Application of anther culture technology in variety development generation of donor parentals and QTL mapping in rice

Dihaploid technology has become a promising tool in breeding for producing homozygous lines more rapidly than most conventional breeding methods. Doubled haploid (DH) are also excellent materials for genetic studies because of their homozygosity and uniformity. A total of 313 DHs were generated thru anther culture from the F1 of PSB Rc10 and Nipponbare. Characterization of these DHs revealed the very high homogeneity and stability at the DNA level using SSR analysis and under field conditions. Field trials of 237 DHs in 2009 WS resulted in selection and advancement of 54 superior lines in 2010 DS and WS. Ten DHs lines have been selected as promising lines based on high yield, phenotypic acceptability, tolerance to major pests, and uniformity which are better/ comparable to the checks; PSB Rc10, PSB Rc18, and PSN Rc82. In less than 3 years, elite breeding lines were developed while conventionally, it takes 6-7 years for selected inbreds to reach yield trial. Stable and potential donor parentals were also developed and included in the germplasm pool based on resistance to blast (9), early maturity (3), enhanced grain quality (3), and short to medium plant height (10). On the other hand, a mapping population consisting of 219 DHs was used for identifying QTL for grain quality traits using 205 SSR markers. Thirteen QTLs were identified; three for amylose content and five each for gel consistency and gelatinization temperature. QTL mapping for drought tolerant traits such as days to maturity, spikelet fertility, early vigor, and green leaf retention is now ongoing using the same mapping population. Information on mapped QTLs associated with these traits and the SSR markers that have tight linkage to them may be used to speed up the process of breeding new rice varieties with better quality and drought tolerance through molecular marker-assisted selection (MAS).