Survival and development of Sitotroga cerealella (Oliv.) on seeds from species of Oryza other than Oryza sativa L.

Abstract

Fifty accessions of wild Oryza spp (those other than Oryza sativa L.) were acquired and grown in pots to increase the seed. Physical and chemical characteristics of the seed were measured. The amylose content of most of the species of wild Oryza was high (>23%) but all were within the range required for cultivated rice. Gelatinization temperatures also were within required ranges. Therefore, should any of these Oryza spp possess insect or disease resistance, general hardiness, cold-tolerance or other characteristics desirable for new varieties of rice, the transfer may be made easier because the cooking quality characteristics (amylose and gelatiniziation temperature type) of these species, being within ranges common in commercial varieties of rice, would not require alteration. Resistance or susceptibility to Sitotroga cerealella (Oliver) was tested in the wild Oryza spp and in three varieties of rice. Survival and developmental time from larvae to adult were the criteria used to assess resistance/ susceptibility. Insect performance was adversely affected by intact hulls and small seed size. The hull character in wild Oryza is no stronger than that previously observed in rice and small seed size is not a viable option as a resistant base. A resistant character for S. cerealella that would justify an attempt to transfer the trait from one species to another apparently is not available in the accessions of wild Oryza that were tested.