1. Improvement of Rainfed Lowland Rice Variety for Cooking Quality Traits using MAS Sureeporn Katengam Uraiwan Kotchasatit UBONRATCHATHANI, THAILAND

2. Background Rice production in NE of Thailand Area of production ranging from drought-prone lands to flooding area Abiotic stresses related with unpredictable rainfall pattern are main problems

3. State of problem Abiotic stresses associated with unpredictable rainfall pattern are main problems for rice production in NE of Thailand. Elite cultivars resistance to drought are required.

4. State of problem (cont.) KDML105, an aromatic rice with good cooking quality, is widely grown in NE, however, its production is dominating constraint with the drought problem. Drought tolerance is a complex traits since this trait is governed by many QTLs locating in many chromosome (ch1, ch2, ch3, ch4, ch7, ch8,and ch9). Therefore, improvement KDML105 for drought resistance is not an easy tasks.

5. State of problem (cont.) In the opposite way, improving of well adapted variety to drought prone areas for other quality traits such as cooking quality is worth to reconsider. Cooking quality trait is determined by three characters specifying the physical properties of starch in the endosperm: Amylose content (AC) Gel consistency (GC) Gelatinization temperature (GT)

6. Objectives Marker-assisted backcross breeding is aimed at improving well drought adapted variety to rainfed lowland area of NE of Thailand for cooking quality traits utilizing tightly linked DNA markers. The major QTL controlling AC, GC, and GT are located on Ch.6. DNA marker of flanking markers closely linked to this major QTL controlling quality traits will be carried out for MAS.

7. Plant materials Donor parent: KDML105 low AC (~16-17%): major QTL on ch6 (at Wx gene ) low GT: major QTL on ch6 medium GC: major QTL on ch6 (at Wx gene ) Recipient parent: IR57514-drought

8. Breeding scheme: