Melhoramento da batata doce

Resistência à ferrugem branca e à broca

Abstract

1 — As an attempt to secure data for the program of improving sweet potato, records were taken on the resistance for both the rust (Albugo ipomea penduranae) and the weevil (Euscepes postfasciatus).

2 — A collection of 48 varieties were grown out in the field and the data recorded were on the basis of attack. For the rust, 35 varieties (75%) seems to be imune, 6 (13%) resistant, 2 (4%) susceptible and 5 (15%) very susceptible. For the weevil, 12 (25%) seems to be imune, 21 (44%) resistant, 13 (27%) susceptible and 2 (4%) very susceptible.

3 — All the data recorded were taken on the leaves primarily, secondly on the plant itself and finally on the variety as a whole. The plants were 8 months old and to the Author in seems advisable to harvest not further than 7-8 months, as the delaying of harvest tends to increase the destruction by the weevil as well as bt the rust.