PI. 53, D) present are rather typical of those found on Poncirus 
trifoliata. This is probably due to the leaf texture, which is about the same as that 
of the trifoliate orange. 
Cicitrange ( Poncirus trifoliata X Colman citrange, and Poncirus trifoliata X Sanford 
citrange). (CPB 48290, 48316A, seedlings), I, II and I, II. 
Most of the plants (8-20 inches) have been in fine shape for infection. Citrus- 
canker appeared shortly after inoculation and spread rapidly to the new growth, 
where it was very severe, causing considerable defoliation. The spots are present 
* on the leaves, twigs, and thorns. The plants are as susceptible as the trifoliate 
orange. It is interesting to note that the citranges used in the crosses are both very 
susceptible. The spots (PI. 53, C) are typical of those found on the trifoliate orange. 
Citrangequat (Willits citrange X Fortunella margarita). (CPB 48010, seedlings), I, II. 
These interesting plants (12 inches) have made a very slow growth while in the 
cases, but new growth has been present practically all the time. Even though the 
plants were set under plants literally covered with Citrus-canker, they have remained 
resistant. This hybrid is the most promising of all the hybrids so far tested. Further 
inoculations both in the field and greenhouse will be carried out with a number of 
plants under different conditions to test out this resistance. 
It might be pointed out in this connection that the Willits citrange, which shows 
more resistance than any of the other citranges, was used as one of the parents of this 
hybrid. 
Citranguma (C. nobilis var. unshiu t Satsuma, X Morton citrange). (CPB 48055A, 
seedlings), I, II. 
The plants (8 to 10 inches) have made a slow growth in the cases and have not been 
in good condition for infection. No Citrus-canker has developed on the plants, which 
are apparently resistant, although both parents are susceptible, especially the Mor¬ 
ton citrange, which is highly so. Further tests will be made with this hybrid. 
Limequat (C. aurantifolia, West Indian lime, X Fortunella japonica, Round kumquat). 
(CPB 48787A, 48787B, seedlings), I, II. 
The plants (8 to 12 inches) have been in good shape for infection. This was espe¬ 
cially true during the first two months, when Citrus-canker was rather severe on the 
leaves. Some defoliation resulted on one or two of the plants. The limequat is not 
as susceptible as the lime and not as resistant as the kumquat. Apparently where 
limes are used as a parent we can expect the hybrid to be susceptible, even though 
the other parent is fairly resistant. The susceptibility of the limequat should be 
contrasted with that of the citrangequat, where both parents are fairly resistant to 
canker. The spots (PI. 53, J), while not as numerous per leaf area as those on the 
sour lime, are identical in character, except in size. 
Limelo (C. aurantifolia, West Indian lime, X C. grandis, sour pummelo). (CPB 40502, 
40526A, 40567B, seedlings), I, II, I, II. 
The plants (8 to 19 inches) have been in fairly good shape for infection. Citrus- 
canker appeared very early in the experiment and spread rapidly. Spots are 
present on the leaves, petioles, twigs, and thorns, and some defoliation has resulted. 
The plants are apparently as susceptible, or more so, than either of the parents. 
The spots (PI. 52, D) are typical of those found on grapefruit. 
