Bui Chi Buu¹, Pham Thi Thu Ha²,  Bui Phuoc Tam², Tran Thi Nhien², Nguyen Van Hieu²,  Nguyen Trong Phuoc², Luong the Minh¹, Ly Hau Giang¹, Nguyen Thi Lang²

¹ Institute of Agricultural Science for Southern VietNam (IAS), Ho chi Minh City, Vietnam

² Cuu Long Delta Rice Research Institute (CLRRI), Can Tho City, Vietnam

ABSTRACT

A total of 310  lines (BC₂F₂) derived from the cross of OM5930/N22 were evaluated for heat stress at flowering. Genetic map was set up with 264 polymorphic SSRs to detect linkage to the target traits. The map covers 2,741.63 cM with an average interval of 10.55 cM between marker loci. Markers associated with heat tolerance were located mostly on chromosomes  3, 4, 6,  8 , 10, and 11. The proportion of phenotypic variation explained by each QTL ranged from  markers  RM3586, RM160 on chromosome 3 and RM3735 on chromosome 4  as 36.2, 17.1 and 32.6%, respectively. Four QTLs were detected for filled grains per panicle on chromosome 4 at the interval of RM468-RM7076 and RM241 –RM26212, explaining 13.1% and 31.0% of the total phenotypic variation, respectively. Two QTLs controling unfilled grain percentage was also detected at loci RM554, RM3686 on chromosome 3 explaining only 25.0% and 11.2%  of the total phenotypic variance. One QTL was detected for 1,000-grain weight located at the locus RM103 on chromosome 6, explaining 30.6% of the total phenotypic variance. A single QTL at the locus RM5749 on chromosome 4 was identified explaining 10.8% of the total phenotypic variance of grain yield. Attentions were paid to the interval of RM3586- RM160 on chromosome 3 at the range of 10.1 cM for heat tolerance score.

Key words: heat tolerance, interval mapping (IM), single marker analysis (SMA), QTL.

Correspondence should be addressed to Bui Chi Buu; buu.bc@iasvn.org and Nguyen Thi Lang; ntlang@hcm.vnn.vn