René Cortázar S.1, Ignacio Ramírez A.1, Mireya Zerené Z.1, Ernesto Hacke E.1, Oscar Moreno M.1 y Fernando Riveros B.1
The development and economic importance of the wheat aphids species introduced in Chile from 1966 to 1987, are reported. The parasites and predators species introduced and multiplied in Chile to control these insects and the species that became established is indicated. The Barley Vellow Dwarf Virus (BVDV) caused important damage in the country from 1973 to 1978, however from 1979 to 1987 the losses were very low. In the period 1975 to 1978 the BVDV was of great importance in the irrigated central plain and in 1975 the losses amounted to a 30% of the production, however in the coastal drylands the damage was very low. In the breeding program the lines at INIA with tolerance to BYDV were selected and also tolerant lines from CIMMYT and Canada were introduced. A large number of crosses were made to obtain more tolerant genotypes and also crosses between the tolerant lines and the best cultivars. As it is believed that the tolerance is due to many minor genes, a program was developed using recurrent selection to accumulate the genes of several cultivars. For these purposes the 20 more tolerant lines were selected and a dominant gene for male sterility was used to facilited the crossing among the selected lines. As a result of several hundred crosses, subjected to a high level of infestation with viruliferous aphid, lines with a good level of tolerance have been selected.
Key words: Triticum aestívum L, recurrent selection, virus and aphids importance.
1 Estación Experimental La Platina (INIA), Casilla 439, Correo 3, Santiago, Chile.