USE OF BRIDGE PARENTS WITH HIGH ANTHER CULTURABILITY IN DOUBLED HAPLOID BREEDING OF SOUTHERN U.S. LONG-GRAIN RICE (Oryza sativa L.)

摘要

The capacity to regenerate sufficient numbers of doubled haploid (DH) plants to produce adequate population sizes from which to select is an important component in the use of anther culture (AC) technology for varietal improvement. Crosses with japonica germplasm responded well in anther culturability (6-8%), while crosses with indica genotype showed anther culturability of less than 1%. Southern U.S. crosses with most javanica germplasm initially showed a mean anther culturability of 1.2%, which isbetween the japonica and indica eco-geographic race. Several bridge parents were selected in the crossing nursery due to their high culturability in AC, good yield potential, and acceptable agronomic traits. The use of bridge parents crossed with U.S. leading cultivars has shown cyclic improvement of anther culturability. The mean anther culturability for 16 Fj crosses carrying the bridge parent is 29%, which is significantly higher compared with those of the crosses without the bridge parent (1%). Thecrosses with two bridge parents as male and female had anther culturability ranging from 19.7 to 55%. In the last 3 years, all crosses made in the AC project involved the use of bridge parents. Dozens of DH lines tested in the advanced yield trial and inmulti-state yield trials (URRN) have shown high yield potential compared with leading cultivars. Therefore, using bridge parents in AC breeding can significantly improve the culturability and the breeding efficiency of southern U.S. long-grain crosses.