Fruit Section, Punjab, Jullundur
The present investigations show that Blood-red and Jaffa varieties of sweet orange make good union with ‘Karna Khatta’ rootstock in the nursery row. However, Bajwa and Singh (1) and Singh and Singh (3) contend that Blood-red upon Karna Khatta rootstock exhibits incompatibility in the orchard. Obviously this stock-scion combination seems to be a case of delayed incompatibility, where a scion makes a good union with the stock in the nursery, but subsequently proves short-lived and unproductive. Randhawa and Upshall (2) working with dwarf pear, observe that a union good in the nursery does not necessarily assure a continuously good union in the orchard. Recent information available from the Indian Agricultural Research Institute, New Delhi and from some other places also reveals, beyond any doubt, that Blood-red trees on ‘Karna Khatta’ stock exhibit signs of incompatibility in the orchard. The trees not only remain dwarf but become unproductive after a period of time. It is, therefore, desirable that the commercial nurserymen should never use ‘Karna Khatta’ as a rootstock for Blood-red variety of sweet orange.
The present studies also show that the variety Jaffa makes compatible union with ‘Kama Khatta’ rootstock. Experience shows that this stock-scion combination is also long-lived and productive. It is, therefore, safe to use ‘Karna Khatta’ root-stock for Jaffa orange.
