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

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

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.

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.

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)

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.

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

Breeding scheme:

Chr.6 Chr.11 Map location of QTLs controlling cooking quality traits Genetic map (Azu / IR64 )

Survey of SSR markers for parent screening

1 KD 2 IR KD RM597RM190 RM204 RM205 RM225RM111 RM50 RM121RM136 GT11 RM229RM457 RM473E RM206RM254 RM21 PSS II-1PSS II-2 BADH WAXY RM21 RM bp 553bp 500bp 427bp 311bp 249bp 200bp 151bp 140bp 118bp 100bp PCR condition Thermal cycling Screening parents with SSR markers

SSR markers chosen for parents screening

donor recipient KD X IR nd workshop on December MAS for BC1F1 F1 F1 X IR57514 BC1F1 mid-October mid-July late-June Planting parents mid-November Planting F1 and recipient parents ………………………………..200 lines Line selection with selected SSR markers early-April early-August late -November MAS