19, 4 Reinking and Groff: Siamese Seedless Pummelo 431 
ments were right, have not been given proper culture and care. 
The orchardists gave the same treatment as is given to the 
Kao Phuang tree, which is hardy and can withstand lack of 
attention. Therefore, after the other essential needs such as 
salt application have been provided for, proper culture is un- 
doubtedly an important requirement for the production of a 
Kao Pan seedless pummelo of good quality. Careful experimen- 
tation in the use of proper culture will have to be conducted to 
prove whether or not the true quality and seedless characters 
can be retained when the pummelo is grown in any other than 
the Nakorn Chaisri region. 
The relation of seedless fruit to pollination and the presence 
or the absence of the foreign pollen will have to be carefully inves- 
tigated: before any definite statements can be made. Whether 
the pollen of the Kao Pan is not viable for the main part of the 
year, or whether the stigma is not receptive, cannot be stated. 
All that is known is that the fruit contains only abortive seeds 
in every month except November. During this month the great- 
est crop is produced, and the fruit is apt to be seedy. Wild 
bees are present in the orchards at all times, and provide a 
method for the interchange of pollen. Frequently interplanted 
with the seedless pummelos are other varieties of pummelos, 
such as the Kao Phuang, that are extremely seedy, as well as 
seedy limes, and mandarin and other oranges. In no case was 
there any indication that the seedless pummelo trees adjacent 
to the other seedy citrus trees were any different from the rest 
of the Kao Pan trees, from the standpoint of seediness. Seeds 
were never developed in the fruits of these trees except as re- 
ported, in November. From all observations it appears that the 
Kao Pan is a distinct variety, which is characterized by its seed- 
less nature throughout most of the year. Frequently the fruit 
of the Kao Phuang and other seedy pummelos grown about 
Bangkok are seedless. This is generally true of the fruits that 
have developed from adventitious flowers, those flowers that 
have come latest and have been produced out of the usual flow- 
ering season. 
The very restricted area of about 48 square kilometers, de- 
voted to the production of the Nakorn Chaisri seedless pummelo, 
would indicate that the soil or the meteorological conditions are 
of a special nature in this section. The topsoil is a loose clay 
loam and the subsoil is a heavy gray clay which seems to be 
characteristic for the entire delta region. 
